Tungsten(V) dimeric complexes with heterocyclic dithiocarbamates

In this paper we report the syntheses and study of a number of oxo- and sulphido-bridged tungsten(V) complexes with morpholine dithiocarbamate and piperidine dithiocarbamate as ligands. We assign the following formulae to the complexes: W₂O₃(Rdtc)₄, W₂O₄(Rdtc)₂, W₂O₂S₂(Rdtc)₂ and W₂O₃S(Rdtc)₂ (where R = morpholine and piperidine), based on the analytical data. We have studied the complexes by IR and electronic spectra, and magnetic susceptibility measurements. We assign in the IR spectra the following bands: W=O (ν_s=939–948 cm^?1), W-O_b(ν_a=813–819 cm^?1, ν_s = 431–448 cm^?1), W-S_b (ν_a=470–476 cm^?1, ν_s = 368–370 cm^?1, C-N (β = 1511–1519 cm^?1) and C-S (ν = 1090–1113 cm^?1). The low values of the magnetic moments (0.03–0.60 B.M.) are in accordance with a dimeric species of tungsten(V).     

过渡金属取代的钨铝杂多配合物的制备、表征和性质

用分步设计法合成了以铝为中心原子的过渡元素与钨的三元杂多配合物,经ICP、TG分析确定其化学式为K_4，6，7[AlM(OH₂)W₁₁O₃₉]·xH₂O(M=V⁵⁺、Cr³⁺、Mn²⁺、Fe³⁺、Co²⁺、Ni²⁺、Cu²⁺、Zn²⁺、Cd²⁺)。采用IR、UV、XRD、¹⁸³W和²⁷Al NMR等对配合物的结构进行了表征,表明配合物具有Keggin结构；循环伏安法对该系列配合物的氧化还原性质研究表明,其氧化还原过程为不可逆的两电子还原,配合物的磁化率测试均表现为顺磁性,还对其热稳定性进行了讨论。     

Reactions of silicon-, germanium- and tin-containing carbene complexes of tungsten Ph3E-CW(OBu)3 (E=Si, Ge, Sn) with hydrogen chloride: crystal structures of carbene complexes Ph3E-CHWCl2(OBu)2 (E=Si, Ge)

The novel organosilicon, -germanium and -tin-containing carbene complexes of tungsten of the type Ph₃E-CHWCl₂(OBu^t)₂ (E=Si, Ge, Sn) have been prepared by the reaction of heteroelement-containing carbene complexes of tungsten Ph₃E-CW(OBu^t)₃ (E=Si, Ge, Sn) with hydrogen chloride. The tin-containing carbene complex was identified in solution by ¹H NMR spectroscopy. Silicon- and germanium-containing carbene complexes were isolated in high yields as crystalline solids and characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR and ²⁹Si NMR spectroscopy and X-ray diffraction studies. The geometry of the W atoms in the compounds can be described as a distorted square pyramid.     

Synthesis and characterization of tungsten carbonyl complexes containing N-methyl substituted urea and thiourea ligands

Six new mixed-ligand tungsten carbonyl complexes containing N-methyl substituted urea and thiourea of the type W(CO)₄[RCH₂N-(C=X)NH₂] where X?=?O or S and R?=?morpholine, piperidine and diphenylamine are reported. These have been prepared by refluxing hexacarbonyl tungsten(0) with corresponding ligands in THF to produce cis-disubstituted products, [(L-L)W(CO)₄] where L-L?=?a chelating bidentate ligand, morpholinomethyl urea (MMU), morpholinomethyl thiourea (MMTU), piperidinomethyl urea (PMU), piperidinomethyl thiourea (PMTU), diphenylaminomethyl urea (DAMU) and diphenylaminomethyl thiourea (DAMTU). The compounds have been characterized by elemental analysis, IR, electronic and ¹³C NMR spectra, magnetic moments and conductivity measurements. The IR spectra suggests that in all the complexes, the ligands are bidentate chelating, coordinating the metal through carbonyl oxygen or thiocarbonyl sulphur and the ring nitrogen or tert-nitrogen of diphenylamine. The CO force constants and CO–CO interaction constants for these derivatives have also been calculated using Cotton–Kraihanzel secular equations, which indicate poor π-bonding ability of the ligands. ¹³C NMR and electronic spectra reveal loss of cis-carbonyl ligands to produce cis-disubstituted tetracarbonyl derivatives. Molecular modeling studies have been carried out using Hyperchem release 7.52 which suggest a distorted octahedral geometry for these complexes.     

Synthesis, spectroscopic, antimicrobial, DNA binding and cleavage studies of some metal complexes involving symmetrical bidentate N, N donor Schiff base ligand

The Schiff base ligand, N,N′-bis-(4-isopropylbenzaldimine)-1,2-diaminoethane (L), obtained by the condensation of 4-isopropylbenzaldehyde and 1,2-diaminoethane, has been used to synthesize the complexes of the type [ML₂X₂] [M = Co(II), Ni(II) and Zn(II); X = Cl and OAc]. The newly synthesized ligand (L) and its complexes have been characterized on the basis of elemental analyses, mass, ¹H and ¹³C-NMR, molar conductance, IR, UV–vis, magnetic moment, CV and thermal analyses, powder XRD and SEM. IR spectral data show that the ligand is coordinated to the metal ions in a bidentate manner. The geometrical structures of these complexes are found to be octahedral. Interestingly, reaction with Cu(II) ion with this ligand undergoes hydrolytic cleavage to form ethylenediamine copper(II) complex and the corresponding aldehyde. The antimicrobial results indicate that the chloro complexes exhibit more activity than the acetato complexes. The complexes bind to CT–DNA by intercalation modes. Novel chloroform soluble ZnL₂Cl₂ complex exhibits tremendous antimicrobial, DNA binding and cleaving properties.     

Two New Trinuclear MII (M = Mn,Co) Complexes Based on 2,4‐Dichlorobenzoic Acid: Synthesis,Structures and Magnetic Properties

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 Co^II ions.     

Complexes of the Lighter Lanthanoid Nitrates with 15-crown-5 and 18-crown-6 ethers: Synthesis and characterization

Complexes of lanthanoid trinitrates Ln(NO₃)₃ with 15-crown-5 ether 1 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd) and with 18-crown-6 ether 2 (Ln = La, Ce, Pr, Nd) having a 1:1 stoichiometry as well as 4:3 complexes with 2 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd) have been synthesized and characterized. All the isolated complexes are solvent free. At 170–220° the 1:1 complexes of 2 are quantitatively transformed into 4:3 complexes. X-Ray powder diagrams of the neodymium complexes with 2 indicate that both the 1:1 and 4:3 complexes are genuine compounds. All the 1:1 complexes show a characteristic IR. absorption band at 875–880 cm^?1 absent from both the spectra of the free ligands and of the 4:3 complexes. The spectroscopic properties (IR. and electronic spectra, fluorescence lifetimes) of the complexes and the low magnetic moments of the Ln(III) ions in the complexes with Ln = Ce-Eu are indicative of a strong interaction between the lanthanoid ions and the crown ethers 1 and 2 .     

Synthesis and magnetic properties of novel containing 1,10-phenanthroline polymeric complexes

The polymer (DAPcTPA) was synthesized by polycondensation of 5,6-diamine-1,10-phenanthroline (DAP) with terephthaldehyde (TPA). Three polymeric complexes were first prepared from polymer (DAPcTPA) and NiSO₄, CoCl₂ or FeSO₄, respectively. The structures of polymer and complexes were characterized by IR, ¹H NMR spectra and elemental analysis. The magnetic behavior of these complexes was measured as a function of magnetic field strength (0-50 kOe) at 5 K and as a function of temperature (5-300 K) at a magnetic field strength of 30 kOe. The results show that DAPcTPA-Ni²⁺ and DAPcTPA-Co²⁺ are soft ferromagnets, while DAPcTPA-Fe²⁺ exhibits features of an antiferromagnet.     

Syntheses,toxicity and biodistribution of CO‐releasing molecules containing M(CO)5 (M = Mo,W and Cr)

A series of CO‐releasing molecules M(CO)₅ L (M = Mo, W and Cr), ( 1 , 2 , 3 , L = glycine methyl ester; 4 , 5 , 6 , N‐methylimidazole; 7 , 8 , 9 , 2‐aminopyridine; 10 , 11 , 12 , 3‐aminopyridine; 13 , 14 , 15 , 4‐aminopyridine), were synthesized. All complexes have been characterized by NMR, IR and electrospray ionization mass spectroscopy; the octahedral structures of 14 and 15 were also established by X‐ray crystallography. Furthermore, all complexes were evaluated for toxicity, pharmacokinetics and metabolic processes. Cytotoxic effects on the proliferation of fibroblast cell line were assayed by MTT. Among the complexes, Mo complex 1 showed the lowest cytotoxicity (IC₅₀ = 597 µmol l^?1) and W complex 2 showed a remarkable toxic effect, with IC₅₀ = 52 µmol l^?1. With the same ligand, the toxic effects of the complexes increase in the order of metal element W < Cr < Mo. For the same central metal element, the complexes containing imidazole showed lower toxic effects than those containing amino acid ester or aminopyridine. In accordance with the results from cytotoxicity, the complexes also showed corresponding toxic effects in animal models. The biodistributions of the complexes were established by inductively coupled plasma–atomic emission spectroscopy, measuring metal in tissues and organs. The results show that the complexes were gradually absorbed and unevenly distributed in vivo. The complexes containing imidazole entered tissues and organs faster than those containing amino acid ester. The complexes containing W atom were absorbed and distributed more slowly than those containing Mo or Cr atoms. Copyright © 2014 John Wiley & Sons, Ltd.     

Cobalt(II), Nickel(II), and Copper(II) Complexes with Diphenylthiocarbazide

New [ML(H₂O)₂] complexes (M = Co²⁺, Ni²⁺, or Cu²⁺; H₂L = diphenylthiocarbazide) were synthesized and studied using IR and diffuse reflection electronic spectroscopy, magnetic chemistry, conductometry, and DTA. The metals were shown to coordinate L^2–through nitrogen and sulfur atoms. The complex [CuL(H₂O)₂] is a dimer.     

Macrocyclic divalent transition metal complexes of acetylacetone buckled with two different diamines

Metal-mediated condensation of o-phenylenediamine with bisacetylacetone-ethylenediimine yields 14-membered tetraaza macrocyclic six-coordinate complexes of the type [M(mac)Cl₂],[M(mac)SO₄·H₂O] (where M = Fe^II, Co^II and Cu^II; MAC = macrocyclic ligand formed in the template reaction). The metal ions are coordinated by four azomethine nitrogen atoms bridged by acetylacetone moieties. The electrical conductance magnetic moments, electronic and IR spectral data of all complexes are discussed.     

Synthesis and characterization of two binuclear iron(III) complexes of aminoethanol derivatives of aminophenol as models for non-heme iron enzymes active sites

Two aminoethanol derivatives of aminophenol ligands were synthesized and characterized by IR and ¹H NMR spectroscopies. The binuclear iron(III) complexes of these ligands have been prepared and characterized by IR, ¹H NMR and UV-Vis spectroscopic techniques, cyclic voltammetry, single crystal X-ray diffraction and magnetic susceptibility studies. X-ray analysis revealed binuclear complexes, Fe₂(L₂), in which Fe(III) centers are surrounded by two phenolate and hydroxyl oxygen atoms, and amine nitrogens of the ligands. The metal active sites of both complexes are held together by the two above mentioned hydroxyl bridges. Variable temperature magnetic susceptibility indicates antiferromagnetic coupling between the iron centers of both complexes. This exchange coupling is stronger for Fe₂(L^ae)₂, such that it shows a room temperature strong coupling between the two iron centers. The investigated complexes undergo irreversible electrochemical oxidation and reduction.     

Syntheses and structures of layered compounds based on lanthanides(iii) and cubane molybdenum and tungsten telluride cyano complexes

Eight isostructural polymeric coordination compounds of the general formula [Ln(DMF)(H₂O)₄][Ln(DMF)₂(H₂O)₄][M₄Te₄(CN)₁₂]·DMF·nH₂O (Ln = Er, Ho, Gd, or Sm; M = W or Mo) were prepared for the first time by evaporation in air of aqueous solutions containing the cuboidal telluride anionic complex of tungsten [W₄Te₄(CN)₁₂]^6– or molybdenum [Mo₄Te₄(CN)₁₂]^7–, lanthanide chlorides, and dimethylformamide. The resulting polymeric coordination complexes with layered structures were characterized by X-ray diffraction analysis and IR spectra. The magnetic susceptibilities of the gadolinium complexes were measured.     

Synthesis,structural studies and bio-activity of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with p -amino acetophenone salicyloyl hydrazone

Complexes of the type [M(pash)Cl] and [M(Hpash)(H₂O)SO₄] (M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpash = p-amino acetophenone salicyloyl hydrazone) have been synthesized and characterized by elemental analyses, molar electrical conductance, magnetic moments, electronic, ESR and IR spectra, thermal studies and X-ray powder diffraction. All the complexes are insoluble in common organic solvents and are non-electrolytes. The magnetic moment values and electronic spectra indicate a square-planar geometry for Co(II), Ni(II) and Cu(II) chloride complexes and spin-free octahedral geometry for the sulfato complexes. The ligand coordinates through >C=N–,–NH₂ and a deprotonated enolate group in all the chloro complexes, and through >C=N–, >C=O and–NH₂ in the sulfato complexes. Thermal analyses (TGA and DTA) of [Cu(pash)Cl] show a multi-step exothermic decomposition pattern. ESR spectral parameters of Cu(II) complexes in solid state at room temperature suggest the presence of the unpaired electron in d _{x ² ? y ²} . X-ray powder diffraction parameters for [Cu(pash)Cl] and [Ni(Hpash)(H₂O)SO₄] correspond to tetragonal and orthorhombic crystal lattices, respectively. The complexes show a fair degree of antifungal activity against Aspergillus sp., Stemphylium sp. and Trichoderma sp. and moderate antibacterial activity against E. coli and Clostridium sp.     

Mass, EPR, IR and electronic spectroscopic studies on newly synthesized macrocyclic ligand and its transition metal complexes

Manganese(II), cobalt(II), nickel(II) and copper(II) complexes have been synthesized with a new tetradentate ligand viz. 1,3,7,9-tetraaza-2,4,8,10-tetraketo-6,12-diphenyl-cyclododecane (L) and characterized by the elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H NMR, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMF correspond to be nonelectrolytic nature for Mn(II), Co(II) and Cu(II) while 1:2 electrolytes for Ni(II) complexes. Thus, these complexes may be formulated as [M(L)X₂] and [Ni(L)]X₂ (where M = Mn(II), Co(II) and Cu(II) and X = Cl⁻ and NO₃⁻).On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Mn(II) and Co(II) complexes, square-planar for Ni(II) whereas tetragonal for Cu(II) complexes. The ligand and its complexes were also evaluated against the growth of bacteria and pathogenic fungi in vitro.     

The IR and Raman spectra of 2-amino pyrimidine complexes of some Zn(II), Cd(II) and Hg(II) halides

A series of complexes of the type HgX₂(2-AMP) and MX₂(2-AMP)₂ where M = Zn(II) or Cd(II), X = Cl, Br or I and 2-AMP = 2-amino pyrimidine have been prepared, characterized and their IR and Raman spectra recorded. The IR spectra show that the ligand coordinates through the amino group, and that the heterocyclic nitrogens do not play an important role in coordination. The above conclusion is also supported by the ¹H and ¹⁹C NMR spectra. The far-IR and Raman spectra show that the HGX₂(2-AMP) species possess a trans halogen-bridged structure of C_2h symmetry, whereas the Zn₂(2-AMP)₂ and CdI₂(2-AMP)₂ complexes are pseudotetrahedral of C_2υ symmetry.     

Synthesis and spectral characterization of some binuclear complexes designed from N4O and N2O3 donor Schiff-base ligands of 2,6-diformyl-4-methylphenol

New pentadentate binucleating ligands containing phenoxide as an endogenous bridging group, 2,6-diformyl-4-methylphenol bis(carbohydrazone) (L¹H), and 2,6-diformyl-4-methylphenol bis(semicarbazone) (L²H), and their binuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes of general formula [M₂LCl₃] · nH₂O with chloride as an exogenous bridge have been synthesized. The complexes were characterized on the basis of elemental analysis, conductivity measurements, thermal analysis, IR, Far-IR, NMR, UV–Vis, EPR, FAB-mass and magnetic data. The coordination mode (N₄O, N₂O₃), as well as endogenous phenoxide bridge and an exogenous chloride bridge have been established on the basis of IR, Far-IR and ¹H-NMR spectral data. Electronic spectral data of the complexes indicate square-pyramidal geometry. EPR spectra show line broadening, which is further supported by weak antiferromagnetic interaction from the room temperature magnetic moment data. All compounds show appreciable antimicrobial activity.     

Molybdenum(0) and Tungsten(0) Complexes with P,S and P,Se Monooxidized Bis(phosphanyl)amine Ligands

Reactions of monooxidized thioyl and selenoyl bis(phosphanyl)amine ligands C₁₀H₇‐1‐N(P(E)Ph₂)(PPh₂) [E = S ( 1 ), Se ( 2 )] with Mo(CO)₄(pip)₂ and W(CO)₄(cod) afforded the complexes [M(CO)₄{ 1 ‐κ²P,S}] [M = Mo ( 3 ), W ( 4 )] and [M(CO)₄{ 2 ‐κ²P,Se}] [M = Mo ( 5 ), W ( 6 )]. Complexes 3 – 6 were characterized by multinuclear NMR (¹H, ¹³C, ³¹P, and ⁷⁷Se NMR) and IR spectroscopy. Crystal‐structure determinations were carried out on 3 , 5 , and 6 , which represent the first examples of structurally characterized complexes of such ligands with group‐6 metal carbonyls.     

Synthesis and properties of the copper(Ⅱ) complexes with stable radical

Four novel copper(Ⅱ) complexes have been synthesized,namely Cu(hfac)2NITPhNO2 (1),Cu(hfac)2NITPhCH3 (2),Cu(pfpr)2NITPhNO2,(3) and Cu(Pfpr)2NITPhCH3 (4),where hfac= hexafluoro-acetylacetonate,pfpr=pentafluoropropionate,NITR.=2-R-4,4,5,5-tetraniethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide.(R=4-nitrophenyl,4-methylphenyl).These complexes were rharicter-ized by elemental analyses,IR,electronic spectra and molar conductance.The temperature-dependent magnetic susceptibility of complexes 1 and 3 have been studied in the 4 300 K range,giving I he exchange integral J=10.56 cm-1 for complex 1 and J =-30.9 cm-1 for complex 3.     

Synthesis and physico-chemical studies of metal(II) complexes with diacetyl benzaldehyde acyldihydrazones and their bio-activity

Complexes of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with diacetyl benzaldehyde oxalic acid dihydrazone (dbodh), CH₃COC(CH₃)=NNHCOCONHN=CHC₆H₅ and diacetyl benzaldehyde malonic acid dihydrazone (dbmdh), CH₃COC(CH₃)=NNHCOCH₂CONHN=CHC₆H₅ of general composition [M(dbodh)Cl]Cl and [M(dbmdh)Cl]Cl were synthesized and characterized by microanalyses, molar conductance, magnetic susceptibility, UV–Vis, ESR and IR spectra and X-ray diffraction studies. The complexes are 1 : 1 electrolytes in DMF and are insoluble in water and common organic solvents. The dbodh and dbmdh are neutral tridentate ligands in most complexes and coordinate via one >C=O and two >C=N–groups. In Cu(II) complexes the ligands are pentadentate coordinating through three >C=O and two >C=N–groups. The magnetic moment values and UV–Vis spectra suggest square-planar geometry for Co(II) and Ni(II) complexes and distorted octahedron for both Cu(II) complexes. The ESR spectra of Cu(II) complexes show well-defined copper hyperfine lines in DMSO solution at 120 K and exhibit d _{x ² ?y ²} as the ground state. The X-ray diffraction parameters for [Ni(dbodh)Cl]Cl and [Co(dbmdh)Cl]Cl correspond to a tetragonal crystal lattice. The complexes show significant antifungal activity against Alternaria sp., Curvularia sp. and Colletotrichum sp. and fair antibacterial activity against Bacillus subtilis and Pseudomonas fluorescence.