Study on synthesis, structure, and DNA-binding of Ni, Zn complexes with 2-phenylquinoline-4-carboylhydrazide

2-Phenylquinoline-4-carboylhydrazide (HL), and its novel nickel(II), zinc(II) complexes [M(HL)₂(L)]·2H₂O·NO₃ (M = Ni (1), M = Zn (2)), have been synthesized and characterized by elemental analysis, molar conductivity, and IR spectra. The crystal structure of [Ni(HL)₂(L)]·2H₂O·NO₃ obtained from ethanol solution was determined by X-ray diffraction analysis, crystallized in the rhombohedral system, space group , Z = 18, a = 31.913(3) Å, b = 31.913(3) Å, c = 27.709(2) Å, α = 90°, β = 90°, γ = 120°, R₁ = 0.0647. The interactions of the complexes and the ligand with calf thymus DNA had been investigated using UV-Vis spectra, fluorescent spectra, CD (circular dichroism) spectra, CV (cyclic voltammetry) and viscosity measurements. These compounds were tested against MFC (mouse forestomach carcinoma) cell lines. The complex 1 showed significant cytotoxic activity against MFC cell lines. The cleavage reaction on plasmid DNA has been monitored by agarose gel electrophoresis. Results suggest that the two complexes bound to DNA via a groove binding mode and the complexes can cleave pBR322 DNA.     

A new cyano-bridged one-dimensional GdFe coordination polymer with o-phenanthroline as the blocking ligand: synthesis, structure, and magnetic properties

Synthesis, structural characterization, and magnetic properties of a new cyano-bridged one-dimensional iron (III)-gadolinium (III) compound, trans-[Gd(o-phen)₂(H₂O)₂(μ-CN)₂Fe(CN)₄]_n · 2no-phen (o-phen = 1,10-phenanthroline), have been described. The compound crystallizes in the triclinic space group with the following unit cell parameters: a = 10.538(14) Å, b = 12.004(14) Å, c = 20.61(2) Å, α = 92.41(1)°, β = 92.76(1)°, γ = 112.72(1)°, and Z = 2. In this complex, each gadolinium (III) is coordinated to two nitrile nitrogens of the CN groups coming from two different ferricyanides, the mutually trans cyanides of each of which links another different Gd^III to create -NC-Fe(CN)₄-CN-Gd-NC- type 1-D chain structure. The one-dimensional chains are self-assembled in two-dimensions via weak C-H?N hydrogen bonds. Both the variable-temperature (2-300 K, 0.01 T and 0.8 T) and variable-field (0-50 000 Gauss, 2 K) magnetic measurements reveal the existence of very weak interaction in this molecule. The temperature dependence of the susceptibilities has been analyzed using a model for a chain of alternating classic (7/2) and quantum (1/2) spins.     

Single nucleotide polymorphism in hMLH1 promoter and risk of tobacco-related oral carcinoma in high-risk Asian Indians

hMLH1 is a member of mismatch repair genes (MMR) that plays a crucial role in correcting replication errors, cell cycle arrest, apoptosis and oxidative stress. We explored the risk associated with hMLH1 − 93 A>G (rs 1800734) single nucleotide polymorphism (SNP) with the oral squamous cell carcinoma (OSCC) in Asian Indians. We genotyped 242 patients with tobacco-related OSCC and 205 healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The frequency of AA genotype was found to be significantly (P_c < 0.0006) lower in patients as compared to the controls (21.49% vs. 47.8%) while GG genotype showed significantly higher (P_c < 0.0006) prevalence in patients as compared to the healthy controls (41.32% vs. 13.66%). In logistic regression analysis AG (adjusted OR = 1.95, 95% CI = 0.72–5.26) and GG genotype (adjusted OR = 4.5, 95% CI = 1.54–13.16, P = 0.006) appeared susceptible when compared with the wild-type AA genotype. The allelic distribution showed that variant G allele is significantly higher (P_c < 0.0004) in patients and associated with increased risk (adjusted OR = 2.36, 95% CI = 1.33–4.19, P = 0.003) as compared to the wild-type A allele. Altogether, our results suggest that the hMLH1 − 93 A>G polymorphism is associated with the higher risk of tobacco-related OSCC in Asian Indians and could be useful in screening population at a higher risk.     

Coordination environment friendly silicon in copper(I) chloride π-complexes with tetravinylsilane and dimethyltetravinyldisiloxane

Two crystal complexes of copper(I) chloride with tetravinylsilane (TVS) dimethyltetravinyldisiloxane (DMTVDS) were prepared and examined by IR spectroscopy and X-ray diffraction: sp. gr. P2/a, Z = 4, a = 13.428(1) Å, b = 7.9584(7) Å, c = 14.694(1) Å for [Cu₄Cl₄(TVS)]; sp. gr. P2₁/c, a = 10.505(1) Å, b = 13.487(1) Å, c = 13.870(1) Å for [Cu₄Cl₄(DMTVDS)]. The influence of the vinylsilicon ligands on the efficiency of the Cu?CC interaction is discussed. Thus, the consideration of d_Si ← π∗_CC ← d_Cu conjugate system may help to understand how the silicon π-acceptor properties influence on the degree of trigonal distortion of the Cu(I) coordination tetrahedron as well as on the inorganic part organization. The present studies are aimed at the use of the structure controlled nanoparticles supported on vinyl modified silicon (or silicone) substrate.     

Counter-anions and their coordination behavior with Cu(II) complexes of thiophen-3-yl-dipicolylamine

A new ligand, 1-(pyridin-2-yl)-N-(pyridin-2-ylmethyl)-N-(thiophen-3-ylmethyl)methanamine, ThDPA, was synthesized, as a new example of an N₃S donor. Cu(II) complexes of this ligand were isolated. When Cu(NO₃)₂ was used as the metal source, a homobinuclear complex with the formula [CuThDPA(NO₃)₂]₂·H₂O, 1, with two different types of nitro coordination was isolated. 1 crystallizes in the monoclinic P2₁/n space group with a = 15.193, b = 8.181, c = 32.827 Å, β = 103.3° and V = 3971.9 Å³. In the case of CuSO₄ as the source of copper(II), uncommon sulfato-bridged structures were isolated. The homobinuclear complex crystallized in two different lattices, depending on the solvent evaporation rate. Compound 2, with the formula [CuThDPA(SO₄)]₂·3H₂O, crystallizes with 3 water molecules per binuclear structure in the monoclinic space group P2₁/c with a = 10.143, b = 17.013, c = 11.793 Å, β = 97.18° and V = 2019.1 Å³, and 3, [CuThDPA(SO₄)]₂·4H₂O, crystallizes with 4 water molecules per binuclear structure in the triclinic space group, with a = 9.2906, b = 10.7297, c = 12.7236 Å, α = 79.66, β = 72.18, γ = 67.1° and V = 1109.7 Å³.     

A novel unexpected luminescent quarternary coordination polymer {Sm3(C8H4O4)4(C12N2H8)2(NO3)}n with three high asymmetrical central Sm fragments by hydrothermal assembly

A novel chain-like luminescent samarium coordination polymer {Sm₃(C₈H₄O₄)₄(C₁₂N₂H₈)₂(NO₃)}_n (C₈H₄O₄ = phthalate, C₁₂N₂H₈ = 1,10-phenanthroline) has been assembled by hydrothermal process. The title complex crystallizes in the monoclinic system, space group P2(1)/c, with lattice parameters a = 22.56(3) Å, b = 11.155(15) Å, c = 20.32(3) Å, β = 96.70(2)°, V = 5078(12) ų, F(000) = 2964, GOF = 0.857, R₁ = 0.0358, wR₂ = 0.0597, Z = 4. Samarium ions exhibit different coordination modes from each other and lead to the unexpected high asymmetrical structure. To our knowledge, it is the first example of lanthanide coordination polymers comprising the three asymmetrical central Sm³⁺ fragments. The photophysical properties have been studied with excitation and emission spectra.     

4,4′-Bis(tert-butyl)-2,2′-bipyridinedichlorometal(II) - Synthesis, structure and EPR spectroscopy

Due to the better solubility of the 4,4′-substituted bipyridine ligand a series of 4,4′-bis(tert-butyl)-2,2′-bipyridinedichlorometal(II) complexes, [M(tbbpy)Cl₂], with M = Cu, Ni, Zn, Pd, Pt was synthesised and characterised. The blue copper complex 4,4′-bis(tert-butyl)-2,2′-bipyridinedichlorocopper(II) was isolated in two different polymorphic forms, as prisms 1 with a solvent inclusion and solvent-free as needles 2. Both structures were determined by X-ray structure analysis. They crystallise in the monoclinic space group P2₁/c with four molecules in the unit cell, but with different unit cells and packing motifs. Whereas in the prisms 1, with the unit cell parameters a = 12.1613(12), b = 10.6363(7), c = 16.3074(15) Å, β = 94.446(8)°, the packing is dominated by intra- and intermolecular hydrogen bonds, in the needles 2, with a = 7.738(1), b = 18. 333(2), c = 13.291(3) Å, β = 97.512(15)°, only intramolecular hydrogen bonds appear and the complex molecules are arranged in columns which are stabilised by π-π-stacking interactions. In both complexes the copper has a tetrahedrally distorted coordination sphere. These copper complexes were also studied by EPR spectroscopy in solution, as frozen glass and diamagnetically diluted powder with the analogue [Pd(tbbpy)Cl₂] as host lattice.     

Two cadmium-thiocyanate coordination polymers with organic cations: Synthesis, crystal structures and luminescent properties

Two new inorganic-organic hybrid polymers [ClBzQl]₂[Cd(SCN)_3.5Br_0.5]·0.25H₂O (1) and [ClBzMePy][Cd(SCN)₃] (2) (ClBzQl = 1-(4′-Cl-benzyl)quinolinium cation and ClBzMePy = 1-(4′-Cl-benzyl)-2-methylpyridinium cation) have been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Crystal structure analyses show that two polymers belong to the monoclinic space group P2/n (1) and P2₁/c (2) with a = 18.548(2) Å, b = 9.526(1) Å, c = 20.689(2) Å, β = 94.008(1)°, V = 3646.6(5) Å³ for 1, and a = 11.195(2) Å, b = 16.415(3) Å, c = 10.751(2) Å, β = 102.930(3)°, V = 1925.7(7) Å³ for 2. The Cd atom exhibits a distorted octahedral coordination geometry for 1 and 2. For 1, a pair of 1,1-μ-SCN⁻ anions and a pair of 1,3-μ-SCN⁻ anions are alternately bridge adjacent Cd centers to form infinite polymeric chains. For 2, adjacent Cd atoms are linked by three 1,3-μ-SCN⁻ anions to form infinite [Cd(SCN)₃⁻]_∞ polymeric chains. The luminescent properties of the two polymers in the solid state at room temperature were investigated.     

Synthesis and characterization of new coordination polymers generated from oxadiazole-containing ligands and IIB metal ions

The coordination chemistry of the oxadiazole-containing rigid bidentate ligands 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L1) and 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L2) with inorganic IIB metal salts have been investigated. Five new coordination polymers (1-5) were prepared by solution reactions and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Cd(L1)₂(CH₃CN)₂](ClO₄)₂ · (CH₃CN)₂ (1) crystallized in the monoclinic space group P2₁/c, a = 8.4028(5) Å, b = 21.3726(13) Å, c = 10.5617(7) Å, β = 95.1200(10)°, and Z = 2. In the solid state, it adopts an infinite two-dimensional polymeric structural motif with effective cross section of ca. 14.31 × 14.31 Å. Cd(L2)(H₂O)(NO₃)₂ (2) crystallized in the monoclinic space group Ia, a = 7.1203(5) Å, b = 22.2475(15) Å, c = 20.2652(16) Å, β = 90.6080(10)°, and Z = 8. In the solid state, the two Cd(II) centers are connected to each other by L2 ligands and bridging nitrates into a two-dimensional network. [ZnCl₂(L1)] (3) and [HgI₂(L1)] · CH₃CN (4) crystallized in the monoclinic crystal system (3: P2₁/c, a = 5.3702(3) Å, b = 20.4800(11) Å, c = 12.4093(7) Å, β = 94.7930(10)°, and Z = 4; 4: P2/n, a = 17.2733(11) Å, b = 5.2173(3) Å, c = 20.4069(13) Å, β = 102.8690(10)°, and Z = 4). In the solid state, Zn(II) and Hg(II) metal centers are connected to each other by L1 ligands into a zigzag chain motif. Compound 5 (HgBr₂(L2) is different from 3 and 4, monoclinic, P2(1)/n, a = 5.470(4) Å, b = 16.271(13) Å, c = 16.486(12) Å, β = 93.197(15)°, and Z = 4) adopts a novel one-dimensional helical chain motif which resulted from the relative different coordinated orientation of the two N-donors on L2 ligand.     

Synthesis and characterization of new water stable antimony(III) complex with pyrimidine-2-thione and in vitro biological study

A novel water stable, antimony(III) complex with the heterocyclic thioamide; 2-mercapto-pyrimidine (pmtH), of formula [Sb(pmt)₃] · 0.5(CH₃OH), has been synthesized and characterized by elemental analysis, ¹H, ¹³C NMR and FT-IR spectroscopic techniques. Crystal structure of the molecule has been determined by X-ray diffraction at ambient conditions. The compound [C₁₂H₉N₆S₃Sb · 0.5(CH₃OH)] is monoclinic, space group P2₁/c, a = 7.0646(7), b = 16.3767(14), c = 14.7265(13) Å, β = 92.016(7)°, Z = 4. In complex, three sulfur and three nitrogen atoms from thione ligands form a distorted pendagonal pyramidal geometry around antimony(III). The toxicity of the compound against tumor pleiomorphic cells, which has been isolated from a leiomyosarcoma tumor in the Wistar rat (chemical carcinogenesis using BaP) was studied in vitro. The results show that the compound did not destroy or prevent multiplication in vitro in leiomyosarcoma cells in low doses. The influence of the compound in the platelet aggregation, which correlates with the above tumor cells enhanced metastatic potential, has also been studied. The anti-metastatic capability study shows that the compound inhibited cancer cell induced aggregation up to the value of 10% in all mM concentrations tested.     

Formation of structurally different solvated and non-solvated [Ni(PTSC)(PPh3)] (PTSC = salicylaldehyde-N-phenylthiosemicarbazide anion) crystals from single pot

New thiosemicarbazone nickel(II) complex, derived from salicylaldehyde-N-phenylthiosemicarbazone, was synthesized and characterized by means of IR, electronic, and mass spectral techniques. Its two different types of crystal structures were also characterized by single crystal X-ray diffraction technique and reported here. In type A, the complex crystallizes in the monoclinic space group P2₁/c with four molecules per cell and has the dimensions of a = 9.2066(7), b = 19.1090(13), c = 18.589(2) Å, β = 92.87 (1)°. In type B, the complex crystallizes in the triclinic space group with two molecules per cell and has the dimensions of a = 10.406(4), b = 10.876(4), c = 14.614(5) Å, α = 64.81(1), β = 74.07(2), γ = 70.85(2)°.     

Synthesis, structural determination and magnetic properties of a heterobimetallic CuRe complex containing a macrocyclic ligand

Reaction of the rhenium(IV) compound, [Bu₄N]₂ReCl₄ox, with the highly unsaturated tetraazabismacrocyclic copper(II) complex cation [CuCuL]⁴⁺ (L = 6,13-Bis(dodecylaminomethylidene)-1,4,8,11-tetraazacyclotetradeca-4,7,11,14-tetraene) produced a new kind of heterobimetallic compound: [CuCuL][ReCl₄ox]₂ · 2DMF in which [ReCl₄ox]²⁻ anions and [CuCuL]⁴⁺ cations are linked by electrostatic forces. The crystal structure of this compound was determined at 173(2) K. It crystallizes triclinic, space group , with a = 9.441(4), b = 11.032(5), c = 15.261(7) Å, α = 89.05(1)°, β = 88.93(1)°, γ = 77.09(1)°, Z = 1, R₁ = 0.0557, wR₂ = 0.1332. The magnetic behavior of this compound has been investigated over the temperature range 1.72-300 K. The compound behaves as a ferrimagnetic Cu^IIRe^IV bimetallic, chain with intrachain antiferromagnetic coupling.     

Hydrothermal synthesis and structure of a Cu(I) bromide coordination polymer, [(tpyprz)3Cu10Br10] (tpyprz = tetra-2-pyridylpyrazine)

The hydrothermal reaction of CuBr₂ and tpyprz in the presence of NH₄VO₃ and HF for 72 h at 170 °C provided [(tpyprz)₃Cu₁₀Br₁₀] (1) in 20% yield. The two-dimensional structure of 1 may be described as Cu(I)-tpyprz chains, linked through {Cu₄Br₅}⁻ clusters in the ac-plane and decorated with {Cu₃Br₅}²⁻ clusters projecting from one face of the layer in the b-direction. The Cu(I) sites exhibit distorted trigonal coordination {CuBr₃} and distorted tetrahedral geometries, {CuBr₂N₂} and {CuN₄}. Crystal data for 1: monoclinic space group C2, a = 12.7561(8) Å, b = 19.359(1) Å, c = 15.860(1) Å, β = 97.178(1)°, V = 3885.8(4) Å³, Z = 2, D_calc = 2.222 g cm⁻³, μ(Mo Kα) = 78.75 cm⁻¹.     

Synthesis, structure and magnetic property of a 2D grid-like copper(II) complex with end-on azido and pyrazine bridges

A 2D grid-like copper(II) complex [Cu(N₃)₂(pyz)](pyz = pyrazine) (1) has been synthesized and characterized by single crystal X-ray analysis and magnetic measurements. The 2D grid-like network of 1 consists of 1D chain of Cu-pyz units connected by end-on azido bridge. 1 crystallizes in the monoclinic space group C2 with a = 15.148(6) Å, b = 6.877(2) Å, c = 3.4591(12) Å and Z = 2. The magnetic investigation showed the presence of an antiferromagnetic interaction between the copper(II) ions mainly mediated through pyrazine bridge.     

One-dimensional azido-bridged chiral copper(II) coordination polymers: Syntheses, structures and magnetic studies

Two new one-dimensional azido-bridged chiral copper(II) coordination polymers, [(μ-1,1,3-N₃)₂{Cu₂(R-L)₂(N₃)₂}]_n (1) (R-L = R-2-(N-(2-hydroxybutyl)carbaldimino) pyridine) and [(μ-1,1,3-N₃)₂{Cu₂(S-L)₂(N₃)₂}]_n (2) (S-L = S-2-(N-(2-hydroxybutyl)carbaldimino)pyridine) have been synthesized and structurally characterized. Complexes 1 and 2 crystallize in the monoclinic chiral space group P2₁. For 1, with a = 6.9565(17) Å, b = 20.675(5) Å, c = 9.859(2) Å, β = 105.944(5)° and Z = 2. In the case of compound 2, a = 6.9650(17) Å, b = 20.705(5) Å, c = 9.878(2) Å, β = 105.941(4)° and Z = 2. Both complexes consist of one-dimensional chiral structures in which the copper(II) ions with a distorted octahedral geometry are interlinked by the unusual μ-1,1,3 azido ligands. Circular dichroism spectra demonstrate that 1 and 2 are a pair of enantiomers. Their magnetic properties have been studied. Fitting of the susceptibility data for 1 and 2 using the Bleany-Bowers expression derived from the isotropic spin-exchange Hamiltonian H = −2JS₁S₂ leads to the parameters g = 2.21, J = −2.06 cm⁻¹, zJ′ = −0.0309 cm⁻¹ and R = 4.0 × 10⁻⁴.     

Crystal structures of mixed oxonium-cadmium(II) salts with [SbF6]/[Sb2F11] anions: From complex chains to layers and three-dimensional frameworks

Pure H₃OCd(SbF₆)(Sb₂F₁₁)₂ is prepared by the reaction of CdO with nSbF₅ (n ? 5) or by reaction of H₃OSbF₆, Cd(SbF₆)₂ and nSbF₅ (n ? 2) in anhydrous hydrogen fluoride. H₃OCd(SbF₆)(Sb₂F₁₁)₂ crystallizes in the monoclinic space group P2₁/a (No. 14) with a = 986.1(4) pm, b = 1257.3(5) pm, c = 1826.8.4(8) pm, β = 98.062(4)° and Z = 4.Reaction of CdO with SbF₅ (n ? 3) in anhydrous HF yields only a mixture of H₃OSbF₆ and Cd(SbF₆)₂. No reactions were observed also when different ratios of H₃OSbF₆ and Cd(SbF₆)₂ were used as starting materials. However, the re-crystallization of these mixtures yielded single crystals of new phases: (H₃O)₂Cd(SbF₆)₃(Sb₂F₁₁) and (H₃O)₂Cd₂F(SbF₆)₅. The former crystallizes in the orthorhombic Pcca space group (No. 54) with a = 2189(2) pm, b = 1121.2(8) pm, c = 1894(1) pm and Z = 8 and the latter in the monoclinic P2₁/a space group a = 1019(4) pm, b = 1112(1) pm, c = 1147(1) pm, β = 107.81(1)° and Z = 2. The attempt to prepare single crystals of Cd(SbF₆)₂ resulted in the preparation of few single crystals of (H₃O)[Cd(HF)]₄(SbF₆)₉, which crystallizes in the monoclinic space group C2/c (No. 15) with a = 2087(3) pm, b = 1021(5) pm, c = 2112(2) pm, β = 99.36(2)° and Z = 4.     

Synthesis, characterization, and luminescence properties of magnesium coordination networks using a thiophene-based linker

By varying the solvents and temperatures under solvothermal conditions, two new magnesium based coordination networks were synthesized using 2,5-thiophenedicarbxoylate as a linker. Mg₃(TDC)₃(DMF)₃ [1; TDC = 2,5 thiophenedicarboxylate; space group P2₁/c, a = 17.747(4) Å, b = 9.805(2) Å, c = 21.359(4) Å, β = 103.13(3)°] is constructed by a combination of magnesium polyhedral trimers, which are connected by the TDC²⁻ linkers to form a 3-D network. Coordinated DMF molecules are present within the channels. Mg(TDC)(H₂O)₂ [2; space group Pnma, a = 7.296(4) Å, b = 17.760(4) Å, c = 6.6631(3) Å] is formed by 1-D chains of magnesium octahedra connected by the TDC²⁻ linker. Water molecules are coordinated at the axial positions of the magnesium octahedra. Compound 1 is formed using DMF as the synthesis solvent at 180 °C, while compound 2 is formed using ethanol as the synthesis solvent at 100 °C. Both compounds show enhanced photoluminescence intensity when excited at 397 nm compared to the free TDC ligand, suggesting a charge transfer between the ligand and the magnesium metal center.     

Novel polynuclear thallium thiolates with cage structures

Yellow thallium(I)-tetra(2-butanethiolato)-thallium(III) Tl[Tl(SC₄H₉)₄] (1) crystallizes from a solution of thallium(I) carbonate and 2-butanethiol in DMF after heating under reflux in air. In the crystal structure (space group: , a = 8.941(3) Å, b = 11.078(4) Å, c = 13.458(4) Å, α = 70.81(3)°, β = 83.65(3)°, γ = 74.78(3)°, Z = 2) regular, TlS₄ tetrahedra are bridged by thallium(I) atoms to an one-dimensional framework. The thallium(I) atoms are in fivefold distorted coordination and are linked to four further TlS₄ tetrahedra. The resulting Tl₄(S-Bu)₈ units consist of two face-sharing Tl₃S₄ defect cubane entities.TlSC₃H₇ (2) was obtained from a solution of thallium(I) carbonate and 2-propanethiol in DMF after heating under reflux in air. The crystal structure (space group C2/c, a = 22.501(5) Å, b = 10.360(2) Å, c = 12.760(3) Å, β = 107.92(2)°, Z = 16) contains novel [Tl₄(SPr)₅]⁻ units which are linked via thallium atoms to one-dimensional molecular chains running parallel to [0 0 1].     

Three dimensional metal-malonate frameworks with pillared layered architecture: Unusual role of metal-chelate as pillar

One hetero-bimetallic Cu(II)/Cd(II) compound, [Cd^II(H₂O)₂][Cu^II(mal)₂(H₂O)₂]_n (1) (H₂mal = malonic acid) has been synthesized and characterized using single crystal X-ray crystallography, thermogravimetric (TG) studies and X-ray powder diffraction (XRPD) measurements. The compound crystallizes in orthorhombic Pbcn space group having cell dimensions a = 6.6260(12) Å, b = 13.958(2) Å and c = 13.052(2) Å. The solid state structure of compound 1 demonstrates a 3D pillared layered coordination network generated through the simultaneous bridging as well as chelating mode of malonate towards the Cd(II) and Cu(II), respectively. TG analysis reveals relatively high thermal stability for the compound (decomposition temperature ∼320 °C). The thermal study also reveals that the coordinated waters attached to both the metal centers (Cd(II) and Cu(II)) are reversibly lost and gained and this behavior is also corroborated by XRPD studies.     

Synthesis and X-ray structural characterization of tris(l-glycinato)vanadium(III) and trans-tetraquadichlorovanadium(III) chloride

Despite the importance of V^III in biology, only three V^III complexes of naturally occurring amino acids have been structurally characterized. We report the structure of the first vanadium complex incorporating a glycine ligand, [V(Gly)₃] · 2DMSO, which crystallizes in a monoclinic system with space group Cc, a = 8.9186(5) Å, b = 21.5347(9) Å, c = 9.9064(5) Å and β = 110.536(3)°. The X-ray structural data show the central V^III metal octahedrally coordinated by three bidentate glycinato ligands arranged a mer configuration, with both Δ and Λ enantiomers present in the unit cell. The bulk sample was isolated as [V(Gly)₃] · DMSO · NaCl. Structural comparisons are made with the corresponding homoleptic glycinato complexes of Co^III, Cr^III and Ni^II. The structure of trans-[V(OH₂)₄Cl₂]Cl · 2H₂O has also been re-determined. This latter complex crystallizes in a monoclinic system in the P2(1)/c space group, a = 6.4381(9) Å, b = 6.3843(9) Å, c = 11.7980(17) Å and β = 98.057(2)°. The vanadium atom lies at a crystallographic inversion centre within the distorted octahedron formed by the four water and two chloride ligands.