Infrared and Raman spectra of 2-(α-hydroxybenzyl)thiamine, 2-(α-hydroxycyclohexylmethyl)thiamine,their protonated forms and their complexes with zinc(II), cadmium(II) and mercury(II)

The infrared and Raman spectra of the ligands; 2-(α-hydroxybenzyl)thiaminium chloride (HBT), 2-(α-hydroxycyclohexylmethyl)thiaminium chloride (HCMT), and their protonated forms HBT·HCl and HCMT·HCl, as well as of their zwitterionic type complexes Zn(HBT)Cl₃, Cd(HBT)Cl₃, Hg(HBT)Cl₃ and Zn(HCMT)Cl₃, Cd(HCMT)Cl₃, Hg(HCMT)Cl₃, have been recorded in the region 4000-50 cm⁻. Several characteristic bands have been identified or tentatively assigned and are discussed in relation to the structures of the complexes. It is concluded from the spectra that the complexes are isostructural and that the bonding site of the ligands is the N(1′) atom of the pyrimidine moiety.     

Synthesis,structure and magnetic studies of copper(II)-nickel(II) complexes withN,N′-bis(2-aminopropyl)oxamidocopper(II)

Three novel heterobinuclear complexes have been prepared and identified as [Cu(oxap)Ni(L)₂](ClO₄)₂·ξH₂O, where oxap denotes theN,N′-bis(2-aminopropyl)oxamido dianion and L denotes 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 5-nitro-1,10-phenanthroline (NO₂-phen). The crystal structure of [Cu(oxap)Ni(phen)₂]-(ClO₄)₂·2H₂O has been determined. Crystal data: triclinic, space group , a=12.079 (6), b=12.409 (4), c=17.261 (8) ?, α=70.91 (2), β=86.72 (4), γ=89.19 (3)^o. At room temperature, Z=2. The Cu^II is in a square planar environment and the Ni^II is in an octahedral environment. The Cu−Ni distance is 5.292 ?. The temperature dependences of the magnetic susceptibilities of [Cu(oxap)Ni(phen)₂]-(ClO₄)₂·2H₂O and [Cu(oxap)Ni(bipy)₂](ClO₄)₂ have been studied in the 4.2–300 K range, giving the exchange integral J=−92.4 cm⁻¹ for bipy and J=−94.3 cm⁻¹ for phen. These results are commensurate with antiferromagnetic interactions between the adjacent metal ions.     

Palladium(II) and platinum(II)-C(3)-substituted 2,2′-bipyridines

Reaction of Pd(OAc)₂ with HL¹ and HL² (HL¹=6-iso-propyl-2,2-bipyridine; HL²=6-neo-pentyl-2,2-bipyridine), followed by treatment with LiCl or KI, gives [PdCl(L¹)]₂, (1), [PdCl(L²)]₂ (2), and [PdI(L²)]₂ (3), respectively. The chloride bridge in complexes1 and2 is split by PPh³ to give the mononuclear species PdCl(L¹)(PPh₃) (4) and PdCl(L²)(PPh₃) (5). Spectroscopic data provide evidence for coordination of the deprotonated ligands through a nitrogen and the C₍₃₎ atom of the 6-substituted pyridine. An analogous platinum complex PtCl(L³)(SMe₂) (6) (HL³=6-tert-butyl-2,2-bipyridine) was obtained from trans-PtClMe(SMe₂)₂ and HL³. The crystal structures of compounds1 and6 have been solved by X-ray diffraction analysis.Dipartimento di Chimica, Universita di Sassari, via Vienna 2, I-07100 Sassari, Italy; Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Universita di Milano, Centro CNR, I-20133 Milano, Italy; Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1127–1137, August, 1999.     

Copper(II) and palladium(II) complexes of N,N′-bis(2-hydroxyethyl)stilbenediamine

A new 1,2-diamine ligand, N,N-bis(2-hydroxyethyl)stilbenediamine (L), has been prepared by reduction of the condensation product of benzaldehyde with 2-aminoethanol with Al amalgam. Mononuclear complexes of the [CuL(H₂O)]X₂ type where X=Cl^– or AcO^– with Cu^II and PdLCl₂ with palladium(II) have been prepared and characterized by elemental analysis and i.r., u.v.–vis. or ¹H-n.m.r. spectroscopy.     

Synthesis and Structure of Acetonitrile Solvates of Copper(II) Monofluoroacetate and Silver(I) Trifluoroacetate, [Cu2(CH2FCOO)4· 2CH3CN](CH3CN) and Ag3(CF3COO)3(CH3CN)2

Compounds [Cu₂(CH₂FCOO)₄· 2CH₃CN](CH₃CN) (I) and Ag₃(CF₃COO)₃(CH₃CN)₂(II) were synthesized and studied by X-ray structural analysis. Crystals Iare monoclinic, space group C2/c, a= 27.854(6), b= 8.286(2), c= 19.428(4) Å, = 106.82(3)°, V= 4292(2) ų, Z= 8, R ₁= 0.0426; crystals IIare triclinic, space group , a= 8.676(2), b= 9.819(2), c= 11.961(2) Å, = 95.27(3), = 109.59(3)°, = 104.60(3)°, V= 911.4(3) ų, Z= 2, R ₁= 0.0252. Structure Iis composed of the structural units (lanterns) typical of copper(II) carboxylates. The presence of an additional acetonitrile molecule noncoordinated by the copper atoms makes it possible to consider compound Ias a lattice clathrate. Structure IIhas no analogs among the silver carboxylates. It simultaneously contains silver atoms with coordination numbers varying from 2 to 4.     

Synthesis,crystal structure,thermal decomposition,and XPS studies of homo and heterotrinuclear Cu(II)–Cu(II)–Cu(II) and Cu(II)–Ni(II)–Cu(II) complexes obtained from salpn type ligands

In this study, a mononuclear CuL complex was prepared by the use of bis-N,N′-(salicylidene)-1, 3-propanediamine (LH₂) and Cu²⁺ ion. NiCl₂ and NiBr₂ salt were treated with this complex in dioxanewater medium and two new complexes [(CuL)₂NiCl₂(H₂O)₂] and [(CuL)₂NiBr₂(H₂O)₂)] with Cu(II)–Ni(II)–Cu(II) nucleus structure were obtained. In addition to this bis-N,N′-(2-hydroxybenzyl)-1,3-diaminopropane (L^HH₂) was prepared by the reduction of LH₂ with NaBH₄ in MeOH medium. The treatment of this reduced complex with Cu²⁺ ion resulted a complex [(CuL^H)₂CuCl₂] with a structure of Cu(II)–Cu(II)–Cu(II). The complexes prepared were characterized by the use of elemental analysis, IR spectroscopy, thermogravimetric and X-ray diffraction methods. The crystal structures of [(CuL)₂NiBr₂(H₂O)₂] (СIF file CCDC 1448402) and [(CuL^H)₂CuCl₂] (СIF file CCDC 1448401) complexes were elucidated. It was found that halogen ions are coordinated to terminal Cu²⁺ ions which are in a distorted square pyramid coordination sphere. It was determined that the central Cu(II), which joins terminal square pyramidal Cu(II), was coordinated only by the phenolic oxygens of the ligand while the central Ni(II) was coordinated by two phenolic oxygens of the organic ligand and two water molecules. These complexes were investigated by XPS and it was found that the terminal and central Cu²⁺ ions were different in Cu(II)–Cu(II)–Cu(II) complex. Also, the thermal degradation of the CuLH complex unit was observed to exothermic in contrast to the expectations.

     

Nickel(II) and copper(II) – l-cysteine,l-methionine,l-tryptophan-nucleotide ternary complexes

Four new ternary complexes of Cu^II with l-methionine and the nucleotides 5AMP (adenosine 5-phosphate), 5GMP (guanosine 5-phosphate) and 5IMP (inosine 5-phosphate), and with l-tryptophan and 5AMP, were synthesized and characterized by elemental analysis and i.r. spectroscopy. One ternary complex of N^II with l-cysteine and 5IMP was also prepared and characterized. The study of the three ternary compounds of Cu^II, of general formulae Cu-5NMP-l-methionine, indicates coordination of the phosphate group and of N(7) of the purinic ring. l-Methionine is bound by the carboxylic and amino groups. The ternary complex obtained from a mixture of Cu-5AMP and l-tryptophan is a dimer in which the nucleotide bridges the two copper atoms. In the complex of Ni-5IMP and l-cysteine, the nucleotide seems to bind the metal through the N(7) of the heterocyclic ring, and the l-cysteine is coordinated as a bidentate chelate by the carboxyl and thiol groups. E.s.r. spectra of the copper complexes are in good agreement with the low symmetry structure proposed. The one-electron reduction potentials E_c(Fc⁺/Fc) (V) of Cu^II to Cu^I were established for the four copper complexes from cyclic voltammetry studies. The one-electron oxidation potential E_a(Fc⁺/Fc⁺) (V) of Ni^II to Ni^III was also measured for the nickel complex.     

Interaction of Co(II), Ni(II), Cu(II), and Zn(II) with N,N′-(aldose)2-thiocarbohydrazide: synthesis,electrochemistry, and spectral characterization

Complexes of Co(II), Ni(II), Cu(II), and Zn(II) with N,N′-(aldose)₂–thiocarbohydrazide (LH₂) were synthesized, isolated as solid products and characterized by analytical means as well as by spectral techniques, FTIR, ¹H NMR, EPR, UV spectroscopy, and CD. All the metal ions formed M[LH]X complexes. Molar conductance values in DMF indicate non-electrolytic complexes. In DMSO with tetramethylammonium chloride supporting electrolyte, the copper complex displays irreversible cyclic voltammetric responses with E _p near ?0.621 and 0.461 V versus Ag/AgCl at scan rate of 0.1 V s^?1. Probable structures for the complexes are proposed.     

Solvent free synthesis,characterization, DFT,cyclic voltammetry and biological assay of Cu(II), Hg(II) and UO2(II) – Schiff base complexes

A series of metal ion complexes was prepared in solid state from Cu(II), Hg(II) and UO₂(II) ions with 3-oxo-3-(2-(2-oxoindolin-3-ylidene)hydrazineyl)-N-phenylpropanamide (H₃L) ligand through solvent free synthesis methodology. The chemical formulae of the new compounds were estimated according to variable spectral and analytical investigations. The ligand exhibited a neutral or mononegative tetradentate mode of coordination towards the central ions inside the octahedral arrangement that proposed for the three complexes. The DFT/B3LYP method was applied under different basis sets (6-31G*or SDD) to optimize the structures of new compounds except the UO₂(II) complex. The computational data were investigated to verify the binding mode that suggested spectrally. Moreover, studies in solution regarding Cu(II) ion via cyclic voltammetry were performed in absence or presence of H₃L, to realize the significant effect of complex formation on the electrochemical manners of copper. The shifts in the potential peaks accompanied by the changes in the values of parameters correspond to kinetic and thermodynamic. Also, the solvation and kinetic characteristics for the cathodic and anodic potential of Cu(II) ion in absence or presence of H₃L at different scan rates, were estimated. Finally, the ligand and copper ion exhibited high affinity towards complexation in solution. Furthermore, the activity of the new compounds towards inhibiting microbes was studied against Staphylococcus aureus (G+) and Escherichia coli (G-) bacteria as well as Candida albicans (fungus) by determining the inhibition zone diameter. Also, both the antioxidant and cytotoxic activity of the isolated compounds were evaluated. Commonly, a remarkable antimicrobial and anticancer activity was appeared with UO₂(II) complex and the ligand. While, the antioxidant activity of all compounds appeared lower.     

Palladium(II) and Platinum(II) Complexes of N-Phenyl- and N-Ethyl-N′-pyrimidin-2-ylthiourea

Palladium(II) and platinum(II) complexes of N-ethyl-N′-pyrimidin-2-ylthiourea(HL¹) and N-phenyl-N′-pyrimidin-2-ylthiourea (HL²) have been prepared, and the complexes [M(HL)Cl₂], [Pt(L)₂], [Pd(HL¹)₂]Cl₂, and [Pd(L²)₂] (where M = Pd^II or Pt^II) were characterized. The spectroscopic data are consistent with coordination of thioureas as neutral or monoanionic ligands to Pd^II and Pt^II through S and a pyrimidine-N. The IR spectra show shifts of CS and pyrimidine ring stretch bands to lower and higher frequencies, respectively. The ¹H NMR spectra differentiate between H(4′) and H(6′) resonances and indicate downfield shifts for all protons of pyrimidine [H(4′), H(5′), and H(6′)], two resonances for two N?H protons for complexes containing the neutral ligand (HL), and only one N?H proton chemical shift for complexes containing the monoanion (L). ¹³C NMR chemical shifts of pyrimidine carbons are correlated with the type of bonding between Pd^II or Pt^II and pyrimidine-N. The magnetic susceptibilities suggest a diamagnetic planar structure for all complexes.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and Characterization of Cobalt(II), Nickel(II), and Zinc(II) Complexes with N,N ′-bis( Trans- Cinnamaldehyde)-1,2-Diiminoethane Ligand, (ca 2 en): Crystal and Molecular Structures of Co(ca 2 en)Cl 2 , Co(ca 2 en)Br 2 and Ni(ca 2 en)Br 2

A series of new complexes of the Schiff base obtained from trans- cinnamaldehyde and 1,2-diaminoethane (en) with the general formula of M(ca 2 en)X 2 (M = Co(II), Ni(II), Zn(II); X = Cl, Br, I, NCS, N 3 ; (ca 2 en) = N,N '-bis( trans- cinnamaldehyde)-1,2-diiminoethane) have been synthesized and characterized. The crystal structures of three pseudo -tetrahedral complexes, Co(ca 2 en)Cl 2 ( 1 ), Co(ca 2 en)Br 2 ( 2 ), and Ni(ca 2 en)Br 2 ( 5 ), were determined by X-ray diffraction. Crystal data for 1 , Co(ca 2 en)Cl 2 : monoclinic; space group P 2 1 / c ; a = 7.1925(14) Å, b = 20.327(4) Å, c = 14.029(3) Å; g =95.06(3)°; V = 2043.1(7) Å 3 ; Z = 4; and final R 1 = 0.0381 ( wR 2 = 0.0718) for 4653 independent reflections with I > 2 σ ( I ) and 226 parameters; 2 , Co(ca 2 en)Br 2 ; monoclinic, space group P 2 1 / c ; a = 7.3780(6) Å, b = 20.4372(17) Å, c = 14.1649(12) Å; g = 94.902(2)°; V = 2128.1(3) Å 3 ; Z = 4; and final R 1 = 0.0491 ( wR 2 = 0.1052) for 5858 independent reflections with I > 2 σ ( I ) and 227 parameters; 5 , Ni(ca 2 en)Br 2 : monoclinic, space group P 2 1 / c ; a = 7.2388(6) Å, b = 20.4651(16) Å, c = 14.2782(12) Å; g = 94.160(2)°; V = 2109.6(3) Å 3 ; Z = 4; R 1 = 0.0481 ( wR 2 = 0.0907) for 5914 independent reflections with I > 2 σ ( I ) and 227 parameters. The structures consist of discrete molecules in which the coordination polyhedra about the central metal ion are highly distorted tetrahedra with Cl(1)-Co-Cl(2), 115.51(3)°; N(1)-Co-N(2), 83.71(7)°; Br(1)-Co-Br(2), 114.58(4)°; N(1)-Co-N(2), 84.92(19)°; and Br(1)-Ni-Br(2), 125.23(3)°; N(1)-Ni-N(2), 85.11(15)° in 1 , 2 , and 5 , respectively. The stiryl groups are cis -endo with respect to the metal atom and the chelate ring is puckered. Utilization is made of electronic and vibrational spectra in structural diagnosis of other complexes.     

Zinc(II) and cadmium(II) complexes having racemic and enantiomeric ligands: [Zn(La)2](NO3)2 · CH3CH2OH and [Cd(Lb)2Cl](ClO4) (La = D,L and Lb = D-(+)-1,2, 2-trimethylcyclopentane-1,3-diamine)

Two d¹⁰ transition-metal complexes having racemic and enantiomeric 1,2,2-trimethylcyclopentane-1,3-diamine ligands, [Zn(L_a)₂](NO₃)₂ · CH₃CH₂OH (1) and [Cd(L_b)₂Cl](ClO₄) (2) (L_a = D,L-1,2,2-trimethylcyclopentane-1,3-diamine, L_b = D-(+)-1,2,2-trimethylcyclopentane-1,3-diamine or (1R,3S)-1,2,2-trimethylcyclopentane-1,3-diamine), were synthesized and characterized by X-ray single-crystal diffraction. They crystallize in the Pbca and P2₁2₁2₁ space groups, respectively, and have different coordination numbers and coordination geometry (four-coordinate tetrahedron for Zn(II) in 1 and five-coordinate square-based pyramid for Cd(II) in 2) mainly due to their different ionic radii.     

Tetranuclear azido-bridged copper(II) complex [Cu4(μ-salpn)2(μ1,1-N3)2(N3)2(H2O)2]: Synthesis,characterization and crystal structure

The reaction of salpnH₂ Schiff-base ligand (salpnH₂ = N,N′-bis(salicylidene)-1,3-propylenediamine) with Cu(NO₃)₂·3H₂O and a large excess of NaN₃ (1:2:8 molar ration), lead to the formation of [Cu₄(μ-salpn)₂(μ_1,1-N₃)₂(N₃)₂(H₂O)₂] (1), which has been successfully obtained and characterized by elemental analyses, IR spectroscopy and single-crystal X-ray diffraction. The strong absorption band at about 2000–2100 cm^?1 and at 1597 cm^?1 regions of the IR spectrum of 1 clearly proves the presence of the both end-on (EO) bridging and terminal azido ions and CN (azomethine) groups, respectively. Single-crystal X-ray analyses revealed that the copper atoms are bridged alternately by end-to-on (EO) azido and phenoxo-salpn ligands in the prepared tetranuclear copper(II) complex [Cu₄(μ-salpn)₂(μ_1,1-N₃)₂(N₃)₂(H₂O)₂] (1).     

Ionic coordination complexes based on [Re6S8(CN)4L2]n– (L = OH–, NH3; n = 2, 3) cluster anions,and Ni(II) and Cd(II) ammine cations

Two new complexes containing M(II) ammine cations (M = Ni, Cd) and octahedral rhenium(III) thiocyanoammine and thiocyanohydroxoammine cluster anions, [Ni(NH₃)₆][Re₆S₈(CN)₄(NH₃)₂]?2H₂O (1) and [Cd(NH₃)₆][{Cd(NH₃)₅}{Re₆S₈(CN)₄(OH)(NH₃)}]₂?5H₂O (2), have been synthesized by hydrothermal reactions starting from Cs_1.83K_2.17[Re₆S₈(CN)₄(OH)₂]?2H₂O. The compounds were structurally characterized by single-crystal X-ray diffraction analysis, elemental analysis, energy dispersive spectroscopy, and IR spectroscopy. Both compounds adopt monoclinic crystal structures composed from discrete ionic species which are held together by multiple hydrogen bonds between CN^–, OH^–, and NH₃ ligands and lattice water. 2 consists of {Cd(NH₃)₅}²⁺ attached to the OH group of the [Re₆S₈(CN)₄(OH)(NH₃)]^3– cluster anion via the Re–OH–Cd linkage.     

Synthesis,characterization and crystal structures of copper(II), zinc(II) and vanadium(V) complexes,derived from 3-methyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide,with antibacterial activity

Three copper(II), zinc(II), and vanadium(V) complexes, [CuL(HL)]ClO₄ (1), [ZnL₂] (2) and [VO₂L] (3), where L is the anionic form of 3-methyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL), were prepared and characterized by IR, UV–vis and single-crystal X-ray determination. X-ray analysis indicates that the complexes are mononuclear species, with the Cu and Zn ions in 1 and 2 in octahedral coordination, and with the V ion in 3 in trigonal bipyramidal coordination. The hydrazone compound and the three complexes were evaluated for antibacterial activities. The copper complex has effective activities.     

Synthesis,crystal structures,and selected properties of Cu(II) and Zn(II) complexes with in situ formed 2-hydroxy-N′-(propan-2-ylidene)benzohydrazide

Cu(C₁₀H₁₁O₂N₂)₂ (1) and [Zn(C₁₀H₁₂O₂N₂)₂(H₂O)₂](NO₃)₂ (2) were synthesized and characterized by elemental analysis, FT-IR spectra, UV-Vis absorption spectroscopy, and X-ray single-crystal diffraction. Both complexes show distorted octahedral geometry. In 1, Cu(II) is coordinated by four oxygen atoms from four ligands and two nitrogen atoms from two ligands. In 2, Zn(II) is coordinated by two oxygen atoms and two nitrogen atoms from two ligands, and two water molecules. The crystal structures suggest that original ligand o-carboxybenzaldehyde salicyloylhydrazone (C₁₅H₁₂O₄N₂) changed into acetone salicyloylhydrazone (C₁₀H₁₂O₂N₂). The TG-DTG curves of these complexes indicate two different decomposition processes. 1 and 2 display catalytic activities to decomposition of hydrogen peroxide. Interaction between the complexes and DNA studied by UV-Vis titration shows the insert interaction.     

Trinuclear Cu(II) and Zn(II) complexes bridged by μ3-carbonato anion

The trinuclear Cu(II) and Zn(II) complexes [(CuTPA),(μ₃-CO,)] (C10₄)₄(1) and [(ZnTPA),(μ₃-C0₃)](C10₄)₄ (2) (TPA = tri(pyridylmethy1)amine) have been synthesized. X-ray structure analysis of the two complexes proves that CO₃ ^2- anion has an unusual triply bridging ligand, bridging three CuTPA and ZnTPA units respectively, and assembles new trinuclear complexes. The CO₃ ²- comes from atmospheric CO₂. The structure of each trinuclear unit consists of three copper or zinc atoms in a five-coordinate triangular hipyramidal environment. The [(CuTPA)₃(μ₃-C0₃) ](C10₄), compound shows a very weak antifemmagnetic coupling. Project supported by the National Natural Science Foundation of China (Grant No.29771021).     

Synthesis and magnetic properties of heterobinuclear copper(II)–iron(II) complexes with N,N′-bis(2-aminopropyl)oxamidocopper(II)

Six new -oxamido heterobinuclear complexes, namely [Cu(oxap)Fe(L)2]SO4, where oxap denotes the N,N-bis(2-aminopropyl)oxamido dianion and L represents 1,10-phenanthroline (phen); 5-nitro-1,10-phenanthroline (NO2-phen); 5-chloro-1,10-phenanthroline (Cl-phen); 5-methyl-1,10-phenanthroline (Me-phen); 2,2-bipyridine (bpy); and 4,4-dimethyl-2,2-bipyridine (Me2bpy), have been synthesized and characterized by elemental analyses, i.r. spectra, electronic spectra, magnetic moments (at room temperature) and molar conductivity measurements. The temperature dependent magnetic susceptibilities of [Cu(oxap)Fe(bpy)2]SO4 (1) and [Cu(oxap)Fe(phen)2]SO4 (2) have been studied in the 4.2–300K range, giving the exchange integrals J=–20.9cm–1 for (1) and J=–22.5cm–1 for (2). These results are commensurate with antiferromagnetic interactions between adjacent metal ions within each molecule.     

Copper(II) and nickel(II) complexes of N,N′-bis(2-cyanoethyl)-5, 7-dioxo-1,4,8,11-tetra-azacyclotetradecane

Summary Reaction of 5,7-dioxo-1,4,8,11-tetra-azacyclotetradecane with acrylonitrile gives the dicyanoethylated ligand (L). The Cu^II complex [CuLH_-2]·2H₂O has been isolated from basic solution where the macrocycle is deprotonated and acts as a dinegative quadridentate ligand. The ligand L is protonated in acidic solution and the ionisation equilibria can be summarised as LH _inf2 ^sup2+ LH⁺ +H⁺; K₁ LH⁺ L + H⁺; K₂ where pK₁ = 3.05 and pK₂ = 5.94 at 25 °C and I = 0.1 mol dm^-3 (NaNO₃). Complexation with Cu^II can be represented by the equilibria at 25 °C. Cu²⁺ + L [CuLH_-1]⁺ + H⁺; log_{11 – 1} = -3.43 Cu²⁺ + L [CuLH_-2] + 2H²⁺; log_{11 – 2} = -9.18 For Ni^II only the single equilibrium is of importance. Ni²⁺ + L [NiLH_-2] + 2H²⁺; log_{11 – 2} = -14.45     

Copper(II), zinc(II), and cadmium(II) coordination polymers with 2-methylglutarato and 4,4′-dipyridyldisulfide

Three new coordination polymers of copper(II), zinc(II) and cadmium(II), Cu(H₂O)(Dpds)(2-MGA) (I), [Zn(Dpds)(2-MGA)] · 1.25H₂O (II) and [Cd(H₂O)(Dpds)(2-MGA)] · 0.25H₂O (III) (Dpds = 4,4′-dipyridyldisulfide, H₂MGA = (RS)-2-methyl glutaric acid), have been synthesized and characteried by X-ray single crystal structure determination. The Cu atoms in I are alternately bridged by Dpds ligands and 2-methylglutarato ligands to generate 1D chain. The resulted chains are assembled via S...S weak interactions into 2D layers, which are through twofold 2D parallel/2D parallel mode inclined interpenetration to induce 3D supramolecular architecture. In II, the ZnN₂O₂ tetrahedras are bridged by 2-MGA anion and Dpds ligands to form 2D (4,4) networks, which are assembled via hydrogen bonds to 3D supramolecular architecture. The centrosymmetric binuclear units Cd₂(2-MGA)₂ in III are bridged by Dpds ligands to form 1D repeated rhomboids chains, which are interlinked via S...S weak interactions into 2D layer, and the resulting 2D sheets are inclined parallel into 3D network.