Synthesis and characterization of new metal complexes of thiosemicarbazone derived from 4-phenyl-3-thiosemicarbazide and chromone-3-carboxaldehyde

Summary The reaction between chromone-3-carboxaldehyde-4-phenylthiosemicarbazone (HCPT) and some hydrated metal salts of Co^II, Ni^II and Cu^II give complexes of the type [Cu(HCPT)Cl₂],[Cu(CPT)BrH₂O],[Cu(CPT)₂]·2H₂O, [Ni(CPT)₂(H₂O)₂]·2H₂O, [Co(CPT)₂(OAc)] and [Co(CPT)₂(H₂O)₂]X·2H₂O (where X=Cl or Br). The metal complexes were characterized by elemental analyses, molar conductivities, and spectal (i.r. and visible) and magnetic studies. I.r. spectra show that the HCPT coordinates in the thione or thiol form and behaves in a bidentate manner. Also, HCPT behaves as an oxidizing agent towards Co^II forming diamagnetic Co^III complexes. An octahedral structure is proposed for both Co^III and Ni^II complexes, while a square-planar structure is proposed for Cu^II complexes on the basis of magnetic and spectral measurements.     

Copper(II), cobalt(II), nickel(II) and mercury(II) complexes of 1,4-diphenylthiosemicarbazide

Summary The preparation and characterization of Cu^II, Co^II, Ni^II and Hg^II complexes containing 1,4-diphenylthiosemicarbazide (DPhTSC) of the type [Cu(DPhTSC-H)X.H₂O]nH₂O (X= Cl, Br or Ac; n=0 or 1) · [M(DPhTSC-H)₂yH₂O] (M=Co^II or Ni^II; y=0 or 1) and [Hg(DPhTSC)Cl₂]2 H₂O and [Cu(D-PhTSC)₂SO₄]H₂O are reported. The stereochemistry of the complexes have been studied with the help of magnetic and electronic measurements. The anomalous magnetic moments observed in all cases have been explained. The i.r. spectral studies have been used to determine the bonding sites in the complexes.     

Synthesis and structural characterization of 3d-metal complexes of pyridine-4-carboxaldehyde thionicotinoyl hydrazone

Summary Pyridine-4-carboxaldehyde thionicotinoyl hydrazone (4-PTNH) forms 1:1 adducts with metal(II) halides and 1:2 complexes (metal to ligand) with metal(II) thiocyanates. Magnetic and spectral studies indicate polymeric octahedral geometry for M(4-PTNH)X₂ (M=Co^II or Cu^II, X=Cl; M=Ni^II, X=Cl, Br or I), five coordinate geometry for Co(4-PTNH)X₂ (X=Br or I) and octahederal geometry for [M(4-PTNH)₂(NCS)₂] (M=Co^II or Ni^II). I.r. spectral studies show that 4-PTNH acts as a neutral bidentate ligand in all the complexes, the bonding sites being the thione sulphur and azomethine nitrogen.     

Studies ono-hydroxyacetophenone-2-furoylhydrazone complexes of some 3d-bivalent metal ions

Summary Complexes ofo-hydroxyacetophenone-2-furoylhydrazone, H₂L, of the types M(H₂L)C1₂ · nH₂O [Mn = Co^II, n=0; Ni^II, n=2]; Cu(HL)Cl, M(HL)₂ [M = V^IVO, Co^II, Ni^II or Cu^II] and M(L)(H₂O)_n [M = Co^II or Ni^II, n=2; M = Cu^II, n=0] have been prepared and characterized by elemental analyses, molar conductance, magnetic susceptibility, visible, e.s.r. and i.r. spectral studies. The different modes of ligand chelation and the stereochemistry around the metal ions are discussed.     

Preparation,characterization and antifungal properties of transition metal ion complexes of quadridentate N3S ligands

Summary New metal complexes [M(NNNS)X] (M = Ni^II, Cu^II, Zn^II and Cd^II; NNNS^– = anion of the quadridentate ligands formed from S-methyl--N-(2-aminophenyl)-methylenedithiocarbazate and pyridine-2-aldehyde or 6-methylpyridine-2-aldehyde; X = Cl, NCS, NO₃ or I) and [Co(NNNS)Cl₂]·2H₂O have been prepared and characterized by elemental analysis and conductance measurements. Magnetic and spectroscopic evidence support a five-coordinate structure for [M(NNNS)X] (M = Ni^II, Cu^II, Zn^II and Cd^II; X = Cl, NCS) and a squareplanar structure for [Ni(NNNS)]X (X = NO₃ or I). The [Co(NNNS)Cl₃]·2H₂O complex is low-spin and octahedral. The Schiff bases and some of their metal complexes were tested against three pathogenic fungi, Alternaria alternata, Curvularia geniculata and Fusarium palidoroseum. The metal complexes are less fungitoxic than the free ligands.     

The preparation and characterization of some new nickel(II), copper(II), zinc(II) and cadmium(II) complexes of the pyrrole-2-carboxaldehyde Schiff bases ofS-alkyl esters of dithiocarbazic acid

Summary New complexes of general formulae [Ni(HL)₂], [ML]·H₂O and [Cu(HL)X] (H₂L = pyrrole-2-aldehyde Schiff bases ofS-methyl- andS-benzyldithiocarbazates; X = Cl or Br; M = Ni^II, Cu^II, Zn^II or Cd^II) were prepared and characterized by a variety of physicochemical techniques. The Schiff bases coordinate as NS bidentate chelating agents in [Ni(HL)₂] and [Cu(HL)X], and as tridentate NNS chelates in [ML] (M = Ni^II, Cu^II, Zn^II or Cd^II). Both the [Ni(HL)₂] and [NiL] complexes are diamagnetic and square-planar. Based on magnetic and spectroscopic evidence, thiolate sulphur-bridged dimeric square-planar structures are assigned to the [Cu(HL)X] and [ML] (M = Ni^II or Cu^II) complexes. The complexes ML (M = Zn^II or Cd^II) are polymeric and octahedral.     

Preparation and characterization of some transition metal complexes of benzoic acid hydrazones of 2-aminonicotinaldehyde

Summary Cu^II, Ni^II, Co^II, Zn^II and Pd^II complexes of tridentate Schiff base ligands derived from the condensation of benzoic acid hydrazides with 2-aminonicotinaldehyde have been prepared and characterized. For M=Cu, Ni, Co and Zn the complexes were formulated as [M(ligand)(H₂O)X] (X=Cl, Br), with a distorted octahedral geometry and tridentate Schiff base ligands. The Pd complexes were formulated as Pd(ligand)Cl₂, with square planar geometries and bidentate Schiff base ligands. The e.s.r. spectra of the Cu^II complexes are discussed.     

The coordination chemistry ofN,N′-ethylenebis(2-acetylpyridine imine) andN,N′-ethylenebis(2-benzoylpyridine imine); two potentially tetradentate ligands containing four nitrogen atoms

Summary New complexes of the general formulae [ML_A(H₂O)₂]-Cl₂ (M=Ni or Cu), [ML_AX₂] (M=Co or Cu; X=Cl or Br), [NiL_ABr₂]·H₂O, [ML_A] [MCl₄] (M=Pd or Pt), [NiL_B(H₂O)₂]Cl₂·2H₂O, [ML_BCl₂] (M=Co, Ni, Cu, Pd or Pt; X=Cl or Br) and [ML_B] [MCl₄] (M=Pd or Pt), where L_A=N,N-ethylenebis(2-acetylpyridine imine) and L_B=N, N-ethylenebis(2-benzoylpyridine imine), have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, t.g./d.t.g. methods, magnetic susceptibilities and spectroscopic (i.r., far-i.r., ligand field,¹Hn.m.r.) studies. Monomeric pseudo-octahedral stereochemistries for the Co^II, Ni^II and Cu^II complexes andcis square planar structures for the compounds [ML_BX₂] (M=Pd or Pt; X=Cl or Br) are assigned in the solid state. The molecules L_A and L_B behave as tetradentate chelate ligands in the Co^II, Ni^II, Cu^II and Magnus-type Pd^II and Pt^II complexes, bonding through both the pyridine and methine nitrogen atoms. A bidentateN-methine coordination of the Schiff base L_B is assigned in the [ML_BX₂] complexes (M=Pd or Pt; X=Cl or Br). The anomalous magnetic moment values of the Co^II complexes are discussed.     

N-Phthaloylglycinate ternary complexes with cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) metal ions and aromatic mono,bi and tridentate amines

Complexes of N-phthaloylglycinate (N-phthgly) and Co^II, Ni^II, Cu^II, Zn^II and Cd^II containing imidazole (imi), N-methylimidazole (mimi), 2,2-bipyridyl (bipy) and 1,10-phenanthroline (phen), and tridentate amines such as 2,2,2-terpyridine (terpy) and 2,4,6-(2-pyridyl)s-triazine (tptz), were prepared and characterized by conventional methods, i.r. spectra and by thermogravimetric analysis. For imi and mimi ternary complexes, the general formula [M(imi/mimi)₂(N-phthgly)₂]·nH₂O, where M = Co^II, Ni^II, Cu^II and Zn^II applies. For Cd^II ternary complexes with imi, [Cd(imi)₃(N-phthgly)₂]·2H₂O applies. For the bi and tridentate ligands, ternary complexes of the formula [M(L)(N-phthgly)₂]·nH₂O were obtained, where M = Co^II, Ni^II, Cu^II and Zn^II; L = bipy, phen, tptz and terpy. In all complexes, N-phthgly acts as a monodentate ligand, coordinating metal ions through the carboxylate oxygen, except for the ternary complexes of Co^II, Ni^II and Cu^II with mimi and Cu^II and Zn^II with imi, where the N-phthgly acts as a bidentate ligand, coordinating the metal ions through both carboxylate oxygen atoms.     

Synthesis and spectral studies of copper(II), nickel(II) and cobalt(II) complexes of 2-hydroxy-ω-4-X-cinnamoyl acetophenones and their pyridine adducts

Summary Complexes of the type M(HXCA)₂·nH₂O (M = Cu^II, Ni^II or Co^II; HXCA = 2-hydroxy--4-X-cinnamoyl acetophenone; X = H, Cl, Me or OMe; n = 0 or 2) have been synthesized, and characterized by elemental analysis, i.r., electronic, ¹H-n.m.r. and e.s.r. spectroscopies, and magnetic susceptibility measurements. The spectral data indicate that the ligand coordinates through both carbonyl and enolic oxygens. The anhydrous Cu^II complexes are monomeric and square planar, while the Ni^II and Co^II analogues possess polymeric high-spin octahedral structures. The diaquates and dipyridinates of Co^II and Ni^II have monomeric high-spin octahedral geometries.     

Isonitrosoacetylacetone dithiosemicarbazone complexes of some first row transition metals

Summary Complexes of the potentially tetradentate ligand isonitroso-acetylacetone dithiosemicarbazone (inbtH₂) of formulae [Ti(inbtH₂)Cl₂]Cl₂, [M(inbt)], where M = V^IV O, Mn^II, Ni^II or Zn^II, [M(inbtH₂)X₂], where M = Co^II and X = Cl, or M = Ni^II and X = Cl, Br or I, and [M(inbtH₂)Cl₂]Cl, where M = Cr^III or Fe^III, have been prepared and characterized by physico-chemical and spectroscopic methods. In all the compounds the metal is coordinated by the thiocarbonyl sulphur and imine nitrogen, as revealed by i.r. studies. The n.m.r. spectra of the complexes of Ni^II and Zn^II confirm coordination through nitrogen. Possible structures for the complexes are proposed. The Mössbauer spectrum of the Fe^III complex is discussed.     

Metal complexes of 2-acetylpyridine N(4)-dihexyl- and N(4)-dicyclohexylthiosemicarbazones

Summary 2-Acetylpyridine N(4)-dihexyl- and N(4)-dicyclohexylthiosemicarbazone, HAc4DHex and HAc4DCHex, respectively, and Fe^III, Co^II, Co^III, Ni^II, Cu^II and Zn^II complexes have been prepared and characterized by molar conductivities, magnetic susceptibilities and spectroscopic techniques. For many of the complexes, loss of the N(2)H hydrogen occurs, and the ligands coordinate to the metal centres as NNS monoanionic, tridentate ligands, e.g., [M(NNS)X] (M = Co^II, Ni^II, Cu^II, NNS = Ac4DHex or Ac4DCHex and X = Cl or Br), [Fe(NNS)₂]ClO₄, [Co(NNS)₂]BF₄, [Cu(NNS)NO₃] and [Zn(NNS)OAc]. Zn^II ion is also chelated by neutral ligands in [Zn(HNNS)X₂] (X = Cl, Br). In addition, [Ni(Ac4DHex)-(HAc4DHex)]X (X = BF₄, ClO₄) and [Ni(HAc4DCHex)₂]-(BF₄)₂ are reported where the neutral thiosemicarbazone is coordinated via the pyridyl nitrogen, azomethine nitrogen and thione sulfur. Crystal structure determinations of HAc4DCHex and [Cu(Ac4DHex)Br] show the former to contain the bifurcated hydrogen bonded form and the latter to be planar with no significant interaction between neighbouring centres.     

Complexes of 2-furaldehyde 4-phenyl semicarbazone

The synthesis of Co^II, Ni^II, Cu^II and Cd^II complexes of 2-furfural 4-phenyl semicarbazone (FPSC) with stoichiometric formulae: [M(FPSC)₂X₂] (M = Co, Ni or Cu; X = Cl or Br), [CuCl₂(FPSC)] and [(CdCl₂)₂(FPSC)] has been obtained for the first time. The complexes were characterized by elemental analysis, molar conductivity, magnetic measurements, i.r., far i.r. and electronic spectra. FPSC is deduced to act as a bidentate ligand in the Co^II, Ni^II and Cu^II complexes and as a tetradentate one in [(CdCl₂)₂(FPSC)].     

Structural studies of 4-benzamido-1-o-aminoacetophenone-3-thiosemicarbazone complexes

Summary Complexes of Cu^II, Ni^II, Co^II, Zn^II, Cd^II and Hg^II with 4-benzamido-1-o-aminoacetophenone-3-thiosemicarbazone (H₂BATS) are reported and have been characterized by elemental analyses, molar conductivities, magnetic moments, spectral (visible, i.r.) and thermal (d.t.a., t.g., d.t.g.) measurements. I.r. spectra show that H₂BATS behaves as a dianionic, monoanionic or neutral tetradentate ligand or as a monoanionic tridentate ligand. [Cu₂(H₂BATS)Cl₂]·2H₂O and [Cu₂(H₂BATS)Ac₂]·2H₂O complexes are diamagnetic while [Co(HBATS)OH]·2H₂O and [Ni(HBATS)OH]·2H₂O are octahedral. All the complexes are non-electrolytes. Generally, the solid metal acetate complexes have a unique decomposition exotherm profile which can be used as a rapid and sensitive tool for the detection of acetate-containing complexes.     

Synthesis and antibacterial activity of metal complexes of ciprofloxacin

The interactions of ciprofloxacin (HCipro) with transition metals have been investigated. Two types of complexes, [M(Cipro)(OAc)(H₂O)₂] · 3H₂O (M = Mn^II, Co^II, Cu^II or Cd^II) and [M(Cipro)(OAc)] · 6H₂O (M = Ni^II or Zn^II), were obtained and characterized by physicochemical and spectroscopic methods. The i.r. spectra of the complexes suggest that the ciprofloxacin behaves as a monoanionic bidentate ligand. In vitro antibacterial activities of the HCipro and the complexes were tested.     

Binuclear metal complexes. Part III. Complexes of 1-hydroxy-2, 3-dimethyl-5-carboxylato-1,4-diaza-1,3-pentadiene and 1-hydroxy-2,3-dimethyl-4(2′-carboxyphenyl)-1,4-diaza-1, 3-butadiene with bivalent transition metal ion complexes

Summary Binuclear complexes of the type [M(HDCDP)(H₂O)_n]₂ and [M(HDCDB)(H₂O)_n]₂, where HDCDP and HDCDB are Schiff bases derived from glycine and diacetylmonoxime, and orthoaminobenzoic acid and diacetylmonoxime respectively, M=VO^II, Co^II, Ni^II, Cu^II or Ag^II and n=0 or 2, have been synthesized. Physical and spectroscopic analyses indicate a binuclear structure for the complexes with metal ions in an octahedral environment, where the ligands coordinate to the metal centre through azomethine nitrogens, oxime and carboxylate oxygen in a tetradentate manner.     

Complexes of NS and NSO donor ligands. Nickel(II), copper(II) and cobalt(II) complexes of glyoxal bis(morpholineN-thiohydrazone) and diacetyl bis(morpholineN-thiohydrazone)

Summary Reactions of glyoxal bis(morpholineN-thiohydrazone), H₂gbmth, with NiCl₂·6H₂O, Ni(OAc)₂·4H₂O, Ni(acac)₂· H₂O, CuCl₂·2H₂O, Cu(OAc)₂·H₂O, Cu(acac)₂, CoCl₂· 6H₂O, Co(OAc)₂·4H₂O and Co(acac)₂·2H₂O yield complexes of the type [M(gbmth)], [M=Ni^II, Cu^II or Co^II]. Diacetyl reacts with morpholineN-thiohydrazide in the presence of nickel salts to yield [Ni^II(dbmth)], [Ni^II(dmth)(OAc)]H₂O and [Ni^II(Hdmth)(NH₃)Cl₂] involving N₂S₂ and NSO donor ligands. Copper and cobalt complexes of N₂S₂ and NSO donor ligands with compositions [Cu^II(dbmth)], [Co^II(dbmth)]·4H₂O and [Co^II(H₂dbmth)]Cl₂, have been isolated. The compounds have been characterised by elemental analyses, magnetic moments, molar conductance values and spectroscopic (electronic and infrared) data.     

Metallo-guanines and metallo-guanosines

Metallo-guanines of the type [M(G)₂·2H₂O] [M = Ni^II, Fe^II, Cu^II and UO₂ ^II; G = anionic guanine], [M(G)₂(GH)· H₂O] (M = Co^II and Mn^II; GH = neutral guanine), [Pd(G)₂]·2H₂O and [Zn(G)Cl]₂ have been isolated and characterised. Anionic guanine functions as a bidentate ligand and links through N(3) and N(9). E.p.r. data indicate that the Cu^II complex has a highly distorted octahedral structure. The magnetic susceptibility data suggest that the Co^II and Ni^II complexes possess pseudooctahedral geometry. Neutral guanines are probably unidentate and coordinate either through N(3) or N(9). The isolated guanosine complexes are of the types: [M(Gs)₂·H₂O] [M = Ni^II and Cu^II, Gs = anionic guanosine] [Pd(Gs)₂]·2H₂O and [UO₂(Gs)₂]. I.r. data indicate that guanosine also functions as a bidentate ligand, but coordinates through N(1) and C₂ — NH₂. The electronic absorption spectra of the complexes indicate that guanine is a stronger ligand than guanosine.     

Copper(II), nickel(II) and cobalt(II) complexes of pyridyl and quinolylhydrazones of isatin and methylisatin: Ligand dependent stereochemistry

Summary [M^II(Lig)X] (M = Cu^II, Ni^II or Co^II and Lig = deprotonated pyridylhydrazone, (IPH-H), quinolylhydrazone of isatin (IQH-H) andN-methylisatin (MIQH-H)) have been characterized by magnetic susceptibility measurements, optical spectra and infrared spectral studies. [M^II(IPH-H)Cl] (M = Ni^II and Co^II) are tetrahedral while [M^II(MIQH-H)X] (M = Ni^II or Co^II and X = Br or Cl), [Ni^II(IQH-H)Br] and [Cu^II(IPH-H)Cl] are planar.     

Metal complexes of tetramethylethylenediaminetetraacetate

Summary A number of metal complexes of the ligand tetramethylethylenediaminetetraacetate [Edta(OMe)₄ = L] have been characterised. The complexes may be formulated MLCl₂ · xH₂O where M²⁺ = Mn^II, Fe^II, Co^II, Ni^II, Cu^II, Cd^II, Hg^II and Sn^II. I.r., conductivity, magnetic susceptibility and electronic spectral data are discussed.