Cobalt(II) and Copper(II) Complexes of (2-Acetylpyridine)-(5,6-Diphenyl-[1,2,4]Triazin-3-YL) Hydrazone

• Published in: Journal of coordination chemistry 2004-01, Vol.57 (2), p.105-113
• Main Authors: Kandil, Samir S., El-Dissouky, Ali, Ali, Gamila Y.
• Format: Article
• Language: English
• Subjects: Cobalt; Copper; Hydrazone; Triazine
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958970410001664956

A series of cobalt(II) and copper(II) complexes of (2-acetylpyridine)-(5,6-diphenyl-[1,2,4]triazin-3-yl) hydrazone, APyTHy, L, having the formulae [LMCl 2 ]·nH 2 O, [L 2 Cu(H 2 O) 2 ](ClO 4 ) 2 and [L 2 M]X 2 ·nH 2 O (X = ClO 4 or OAc; M = Co or Cu and n = 0, 2 or 4) were isolated and characterized by elemental analysis, molar conductance, magnetic moment and IR, electronic and ESR spectral measurements. The IR spectra indicate that APyTHy behaves as a neutral tridentate ligand, coordinating via a triazine-N, azomethine-N and pyridine-N, except for [LCuCl 2 ] and [L 2 Cu]X 2 ·nH 2 O (X = OAc or ClO 4 ), where it acts as a bidentate, not using the triazine-N in complexation. The magnetic moment and electronic spectral data suggest a distorted octahedral structure for 1 : 2 Co(II) complexes, a tetrahedral geometry for 1 : 2 Cu(II) complexes and a trigonal bipyramidal structure for [LCu(H 2 O) 2 ](ClO 4 ) 2 and [LMCl 2 ]·nH 2 O (M = Co II or Cu II ; n = 0 or 2) complexes. Upon heating the green [LCuCl 2 ]·2H 2 O, brown square planar [LCuCl 2 ] was produced. The mixing coefficients and covalency factors for the copper(II) complexes estimated from the combined X-band ESR g-values and electronic d-d transitions using Reinen's method imply that the CuN 3 X 2 chromophore is considerably distorted towards square pyramidal.