G. Devoto

3,5-diphenylisoxazole as ligand. Complexes of cobalt(II), nickel(II) and copper(II)

Abstract Some complexes of cobalt(II), nickel(II) and copper(II) chloride, bromide, iodide, thiocyanate and perchlorate with 3,5-diphenylisoxazole (3,5-diPhisox) have been prepared and characterized. On the basis of vibrational and electronic spectroscopy, magnetism and conductivity measurements, the structures of these complexes were identified. The ligand behaves both as monodentate N-bonded, and as a bridging N- and O-bonded ligand. All the compounds here reported have an octahedral stereochemistry with the exception of [Co(3,5-diPhisox)2X2] (X = Cl, Br, I, NCS), which are tetrahedral, while the complex [Cu(3,5-diPhisox)4] (ClO4)4·4H4O is square planar.

Complexes of copper(II), nickel(II) and cobalt(II) with 2-fluoro,5-nitroaniline and 4-fluoro,2-nitroaniline

Abstract Preparation of new complexes of 2 - fluoro,5 - nitroaniline (2-F,5-NA) and 4 - fluoro,2 - nitroaniline (4-F,2-NA) of the type ML n X 2 · m H 2 O (where M = Cu(II), Ni(II), Co(II); L = 2-F,5-NA; 4-F,2-NA; n = 2,4,6; X = Cl − , Br − , SCN − , ClO 4 − ; m = 0–2) are described and their i.r., electronic spectra, and magnetic moments are reported. The ligands act always as monodentate O-bonded. The compounds are generally high spin, non electrolytes, and present square planar, tetrahedral and hexacoordinate structures.

Cobalt(II) and copper(II) complexes of 3-amino-5-methylisoxazole

SummaryCobalt(II) and copper(II) halide, nitrate, thiocyanate and perchlorate complexes of 3-amino-5-methylisoxazole (3-AMI) have been prepared and characterized by means of magnetic, spectroscopic and molar conductivity measurements. In Cu(3-AMI)2X2 compounds (X = Cl, Br, N02) the 3-AMI ligand is bridging and bidentate [N (ring), O(bonded)]. In the other derivatives it is monodentate [N(ring) bonded]. All cobalt(II) complexes have an octahedral stereochemistry, if the Co(3-AMI)2X2 derivatives (X = Cl, Br), which are tetrahedral, are excluded. Copper(II) complexes have generally a distorted square pyramidal stereochemistry in the solid state and in solution.

Inhibitory activity of bivalent transition-metal complexes with diamines toward a diamine oxidase

Abstract Various complexes of bivalent transition metals with diamines have been synthesized and studied “ in vitro ” with a diamine oxidase. The inhibition type and K i value of these compounds have been determined. For the linear-chain diamine complexes the inhibition was competitive and the highest inhibition was for the 1,3-diaminopropane-copper complexes.

Metal complexes with some 3-aryl-1,2,4-oxadiazoles

Abstract Complexes of empirical formula M(L) 2 X 2 were synthesized and characterized, where L = 5-methyl-3-(2,4,6-trimethoxiphenyl)-1,2,4-oxadiazole (topho), M = Zn(II), Cu(II), Co(II), Pd(II), Pt(II), X = Cl, M = Pd(II), Pt(II), X = Br, M = Zn(II), X = I; L = 5-methy]-3-(3,5-dichloro,2,4,6-trimethyl-phenyl)-1,2,4-oxadiazole (ctpho), M = Cu(II), Co(II), X = Cl; L = 5-methyl-3-(2,4,6-trimethylphenyl)-1,2,4-oxadiazole (tpho), M = Cu(II), X = Cl. Magnetic, spectral, conductivity and elemental analysis data indicate that the ligands always act as monodentate, N -bonded. The Pd(II) and Pt(II) complexes are square planar and all the other derivatives are tetrahedral.

Spectroscopic and biological studies on palladium(II) complexes with N-ethyl and N-propylimidazole

Abstract Palladium(II) halide complexes with N-ethylimidazole (N-EtIm) and N- propylimidazole (N-PropIm) with general formulae Pd(L) 2 X 2 and Pd(L) 4 X 2 (X = Cl, Br, I) were prepared and characterized by spectroscopic methods and conductivity measurements. These complexes are diamagnetic and have square planar stereochemistry. The Pd(L 2 )X 2 derivatives, are non-conductors, and have trans -structures except for the cis -Pd(N-EtIm) 2 Br 2 . The biological activity of water soluble Pd(II) compounds is also reported.

Copper(II) chloride complexes of 2-(4′-Methyl-2′-pyridyl)-benzoxazole, their sulphur and nitrogen analogues and 2-(4′-Methyl-2′ {or8′} -quinolyl)benzoxazoles

SummaryCopper(II) complexes CuLCl2, where L=2-(4′-methyl-2′-pyridyl)benzimidazole(mpbi); 2-(4′-methyl-2′-pyridyl)benzothiazole(mpbt); 2-(4′-methyl-2′-pyridyl)benzoxazole (mpbo); 2-(4′-methyl-2′-quinolyl)benzoxazole (mqbo); 2-(4′-methyl8′-quinolyl)benzoxazole (mq′bo), and Cu(mpbi)2Cl2(H2O) have been synthesized and characterized by conductivity and magnetic measurements as well as by i.r., electronic and e.s.r. spectra. The ligands are bidentate donors through the pyridine and isoxazole nitrogen atoms. The CuLCl2 complexes exhibit spectral properties consistent with CuN2Cl2 chromophores differing in the degree of tetrahedral distortion, which is found to parallel the steric hindrance near the donor sites. Cu(mpbi)2 Cl2(H2O) is five-coordinate.

Copper(II) chloride and bromide complexes of 2-(2'-Methyl-8'-quinolyl)benzoxazole and 2-(2' or 4'-methyl-8'-quinolyl)benzimidazole

SummaryCopper(II) complexes [CuLX2], where L = 2-(2′-methyl-8′-quinolyl)benzoxazole, 2-(2′-methyl-8′-quinolyl)benzimidazole or 2-(4′-methyl-8′-quinolyl)-benzimidazole and X = Cl or Br, have been synthesized and characterized by conductivity and magnetic measurements, i.r., electronic and e.s.r. spectra.The ligands always behave as bidentateN-donors giving rise to monomeric compounds withpseudo-tetrahedral coordination geometry.

Cobalt(II) and nickel(II) chloride complexes with some 2-(4′-Methyl-2′-pyridyl and 2′- or 8′-quinolyl)benz-X-azoles

SummaryComplexes of general formula MLmCl2 · nH2O, where M=cobalt(II) or nickel(II); L=2-(4′-methyl, 2′-pyridyl)-benzimidazole (mpbi), 2-(4′-methyl, 2′-pyridyl)benzothiazole (mpbt), 2-(4′-methyl, 2′-pyridyl)benzoxazole (mpbo), 2-(4′-methyl, 2′-quinolyl)benzoxazole (mqbo), or 2-(4′-methyl, 8′-quinolyl)benzoxazole (mq′bo); m=1,2; n=0–3, were prepared and characterized by t.g.a., conductance and magnetic measurements, i.r. and diffuse-reflectance electronic spectra.All the ligands behave as bidentate and coordinate through the pyridine- and isoxazole-nitrogen atoms.The nickel complexes have distorted octahedral or fivecoordinate structures. The cobalt complexes arepseudo-tet- rahedral except Co(mpbo)2Cl2·2H2O where the metal is six-coordinate.

Cobalt(II) and nickel(II) chloride and bromide complexes of 2-(2′-methyl-8′-quinolyl)benzoxazole and 2-(2′ or 4′-methyl 8′-quinolyl)benzimidazole

SummaryCobalt(II) and nickel(II) halide complexes of the ligands 2-(2′-methyl-8′-quinolyl)benzoxazole (m′q′bo), 2-(2′-methyl8′quinolyl)benzimidazole (m′q′bi) and 2-(4′-methyl-8′-quinolyl)benzimidazole (mq′bi) were synthesized and characterized by analytical, thermogravimetric, conductivity and magnetic data, and i.r. and electronic spectra.The ligands are bidentate N-donors yielding complexes where the coordination geometry depends on the metal ion and steric hindrance. All the cobalt complexes have formula [CoL2X2] and distorted tetrahedral geometry. Different types of nickel compounds were obtained: i) complexes of formula NiLX2 · n H2O (or EtOH) (L = m′q′bo or m′q′bi; n=0–1.5) which arepseudo-tetrahedral or five-coordinate and ii) complexes NiL2X2 · n H2O (L = mq′bi, n=3 or 4) where the metal is bound to four nitrogen atoms and the overall coordination geometry is tetragonal. The structural changes occurring after removal of water or alcohol from the complexes are also reported.