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In this study, a new dinuclear cobalt(II)–radical complex [Co2(3,5-DBSQ)4(bpym)]·(3,5-DBCatH2)4 (1) (3,5-DBSQ = 3,5-di-tert-butylsemiquinone, 3,5-DBCatH2 = 3,5-di-tert-butylcatecholato, bpym = 2,2′-bipyrimidine) was synthesized and characterized using single-crystal X-ray crystallography. Simulated results indicated relatively strong antiferromagnetic exchange coupling between cobalt(II) centers and semiquinone radical ligands. [ABSTRACT FROM AUTHOR]

The four copper(II) complexes involving ethylenediamine- N , N -diacetic acid (H 2 edda) and ethylenediamine (en), viz. [Cu(edda)(en)] H 2 O 1 , [Cu(en)Cl 2 ] 2 , [Cu(edda)] 3 and [Cu 2 (Hedda) 2 Cl 2 ] 4 , were synthesized and characterized by various physical means. The crystal structures of 1 and 4 established them as mononuclear and dichlorido-bridged dicopper(II) complexes respectively. Complexes 1 and 4 showed weak and strong antiferromagnetic Cu…Cu interaction. Dynamic light scattering data of 3 suggested it to be a 3-dimensional coordination polymer in aqueous solution, gel and solid forms. The copper(II) species of 1–4 in aqueous solution were analysed by UV–visible and molar conductivity data. The weak hydroxyl radical-inducing property of free copper(II) ions in solution was enhanced by the chelation of both types of ligands. However, chelation of each or both of these ligands reduce the strong proteasome inhibitory property of the copper(II). All complexes inhibited the three proteolytic sites of the 20S proteasome, with the Trypsin-like site been mostly selectively inhibited. [ABSTRACT FROM AUTHOR]

Spin doctor: A mononuclear ferric complex [Fe(H‐5‐Br‐thsa)(5‐Br‐thsa)]⋅H2O (1) (H2‐5‐Br‐thsa=5‐bromo‐2‐hydroxybenzylidene)hydrazinecarbothioamide) was synthesized and its magnetic properties and structure were investigated by DFT calculations. This complex shows unprecedented reversible, six/five‐step spin‐crossover behavior accompanied by symmetry breaking. More importantly, each step in the multi‐step transition was successfully characterized by single‐crystal X‐ray diffraction. [ABSTRACT FROM AUTHOR]

A novel third-order nonlinear optical (NLO) crystal based on the organic borate carboxylate ester, with formula [Na4(H2O)5][B{O2CCH(O)Ph}2]4(abbreviated as LMBNa), has been prepared in aqueous solution. Single-crystal X-ray diffraction analysis reveals that the boron atom is coordinated with two l-mandelic ligands by alkoxide and carboxylate groups, forming the [B{OOCCH(O)C6H5}]−anion. The sodium cation supports its structural framework of borate anions in the formation of a cross-linked structure. Bulk single crystals of LMBNa were grown from acetonitrile/water by the temperature lowering method. Studies of its third-order NLO properties using a Z-scan technique demonstrate that the LMBNa crystal possesses a strong saturable absorption and the self-focusing effect. Its second molecular hyperpolarizability (γ) at 532 nm is calculated to be (3.9 ± 0.2) × 10−31esu. Furthermore, dielectric experiments reveal that LMBNa has a quite low-dielectric constant (∼3.43) and shows an anisotropy of frequency dependence along the different crystallographic directions. Such dielectric behaviors will favor the application of the LMBNa crystal under the electric field. All the results indicate that LMBNa might be a potential candidate material for the third-order NLO applications. [ABSTRACT FROM AUTHOR]

Two polynuclear mixed-valence manganese clusters, [Mn13] and [Mn16], containing mixed chelating ligands were synthesized and structurally characterized. The alternating current (AC) susceptibilities of both complexes reveal nonzero frequency-dependent out-of-phase (χM′′) signals. [ABSTRACT FROM AUTHOR]

An unprecedented 4d–4f heterometallic helix-based MMOF with a new (3,4,5,6)-connected topology, {[Ln2Ag3(ina)6(ox)0.5(μ2-OH2)(H2O)2.5]·1.5H2O·2NO3}n, is presented, which consists of coaxial bi-strand helices interconnected by the carboxyl groups of the ligands. Selective anion-exchange functions of the title compound containing NO3−counter anions were identified. [ABSTRACT FROM AUTHOR]

Abstract: Fe(II) and Ni(II) complexes of 4-p-tolyl-2,6-di(2-pyrazinyl)pyridine (tdpzpy) have been synthesized and characterized. The N⋯π interaction involving the uncoordinated pyrazinyl N atom, which is stronger than the corresponding C–H⋯π hydrogen bonding in a similar 4-p-tolyl-2,2′:6′,2″-terpyridine complex, was distinguished as a supramolecular motif. It acts as an edge-to-face force in assembling cations of [Fe(tdpzpy)2]2+ or [Ni(tdpzpy)2]2+ into chains via embrace interlocking. C–H⋯π hydrogen bonds further link the chains into higher dimension net. The electronic absorption and emission properties of [Fe(tdpzpy)2]2+ and [Ni(tdpzpy)2]2+ are largely ligand-centered. [Fe(tdpzpy)2]2+ displays an MLCT absorption at 567nm. The fluorescence of [Ni(tdpzpy)2]2+ is different markedly in methanol and acetonitrile. The ligand-based fluorescence is quenched to some extent by coordination to the d-orbital unfulfilled Fe(II) or Ni(II) atom. [Copyright &y& Elsevier]

Several 0D, 1D, and 3D metal–organic hybrid frameworks of ZnIIhave been synthesized by using the asymmetric ligand 6-(1H-benzoimidazol-2-yl)pyridinecarboxylic acid (HL) with control of the temperature and solvent in a solvothermal synthesis technique. In DMF, the structure at room temperature confirms that the resulting compound Zn(L)2·2(H2O) (1) is the 0D mononuclear structure, above ∼80 °C, C–N bond cleavage of partial DMF molecules induces the formation of the 1D chain-like compound {[Zn(L)(HCOO)]·2(H2O)}n(2), but on warming up to 120 and 160 °C, due to the decomposition of a large number of DMF molecules, the same reaction, respectively, gives two 3D metal–organic coordination polymers with 3D channels reported previously {[Zn(HCOO)3]−·[H2N(CH3)2]+}n(3) and [Zn(HCOO)2]n(4), in which the 3D channels of 3contain guest [H2N(CH3)2]+motifs, while at high temperature the 3D channels of 4are an open stable system without any guest molecules. Replacing DMF in the above reaction by ethanol or acetonitrile, only 0D compound 1is obtained in the range from room temperature to 160 °C. However, the same reaction in DMSO provides a 1D wave-like compound {[Zn(L)(DMSO)]·(ClO4)·H2O}n(5), in which the solvent DMSO molecule coordinates to the central metal ZnIIion. Furthermore, in three new complexes 1, 2and 5, through ππ stacking and hydrogen bonding interactions, 3D supramolecular networks are assembled. It is worth noting that the existence of the twelve-membered cyclic water–perchlorate dimers [(ClO4)(H2O)]22−with chair-conformation in the solid state of 5not only increases the stability of the supramolecular structure, but also results in a stronger fluorescence signal compared with ligand HL, 1and 2. [ABSTRACT FROM AUTHOR]

Three new metal–organic coordination polymers, [Cu(2,3-pydc)(bpp)]·2.5H2O (1), [Zn(2,3-pydc)(bpp)]·2.5H2O (2) and [Cd(2,3-pydc)(bpp)(H2O)]·3H2O (3) (2,3-pydcH2= pyridine-2,3-dicarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane), have been synthesized at room temperature. All complexes have metal ions serving as 4-connected nodes but represent two quite different structural motifs. Complexes 1and 2are isomorphous, both of which feature 2D → 3D parallel interpenetration. Each two-dimensional (2D) layer with (4, 4) topology is interlocked by two nearest neighbours, one above and one below, thus leading to an unusual 3D motif. Complex 3has a non-interpenetrating 3D CdSO4framework with cavities occupied by uncoordinated water molecules. The compounds have been characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis and X-ray crystallography. The photoluminescent studies of 2and 3show that both complexes exhibit intense fluorescent emissions at room temperature. [ABSTRACT FROM AUTHOR]

A porous material with cobalt–oxygen cluster framework has been synthesized hydrothermally, which possesses large and rigid channels and manifests strong antiferromagnetic interactions, and the pyridinedicarboxylate ligand exhibits two types of rare coordination modes. [ABSTRACT FROM AUTHOR]

Reactions of Zn(BF4)2 and pyridine-2,4-dicarboxylic acid (2,4-pydcH2) in the presence of 1,2-bis(4-pyridyl)ethylene or 1,3-bis(4-pyridyl)propane under hydro(solvo)thermal conditions yielded two polymorphic metal–organic coordination polymers formulated as Zn2(OH)2(2,4-pydc) (1 and 2). Polymorph 1 features a two-dimensional (2-D) layer-like structure that is constructed by 2,4-pydc ligands bridging between the Zn–OH–Zn double-chain units. Each single Zn–OH–Zn chain is composed of μ2-OH groups connecting trigonal bipyramidal and tetrahedral Zn centers. Polymorph 2 is a 3-D coordination polymer containing 2-D Zn–OH–Zn sheets that consist of μ2- and μ3-OH groups and trigonal bipyramidal Zn centers. The sheets are pillared by 2,4-pydc ligands to form an acentric structural architecture. 1 and 2 are rare examples that the two polymorphs exhibit a centrosymmetric 2-D coordination network and an acentric 3-D coordination network, respectively. The different structures lead to differences in photoluminescent properties and thermal stabilities for 1 and 2. [ABSTRACT FROM AUTHOR]

Two tridentate phosphinethiolate ligands, [PhP(C6H4S-2)2]2-, coordinate to the GeIV centre in a facial manner yielding the title compound, [Ge(C18H13PS2)2], which exhibits a pseudo- twofold symmetry with the two P-atom donors in a cis configuration. The Ge centre has a distorted octahedral environment. Two phenyl rings, one from each of the phosphinethiolate ligands, are parallel to one another, indicating π-π interactions. The molecules are linked by weak C—H···π and C—H···S interactions. [ABSTRACT FROM AUTHOR]

The structure of the title compound, [Cu2Cl2(C12H10N2)] n, contains infinite CuCl staircase-like chains, which lie about inversion centres. The trans-1,2-di-4-pyrid­ylethyl­ene mol­ecules also lie about inversion centres and connect the CuCl chains through Cu—N coordination bonds into a two-dimensional organic–inorganic hybrid network. The planar sheets are stacked along the c axis and associated through weak C—H⋯Cl inter­actions. The results show a reliable structural motif with controllable separation of the CuCl chains by variation of the length of the ligand. [ABSTRACT FROM AUTHOR]

Three Pb-based metal-organic frameworks, [Pb6(L1)4]·H2O (1), [Pb2(L2)2(H2O)]·H2O (2), and [Pb(L2)(H2O)]·H2O (3) were constructed based on two asymmetrical tritopic ligands, 3-(2',5'-dicarboxylphenyl) benzoic acid (H3L1) and 3-(2',5'-dicarboxylphenyl)pyridine acid (H2L2), under hydrothermal conditions. The substituents on the two ligands and the induced temperature had effects on the resulting structures. All of the complexes were structurally characterized by X-ray diffraction analyses and further identified by infrared spectra, elemental analyses, powder X-ray diffraction, and thermogravimetric analyses. Complexes 1 and 3 are 3D frameworks, which construct from 1D inorganic Pb-O-Pb rod-shaped secondary building units (SBUs) and H3L1/H2L2 ligands as pillars. Complex 2 is a 3D framework based on discrete tetranuclear Pb4(COO)8 clusters SBUs and H2L2 ligands. The effects of both the substituent groups on the aromatic rings and the reaction temperature are discussed in details. The fluorescence properties and thermal stabilities of complexes 1-3 were also measured. [ABSTRACT FROM AUTHOR]

Abstract: Three novel lanthanide complexes, namely, [Ce(Himdc)(H2imdc)(H2O)3]·H2O (1), {[Dy(Himdc)(Ox)0.5(H2O)2]·H2O} n (2), and {[Nd(Himdc)(Ox)0.5(H2O)2]·H2O} n (3) (H3imdc=imidazole-4,5-dicarboxylic acid, Ox=oxalate), have been successfully prepared by the assembly of lanthanide ions and H3imdc ligand under different synthetic conditions. All of the complexes have been characterized by means of elemental analysis, IR, TG analysis, luminescence spectroscopy as well as single-crystal X-ray diffraction analysis. The 3D supramolecular structure of 1 is constructed from 1D zig-zag chains through the hydrogen bonding interactions. Complex 2 possesses the chair-shaped secondary building units (SBUs) with Dy6(Himdc)4(Ox)2 and meso-helical chains (P+M), resulting in a novel 2D structure based on the linkages of oxalate ligand. Complex 3 also presents 2D layer structure with uninodal 6-connected net topology, but crystallizes in the different space group and owns higher coordination number of the central metal atom than complex 2. The luminescence property of 2 is investigated in the solid state at room temperature. [Copyright &y& Elsevier]

The reaction of 2,2′-(1,5-dibutoxy-2,4-phenylene)bis(1-phenyl-1 H -benzo[ d ]imidazole) ( 1 ) with K 2 PtCl 4 in refluxing HOAc afforded the pincer Pt(II) chloride complex 2 . Treatment of 2 with KI gave the corresponding Pt(II) iodide complex 3 . While reaction of 2 with 4-(methoxy)phenylacetylene in the presence of NaOH easily produced the Pt(II) acetylide complex 4 . All of the new compounds have been well characterized by elemental analysis (HRMS for 1 ), NMR, and IR spectra. Additionally, the molecular structures of Pt(II) complexes 2 – 4 have been determined by X-ray single-crystal diffraction. The electronic absorption and photoluminescent properties of Pt(II) complexes 2 – 4 have been investigated. The same level time-dependent density functional theory (TD-DFT) calculations were carried out by using the Gaussian 09 program package. All of the platinum complexes investigated in this study have exhibited luminescence in CH 2 Cl 2 solution, in the solid state and in glass 2-MeTHF solution at 77 K, displaying vibronically structured emission profiles. The luminescence quantum yields in CH 2 Cl 2 solution are 0.05–0.06 and the emission lifetimes are in microsecond range. [ABSTRACT FROM AUTHOR]

Abstract: Four new metal–organic coordination polymers, [Cd2(sbpdc)2(bpy)] (1), [Cd(sbpdc)(bpp) 1/2 ] (2), [Co(sbpdc)(bpy)] (3) and [Co(sbpdc)(bpp)(H2O)] (4) (H2sbpdc=sulfone-4,4′-biphenyldicarboxylic acid, bpy=4,4′-bipyridine, bpp=1,3-bis(4-pyridyl)propane) have been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis and IR spectra. Compound 1 displays a 3D 6-connected twofold interpenetrated net with pcu topology, while 2 contains 1D infinite Cd-O-Cd chains. Compound 3 is a new 3D binodal network with the point symbol of (63) (67 ⋅83), whereas compound 4 has a 1D double chain. Moreover, the PXRD, TGA, luminescent and magnetic property were also investigated. [Copyright &y& Elsevier]

The title compound, {[Mn2(CH3CO2)4(C10H8N2)2]·H2O} n, is a one-dimensional coordination polymer with a ladder-like structure. Two MnII atoms, each coordinated by a chelating acetate ligand, are bridged by two bidentate acetate ligands to form a centrosymmetric [Mn2(CH3CO2)4] unit. Two 4,4′-bipyridine ligands link the [Mn2(CH3CO2)4] units through Mn—N bonds to generate a mol­ecular ladder. The water O atom lies on a crystallographic twofold rotation axis. [ABSTRACT FROM AUTHOR]

Reactions of zinc(II) or cadmium(II) salts with terephthalic acid (H 2tp) and 1,3-bis(4-pyridyl)propane (bpp) have afforded four coordination polymers at room temperature, [Zn(μ-tp)(μ-bpp)] n·2 nH 2O ( 1), [Cd 2(μ-tp) 2(μ-bpp) 3] n·2 nH 2O ( 2), [Cd(μ-tp)(μ-bpp)(H 2O)] n· nH 2O ( 3), and [Cd 2(μ-tp)(μ-bpp) 2(bpp) 2Br 2] n( 4). Single-crystal X-ray diffraction has revealed interesting topological features for these compounds. In 1, the Zn atoms act as 4-connected nodes bridged by the tp and bpp ligands to give a 3-fold interpenetrated 3D network with a unique 6 6topology, which is evidently distinct from 4-connected diamondoid networks. 2represents the first example of a 2-fold interpenetrated coordination polymer, which possesses a 5-connected 3D framework with a unique 6 10topology constructed from Cd nodes and tp and bpp spacers. 3manifests a polyrotaxane motif comprised of two interlocked sets of identical sheets, which result in a 2D → 2D polythreaded layer. Parallel mutual polythreading of 2D layers with dangling bpp ligands is observed in 4, involving five polymeric layers at a time and thus affording a 3D architecture. All compounds were characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis, and their fluorescence properties were also investigated. [ABSTRACT FROM AUTHOR]