Search

Two new polyoxometalate (POM)-based metal–organic supramolecular architectures, [Cu(Hpypa)2(PMo12O40)(μ2-Cl)] 3H2O (1) and [Co(H2bpap)(γ-Mo8O28)0.5(H2O)2] H2O (2), were successfully synthesized by using two self-designed pyrimidine-amide organic ligands [N-(pyridin-3-ylmethyl)pyrimidine-4-carboxamide (pypa) and N,N′-bis(4-pyrimidinecarboxamido)-1,5-pentane (bpap)], as well as Keggin-type POM anions and octamolybdate anions under hydrothermal conditions. Complex 1 is a 1D supramolecular structure containing dinuclear [Cu2(Hpypa)4(PMo12O40)2(μ2-Cl)2] units. Complex 2 exhibits a 3D supramolecular framework consisting of 1D [Co(H2bpap)(H2O)2]n4n+ metal–organic chains and free [Mo8O28]8− anions. The supercapacitor performances of complexes 1 and 2 in a three-electrode system were investigated. When the current density is 1 A g−1, 1 and 2 exhibit specific capacitances of 555 and 675 F g−1, respectively. The symmetrical supercapacitor assembled with complex 2 as the electrode modifier exhibits an energy density of 13.4 W h kg−1 with a power density of 450 W kg−1. Capacitance retention remains at 96% after 6500 cycles. At the same time, the electrochemical sensors prepared with complexes 1 and 2 can be used for the determination of Cr(VI)/Fe(III) ions in aqueous solution with high sensitivity and low detection limit. [ABSTRACT FROM AUTHOR]

Chemical modulation of metal complex structures holds great potential for the preparation of novel functional materials, and functional organic ligands are well-known to play a key role in the construction of metal complexes with specific properties. Herein, we design a multidentate ligand with steric constraint and different types of donors, 6,6′-(((1-(2-hydroxy-3-methoxyphenyl)-2-(pyridin-2-yl)ethane-1,2-diyl)bis(λ2-azanediyl))bis(methylene))bis(2-methoxyphenol) (H3L), to synthesize dysprosium-based complexes and study their magnetic properties. Depending on the experimental conditions, four new Dy-based complexes are obtained, namely, [Dy2(HpyL)(L)(CH3COO)]·2CH3CN·CH3OH (Dy2), [Dy4(HL)2(μ3-OH)2Cl6]·4CH3OH (Dy4), [Dy5(L)(μ4-O)(μ3-OH)(μ3-OCH3)2(CH3COO)7] (Dy5) and [Dy6(L)2(μ3-OH)4 (CH3COO)8]·4CH3OH (Dy6). Their structures are determined by single crystal X-ray diffraction. Magnetic characterization shows that the complexes Dy2 and Dy5 both exhibit slow magnetic relaxation behavior under zero dc field, with the effective energy barrier of magnetization reversal and a relaxation time being Ueff = 5.68 K and τ0 = 2.3 × 10−6 s, respectively, for Dy2, and Ueff = 3.1 K and τ0 = 3.6 × 10−5 s for Dy5. [ABSTRACT FROM AUTHOR]

The TMSCF3-derived CuCF2CF3 species has been successfully applied in pentafluoroethylation of organoboronates and terminal alkynes. By using 1,10-phenanthroline as a ligand, a broad range of (hetero)arylboronates and alkenylboronates were smoothly pentafluoroethylated under aerobic conditions. Furthermore, terminal alkynes can undergo aerobic cross-coupling with the TMSCF3-derived CuCF2CF3 species in the absence of additional ligands. [ABSTRACT FROM AUTHOR]

Four new Keggin-type polyoxometalate (POM)-based metal–organic complexes constructed from two flexible bis(pyrazine)–bis(amide) ligands N,N′-bis(2-pyrazinecarboxamide)-1,2-ethane (bpae) and N,N′-bis(5-methyl-2-pyrazinecarboxamide)-1,2-ethane (bmpae), namely, [Cu2(bpae)2(H2O)2(PMoVI9MoV3O39)]·5.5H2O (1), [Cu2(bpae)2(SiMo12O40)]·3H2O (2), {[Co2(bmpae)2(H2O)4](SiW12O40)}·1.5H2O (3), and [Cu2(bmpae)2(SiW12O40)]·8H2O (4), have been hydrothermally synthesized and structurally characterized. Complex 1 is a [PMoVI9MoV3O39]4− (PMo12)-based 3D coordination framework, which is constructed by three kinds of 1D chains: [Cu(bpae)]n2n+, [PMo12]n4n− and [Cu(PMo12)]n2n− chains. Complex 2 shows a 2D structure, which is composed of tridentate [SiMo12O40]4− anions (SiMo12) and [Cu(bpae)]n2n+ chains. Complex 3 is a 0D structure, which is constructed from [Co2(bmpae)2]4+ binuclear rings and discrete [SiW12O40]4− (SiW12) anions. In 4, the 1D [Cu(bmpae)]n2n+ chains are connected by the SiW12 anions to produce a 2D structure. The diverse structures of 1–4 demonstrate that the different metal ions and POMs have pivotal influences on the formation of the final coordination frameworks. In this work, the adsorption performances of 1–4 for the organic dyes gentian violet (GV) and methylene blue (MB) were examined, and 1 possesses good reusability. In addition, 1–4 can be employed as amperometric sensors to identify multiple analytes (BrO3−, NO2−, Cr(VI) and Fe(III) ions) and possess good selectivity in the presence of some other ions. [ABSTRACT FROM AUTHOR]

A layered coordination polymer (CP) with the fine-tuned alignment of four diolefinic ligands has been designed by shifting the coordination site of the ligand. The trimeric and tetrameric cyclobutane derivatives were reversely achieved by the photoinitiated [2+2] cycloaddition of the CP due to the favorable Schmidt's distance. More interestingly, a dynamic fluorescence shift was observed during the photo-oligomerization and heat-cycloreversion of the CP system. [ABSTRACT FROM AUTHOR]

By using the double chelating ligands 2,3-di-pyridin-2-yl-pyrazine (L1) and 2,3-di-pyridin-2-yl-quinoxaline (L2), six new polyoxometalate-based compounds, namely [AgI4(L1)4(SiMo12O40)] (1), [CuII6(L1)6(H2O)6(SiMo12O40)3]·6H2O (2), [CuII(L1)(H2O)(β-Mo8O26)0.5] (3), [AgI2(L2)(β-Mo8O26)0.5] (4), [CuII(L2)(β-Mo8O26)0.5] (5) and [ZnII(L2)(β-Mo8O26)0.5] (6), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectra and elemental analyses. Using the double chelating ligand L1, compounds 1–3 were obtained. In compound 1, there is a tetra-nuclear Ag loop with four Ag atoms linked by four L1 ligands. The [SiMo12O40]4− anions are sandwiched by these loops alternately. Compound 2 has a hexa-nuclear shield-like Cu cluster, in which six Cu atoms are connected by six L1 ligands. The channel formed by the packing hexa-nuclear loops accommodates the [SiMo12O40]4− anions. By using [β-Mo8O26]4− instead of [SiMo12O40]4−, compound 3 was obtained containing a zigzag metal–organic chain. The chains are linked by [β-Mo8O26]4− anions to construct a layer. By changing L1 to L2, compounds 4–6 containing metal–organic loops were built. In compound 4, two L2 ligands are linked by two Ag atoms to form a bi-nuclear loop. The [β-Mo8O26]4− anions as tetra-dentate inorganic subunits link bi-nuclear loops to build a 2D layer. Compounds 5 and 6 are isostructural, with bi-nuclear Cu/Zn–L2 loops connected by [β-Mo8O26]4− anions alternately to construct a 1D chain. In addition, we also studied the electrochemical properties and selective photocatalytic properties of compounds 1–6. [ABSTRACT FROM AUTHOR]

By changing metal ions, three various transition metal coordination polymers based on different isopolymolybdates, [Ag I (DTBA)(Mo 2 O 6 )] ( 1 ), [Cu II 3 (DTBA) 2 (γ-Mo 8 O 26 )(H 2 O) 6 ]·7H 2 O ( 2 ), and [Co II 3 (HDTBA) 2 (DTBA) 2 (γ-Mo 8 O 26 )(H 2 O) 2 ]·6H 2 O ( 3 ) (HDTBA = 3,5-di(1,2,4-triazol-1-yl) benzoic acid) have been synthesized and characterized. In compounds 1 – 3 , the ligand 3,5-di-[1,2,4]triazol-1-yl-benzoic acid (HDTBA) was in-situ transformed from the 3,5-di-[1,2,4]triazol-1-yl-benzonitrile (DTCN) under hydrothermal conditions and two kinds of isopolymolybdates formed, both of which were directly grafted by the in-situ ligand DTBA. When Ag + ion was presented, a 3D framework 1 is constructed from {[Mo 4 O 13 ](DTBA) 2 } building blocks. Replacing Ag + with Cu 2+ ion, compound 2 shows a (2,4,8)-connected framework based on {(γ-Mo 8 O 26 )(DTBA) 2 } building units. A {(γ-Mo 8 O 26 )(DTBA) 2 } building unit-based (4,4,8)-connected 3D framework 3 is obtained in the presence of Co 2+ ions. The metal atoms may play key roles in tuning the various structures of compounds 1 – 3 , as well as the different isopolymolybdates. The electrochemical properties and photocatalytic activities of compounds 1 – 3 have been investigated here. [ABSTRACT FROM AUTHOR]

To explore the new functional polyoxometalates (POMs)-based metal-organic complexes (MOCs), the asymmetric pyridyl-monoamide ligand N-(pyridin-3-yl)isonicotinamide (PIA) was chosen to assemble with POMs and Ag I ions under the hydrothermal condition. Four novel POMs-based Ag(I)-MOCs [Ag 3 (PIA) 3 ][Ag(SiW 12 O 40 )] ( 1 ), [Ag 3 (PIA) 3 ][Ag(VW 11 VI W V O 40 )] ( 2 ), H[Ag 3 Na 2 (H 2 O) 2 (PIA) 6 (VW 12 O 40 ) 2 ]·8H 2 O ( 3 ), Ag 2 (PIA) 2 (HPMo 12 O 40 )·H 2 O ( 4 ) were obtained. Characterized by single-crystal X-ray diffraction analyses, 1 and 2 are isostructural 3D frameworks constructed from 1D [Ag 3 (PIA) 3 ] chains and 1D [Ag(POM)] chains; 3 exhibits a 1D chain, which was extended into a 3D supramolecular framework through the non-covalent interactions; while 4 shows a 3D structure based on 1D [Ag 2 (PIA) 2 ] chains and PMo 12 O 40 3− anions. The adsorption behaviors for organic dyes of the title complexes were systematically investigated. All the title complexes show efficient adsorption capacity for cationic dyes (MB/RhB), and selective separation ability for the cationic dye MB from the mixture of MB and anionic dye MO. At the same time, complex 2 also can selectively adsorb MB molecules from binary cationic dyes mixtures of MB and RhB. In addition, the electrochemical properties of the title complexes also have been investigated in detail. [ABSTRACT FROM AUTHOR]

Three polymolybdate-based metal–organic complexes (MOCs) constructed from a pyridyl-amide-carboxylate ligand, 6-(pyridine-3-ylcarbamoyl)picolinic acid (HPPA), namely, H 2 [Cd 2 (PPA) 2 (H 2 O) 2 ](β-Mo 8 O 26 )·2CH 3 OH·9H 2 O ( 1 ), H 2 [Co 4 (PPA) 2 (H 2 O) 12 (Mo 10 O 34 )]·6H 2 O ( 2 ), [Ni 4 (PPA) 4 (H 2 O) 6 (β-Mo 8 O 26 )]·8H 2 O ( 3 ), have been successfully synthesized under solvothermal (methanol–water mixed solvent) conditions. Characterized by single-crystal X-ray diffraction analyses, 1 exhibits a 3D supramolecule framework, which is built from binuclear [Cd 2 (PPA) 2 (H 2 O) 2 ] 2+ subunits and β-[Mo 8 O 26 ] 4− anions through the non-covalent interactions; In 2 , Co II was used and the [Mo 10 O 34 ] 8− anion was in situ constructed, which were linked by [Co 2 (PPA)(H 2 O) 6 ] 3+ subunits to yield a 1D double chain. The 1D chains were further linked by H-bond to afford a 3D supramolecular framework; 3 is also a 3D supramolecular structure based on 1D [Ni 2 (PPA) 2 (H 2 O) 2 (β-Mo 8 O 26 )] 2− anionic chains and the free [Ni 2 (PPA) 2 (H 2 O) 4 ] 2+ units with the H-bond interaction. The adsorption behaviors for organic dyes of the title complexes were investigated. All the title complexes show efficient adsorption capacity for cationic dyes methylene blue (MB) and gentian violet (GV), especially complex 3 can selectively separate MB and GV from the mixture of MB&MO/GV&MO, respectively. In addition, the electrochemical properties of the title complexes also have been reported. [ABSTRACT FROM AUTHOR]

Five new Anderson-type polyoxometalate-based metal–organic complexes, [Cu 4 (μ 3 -OH) 2 (H 2 O) 6 (4-dpye) 2 (TeMo 6 O 24 )]·2H 2 O ( 1 ), [Cu(4-dpyb)(CrMo 6 (OH) 6 O 18 ) 2 (H 2 O) 2 ][Cu(4-dpyb)(H 2 O) 4 ](4-H 2 dpyb)·6H 2 O ( 2 ), H[Cu 2 (3-dpyb) 2 (C 2 O 4 )(CrMo 6 (OH) 6 O 18 )]·8H 2 O ( 3 ), [Cu 2 (4-dpyh)(CrMo 6 (OH) 5 O 19 )(H 2 O) 8 ]·10H 2 O ( 4 ) and [Cu 4 (μ 2 -OH)(μ 3 -OH)(H 2 O) 6 (4-dpyh)(TeMo 6 O 24 )]·H 2 O ( 5 ) (4-dpye = N,N′-bis(4-pyridinecarboxamide)-1,2-ethane, 4-dpyb = N,N′-bis(4-pyridinecarboxamide)-1,4-butane, 3-dpyb = N,N′-bis(3-pyridinecarboxamide)-1,4-butane, 4-dpyh = N,N′-bis(4-pyridinecarboxamide)-1,6-hexane), were hydrothermally prepared and structurally characterized by single crystal X-ray diffraction analyses and characterized by single-crystal X-ray diffraction, elemental analysis, IR, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA). Complex 1 is a 2D network, which is constructed from Cu 4 –TeMo 6 inorganic chains and 4-dpye ligands. Complex 2 contains two types of 1D chains. Complex 3 shows a 1D ring-like chain structure, in which the CrMo 6 anions act as fourfold monodentate ligands consolidating the [Cu 2 (3-dpyb) 2 (C 2 O 4 )] rings. Complex 4 is a 0D structure containing a dinuclear complex cation [Cu 2 (4-dpyh)] 4+ and discrete CrMo 6 anion. Complex 5 exhibits a 3D framework constructed from 2D Cu 4 –TeMo 6 inorganic layer and 4-dpyh ligands. The spacer lengths and N-donor sites of the bis-pyridyl-bis-amide ligands, as well as different polyoxometalates play important roles in tuning the structures of the title complexes. The electrochemical behavior and electrocatalytic properties, as well as the photocatalytic activities of the title complexes have been studied. [ABSTRACT FROM AUTHOR]

Bisindoles (BIMs) were modulated as powerful N,N′ donor ligands for the copper-catalyzed . Ligand screening experiments on 11 BIM compounds found that 3,3′-(4-chlorophenyl)methylenebis(1-methyl-1 H-indole) (10%) efficiently accelerated CuCl (5%)-catalyzed of aryl iodides with terminal alkynes. A wide range of substituted aryl iodides and/or alkyl- and aryl-substituted terminal alkynes were examined, leading to the corresponding coupling products with yields up to 99%. An efficient and scalable protocol for the synthesis of BIM ligands on a gram scale, with extremely low catalyst loading of o-ClC6H4NH3+Cl−, was also developed with a reaction time of 20 min with yields up to 93%. This novel N,N′ ligand was air-stable, easily available and highly modulated with low copper loading. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

By introducing a tetrazole- and pyridyl-containing asymmetric amide ligand into polyoxometalate (POM) systems, four POM-based complexes, namely, H4[Cu2(TAAP)4(H2O)](Mo8O26)2·20H2O (1), H2[Co(TAAP)2(H2O)2](Mo8O26)·11H2O (2), H2[Ag4(TAAP)4(H2O)2(PMo12O40)2]·4H2O (3), and H4[Ag2(AAP)4(PW12O40)2]·2AAP·12H2O (4) (TAAP = 3-(1H-tetrazole-1-acetic acid amido) pyridine; AAP = 3-(acetic acid amido) pyridine), have been prepared under solvothermal (methanol–water mixed solvent) or hydrothermal conditions and structurally characterized. Compounds 1 and 2 are isostructural 3D structures, which are based on 3D [M(TAAP)2]n2n+ metal–organic frameworks and noncoordinated [Mo8O26]4− polyanion templates. Compound 3 exhibits a dimeric structure constructed from two Keggin [PMo12O40]3− anions and a tetranuclear [Ag4(TAAP)4(H2O)2]4+ subunit. Compound 4 exhibits a 2D supramolecular network based on 1D infinite chains, which are constructed by [PW12O40]3− and Ag-AAP subunits. In compound 4, the AAP ligand was in situ transformed from TAAP. The structural diversities show that POMs play key roles in the construction of final architectures and the in situ transformation of TAAP. The title compounds represent the first examples of introducing tetrazole- and pyridyl-containing asymmetric amide ligand into the POM system. The electrochemistry, photocatalysis and photoluminescence properties of the title compounds have been reported. [ABSTRACT FROM AUTHOR]

Three transition metal organopolymolybdate hybrid compounds, namely, H2[Mn(H2O)4L3(γ-Mo8O26)] 8H2O (1), H[M2(CH3O)(H2O)6L3(γ-Mo8O26)] [M = Zn (2) and Co (3)] [L = 1,4-bis(3-pyridinecarboxamido)benzene] have been synthesized under solvothermal conditions and characterized by IR spectroscopy, TG analysis, powder XRD and single-crystal X-ray diffraction. Compounds 1–3 were obtained by the one-pot method, and the mixture of methanol and water with different ratios was used as the solvent. In compound 1, the γ-Mo8 anions were connected with pyridine groups of ligand L by the Mo–N bond, forming an uncommon 1D γ-Mo8–L chain. The adjacent chains were connected by [MnL2(H2O)4]2+ moieties through hydrogen bonding interaction to construct a 2D supramolecular network. Compounds 2 and 3 are isostructural, which show a 3D 2,4,6-connected {44·62}{44·66·84·10}{6} framework. The γ-Mo8 anions were connected by [M(H2O)2(CH3O)]+ [M = Zn (2) and Co (3)] subunits forming 1D M–Mo8 chains, which were connected by [ML2(H2O)4]2+ moieties to construct a 2D layer. In compounds 2 and 3, there also exist the same 1D γ-Mo8–L chains as in 1, which extended the 2D networks to 3D frameworks. The Mo–N bond with pyridyl groups was formed under the solvothermal conditions, which is scarcely reported to our knowledge. The effect of the solvent on the assembly of the title compounds and the formation of the Mo–N bond, as well as the role of metal–organic moieties on the construction of diverse organopolymolybdate compounds have been discussed in detail. Furthermore, the electrochemical and photocatalytic properties of 1–3 have been investigated. [ABSTRACT FROM AUTHOR]

Three series of copper-lanthanide/lanthanide coordination polymers (CPs) LnIIICuIICuI(bct)3(H2O)2 [Ln=La ( 1), Ce ( 2), Pr ( 3), Nd ( 4), Sm ( 5), Eu ( 6), Gd ( 7), Tb ( 8), Dy ( 9), Er ( 10), Yb ( 11), and Lu ( 12), H2bct=2,5-bis(carboxymethylmercapto)-1,3,4-thiadiazole acid], LnIIICuI(bct)2 [Ln=Ce ( 2 a), Pr ( 3 a), Nd ( 4 a), Sm ( 5 a), Eu ( 6 a), Gd ( 7 a), Tb ( 8 a), Dy ( 9 a), Er ( 10 a), Yb ( 11 a), and Lu ( 12 a)], and LnIII2(bct)3(H2O)5 [Ln=La ( 1 b), Ce ( 2 b), Pr ( 3 b), Nd ( 4 b), Sm ( 5 b), Eu ( 6 b), Gd ( 7 b), Tb ( 8 b), and Dy ( 9 b)] have been successfully constructed under hydrothermal conditions by modulating the reaction time. Structural characterization has revealed that CPs 1- 12 possess a unique one-dimensional (1D) strip-shaped structure containing two types of double-helical chains and a double-helical channel. CPs 2 a- 12 a show a three-dimensional (3D) framework formed by CuI linking two types of homochiral layers with double-helical channels. CPs 1 b- 9 b exhibit a 3D framework with single-helical channels. CPs 6 b and 8 b display visible red and green luminescence of the EuIII and TbIII ions, respectively, sensitized by the bct ligand, and microsecond-level lifetimes. CP 8 b shows a rare magnetic transition between short-range ferromagnetic ordering at 110 K and long-range ferromagnetic ordering below 10 K. CPs 9 a and 9 b display field-induced single-chain magnet (SCM) and/or single-molecule magnet (SMM) behaviors, with Ueff values of 51.7 and 36.5 K, respectively. [ABSTRACT FROM AUTHOR]

By using two kinds of organic ligands (1-benzyl-1H-(1,2,4)triazole (2-btz) and 1-benzyl-1H-(1,3,4)triazole (3-btz)), six polyoxometalate (POM)-based compounds were hydrothermally synthesized and structurally characterized, [Ag4(2-btz)4(HPMo2VMo10VIO40)] (1), [Ag4(2-btz)4(SiW12O40)] (2), [Ag4(2-btz)5K(SiWVW11VIO40)]·13H2O (3), [Cu4(2-btz)16(Mo8O26)2] (4), [Cu3(3-btz)8(H2O)4](PMo12O40)2·4H2O (5) and [Cu7(3-btz)16(OH)2(H2O)4(P2W18O62)2]·16H2O (6). Compounds 1 and 2 are isostructural with two sets of Ag–(2-btz) chains linked by Keggin anions to construct a “ladder”. Adjacent “ladders” are further connected by Ag1–O13 bonds to build a 3D framework. In compound 3, the anion dimers are linked by Ag5–O9 bonds to form a 1D chain. The chains are fused by Ag3 and K ions and a 3D framework of 3 is built. In compound 4, the Mo8 anions are linked by [Cu(2-btz)4]2+ subunits to construct a 3D structure. By changing 2-btz to 3-btz, we obtained a linear tri-nuclear cluster [Cu3(3-btz)8(H2O)4]6+ in compound 5. The discrete PMo12 anions combine with tri-nuclear clusters through hydrogen bonding interactions to construct a 2D supramolecular layer. Compound 6 contains a cycle tri-nuclear cluster-supporting anion [Cu3(3-btz)6(OH)(H2O)2(P2W18O62)]−, which is further connected by one [Cu(3-btz)4]2+ subunit to construct a discrete anion dimer. The title compounds show good electrocatalytic activities for reducing nitrite, hydrogen peroxide and bromate. These compounds also exhibit excellent photocatalytic activities for the degradation of methylene blue (MB, 1–6 as catalysts) and Rhodamine B (RhB, 5 and 6 as catalysts). Additionally, the magnetic properties of compounds 5 and 6 have been investigated. [ABSTRACT FROM AUTHOR]

Four metal-organic coordination polymers [Cd(4-bpcb)1.5Cl2(H2O)] ( 1), [Cd(4-bpcb)0.5(mip)(H2O)2] ·3H2O ( 2), [Co(4-bpcb)(oba)(H2O)2] ( 3), and [Ni(4-bpcb)(oba)(H2O)2] ( 4) [4-bpcb = N, N′-bis(4-pyridinecarboxamide)-1, 4-benzene, H2mip = 5-methylisophthalic acid, and H2oba = 4, 4′-oxybis(benzoic acid)] were synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, powder X-ray diffraction, and TG analysis. In complex 1, two Cl- anions serve as bridges to connect two Cd-(μ1-4-bpcb) subunits forming a dinuclear unit, which are further linked by μ2-bridging 4-bpcb to generate 1D zigzag chain. Complex 2 shows a 2D 63 network constructed by [Cd-mip] n zigzag chains and μ2-bridging 4-bpcb ligands. Complexes 3 and 4 are isostructural 2D (4, 4) grid networks derived from [ M-oba] n ( M = Co, Ni) zigzag chains and [ M-(4-bpcb)] n linear chains. The 1D chains for 1 and the 2D networks for 2- 4 are finally extended into 3D supramolecular architectures by hydrogen bonding interactions. The roles of dicarboxylates and central metal ions on the assembly and structures of the target compounds were discussed. Moreover, the thermal stabilities, photoluminescent properties, and photocatalytic activities of complexes 1- 4 and the electrochemical properties of complexes 3 and 4 were investigated. [ABSTRACT FROM AUTHOR]

Five new transition metal coordination polymers, namely, [Co(bbbm)(BSTDA)] ( 1 ), [Co(bdmbmb)(BSTDA)(H 2 O)]·(H 2 O) ( 2 ), [Ni(bbbm)(BSTDA)(H 2 O) 2 ] ( 3 ), [Ni 2 (3-dpyh) 2 (BSTDA) 2 (H 2 O)] ( 4 ) and [Cd(bbbm) 1.5 (BSTDA)] ( 5 ) have been synthesized from an S-/thiadiazole-containing dicarboxylate [H 2 BSTDA = bis(sulfanediyl) thiadiazole diacetic acid] and different flexible/semi-rigid N-donor ligands [bbbm = 1,1-(1,4-butanediyl) bis-1H-benzimidazole, bdmbmb = 1,4-bis(5,6-dimethylbenzimidazole-1-yl)benzene and 3-dpyh = N,N′-bis(3-pyridinecarboxamide)-1,6-hexane]. Structural analysis indicates that the title complexes present different structures although using the same S-/thiadiazole-containing dicarboxylate. Complex 1 is a 3D framework constructed from 2D (6 3 ) Co-BSTDA layers and 1D Co-bbbm chains. When the flexible bbbm in 1 was replaced by a semi-rigid bdmbmb ligand, a 2D parallelogram (4,4) network 2 derived from 1D Co-BSTDA and Co-bdmbmb single chains has been obtained. Complex 3 , with Ni II ion as substitute of Co II ion in 1 , exhibited a 2D (4,4) network constructed form 1D Ni-BSTDA and Ni-bbbm single chains. When the bbbm in 3 was replaced by a longer and more flexible N-donor ligand 3-dpyh in 4 , a 2D wave-like (4,4) layer constructed from [Ni-BSTDA] 2 and [Ni-(3-dpyh)] 2 double chains with bimetallic nodes was generated. While the Co II ion in 1 was substituted by Cd II ion in 5 , a 3D framework crossed by 2D (6 3 ) wave-like Cd-bbbm layers and 1D zigzag Cd-BSTDA chains was obtained. Structural diversity in complexes 1 – 5 demonstrates that the coordination characters of metal ions, the spacer length and flexibility of N-donor ligands have great influence on the final structures of the title complexes. In addition, fluorescence properties of complexes 1 – 5 are also reported in this paper. [ABSTRACT FROM AUTHOR]

Through tuning the N-donor site of the pyridyl group in 5-(x-pyridyl)-1H-tetrazole ligands (x = 2, 4), four new Keggin-based compounds, [Cu7(2-ptz)8(OH)2(H2O)2(HPMoVI10MoV2O40)]·4H2O (1), [Cu5(2-ptz)6(HPMoVI10MoV2O40)(H2O)4]·4H2O (2), [Ag6(4-ptz)4(H2SiMo12O40)] (3) and [Ag5(4-ptz)4(H2PMo12O40)]·5H2O (4) (2-ptzH = 5-(2-pyridyl)-1H-tetrazole, 4-ptzH = 5-(4-pyridyl)-1H-tetrazole), were successfully synthesized under hydrothermal conditions and structurally characterized. Compound 1 possesses two kinds of CuII subunits: penta-nuclear clusters and mono-nuclear subunits, which connect with each other to form a one dimensional (1D) stair-like metal–organic chain. The adjacent 1D stair-like chains are further linked by tetradentate Keggin anions to construct a 2D layer. In compound 2, the tetra-nuclear CuII clusters and mono-nuclear CuII subunits construct a 2D metal–organic layer, which is further linked by bidentate Keggin anions to build a 3D framework. In compound 3, the 4-ptz ligand links AgI ions with tetrazole groups to form 1D infinite Ag–ptz chains, which are extended by the pyridyl group of 4-ptz and the tetrazole groups of other 4-ptz molecules to construct a 2D layer. The adjacent 2D layers are further linked by 6-connected Keggin anions to build a 3D framework. In compound 4, the 4-ptz ligands are linked by AgI ions to form 1D infinite Ag–ptz belts. The Keggin anions are linked by AgI ions to construct another infinite inorganic chain, in which each Keggin anion provides six oxygen atoms to coordinate with the AgI ions from adjacent Ag–ptz belts to construct a 2D layer. The roles of the ptz ligands with different N-donor sites in the construction of multinuclear clusters and 1D chains are discussed. The electrochemical and photocatalytic properties of the title compounds were investigated as well. [ABSTRACT FROM AUTHOR]

A series of metal-organic coordination polymers based on two isomeric semirigid bis-pyridyl-bis-amide ligands and 5-methylisophthalic acid (5-H2MIP), namely, [Cu(3-bpah)(5-MIP)] 2 H2O (1), [Ni(3-bpah)(5-MIP)] H2O (2), [Co(3-bpah)(5-MIP)] H2O (3), [Cu(4-bpah)(5-MIP)(H2O)] (4), [Ni(4-bpah)(5-MIP)(H2O)] H2O (5), [Co(4-bpah)(5-MIP)] (6), [Zn(4-bpah)(5-MIP)] (7), and [Cd(4-bpah)(5-MIP)] (8) (3-bpah=N,N'-bis(3-pyridinecarboxamide)-1,2-cyclohexane, 4-bpah=N,N'-bis(4-pyridinecarboxamide)-1,2-cyclohexane), have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction analyses. The title coordination polymers display versatile structural features with one-, two-, and three-dimensional frameworks. Complex 1 exhibits a two-dimensional (4,4) network named as type c, which is constructed from the arched 3-bpah and 5-MIP anions with alternating orientations. Complexes 2 and 3 show similar three-dimensional frameworks, which feature a trinodal (2,3,5)-connected topology with the Schläfli symbol of (4² -6-84 10² 12)(4² 6)(8). Complex 4 exhibits an undulated two-dimensional (4,4) network of type b, in which the twist angles of the ligands are different from those of 1. Complex 5 reveals a one-dimensional double-strand chain, whereas complexes 6-8 exhibit similar two-dimensional double-layer structures with (4².6)(4³.6.84.10²)(4) topology. The influence of semirigid bis-pyridyl-bis-amide ligands and central metals on the structures of the title complexes has been reported. The fluorescent sensing behaviors of complexes 7 and 8, and the electrochemical and photocatalytic properties of complexes 1-6 have also been investigated in detail. [ABSTRACT FROM AUTHOR]

Tenmultifunctional cobalt(II) coordination polymers with the formulasof [Co(L1)0.5(5-AIP)]·H2O (1), [Co(L2)(5-AIP)(H2O)2] (2), [Co(L3)0.5(5-AIP)](3), [Co(L4)0.5(5-AIP)(H2O)]·2H2O (4), [Co(L5)(5-AIP)](5), [Co(HBTC)(L3)]·H2O (6), [Co(HBTC)(L6)(H2O)]·3H2O (7), [Co(L2)(1,3-BDC)(H2O)2] (8), [Co2(L3)2(1,3-BDC)2]·4H2O (9), and [Co2(L4)1.5(1,2-BDC)(μ2-OH)(μ3-OH)(H2O)]·H2O (10) have been prepared by a hydrothermal technique employingsix flexible bis(pyridylamide) ligands with different spacers (L1= N,N′-bis(3-pyridyl)oxamide, L2= N,N′-bis(3-pyridyl)malonamide, L3= N,N′-di(3-pyridyl)succinamide, L4= N,N′-bis(3-pyridyl)adipamide, L5= N,N′-bis(3-pyridyl)heptandiamide, L6= N,N′-bis(3-pyridyl)sebacicdiamide) and four aromatic polycarboxylicacids mixed ligands (5-H2AIP = 5-aminoisophthalic acid,H3BTC = 1,3,5-benzenetricarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, and 1,2-H2BDC = 1,2-benzenedicarboxylicacid). Compound 1exhibits a two-dimensional (2D) double-layernetwork. Compounds 2and 8are isostructuraland possess one-dimensional (1D) circle-connecting-circle chain structuresderived from 1D [Co(L2)]n“Ω”-like chain and 1D[Co(5-AIP)]n/[Co(1,3-BDC)]nwavelike chain. Compound 3possessesa 3,8-connected three-dimensional (3D) coordination framework with{42.6}2{44.610.79.85} topology. Compound 4is a 2Dnetwork containing a ladder-like chain. Compound 5revealsa novel 3-fold interpenetrating CdSO4-like framework. Compound 6is a double-layer coordination network with a (3,5)-connected{42·67·8}{42·6} topology.Complex 7shows a 2D (4,4) grid layer. Compound 9features a 2-fold interpenetrating 3D α-Po-relatedtopological framework. Compound 10is a 6-connected 3Dcoordination polymer with a {412.63} topology.The spacer length of the bis(pyridylamide) ligands, as well as thesubstituent group and carboxyl group number of polycarboxylates, showsa significant effect on the ultimate architectures of various cobalt(II)compounds 1–10. The electrochemicalbehaviors of carbon paste electrodes (CPEs) bulk-modified by compounds 1–10and the electrocatalytic activitiesof 1-, 6-, 9-, 10-CPEs have been investigated. The photocatalytic properties of compounds 1–10toward the degradation of methyleneblue (MB) in visible light irradiation have been investigated. Thevariable temperature magnetic susceptibilities for compounds 3, 5, 9, and 10indicatethe existence of antiferromagnetic exchange interactions. [ABSTRACT FROM AUTHOR]

Four cobalt(II) mixed ligand coordination polymers based on the flexible N,N′-bis(3-pyridinecarboxamide)-1,6-hexane (3-dpyh) and four isophthalates with different substituent groups, namely [Co(3-dpyh)(5-HIP)(H2O)3]·H2O (1), [Co(3-dpyh)(5-NIP)]·H2O (2), [Co(3-dpyh)(5-MIP)]·H2O (3) and [Co(3-dpyh)0.5(5-AIP)(H2O)]·2H2O (4), have been hydrothermally synthesized and structurally characterized (5-H2HIP=5-hydroxyisophthalic acid, 5-H2NIP=5-nitroisophthalic acid, 5-H2MIP=5-methylisophthalic acid, 5-H2AIP=5-aminoisophthalic acid). X-ray diffraction analyses reveal that complex 1 is a chain constructed from a [Co-3-dpyh] n meso-helical chain and 5-HIP anions, in which each 5-HIP anion adopts a monodentate mode coordinating to one Co(II) ion. The isostructural complexes 2 and 3 are assembled from 5-NIP and 5-MIP anions, respectively, featuring a 2D 3,5-connected network with the {42·67·8}{42·6} topology, in which the two carboxyl groups of dicarboxylates exhibit μ 1:η 1–η 1 and μ 2:η 1–η 1 modes. When the 5-AIP anion is utilized in 4, a different 2D (3,4)-connected {42·63·8}{42·6} network is obtained, in which the two carboxyl groups of AIP exhibit μ 1:η 1–η 1 and μ 1:η 1–η 0 modes, and the N atom of AIP also coordinates to the Co(II) ion. The influence of the substituent groups of the isophthalates on the structures has been discussed in detail. The fluorescent, electrochemical and photocatalytic properties of complexes 1–4 have also been investigated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Three Keggin-based complexes have been obtained with two N-donor mixed ligands. [•] The space length of bis-pyridyl-bis-amide shows obvious effect on the final structures. [•] Introduction of the secondary phen ligand results in the reduction of dimensionality. [•] The electrochemical behavior of 3 and photocatalytic properties of 1–3 are studied. [Copyright &y& Elsevier]

The reaction of an arm-non-equivalent tripodal ligand pyridin-4-ylmethyl-3,5-bis-(pyridin- 4-ylmethoxy)benzoate (pbb) with Zn(NO3)2and Co(SCN)2affords two 2D coordination polymers {[Zn(pbb)(NO3)2]·(H2O)·(DMF)}n(1) and {[Co(pbba)2(SCN)2]·(DMF)}n(2) (pbba = methyl-3,5-bis(pyridin-4-ylme- thoxy)benzoate). In 1, pbb performs as a three-connector to bridge Zn(NO3)2into a 2D brick-wall-like structure. Ligand pbba, originated from pbb in the self-assembly process of 2 under hydrothermal condition, performs as a two connector to bridge Co(SCN)2into (4,4) sheet with 2D→2D interpenetration. [ABSTRACT FROM PUBLISHER]

Three coordination compounds with dimensions from 0D to 2D, namely, [Co(bppdca)2(HL1)2] ( 1) [Co(bppdca)(L2)(H2O)] ·2H2O ( 2) and [Co(bppdca)(L3)] ·3H2O ( 3) [bppdca = N, N′-bis(pyridine-3-yl)pyridine-2,6-dicarboxamide, H2L1 = 2,5-pyridinedicarboxylic acid, H2L2 = 4,4′-oxybisbenzoic acid, H2L3 = 2-carboxymethylsulfanyl nicotinic acid] were hydrothermally synthesized and structurally characterized. Single crystal X-ray diffraction analysis reveals that complex 1 is a discrete 0D complex, in which the bppdca ligand and the H2L1 act as the terminal groups to coordinate with the CoII ions. In coordination polymer 2, two bppdca ligands coordinate in anti configuration with two CoII ions to generate a 28-membered Co2(bppdca)2 loop, which is further extended into 1D ladder-like double chain by pairs of L2 ligands. In 3, the CoII ions are linked by bppdca ligands to generate 1D wave-like chain, which is further connected by the L3 to form a 2D network. Finally, the coordination compounds 1- 3 are extended into 3D supramolecular frameworks through the hydrogen bonding interactions. The CoII ions and the bppdca ligands in the title coordination compounds exhibit different coordination characters and conformations. The effect of organic dicarboxylates with different rigidity and length on the structures of CoII coordination compounds was investigated. In addition, the fluorescence and electrochemical behaviors of coordination compounds 1- 3 were reported. [ABSTRACT FROM AUTHOR]

Six new transition metal coordination polymers, namely, [Co(1,2-BDC)(L)1.5(H2O)] (1), [Co(1,3-BDC)(L)(H2O)2]·H2O (2) [Co(5-AIP)(L)0.5(H2O)]·2H2O (3), [Cu(1,2-BDC)(L)] (4), [Cu(1,3-BDC)(L)(H2O)]·3H2O (5), and [Cu2(5-AIP)2(L)2(H2O)]·6H2O (6) (L = N,N′-di(3-pyridyl)octanediamide, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, 5-H2AIP = 5-aminoisophthalic acid), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. In compound 1, the adjacent CoII ions are connected by L ligands to form a 1D chain with an alternating arrangement of L ligands and Co2L2 dinuclear loops. The 1,2-BDC anions coordinate with one CoII ion in a bis(monodentate) chelate mode. Complex 2 shows a 2D (44) grid network with the sql topology, which consists of the 1D zigzag [Co–L]n chain and 1D linear [Co-1,3-BDC]n chain. When 5-H2AIP is used in compound 3, an interesting 2D terraced-type layer based on 1D [Co-5-AIP]2n ladder-like chains and μ2-bridging L ligands with 3,4-connected {62.10}{6} topology is formed. Under the similar conditions to compound 1, except that the cobalt(ii) salt is replaced by a copper(ii) salt, a 2D wave-like network 4 with 2,4-connected {64.8.10}{6} topology is obtained. Compound 5 displays a 3D coordination polymeric architecture based on 1D [Cu-1,3-BDC]n chains and [Cu–L]n chains, which represents an intriguing 3-fold interpenetrating framework with CdSO4-type topology. When 1,3-BDC is replaced by 5-AIP, another 3-fold interpenetrating 3D CdSO4-type coordination framework for compound 6 is obtained, which is constructed from three types of 1D chains: [La–Cu–Lc]n chain, [Lb–Cu–Lb]n chain and [Cu-5-AIP]n chain. The adjacent 1D chains for 1 and 2D layers for compounds 2, 3 and 4 are further extended by hydrogen bonding interactions to 3D supramolecular frameworks. The effect of dicarboxylates and central metals on the structures of the title complexes has been discussed. Furthermore, the electrochemical behaviors and solid state fluorescent properties for compounds 1–6 are investigated. [ABSTRACT FROM AUTHOR]

Three new metal–organic coordination polymers, [Co2(bbix)3(dnba)4(H2O)]·0.5bbix (1), [Co(bbix)1.5(aip)]·H2O (2) and [Co(bbix)(fma)]·3H2O (3) (bbix=1,4-bis(benzimidazol-1-ylmethyl)benzene, Hdnba=3,5-dinitrobenzoate acid, H2aip=5-amino-isophthalic acid and H2fma=fumaric acid), were obtained under hydrothermal conditions and structurally characterized. Coordination polymer 1 shows a linear chain formed by dinuclear [Co2(dnba)4(H2O)] units and bbix ligands. The chains are further extended into a supramolecular layer by π–π stacking interactions between dnba and bbix. Coordination polymer 2 features a layer constructed from CoII ions and bbix ligands, and the aip anions only consolidate the layer structure. Coordination polymer 3 possesses a three-dimensional (3D) 3-fold interpenetrated diamond framework. In 3, the fma anions link the CoII ions to form a wave-like chain, which is further extended into a 3D architecture by the bbix ligands. The structural analyses clearly indicate that the nature of the secondary auxiliary ligands can effectively influence the coordination environments of the CoII ions and the dimensionality of the coordination polymers 1–3. In addition, the electrochemical and photoluminescent properties of 1–3, as well as magnetic properties of 1, have been investigated. [ABSTRACT FROM AUTHOR]

Four new metal–organic complexes based on four flexible bis-pyridyl–bis-amide ligands with different spacer length and 1,3-benzenedicarboxylic acid, namely [Ni(3-dpye)(1,3-BDC)(H2O)2] (1), [Ni(3-dpyp)(1,3-BDC)(H2O)]·H2O (2), [Ni(3-dpyb)(1,3-BDC)(H2O)2]·H2O (3), [Ni(3-dpyh)(1,3-BDC)(H2O)2]·H2O (4) [3-dpye = N,N′-bis(3-pyridinecarboxamide)-1,2-ethane, 3-dpyp = N,N′-bis(3-pyridinecarboxamide)-1,3-propane, 3-dpyb = N,N′-bis(3-pyridinecarboxamide)-1,4-butane, 3-dpyh = N,N′-bis(3-pyridinecarboxamide)-1,6-hexane, 1,3-H2BDC = 1,3-benzenedicarboxylic acid], have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, PXRD, TG and single crystal X-ray diffraction analyses. X-ray analyses reveal that the title complexes show three different two-dimensional (2D) coordination layers (for complexes 1, 3 and 4) and a one-dimensional (1D) polymer chain (for complex 2). In four Ni(II) complexes, the four flexible bis-pyridyl–bis-amide ligands only show a μ 2-bridging mode. While the 1,3-BDC ligands adopt two kinds of coordination modes in these four complexes: a bis(monodentate) bridging mode with each carboxyl group in a μ 1-η 1:η 0 mode in complexes 1, 3 and 4, a chelating-monodentate bridging mode with one carboxyl group in a μ 1-η 1:η 1 mode and another carboxyl group in a μ 1-η 1:η 0 mode in 2. Finally, the adjacent 2D layers or 1D chains are further extended into 3D supramolecular frameworks via hydrogen bonding or π–π stacking interactions. The spacer length and conformation of the bis-pyridyl–bis-amide ligands play an important role in the final structures of the title complexes. The fluorescent and electrochemical properties of complexes 1–4 have also been investigated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Four new complexes based on bis(benzimidazole)-based ligands have been obtained. [•] The flexibility of N-ligands have a great influence on the dimensionality of 1–4. [•] The electrochemical and fluorescence properties for 1–4 have been investigated. [ABSTRACT FROM AUTHOR]

Thirteennew CuIIcoordination polymers, namely, [Cu(3-dppa)(1,3,5-HBTC)](1), [Cu(3-dpha)(1,3,5-HBTC)(H2O)]·H2O (2), [Cu3(3-dpsea)(1,3,5-BTC)2(H2O)5]·4H2O (3), [Cu(3-dpba)(1,2-BDC)]·H2O(4), [Cu(3-dpha)(1,2-BDC)] (5), [Cu(3-dpsea)(1,2-BDC)]·H2O (6), [Cu2(3-dpyp)(1,3-BDC)2(H2O)4]·3H2O (7), [Cu(3-dppa)(1,3-BDC)(H2O)]·2H2O (8), [Cu(3-dppia)(1,3-BDC)(H2O)2]·2H2O (9), [Cu2(3-dpsea)2(1,3-BDC)2(H2O)2]·7H2O (10), [Cu(3-dpba)(1,4-NDC)]·3H2O (11), [Cu(3-dpyh)(1,4-NDC)(H2O)]·3H2O (12), [Cu(3-dpyh)0.5(1,4-NDC)]·H2O (13), have been purposefully synthesized under hydrothermal conditions[3-dppa = N,N′-di(3-pyridyl)propanediamide,3-dpba = N,N′-di(3-pyridyl)butanediamide,3-dpha = N,N′-di(3-pyridyl)hexanedioicdiamide,3-dppia = N,N′-di(3-pyridyl)pimelicdiamide,3-dpsea = N,N′-di(3-pyridyl)sebacicdiamide,3-dpyp = N,N′-di(3-pyridinecarboxamide)-1,3-propane,3-dpyh = N,N′-di(3-pyridinecarboxamide)-1,6-hexane,1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,3-H2BDC =1,3-benzenedicarboxylic acid and 1,4-H2NDC = 1,4-naphthalenedicarboxylicacid]. Complexes 1–3based on thesame auxiliary ligand show various structures. Complex 1features a one-dimensional (1D) ∞-like double-chain structure,which consists of a [Cu-1,3,5-HBTC]nchainand [Cu-3-dppa]nmeso-helical chain. Complex 2possesses a (2,4) undulatedhoneycomb (hcb) net. Complex 3is a 3-fold interpenetratingthree-dimensional (3D) framework, which shows trinodal (2,3,3)-connectedtopology with the Schläfli symbol of (10·122)2(103)2(12). Complexes 4–6with 1,2-BDC as secondary ligand exhibit differenttwo-dimensional (2D) layer structures. Complex 4exhibitsa 2D (2,4)-connected (4·124·14)(4) net. Complexes 5and 6have similar structures and show 2D networkswith undulated sql topology. For complexes 7–10based on 1,3-BDC secondary ligand, complex 7shows a 1D zigzag chain, while complexes 8–10have similar wave-like 2D structures. When 1,4-NDC wasused as the auxiliary ligand, complex 11is a 2D puckered(4,4) network, complex 12reveals a 4-connected topologywith the point symbol of (44·62), whilecomplex 13exhibits a 3-fold interpenetrating 3D α-Poframework. The structural diversity indicates that the bis-pyridyl-bis-amideligands with different spacers and the aromatic polycarboxylates playimportant roles in tuning the dimensionalities and structures of thetitle complexes. The fluorescent and photocatalytic properties for 1–13have also been investigated in detail. [ABSTRACT FROM AUTHOR]

Two new two-dimensional (2D) metal-organic coordination polymers [Co(ox)(bbbm)]·HO ( 1) and [Cu(ox)(bppdca)]·2HO ( 2) (Hox = oxalic acid, bbbm = 1,1-(1,4-butanediyl)bis-1 H-benzimidazole and bppdca = N, N′-bis(pyridin-3-yl)-2,6-pyridinedicarboxamide) were synthesized under hydrothermal conditions and structurally characterized. Both 1 and 2 exhibit a 2D four-connected network formed by the Co/Cu ions as four-connected nodes; and, the ox anions and bbbm/bppdca ligands as linkers with a (4.6) topology as determined by single crystal X-ray diffraction. In addition, the thermal stability, electrochemical and luminescent properties for 1 and 2 were investigated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Three new 2D networks based on [Cd(P4Mo6)2] dimer have been obtained. [•] It is the first example of combining flexible bis(triazoles) with [P4Mo6] units. [•] Three multi-nuclear CdII subunits have been constructed in the title compounds. [•] Ligand length plays an important role in forming multi-nuclear CdII subunits. [Copyright &y& Elsevier]

Abstract: Two novel three-dimensional (3D) copper(II) complexes [Cu3(3-bpcb)(1,2-BDC)2(μ 2-OH)2] (1) and [Cu2(3-bpcb)1.5(SIP)(μ 3-OH)]·H2O (2), based on a rigid bis-pyridyl-bis-amide ligand [3-bpcb = N,N′-bis(3-pyridinecarboxamide)-1,4-benzene] and two different polycarboxylates [1,2-H2BDC=1,2-benzenedicarboxylic acid, NaH2SIP=sodium 5-sulfoisophthalic acid] have been prepared under hydrothermal conditions. Single crystal X-ray diffraction analysis shows that complex 1 exhibits a 4-nodal mixed (3,4,4,5)-connected 3D structure with the (3·4·5)2(3·42·5·86)2(32·8·92·10)(42·82·102) Schläfli symbol, which is constructed from two-dimensional (2D) Cu(II)-μ 2-OH-3-bpcb layers (3-bpcb: μ 4-bridging coordination mode via two pyridyl nitrogen and two carbonyl oxygen atoms) and the 1,2-BDC bridging ligands. Complex 2 is also a 3D coordination polymer constructed from the μ 2-bridging 3-bpcb ligands (via two pyridyl nitrogen atoms) and the 2D Cu(II)-μ 3-OH-SIP sheets containing tetranuclear copper clusters, showing a novel 3-nodal (5,6,6)-connected (33·43·53·63·72·8)(33·43·53·6)(33·46·54·62) topology. The differences between the final 3D structures for complexes 1 and 2 might be attributed to the different aromatic polycarboxylates and the bis-pyridyl-bis-amide ligand with different coordination modes. Moreover, the electrochemical behavior of complex 1 and the fluorescence properties of the complexes 1–2 have been investigated. [Copyright &y& Elsevier]

Abstract: Three new Cd(II) coordination polymers, [Cd(hbdmbm)(SO4)] n (1), {[Cd3(hbdmbm)4(5-SSPIA)2]·(H2O)2} n (2) and [Cd3(bbdmbm)4(5-SSPIA)2] n (3), based on different O-containing anionic ligands and flexible bis(benzimidazole) derivatives (hbdmbm=1,1′-(1,6-hexanediyl)bis(5,6-dimethylbenzimidazole), bbdmbm=1,1′-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), 5-SSPIA=sodium 3,5-dicarboxybenzenesulfonate), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Structure analysis illustrates that complex 1 possesses a 2D (4, 4) network constructed from the binuclear [Cd(SO4)]2 secondary building unit (SBU) and the hbdmbm. Complex 2 shows a 2D/3D crossed 3D framework with Schläfli symbol of (63)2(65·8)(68·82)2. In 2, Cd(II) ions are connected by hbdmbm ligands to construct a 3D framework showing a topological octagon geometry, and also linked by 5-SSPIA to construct a 2D layer with polygon geometry, in which 5-SSPIA anions act as three-connected nodes. Complex 3 shows more complicated 3D framework with Schläfli symbol (4·64·8)(4·82)(42·53·63·7·8)(42·53·6)(5·6·7·82·9), which contains two kinds of SBUs built by 5-SSPIA and bbdmbm. 5-SSPIA anions act as three-connected nodes and four-connected nodes in 3. The structure-directing role of anionic ligands and the effects of conformations of N-donor ligands on the final structures are discussed. In addition, fluorescence properties of complexes 1–3 are also reported in this paper. [Copyright &y& Elsevier]

Abstract: Two new metal–organic coordination polymers [Co4(bbbm)4(1,2-BDC)4(H2O)]·2H2O (1) and [Co(bbbm)(1,4-BDC)] (2) (bbbm=1,1-(1,4-butanediyl)bis-1H-benzimidazole, 1,2-H2BDC=1,2-benzenedicarboxylic acid and 1,4-H2BDC=1,4-benzenedicarboxylic acid) were obtained under hydrothermal conditions and structurally characterized. Polymer 1 exhibits a two-dimensional (2D) 4-connected network with the CoII ions as four-connected nodes, and the bbbm and 1,2-BDC ligands as linkers. Polymer 2 possesses a novel three-dimensional (3D) 3-fold interpenetrated framework. The position of carboxyl groups for benzenedicarboxylates dominates the final structures of 1 and 2. Furthermore, elemental analysis, IR spectroscopy, thermogravimetric analysis, electrochemical properties and solid state fluorescence for 1 and 2 were investigated. [Copyright &y& Elsevier]

Abstract: Two new isostructural 2D compounds based on hexa-nuclear [Cu6 I(ptz)6] clusters and Keggin anions, [Cu6 I(ptz)6][H3XMo12O40]·2H2O (X = P for 1; As for 2) (ptz = 5-(4-pyridyl)-tetrazole), have been hydrothermally synthesized. The hexa-nuclear [Cu6 I(ptz)6] subunits are constructed from five [Cu2N4] units with a cycle connecting cycle mode and further connected by the ptz to form 1D chains. These adjacent 1D chains are further linked by the Keggin anions to construct the intriguing 2D networks. [Copyright &y& Elsevier]

Two new ruthenium(II) polypyridyl complexes, [Ru(dmb)2(DNPIP)](ClO4)2 (1) (DNPIP = 2-(2,4-dinitrophenyl)imidazo[4,5-f][1,10]phenanthroline, dmb = 4,4′-dimethyl-2,2′-bipyridine) and [Ru(dmb)2(DAPIP)](ClO4)2 (2) (DAPIP = 2-(2,4-diaminophenyl)imidazo[4,5f][1,10]phenanthroline), were synthesized and characterized. The DNA-binding behaviors of these complexes have been studied by UV-Vis absorption titration, viscosity measurements, and photocleavage. The DNA-binding constants are 7.39 (±0.16) × 104 (s = 2.68) and 2.73 (±0.16) × 104 (mol L−1)−1 (s = 0.64) for 1 and 2, respectively. Their evaluation as cytotoxic agents on different cancer cell lines was investigated with IC50 values of 59.5, 51.3, and 70.3 µmol L−1 for 1, >100, 87.9, and 77.9 µmol L−1 for 2 against BEL-7402, HepG-2, and MCF-7 cells, respectively. Complex 1 is more active than 2 against selected cancer cell lines. The apoptosis induced by these complexes was studied. Cellular uptake showed that these complexes could enter into the cytoplasm and accumulate in the nuclei. The cell cycle arrest and antioxidant activity against hydroxyl radicals were also investigated. [ABSTRACT FROM PUBLISHER]

Four new 2-aminobenzothiazole (abt)-based CdII complexes, {[Cd(abt)2(chdc)][Cd(abt)2(chdc)] · 2H2O · CH3OH} n (1), [Cd2(abt)4(bd)2(H2O)2] · 2H2O (2), [Cd(abt)2(o-mb)2] (3), and [Cd(abt)2(m-mb)2] (4) (chdc = cis-1,4-cyclohexanedicarboxylate, bd = cis-butenedicarboxylate, o-mb = o-methylbenzoate, and m-mb = m-methylbenzoate), were obtained by the reaction of CdII with abt ligand in the presence of different carboxylate-containing coligands. As a result of the different number of carboxylate groups appended on the coligands, the complexes exhibit H-bonded supramolecular assemblies consisting of polymeric 1-D array and separate binuclear entity for 1, a centrosymmetric binuclear structure for 2 as well as discrete mononuclear entities for 3 and 4, which are further packed into 2-D supramolecular networks by hydrogen-bonding and/or π–π stacking interactions. The four complexes with comparable thermal stability display intense abt-based emissions, suggesting their potential applications as fluorescent materials. [ABSTRACT FROM PUBLISHER]

Abstract: Two Keggin-based inorganic–organic hybrid complexes, [Co2(H2O)2(btb)4(HPMoVI 10MoV 2O40)] (1) and [Co2(btx)5(HPMoVI 10MoV 2O40)] (2) (btb=1,4-bis(1,2,4-triazol-1-yl)butane, btx=1,6-bis(1,2,4-triazol-1-yl)hexane), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, and thermogravimetric analyses (TGA). Complex 1 exhibits 2D ladder-like metal–organic layers, which are further linked by the Keggin anions to construct a 3D twofold interpenetrating framework. Complex 2 shows a 2D metal–organic network containing two kinds of pores, in which the Keggin anions acting as bidentate inorganic linkages reside alternately. The flexible bis(triazole) ligands btb and btx with different spacer lengths play an important role in the formation of the final structures. In addition, the electrochemical and photocatalytic properties of 1 and 2 have been reported. [Copyright &y& Elsevier]

Four SiMo12O404–(SiMo12)-based compounds, namely, [Ag6Cl2(mmt)4(H4SiMo12O40)(H2O)2] (1), [Ag4(bmte)2(H2O)2(SiMo12O40)] (2), [Ag4(bmtr)2(H2O)2(SiMo12O40)] (3),and [Ag4(bmtb)3(SiMo12O40)] (4) (mmt = 1-methyl-5-mercapto-1,2,3,4-tetrazole,bmte = 1,2-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)ethane,bmtr = 1,3-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)propane, bmtb= 1,4-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)butane), have beensynthesized under hydrothermal conditions. Single crystal X-ray diffractionanalyses reveal that insertion of -(CH2)n- spacers into the reactant mmt ligand plays important rolesin constructing multinuclear AgIclusters in the titlecompounds and tuning the formation of different multinuclear AgIclusters. In compound 1, the mmt ligands linkAgIions forming a three-dimensional non-multinuclear self-penetratingframework with large dimension channels occupied by SiMo12polyanions. In 2, a tetranuclear [Ag4(bmte)2(H2O)2]4橷 SiMo12anions arrange alternately forming a one-dimensional (1D) chain.The structure of compound 3is similar to that of 2, except for different coordination modes of AgIions in tetranuclear clusters and SiMo12polyanions owingto the longer -(CH2)3- alkyl skeleton of bmtrligand. Compound 4exhibits a two-dimensional grid layerformed by a 1D AgI“ribbon” based on binuclearAgIclusters and bridging bmtb ligands with the longest-(CH2)4- alkyl skeleton. The SiMo12polyanions as tetradentate inorganic linkages reside in the grids.The influences of -(CH2)n-spacers on forming and tuning different multinuclear AgIclusters have been discussed. Furthermore, the photochemical catalysisand electrochemical properties of the title compounds have been studied. [ABSTRACT FROM AUTHOR]

Abstract: Four Keggin-based compounds, [CuI 2(bmtm)3]2·[CuI 2(bmtm)4]·(PW12O40)2 (1), (bmtm=1,1′-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)methane), [CuI 3(bmte)3(PW12O40)] (2) (bmte=1,2-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)ethane), [CuII(bmtb)3(HPW12O40)] (3) and [CuII(bmtb)3(HPMo12O40)] (4) (bmtb=1,4-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)butane), have been designed and synthesized under hydrothermal conditions. By tuning the bis(tetrazole)-functionalized thioether ligands, compounds 1–4 exhibit Keggin-based bi-, tri- and mono-nuclear structures respectively, in which copper ion is +I oxidation state in compounds 1–2, and +II oxidation state in compounds 3–4. Compound 1 is composed of three moieties, [PW12O40]3− anion and two kinds of bi-nuclear subunits [CuI 2(bmtm)3]2+ and [CuI 2(bmtm)4]2+. There exist abundant hydrogen-bonding and aryl stacking interactions inducing a two-dimensional (2D) supramolecular network of compound 1. Compound 2 exhibits a tri-nuclear cluster [CuI 3(bmte)3]3+, which is connected by [PW12O40]3− anions to construct a 1D chain. Compounds 3 and 4 are isostructural, and show 2D layer structures, which are constructed from Keggin anions and mono-nuclear [CuII(bmtb)3]2+. In this 2D layer, the Keggin anions act as bidentate linkages to connect the CuII-btmb chains. The oxidation states of copper ions show great influence on the mono- and multi-nuclear structures of this series. In addition, the electrochemical properties of the title compounds have been investigated. [Copyright &y& Elsevier]

By using the flexible bis(triazole) ligand 1,2-bis(1,2,4-triazol-1-yl)ethane (bte), a polyoxometalate-templated compound, [Zn2(bte)4(SiW12O40)]·2H2O (1), was synthesized under hydrothermal conditions. The compound was characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, photoluminescence spectroscopy, and cyclic voltammetry. Compound 1 is constructed from two motifs: the [SiW12O40]4− polyanion and a bi-nuclear metal-organic circle [Zn2(bte)2]4+. The polyanion exerts a template role, inducing the formation of the bi-nuclear circle. The circles build a 1-D circle connecting circle chain through sharing the same Zn ions. Adjacent circles in the chain are vertical with each other. The template polyanion is surrounded by four circles from four different 1-D chains, forming a 3-D supramolecular structure. [ABSTRACT FROM PUBLISHER]

Abstract: Four Cd(II) metal–organic complexes, namely, [Cd(Cl)2(bbdmbm)] (1), [Cd(NO3)(N3)(bbdmbm)1.5] (2), [Cd(BBA)2(bbdmbm)(H2O)] (3), [Cd(DNBA)2(bbdmbm)] (4), (bbdmbm=1,1-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), HBBA=4-bromobenzoic acid, and HDNBA=3,5-dinitrobenzoic acid) have been obtained from hydrothermal reactions of different Cd(II) salts with the mixed ligands of bbdmbm and five anions (Cl−, NO3 −, N3 −, BBA and DNBA). Single crystal X-ray diffraction analyses reveal that the four complexes exhibit different structures. Complex 1 possesses a one-dimensional (1D) helical chain, which is finally extended into a two-dimensional (2D) supramolecular structure through π–π stacking interactions. Complex 2 shows a 1D ladderlike chain bridged by bbdmbm ligands with two kinds of coordination conformations. Complex 3 is a 1D coordination polymer and is ultimately extended into a 2D supramolecular network through H-bonding interactions. Complex 4 displays a dinuclear cluster, which is finally packed into a three-dimensional (3D) supramolecular framework through three kinds of π–π stacking interactions. The Cd(II) exhibits four different coordination modes in complexes 1–4, respectively. The results indicate that the anion ligands with different steric hindrance and size play important roles in the coordination modes of Cd(II) and construction of the title complexes, leading to the structural diversity. In addition, the conformations of bbdmbm ligand also show some effect on the final structures. Fluorescence properties of complexes 1–4 are reported in this paper. [Copyright &y& Elsevier]

Abstract: In the compound [Pb2(L)2(1,4-bdc)2]n (1), each Pb(II) atom is seven-coordinated by two nitrogen atoms from one L ligand, and five carboxylate oxygen atoms from three different 1,4-bdc ligands in a distorted monocapped triangular prismatic coordination geometry (1,4-bdc=1,4-benzenedicarboxylate and L =dipyrido[7,6-a:6′,7′-c]-3-chloropyrido[2,3-b]quinoxaline). The Pb(II) atoms are connected together by the 1,4-bdc ligands to form a 2D network with large windows. The dangling L ligands of each layer are threaded into the voids of the two adjacent layers above and below, thus every window of each layer is threaded by only two dangling ligands that come from opposite directions. Finally, this unique simultaneous threading fashion of adjacent polymeric motifs gives the novel 2D→3D polythreading array. In addition, the strong π–π interactions between the L ligands and the 1,4-bdc ligands of neighboring layers make great contribution to the structural stabilization of 1. [Copyright &y& Elsevier]

Abstract: Three new metal-organic coordination polymers, [Co(3-bpcb)(1,3-BDC)]·H2O (1), [Co(4-bpcb)(1,3-BDC)]·2H2O (2) and [Cu(4-bpcb)(1,3-BDC)]2·0.5(4-bpcb) (3), have been hydrothermally synthesized using N,N′-bis(3-pyridinecarboxamide)-1,4-benzene (3-bpcb) or N,N′-bis(4-pyridinecarboxamide)-1,4-benzene (4-bpcb) and 1,3-benzenedicarboxylate (1,3-H2BDC) mixed ligands and characterized by elemental analyses, IR, TG, XRPD and single-crystal X-ray diffraction. Complexes 1–2 exhibit the similar two-dimensional (2D) network with different undulation degrees and dimensions, owing to different N positions from the 3-bpcb and 4-bpcb ligands. 1,3-BDC ligand in complexes 1 and 2 shows two coordination modes. The adjacent 2D layers for 1–2 are further linked by hydrogen bonding interactions to form a three-dimensional (3D) supramolecular network. Complex 3 possesses infinite 3-fold interpenetrating 2D network composed of three kinds of Cu-4-bpcb one-dimensional (1D) chains and 1,3-BDC ligands, in which 1,3-BDC only shows one coordination mode. The 2D network is further extended into 3D supramolecular framework by hydrogen bonding interactions. The non-coordinated 4-bpcb ligands existing in the 2D network connect with adjacent 2D layers through the hydrogen bonding interactions. In addition, the electrochemical behaviors and the fluorescence property of complexes 1–3 have been reported. [Copyright &y& Elsevier]

Abstract: A new two-dimensional (2D) polyoxometalate (POM)-based helical coordination polymer, [Cu3(μ2-OH)(pdon)3(pca)(H2O)3][SiW12O40]·6H2O (1) (pdon=1,10-phenanthroline-5,6-dione, Hpca=pyridine-4-carboxlic acid), has been synthesized by in situ generation of pyridine-4-carboxlic acid and 1,10-phenanthroline-5,6-dione from 2-(4-pyridine)imidazo[4,5-f]1,10-phenanthroline under hydrothermal condition, and characterized by elemental analysis, IR spectra, TGA and single-crystal X-ray diffraction. In complex 1, each [SiW12O40]4− (SiW12) cluster connects with three trinuclear [Cu3(μ2-OH)(pdon)3(pca)(H2O)3]4+ metal-organic fragments, meanwhile, each metal-organic fragment also links with three SiW12 polyoxoanions to form two types of one dimensional (1D) helical chains. The adjacent 1D chains with different spiral orientations are connected by the terminal oxygen atom of SiW12 polyoxoanions, leading to the formation of a 2D layer network. Moreover, the photochemical catalysis and electrochemical properties of complex 1 are also reported. [Copyright &y& Elsevier]

Three new polymeric frameworks, [Cd(bbbi)(ita)(H2O)] · H2O (1), [Cd(bbbi)(fma)] (2), and [Cd(bbbi)(fma)(H2O)] · 2H2O (3) (bbbi = 1,1-(1,4-butanediyl)bis-1 H-benzimidazole, H2ita = itaconic acid, and H2fma = fumaric acid), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 is a 2-D (4,4) network containing infinite 1-D zigzag Cd(II)-bbbi chains linked by auxiliary ita ligands. In the structure of 2, infinite 1-D linear Cd(II)-bbbi chains are linked by fma ligands to generate an undulated 2-D (4,4) network. In 3, an in situ ligand transformation occurred with malate converted to H2fma by dehydration. Thus, a 2-D (4,4) grid network constructed from bbbi and fma was obtained. The carboxylates with different substituents play an important role in the formation of the final frameworks and coordination modes of Cd(II). Thermal stability and luminescent properties of 1-3 were investigated. [ABSTRACT FROM AUTHOR]

Abstract: Four new polymeric frameworks, [Co(bbbi)(L1)] (1), [Cu(bbbi)(L1)] (2), [Co(bbbi)(L2)] (3) and [Ni(bbbi)(L2)] (4), (bbbi=1,1-(1,4-butanediyl)bis-1H-benzimidazole, H2L1=5-nitroisophthalic acid and H2L2=itaconic acid) have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Complexes 1 and 2 are isomorphous, and they can be described as CsCl-type net utilizing bimetal cores as eight-connected nodes, the bridging bbbi ligands and L1 serve as spacers to yield a unique eight-connected net with 42464 topology. Complexes 3 and 4 are isomorphous. It is interesting that 3D frameworks containing meso-helical chains (left- and right helical chains) have been observed in 3 and 4, in which meso-helical chains are alternately linked by bbbi ligands coordinating to Co1(Ni1) cations with the zigzag shaped conformation to generate a 3D binodal (4,4)-connected net with {53·6·82}{52·64} topology structure. The bbbi ligands adopt three conformations, namely, the completely “M” shaped conformation in 1 and 2, the zigzag shaped conformation and “Ω” shaped conformation in 3 and 4. The influence of carboxylate anions with different flexibility on the construction of different network topology in the self-assembly process has been discussed. Moreover, the thermal stabilities and the voltammetric behavior of complexes 1–4 have been reported. [Copyright &y& Elsevier]

In this study, two new Mn(II) complexes consisting of a phenanthroline derivative and organic acid ligands, [Mn(3-PIP)(1,3-bdc)]n (1) and [Mn(3-PIP)2(1,4-bdc)]n (2) (3-PIP = 2-(3-pyridyl)-imidazo[4,5-f] 1,10-phenanthroline, 1,3-H2bdc = benzene-1,3-dicarboxylic acid, 1,4-H2bdc = benzene-1,4-dicarboxylic acid), have been synthesized via hydrothermal reaction and characterized by Fourier transform infrared (FT-IR) spectra, elemental analyses, and single-crystal X-ray diffraction. Complex 1 is a one-dimensional (1-D) twisted double chain bridged by 1,3-bdc. The 3-PIP ligands in a parallel fashion are alternately attached to both sides of the 1-D double chain. Complex 2 exhibits a 1-D zigzag chain, to which pairs of crossed 3-PIP ligands are alternately attached. The two complexes are further extended into three-dimensional (3-D) supramolecular structures by hydrogen-bonding and π-π stacking interactions. The N-donor ligands with an extended π-system play a crucial role in formation and stabilization of the final supramolecular frameworks. Thermal properties of 1 and 2 and fluorescence of 2 are investigated in the solid state. [ABSTRACT FROM AUTHOR]

Three novel MnIII polymers, [Mn(phox)2(N3)J0 (1)n [Mn(Etphox)2(N3)]n (2), and (Mn(Etphox)2(C2N3)]n (3), using achiral ligand Hphox (Hphox = 2-(4,5-dihydrooxazol-2-yl)phenol) and chiral ligand HEtphox (HEtphox = 2-(4-ethyl- 4,5-dihydrooxazol-2-yl)phenol) were synthesized and stwcturally and magnetically characterized. All complexes are of 1 D chain structures and fonn 2D frameworks by weak interactions. The adjacent 1 D chains of complex 1 are connected by face-to-face ar-jr interactions, C-H∙∙∙π interactions, and hydrogen bonding, which leads to the formation of a supramolecular 20 sheet structure. The three compounds show antiferroniagnetic coupling between MnIII ions. And compound 2 is a spin-canted weak ferromagnet with TN = 5.6K, showing metamagnetic behavior with a two-step magnetic phase transition. [ABSTRACT FROM AUTHOR]

Two new coordination polymers [Cd(TIP)(1,3-bdc)]n (1) and {[La(TIP)(1,3-bdc)1.5] · 0.2H2O}n (2) (TIP = 2-(2-thienyl)imidazo[4,5-f]1,10-phenanthroline and 1,3-H2bdc = isophthalic acid) were synthesized from hydrothermal reactions and characterized by elemental analyses, IR, and single-crystal X-ray diffraction. Complexes 1 and 2 are ribbon structures with different configurations bridged by 1,3-bdc ligand, further extended into 3-D supramolecular structures by π-π stacking and hydrogen bonding interactions. The most interesting feature of these two complexes is that TIP with the large π-system and additional hydrogen bonding group plays a crucial role in the formation of different weak interactions. Thermal properties and fluorescence of 1 and 2 are also investigated in the solid state. [ABSTRACT FROM AUTHOR]