COORDINATION COMPOUNDS OF COPPER(II), NICKEL(II), AND COBALT(II) WITH β-THIOSEMICARBAZONES OF ISATIN AND N-METHYLISATIN

Abstract

Isatin thiosemicarbazone (HL) reacts in aquoeus-ethanolic medium with copper(II) chloride and bromide (pH 7-7.5, ethanolic KOH) to give coordination compounds CuLX·nH2O (X = Cl, Br; n = 3, 4). In the presence of amines (A = C5H5N, 3-CH3C5H 4N, and 4-CH3C5H4N), complexes CuALX·2H2O and CuA2LX·H2O (X = Cl, Br) are formed. With nickel(II) or cobalt(II) chlorides, thiosemicarbazone HL, and pyridine (1:1:3) as starting compounds, compounds MPy 2LCl·H2O (M = Ni, Co) are isolated. Under similar conditions, N-methylisatin β-thiosemicarbazone (HL') reacts with chlorides of the above-noted metals in the presence of pyridine to give complexes MPy 2L'Cl·H2O (M = Cu, Ni, Co). All the complexes are monomeric and have a pseudooctahedral structure of the coordination unit. Thiosemicarbazones HL and HL1 in these complexes behave as tridentate monodeprotonated O,N,S-ligands. Thermolysis of these substances passes through the stages of dehydration (60-90°C), deaquation (135-140°C) or deamination (160-215°C), and complete thermal decomposition (560-670°C).