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A new series of lanthanide metal complexes [Ln(L)3]n (L = p-methoxybenzoic acid, Ln = Pr 1, Eu 2, Tb 3, Dy 4, Ho 5, Er 6, Yb 7) have been synthesized under hydrothermal conditions. Single-crystal X-ray diffraction measurements reveal that these compounds are isostructural, crystallizing in the monoclinic space group P21/c and giving 1D chain structures. Magnetic studies reveal antiferromagnetic behavior for complexes 1, 3, 5 and 6, ferromagnetic behavior for complex 4 and spin-canting behavior for 7. more...

The dicyanamide-bridged polymers with Schiff-base ligand, [CoNaL(dca)]n (1) and [Mn2L(dca)2]n (2) [H2L = bis(3-methoxysalicylidene)benzene-1,2-diamine, dca = dicyanamide] were synthesized and characterized by elemental analyses, IR spectrroscopy and single-crystal X-ray diffraction. The solid-state structures reveal that polymer 1 has double dca bridged loop-like 1D chains, in which the heterodinuclear Co2+-Na+ units (LCoNa) are bridged by dca with coordination mode μ1,3,5. In polymer 2, homodinuclear Mn2+-Mn2+(LMnMn) units are linked by dca in μ1,5-bridging mode to form 2D planes. Magnetic susceptibility studies on 2 reveals antiferromagnetic coupling interactions between the adjacent Mn2+ ions in the LMnMn unit. more...

Four novel heterometallic tetranuclear 3d–4f complexes M2Dy2L10(phen)2 (M = Co (1), Ni (2), Cu (3) and Zn (4); HL = 4-trifluoromethylbenzoic acid, phen = phenanthroline) have been synthesized hydrothermally and characterized by single crystal X-ray diffraction study, IR, elemental analysis and thermal gravimetric analyses. The structures of 1 and 4 are isostructural and the completely deprotonated L ligands adopt μ2: η1, η1 coordination mode to bridge adjacent metal ions which further connect into 1D chains by hydrogen bonds. The tetranuclears in complex 2 were linked by L ligands with μ2: η1, η2 and μ2: η1, η1 coordinated patterns and spread into 2D layers through hydrogen bonds. In complex 3 L ligands possess the same coordinated styles with 2 and a 3D supramolecular network was fabricated via hydrogen-bonding interactions. Dynamic magnetic susceptibility studies reveal slow magnetic relaxation processes for 1 and 3, suggesting SMM type behavior for these compounds. more...

Three novel lanthanide polymers, [Ln(III)(L)3EtOH]n (Ln = Tb(1), Ho(2), Er(3), HL = 2,3,5-trichlorobenzoic acid), have been solvothermal synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy and element analyses. The three polymers crystallize in triclinic space group P-1. The Ln(III) ions are in turn bridged by double and quadruple carboxylate of L− ligands to form one-dimensional (1D) chains. Magnetic studies reveal that polymer 1 demonstrates dominant ferromagnetic behavior, polymer 2 shows antiferromagnetic behavior, and polymer 3 present spin-canting behavior. more...

Two new Zn(II) complexes, namely, [Zn2(BTEC)0.5(ATZ)2(H2O)3]·H2O (1) and [Zn1.5(2,5-PYDC)(ATZ)(H2O)]2 (2) have been assembled from 5-amino-1-H-tetrazole (HATZ) with two aromatic polycarboxylate ligands under hydrothermal conditions (H4BTEC = 1,2,4,5-benzenetetracarboxylic acid, 2,5-PYDC = 2,5-pyridinedicarboxylic acid). Single crystal X-ray analysis reveals that both complexes display three-dimensional (3D) structures. Complex 1 is a binodal (4,4)-connected bbf net with a (64·82)(66)2 topological symbol. Complex 2 displays a trinodal (3,3,4)-connected net with (4·102)2(102·12)2(42·102·122) topology. In the two structures, all the HATZ ligands are deprotonated and act as the anions, and the ATZ− anions all connected two Zn(II) centers with a μ2-mode. In addition, the two complexes display photoluminescence at 442 nm (λex = 342 nm) and 468 nm (λex = 374 nm), respectively. And their thermal stability has also been studied. more...

The 3,5-dichlorobenzoate anion, L–, serves as a bridging ligand and 2,2′-bipyridine, bipy, as a terminal bidentate ligand to yield, through hydrothermal syntheses, the tetranuclear clusters Dy2Co2L10(bipy)2, 1, and Ln2Ni2L10(bipy)2, where Ln is the trivalent La, 2, Gd, 3, Tb, 4, Dy, 5, or Ho, 6, ion. Single-crystal X-ray diffraction reveals that the six complexes are all isomorphous with the monoclinic P21/c space group and with lattice parameters that decrease with the lanthanide contraction. The two cobalt(II) or nickel(II) and two Ln(III) cations are linked by the 10 L– anions to generate Dy2Co2 or Ln2Ni2 3d–4f cationic heteronuclear clusters with a slightly bent Co···Dy···Dy···Co or Ni···Ln···Ln···Ni arrangement. Direct current magnetic susceptibility studies reveal that the complexes are essentially paramagnetic, with room-temperature χMT values close to the expected values for two cobalt(II) or nickel(II) and two Ln(III) cations. The temperature dependence of χMT for 1 and 5 is well reproduced by ab... more...

Two novel lanthanide complexes, [Nd2(L)6(bipy)(H2O)]n (1) and [Sm2(L)6(bipy)(H2O)]n (2) (HL = 3,5-bis(trifluoromethyl)benzoic acid, bipy = 2,2′-bipyridine), have been solvothermal synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy, element analyses and powder X-ray diffraction. Single-crystal X-ray diffraction measurements reveal that the crystal structures are isostructural, crystallizing in the orthorhombic space group P-1 and they consist of linear tetrameric Ln4 units which are connected through carboxylate of L ligands into a one-dimensional (1D) zigzag chain and spread into 2D supramolecular (4,4) sql net. Furthermore, magnetic studies reveal antiferromagnetic behavior for complex 1. The luminescent properties of 2 were also studied. more...

The solvothermal reactions of 3,5-bis(trifluoromethyl)benzoic acid (HL) and 2,2′-bipyridine (bipy) with the corresponding metal salts afforded two novel 3d–4f tetranuclear complexes M2Dy2(L)10(bipy)2 (M = Mn 1, Cu 2), which have been characterized by single-crystal X-ray diffraction, infrared spectroscopy, element analyses, powder X-ray diffraction and thermal gravimetric analyses. Complexes 1 crystallizes in the triclinic space group P-1, and the completely deprotonated L ligands possess μ2: η1, η1 and μ2: η2, η1 coordination modes to bridge adjacent metal ions which further connect into 2D layers by hydrogen bonds. Complex 2 crystallizes in the distinct monoclinic space group P21/c, and adjacent metal ions were linked by L ligands with the same coordinated patterns with 1, and supramolecular sheets were formed in the ab plane. Dynamic magnetic susceptibility studies reveal slow magnetic relaxation processes for 2, suggesting SMM type behavior. more...

The hydrothermal reactions of D(+)-camphoric acid (D-H2Cam) and 1,10-phenanthroline (phen)/2,2′-bipyridine (2,2′-bipy) with the corresponding metal salts gave rise to eleven chiral 3d–4f heterometallic metal-organic frameworks (MOFs). Single-crystal X-ray diffraction measurements reveal that the crystal structures are isostructural, crystallizing in the orthorhombic space group P212121 and they exhibit unique three-dimensional chiral 6-connected frameworks involving 1D zigzag chains aligned parallel to the a axis and the 2D wave-like lanthanide layers, with the Schlafli symbol (49 · 66). Moreover, we have systematically investigated the magnetic behaviors of partial compounds. more...

Two novel lanthanide complexes, [La3(L)8(phen)(OH)(H2O)]n (1) and [Dy(L)3(EtOH)]n (2) (HL = 3,5-dichlorobenzoic acid, phen = phenanthroline), have been solvothermal synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy, element analyses, powder X-ray diffraction and thermal gravimetric analyses. Complex 1 affords one-dimensional chains with hexanuclear La6 units which are peculiar in the coordination chemistry of La(III) and extended into a 3D supramolecular network via π–π stacking and hydrogen-bonding interactions. Whereas complex 2 gives 1D Dy chains, which are in turn bridged by double and quadruple carboxylate of L ligands and construct a 2D layer by weak hydrogen bonds. In addition, magnetic studies reveal antiferromagnetic behavior for complex 2. more...

Two new isostructural complexes, [Mn3(L)6(bipy)2] (1) and [Co3(L)6(bipy)2] (2) (L = 2,4-dichlorobenzoate, bipy = 2, 2′-bipyridine) were synthesized under the hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectroscopy, EA (elemental analysis), and magnetic measurements. The two complexes are found to contain a trinuclear (M3) unit that opens up a possibility of being magnetic materials. The magnetic measurements reveal that 1 exhibits the antiferromagnetic exchange interaction between metal ions and 2 presents a weak ferromagnetic interactions between the CoII ions. more...

Three new 3D transition metal coordination complexes, namely, [Co(Aze)(L)] ( 1 ), [Cu(Aze)(L)] 2 ( 2 ) and [Cd(Aze)(L)]·3H 2 O ( 3 ) (Aze = azelaic acid, L = 1,4-bis (1-imidazolyl)-benzene) have been synthesized hydrothermally from the self-assembly of the transition metal ions (M 2 + ) with flexible aliphatic dicarboxylate ligand (Aze) and the rigid bis(imidazole) ligand (L). All complexes display three-dimensional (3D) structures. Complex 1 shows a three-fold interpenetrating 4-connected dmp net. Complex 2 shows a noninterpenetrating 4-connected cds net. Complex 3 shows the pcu net built on 6-connected Cd 2 units and particularly there exists weave-like water chains penetrating the channels of the pcu net along b direction. Furthermore, thermogravimetric studies of 1 , 2 and 3 , and photoluminescent property of 3 have also been investigated. more...

The hydrothermal reaction of NiCl2·6H2O, azelaic acid (H2aze), and 1,4-bis(1-imidazolyl)benzene (L) has afforded a new 3D polynuclear nickel complex, {[Ni5(aze)3(H2aze)0.5(μ3-OH)2(L)4][Ni(aze)(L)(H2O)2]2Cl2}·4H2O (1). The cationic [Ni5(aze)3(H2aze)0.5(μ3-OH)2(L)4]2+ forms the 3D host-framework, representing as an α-Po net, and neutral [Ni(aze)(L)(H2O)2] displays as left- and right-handed chiral helical chains and acts as guest, penetrating the 1D channels of the host-framework alternately along the b direction. Magnetic studies reveal spin-canting behavior for complex 1. more...

Two chiral complexes, [Cu(L1)(L2)H2O]·3H2O (1) and [Ni(L1)(SCN)(H2O)2]·2H2O (2) (HL1 = L-histidine, HL2 = L-alanine), have been synthesized through slow evaporation of solvent and characterized by single-crystal X-ray diffraction, IR, powder X-ray diffraction, element analysis and circular dichroism measurements. Complexes 1 and 2 crystallize in the monoclinic system with chiral space group P21, respectively. Interestingly, magnetic and ferroelectric studies reveal that complexes 1 and 2 demonstrate ferromagnetic and ferroelectric properties. more...

A novel chiral cyanide-bridged Pr(III)-Cr(III) bimetallic complex, [Pr(DMSO)4(H2O)3Cr(CN)6] (1) (DMSO = dimethylsulfoxide) has been prepared and characterized by single-crystal X-ray diffraction, IR, elemental analysis and solid-state CD spectra. Complex 1 crystallizes in the monoclinic with chiral space group P21 and displays as a dinuclear molecule. The solid-state CD spectra confirm the chiral nature of complex 1. Magnetic studies indicate ferromagnetic interactions between Pr(III) and Cr(III) ions. Ferroelectric measurements reveal that complex 1 exhibits ferroelectric features representing electric hysteresis loops at room temperature with remanent polarizations of 0.111 μC/cm2 and coercive electric fields of 4.13 kV/cm. more...

Two Co(II) complexes, [Co(bimb)(L-1)(2)] (1) and [Co(bix)(L-2)] (2) (bimb =1,4-bis(imidazol-1-yl)-butane, bix = 1,4-bis(imidazol-1-yl-methylene)-benzene, HL1 = 3,5-dinitro-benzoic acid, H2L2 = o-phthalic acid), have been successfully prepared based on achiral flexible bis(imidazole) ligands via spontaneous resolution. Complexes 1 and 2 crystallize in the asymmetrical monoclinic with P2(1) and Cc space groups, respectively. Interestingly, magnetic studies reveal that complex 1 demonstrates dominant ferromagnetic behavior and complex 2 displays spin-canting behavior. More interestingly, both complexes 1 and 2 exhibit ferroelectric features representing electric hysteresis loops with the saturation polarization (P-s) of ca. 0.085 mu C cm(-2) and 0.141 mu C cm(-2). (C) 2012 Elsevier B.V. All rights reserved. more...

Two new MOFs, [Mn(HBTC)(2-PyBim)(H2O)] (1) and [Zn2(BTC)(OH)(2-PyBim)] (2) (H3BTC = 1,3,5-benzenetricarboxylic acid, 2-PyBim = 2-(2-pyridyl)benzimidazole), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction (XRD), infrared spectroscopy (IR), elemental analysis (EA). In 1, adjacent two Mn(II) ions are connected into binuclear Mn2 units which are bridged by HBTC2− anions to generate a two-dimensional (2D) (4,4) network. In 2, the Zn(II) ions are connected into tetranuclear Zn4 units which are bridged by the BTC3− anions to generate a 2D (3,6)-connected non-interpenetrating CdI2-type network with (43)2(46 · 66 · 83) topology symbol. Both 1 and 2 are extended into 3D supramolecular structure by hydrogen bonds and π⋯π interactions. Magnetic studies of 1 indicate that it exhibits ferromagnetic coupling between the binuclear Mn(II) ions, polymer 2 was found to exhibit photoluminescence at about 437 nm (λex = 365 nm). more...

Three new complexes, namely, [M(Pim)(L)] (M = Co ( 1 ), Cd ( 2 ), Pim = Pimelic acid, L = 1,4-bis(1-imidazolyl)-benzene), [Zn(Pim)(L)]·H 2 O ( 3 ), have been synthesized hydrothermally from the self-assembly of the transtion metal ions (M 2 + ) with flexible aliphatic dicarboxylate ligand (Pim) and the rigid bis(imidazole) ligand(L). Both complexes 1 and 2 consist of left- and right-handed single-helical chains and present a two-dimensional (2D) layer with 3 6 - hxl topology. Complex 3 displays a 2D structure constructed by right-handed single-helical chains and left-handed double-helical chains with intercrossed arrangement. Furthermore, thermogravimetric analyses for 1 – 3 and the photoluminescent properties of 2 and 3 have also been studied. more...

A novel chiral copper-based complex constructed from chiral ligand, namely [Cu(L)(H2O)]·H2O (1) (L = (S)-3-phenyl-2-(pyrazine-2-carboxamido) propanoic acid). Complex 1 was prepared through solvothermal reactions and characterized by single-crystal X-ray diffraction. Complex 1 crystallizes in the tetragonal system with non-centrosymmetric polar space group P43 and affords one-dimensional (1D) chiral helical chain. Ferroelectric and magnetic studies reveal that 1 shows both ferroelectric and weak ferromagnetic properties. more...

The hydrothermal reaction of CdCl2·2.5H2O with 3,5-bis-oxyacetate-benzoic acid (H3BOABA) and 4,4′-bis(1-imidazolyl)biphenyl (L) generates a new three-dimensional (3D) coordination polymer, {[Cd2(BOABA)(L)(μ3-OH)]2·3H2O}n (1). In 1, the Cd(II) centers are connected by carboxylate and μ3-OH bridges into Cd-O-C rod-like secondary building units (SBUs) which are further linked by BOABA3 − and L ligands into the 3D framework. Two types of irregular rhombic channels occupied by free water molecules were observed in the framework. And the topology analysis suggests an unusual (4,8)-connected net for 1. Furthermore, the thermal and photoluminescent properties of 1 have also been studied. more...

Two new coordination complexes, {[Co3(nip)2(ina)2(H2O)2]·4H2O}n (1) and {[Mn3(nip)2(ina)2]}n (2) (nip = 5-nitroisophthalic acid, ina = isonicotinic acid), have been hydrothermally synthesized from mixed rigid ligands. Complex 1 consists of linear trimeric Co3 units which are connected through double bridges into a two-dimensional (2D) (4,4) sql net. While for complex 2, the metal Mn centers are connected into infinite {⋯Mn2⋯Mn2⋯Mn1⋯}n chains which are bridged by nip and ina ligands into a 3D structure with pcu topology. Magnetic properties of the two complexes have also been studied, complex 1 displays ferromagnetic interaction between intracluster Co(II) ions, and complex 2 shows antiferromagnetic behavior. more...

A 3D coordination polymer [Cd3(btrc)2(L1)2]n (1) [H3btrc = 1, 2, 4-benzenetricarboxylic acid; L1 = 1, 4-bis(1-imidazolyl)butane] was synthesized under hydrothermal conditions. Single crystal X-ray diffraction study revealed that polymer 1 presents an unusual example of a trinodal (4, 6)-connected net with (44·62)(44·610·8) fsc topology. In addition, this polymer was investigated by IR and luminescence spectroscopy, as well as thermogravimetric analyses. more...

Two novel metal–organic frameworks of [M3(ptz)2(N3)4(H2O)2] (M = Zn(1), Cd(2)) (ptz = 5-(4-pyridyl)tetrazolate) have been prepared hydro(solvo)thermally by reactions of 4-cyanopyridine and excess NaN3 in the presence of zinc and cadmium chloride, respectively. The overall structure motif of complexes 1 and 2 show pillared layered frameworks and feature an unprecedented 3-nodal network with (3,5,6)-connectivity. The layer is of particular interest as it is constructed by μ1,1–N3− and μ1,1,3–N3− bridging modes, simultaneously. Furthermore, the solid fluorescent properties and TGA were studied. more...

Two novel complexes, [Co3(N3)2(bca)4(phen)2] (1, bca = benzenecarboxylic acid, phen = 1,10-Phenanthroline) and [Co3(N3)2(bdc)2(phen)2]n (2, bdc = terephthalic acid), have been synthesized hydrothermally and characterized by single crystal X-ray diffraction (XRD), infrared spectra (IR) and element analysis (EA). Complex 1 features unprecedented discrete linear Co3 clusters that formed by mixed (μ-EO-N3)(μ-COO)2 (EO = end-on) triple bridges whereas 2 presents an extended (2D) network based on the similar trinuclear units as 1. Magnetic studies of 1 and 2 reveal that the mixed (μ-EO-N3)(μ-COO)2 triple bridges transmit ferromagnetic behavior. more...

Two new LaIII–MgII heterometallic polymers, {[La2(oda)6Mg2][Mg(H2O)6]·6H2O}n (1) and {[La2(pda)6Mg3(H2O)6]·11H2O}n (2) (H2oda = oxydiacetic acid, H2pda = pyridine-2,6-dicarboxylic acid), have been synthesized under solvothermal conditions. Structural analysis reveals that 1 contains two types of 3D cavities, one of which is occupied by [Mg(H2O)6]2+ units, and the other is occupied by free water molecules. The metal-only structure of 2 is a hexagonal network, in which the cavities are occupied by free water molecules. The adsorption properties of 1 and 2 have been investigated. The hydrogen adsorption and desorption curves of the two polymers show an unusual, pronounced hysteresis behavior. more...

A novel coordination polymer [Zn3(btrc)2(L1)]n (1) (H3btrc = 1, 2, 4-benzenetricarboxylic acid; L1 = 1, 3-bis(4-pyridyl)propane) has been synthesized under hydrothermal conditions. Single crystal X-ray diffraction study reveals that polymer 1 presents an unusual example of (3, 6, 10)-connected net with (4·6·7) (52·66·77) (416·512·64·713) topology symbol, where btrc3−, Zn2(CO2)4, and Zn4(CO2)8 units act as three-, six-, and ten-connecting nodes, respectively. In addition, the IR spectra, luminescence properties and thermogravimetric analysis of this polymer are investigated in this study. more...

Three novel metal-organic polymers, namely, [Ni(L 1 ) 0.5 (3,5-pdc)(μ-H 2 O)]·H 2 O (1), [Co(L 2 )(3,5-pdc)]·2H 2 O (2), and [Co(L 3 )(3,5-pdc)(μ-H 2 O)]·H 2 O (3) [3,5-pdc = pyridine-3,5-dicarboxylate, L 1 = 1,4-bis(imidazol-1-ylmethyl)benzene, L 2 = 1,1'-(1,4-butanediyl)bis(imidazole), and L 3 = 1,1'-(1,4-hexanediyl)bis(imidazole)], have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction (XRD), thermogravimetric (TG) analysis, and elemental analysis (EA). Polymers 1 and 2 have the identical 2D [M(3,5-pdc)] sheet skeleton, however, different bis(imidazole) ligands cause 1 to have a 2D (3,4)-connected double-layer net featuring the (6 3 )(6 4 ·8 2 ) topology symbol and 2 to have a 2D (3,5)-connected net characterized by the (3 5 2 ) (3 2 ·5 3 ·6 4 ·7) topology symbol. They are both extended to 3D supramolecular frameworks through the O-H···O hydrogen bonds. In particular, in 2 there exists a four-membered Z-shape water cluster. The Co ions in 3 are connected by 3,5-pdc and L 3 to give rise to a complicated 3D framework that can be described as a (3,5)-connected (4 2 ·5)(4 2 ·6 3 ·8 2 ·10 2 ·12) network. In addition, the thermal analysis of these three complexes has been measured and discussed. more...

In this paper we report three new metal-organic frameworks (MOFs), [Zn(oba)(L1) 0.5 (H 2 O)] n (1), [Zn 2 (oba) 2 (L2) 2 ](H 2 O) 3 (2) and (Co(oba)(L1)] n (3) [oba = 4,4'-oxybis(benzoate), L1 = 1,4-bis(imidazol-1-ylmethyl)benzene, L2 = 1,4-bis(imidazol-1-yl)benzene] that have been obtained under hydrothermal conditions and characterized by single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and elemental analysis (EA). A structural investigation revealed that all three coordination compounds present polycatenation features. Interestingly, 1 shows a rare 1D → 2D structure formed by the catenation of 1D ladders. Both 2 and 3, however, are unusual cases that have 3D frameworks constructed from 2D 4 4 -sql layers by parallel polycatenation. The photoluminescence properties of 1 and 2 have also been investigated. more...

Four entangled polymers, namely, [Ni(bpea)(L1)(H2O)]n (1), [Ni(bpea)(L2)]n (2), {[Ni(bpea)(L3)1.5(H2O)]·(L3)}n (3), and [Co(bpea)(L3)]n (4) (H2bpea = biphenylethene-4′,4-dicarboxylic acid, L1 = 1,3-di(4-pyridyl)propane, L2 = 1,4-bis(imidazol-1-yl-methylene)benzene, L3 = 1,4-bis(1-imidazolyl)benzene) have been synthesized by a hydrothermal reaction. Complex 1 has a 2-fold (4,4)-net parallel interpenetrating structure, while complex 2 shows three-dimensional (3D) structure with 2-fold (4,4)-net inclined polycatenation. Complex 3 displays 3-fold interpenetrated 3D structure, which is the first example of an interpenetrated structure of 4466-sqp topology. Complex 4 is a 3D structure with a 3-fold interpenetrated α-Po topology. Our results imply that the self-assembly of long multicarboxylate and long heterocyclic aromatic ligands with metal ions is a facile assay to produce various interpenetrated metal−organic frameworks. Furthermore, their thermal properties were studied by thermogravimetric analysis. The m... more...

Two coordination polymers, [CoIICuI(m-BDC)(BIPY)1.5(m-NBZ)]n (1) and [CoII4(BPTC)2(BBI)4]n (2), (where BIPY = 4,4′-bipyridine, BBI = 1,1′-(1,4-butanediyl)bis(imidazole), m-BDC = 1,3-benzenedicarboxylate, m-HNBZ = m-nitrobenzoic acid and H4BPTC = 3,3′,4,4′-biphenyltetracarboxylic acid), have been obtained under solvo/hydrothermal conditions, which were characterized by single-crystal X-ray diffraction, XRPD, IR, ICP, TGA, and elemental analysis. Both 1 and 2 feature two unusual binodal self-penetrated architectures: 1 presents a 2-D network with (4·62)2(42·62·82) topology in terms of the rationalization of T-shaped CuI and Co2 unit as 3- and 4-connected node, respectively; however, compound 2 built up from a flexible long-chain ligand and a polycarboxylate confers a 3-D (62·84)(64·82)2 net based on the definition of square-planar and tetrahedral 4-connected nodes. The magnetic study of 1 was carried out in the temperature range of 5–300 K, showing antiferromagnetic coupling interaction within the dimeric Co2 unit. In addition, 1 was found to exhibit fluorescence at about 420 nm (λex = 330 nm). more...

The paper presents three interesting entanglement systems, including two polyrotaxane-like and one interpenetrating frameworks, namely, [Co(L1)(bpdc)] (1), [Co(L2)(bpdc)] (2), and [Co(L3)1.5(bpdc)(H2O)]·(L3) (3), constructed from biphenyl-4,4′-dicarboxylate and bis(imidazole) ligands (L1 = 1,6-bis(imidazol-1-yl)-hexane, and rods that are interlaced in a parallel fashion to result in 2D → 2D polyrotaxane-like motifs (L2 = 1,4-bis(imidazol-1-ylmethyl)benzene and L3 = 1,4-bis(1-imidazolyl)-benzene)). Both compounds 1 and 2 contain loops. Compound 3 represents the first example of a triply interpenetrated 5-connected 4466 topology network. more...

Two cyano-bridged cadmium(II) and copper(II)–copper(I) mixed-valence polymer compounds [ Cu II ( en ) 2 ] { [ Cu II ( en ) 2 ] 2 - μ - ( CN ) 4 - [ Cd 3 Cu 6 I ( CN ) 14 ] } 1 and [Cu II (en) 2 ] 0.5 [CdCu I (CN) 3 ] · Cl · H 2 O 2 (en = 1,2-ethanediamine) through systematically varying the solution environment have been synthesized and structurally characterized by single crystal X-ray diffraction analysis. The cyano anions connected the copper and cadmium centres with bidentate or tridentate bridging modes resulting in two complicated 3D networks for 1 and 2 . Compound 1 has a rare 5,6-connected network, while compound 2 can be reduced to a 6-connected α-Po net. The magnetic and thermal properties of 1 and 2 are also studied. more...

Three unprecedented entangled systems are successfully obtained. Compounds 1 and 2 are self-penetrating networks with intracatenated [M2bimh2] loops and two-dimensional [M2(bptc)] sheets ((H4bptc = biphenyl-3,3′,4,4′-tetracarboxylic acid, bimh = 1,6-bis(imidazol-1-yl)-hexane), while compound 3 is a three-dimensional self-penetrating network which results from the hydrothermal in situ formation of a new tetradentate ligand, 1,2,4,5-tetra(4-pyridyl)benzene, through dehydrogenative coupling of 1,3-bis(4-pyridyl)propane molecules. more...

A couple of metal-organic frameworks (MOFs) constructed from rigid bicarboxylates are presented herein, namely, Co3(ndc)3(bbi)(CH3CN)2 (1) and Dy2Mn3(ndc)6(bipy)2 (2), where H2ndc = 2,6-naphthalenedicarboxylic acid, bipy = 2,2′-pyridine, and bbi = 1,1′-(1,4-butanediyl)bis(imidazole). These two coordination polymers have been prepared through solvo/hydrothermal reactions and characterized by single-crystal X-ray study, TG, IR, and elemental analysis. Polymer 1 features a novel self-penetrating network mediated by flexible long-chain ligand and well defines a unique 416·58·64 topology with the treatment of Co3 unit as an 8-connected node, which equals the highest connectivity for monometallic self-penetrating system so far. Polymer 2 represents the first example of a MnII−DyIII (3d-4f) heteropentanuclear complex showing an intriguing 3-D 36·418·53·6 framework upon the assignment of Dy2Mn3 cluster to an 8-connected node. In addition, magnetic studies of 1 reveal that the antiferromagnetic behavior is operati... more...

[(CH3)2NH2]2[Co6(μ3-OH)2(μ-H2O)(ip)6]·2.5H2O (1), where ip2− is the 1,3-benzenedicarboxylate dianion, has been prepared by the solvothermal self-assembly of CoCl2 and H2ip in N,N′-dimethylformamide. Complex 1 contains a rare Co6(μ3-OH)2(μ-H2O)(CO2)12 building block with six crystallographically distinct cobalt(II) ions, one with a trigonal bipyramidal, two with a pseudotetrahedral, and three with a pseudooctahedral coordination environment; the bridging ip2− dianions serve as spacers to yield a unique anionic eight-connected net with 36418536 topology. The magnetic properties of 1 indicate that the six cobalt(II) ions are paramagnetic with, at most, very weak intramolecular antiferromagnetic exchange coupling. more...

Via solvothermal synthesis, the self-assembly of CuCl2, 1,4-benzenedicarboxylic acid, and N,N′-bis(4-pyridylformamide)-1,4-benzene in DMF generated a layer-pillared metal-organic coordination polymer, which affords two-fold interpenetration and considerable solvent-accessible channels where the guest water molecules reside. Further, the TG and XRD researches disclose that such interpenetrating net stabilized by H-bonds can be maintained up to 350 °C even after the release of free water molecules, and through the calcination and immersion experiments, it is suggested that the guest water molecules in the channels are reversible, which is traced by XRD and IR studies. more...

One-pot solvothermal self-assembly is employed to prepare a series of Co3 based porous coordination polymers, viz. 1, [H2N(CH3)2]2[Co3(ip)4]·H2O, 2, [H2N(CH3)2]2[Co3(bdc)4]·(DMF)2, 3, [H2N(CH3)2]2[Co3(bpdc)4]·(CH3OH)2(DMF)1.5, where ip, bdc, bpdc, and DMF are 1,3-benzenedicarboxylate, 1,4-benzenedicarboxylate, 4,4′-biphenyldicarboxylate, and N,N′-dimethylformamide, respectively. Via different organic connectors such as ip, bdc, and bpdc, such Co3 molecular building blocks (MBB), [Co3(CO2)8]2−, are associated together to give a tunable 8-connected topological framework, viz. 42464 for 1, 36414576 for 2, and 36418536 for 3. Upon the geometry and the length of organic connectors, their corresponding porosity occupied by c counterions plus solvent molecules also can be tunable, for example, with the consideration of [H2N(CH3)2]+ counterions, the solvent-accessible volume is 460.2 A3 for 1, equal to 23.9% of the cell volume, 3320.4 A3 for 2, equal to 56.3% of the cell volume, 4107.2 A3 for 3, equal to 50% of t... more...

Two pairs of Cd(II)-5-aminotetrazolate coordination complexes, {[Cd(5-HATZ)2(H2O)2(μ2-SO4)]·H2O}n (1a) and [Cd5(5-ATZ)4(μ3-OH)2(μ5-SO4)2]n (1b), [Cd(5-HATZ)2(μ2-Cl)2]n (2a), and [Cd3(5-ATZ)4(MeCN)2(μ2-Cl)2]n (2b), have been synthesized and structurally characterized. At room temperature 1D single-bridged and double-bridged chain-like compounds 1a and 2a were isolated by solution evaporation method. Under hydrothermal synthesis at 180 °C, two three-dimensional coordination polymers 1b and 2b were isolated from compounds 1a and 2a, respectively. 1b is constructed by 3D [Cd5(μ5-SO4)2(μ3-OH)2]n4+ network templated by 5-ATZ anions. 2b exhibits the 3D metal-organic framework with a (8.122)(844.122)(42.124) topology. 5-Aminotetrazolate is a terminal ligand in 1a and 2a, whereas it is three-coordinated and/or four-coordinated in 1b and 2b. Thermal studies show that high-dimensional structures have higher thermal stability than that of 1D structures. more...

A new long flexible ligand, 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) (L), has been prepared. The hydrothermal reactions of L with various metal ions (M(II) = Cu(II), Cd(II) and Ni(II)) yielded three new coordination compounds consisting of 0D, 1D and 2D structures. Compound 1 is a dinuclear M2L2 metallocycle. Compound 2 is a double-stranded chain running along b axis direction. Compound 3 affords highly undulated 2D (4, 4) layers. In addition, complex 2 exhibits strong blue photoluminescence. more...

Via hydrothermal synthesis, the self-assembly of CuCl 2 · 2H 2 O, NaN 3 , and 2,2′-bpy generated a new azide complex, namely [Cu 2 (2,2′-bpy)(N 3 ) 3 ] n 1 (2,2′-bpy = 2,2′-bipyridyl). In this reaction, the original Cu(II) ions are partly deoxidized to be Cu(I) by 2,2′-bpy and N 3 - ligands, and the Cu(I) ions are associated together by N 3 - ions to give the infinitely helical chain of {Cu(N 3 )} n . Afterwards, these chains are connected by the [Cu(2,2′-bpy)(N 3 ) 2 ] 2 fragments to furnish the 2D honeycomb-type net, where the Cu(I) ions act as 3-connected nodes and the Cu(II) ions locate on the edge. The magnetic measurement suggests the antiferromagnetic interaction of the dinuclear copper fragment mediated by EO azido bridges, which is consisted with the fitting results upon a dinuclear copper mode. more...

This paper presents four interesting entanglement systems, including one self-penetrating and three interpenetrating frameworks, namely, [Ni3(L)3(BTC)2·2H2O]·6H2O (1), [Mn(L)(HBTC)] (2), [Ni2(L)2(BDC)2·2H2O]·H2O (3), and [Mn4(L)4(BDC)4]·H2O (4) (H3BTC = 1,3,5-benzenetricarboxylic acid and H2BDC = 1,4-benzenedicarboxylic acid), based on a rigid 1,4-bis(1-imidazolyl)benzene (L) ligand. Compound 1 is the first example of a (3,4)-connected self-penetrating three-dimensional (3D) polymer containing two types of catenated rings with the unprecedented (6·82)2(62·84)2(64·82) topology. Compound 3 has self-assembled into a 5-fold interpenetrating 3D structure with diamond nets, while both compounds 2 and 4 display 2-fold interpenetrating 3D structures with α-Po structural topology. more...

Under hydrothermal conditions, in the presence of H2BDC, the self-assembly of CdCl2, H2ip or H2NDC at pH = 7 generated two Cd(II)-containing coordination polymers, Cd6(ip)6(μ-H2O)4·H2O (1) and Cd2(NDC)2(μ-H2O)2 (2) (H2BDC/H2ip/H2NDC = 1,4/1,3/1,2-benzenedicarboxylic acid). The structures are 2D metal-organic frameworks constructed from Cd-O-C rod-shaped SBUs (Secondary Building Units). Crystal samples in the solid state display strong fluorescence at 335 and 343 nm. more...

This paper reports eight novel one-dimensional (1D) helical chain polymers consisting of metal salts and flexible bis(imidazole) ligands, formulated as [Co(L1)2(bimb)] (1), [Cu2(bimb)2Cl2] (2), [Co(L2)2(bimb)] (3), [Co(L3)(bix)Cl] (4), [Co(L4)2(bix)] (5), [Co(L5)2(bimb)] (6), [Ni(L6)2(bimb)] (7), and [Ni(L7)2(bimb)] (8) (bimb = 1,4-bis(imidazol-1-yl)-butane, bix = 1,4-bis(imidazol-1-yl-methylene)-benzene, HL1 = 3,5-dinitrobenzoic acid, HL2 = 4-methoxylbenzoic acid, HL3 = benzoic acid, HL4 = 4-methylbenzoic acid, HL5 = 3-nitrobenzoic acid, HL6 = 4-nitrobenzoic acid and HL7 = 4-chlorobenzoic acid), which have been obtained via hydrothermal reaction and characterized by single-crystal X-ray diffraction, elemental analysis, IR and thermogravimetric analyses. 1 consists of chiral polymer chains assembled from achiral components due to the presence of left-handed helices. 2 is a very unusual racemic compound based on perpendicular left- and right-handed helical chains. 3 contains two distinct types of helical c... more...

The first coordination chemistry of a multidentate ligand benzimidazole-5,6-dicarboxylic acid (H2L) was investigated, and six novel two-dimensional (2D) coordination polymers based on this ligand, namely, [MnL]n (1), {[Ni2L2(H2O)4]·3H2O}n (2), {[Tb(L)(HL)(H2O)]·H2O}n (3) and {[Ln2L2(HL)2(H2O)2]}n (Ln = Ho (4), Er (5), Lu (6)), were synthesized under hydrothermal conditions. Compund 1 shows a novel coordination network with 4462 topology and contains unusual five-coordinated one-dimensional {Mn−O}n chains along the b-axis. Compound 2 is a 2D layer structure of 4.82 topology in the ab plane and displays a three-dimensional (3D) supramolecular network via multiple intermolecular hydrogen bonds. Compound 3 also shows a 4462 topology, but its coordination network is completely different from compound 1. Compounds 4−6 were isostructural, and each Ln (Ln = Ho (4), Er (5), Lu (6)) center in the framework acts as a five-connected node to give rise to a unique network with a (3.4.6)(32.4.5.62.74) topology in the ab... more...

An unusual (H2O)16 cluster in a compound of {[Co(C7H3N2O6)2(H2O)4] · 4H2O}2 1 (where C7H3N2O6 = 3,5-dinitrobenzoic acid (DNB)) has been synthesized and characterized by single-crystal X-ray diffraction, thermogravimetry, infrared spectra, and elemental analysis. The (H2O)16 cluster consists of a decameric water cluster and six water molecules, and plays an important role in stabilizing the structure in 1. We believe that the water structure demonstrated herein brings to light yet another novel mode of the cooperative association of the water molecules, and this discovery is helpful in improving the modeling of some of the unexplained properties of water, and understanding better the structure and behavior of hexadecameric water cluster. more...

In this work, we report two 3,8-connected nets. The first one is polymers 1−3, La(pydc)(L)0.5(µ-H2O) (pydc = pyridine-2,5-carboxylate, H2L = adipic acid), which are isostructural and described by the (4·5·6)2(42·56·616·72·82) topology notation, and the other one is polymer 4, Co3(1,4-BDC)(1,2-BDC)2(µ2-H2O)2(µ-H2O)2 (1,4-BDC = 1,4-benzenedicarboxylate, 1,2-BDC = 1,2-benzenedicarboxylate), characterized by the tfz-d net with the (43)2(46·618·84) topology symbol. Comparing with the reported 3,8-connected nets, the present examples show several unique properties: (a) the La2- and Co3-based MBBs are unprecedented; (b) two different multicarboxylate ligands are employed to construct such nets; (c) the 3D matrix of polymers 1−3 is unique and unprecedented. more...