Reactivity of metal chelates of sulphur containing ligands towards lewis bases. Part IV. Reaction of bis [2(1-methyl-2-oxo-propylidenehydrazine- S- methylcarbodithioato)NSO(-1) ] nickel(II) with amines

Abstract

The reactions of octahedral bis[2(1-methyl-2-oxo- propylidenehydrazine - S-methylcarbodithioato) NSO - (-1)]nickel(II) (3, R = CH 3) with aromatic heterocyclicamines (pyridine, 3- and 4-methylpyridine), secondary aliphatic amines (diethyl, di-n-propyl and di- n-butylamine) and alicyclic amines (piperidine and morpholine) have been studied in benzene. Spectrophotometric studies revealed that these reactions proceed by nucleophilic displacement of the two coordinated carbonyl oxygens to give the corresponding bis(amine) adducts. The kinetic measurements of these reactions indicate first-order dependence on the substrate and second-order dependence on the amine concentration. A comparison of the activation parameters suggests the formation of a π adduct in the transition state in the case of the pyridines. In the case of the secondary aliphatic amines, hydrophobic interactions between the alkyl chains and the in-plane ligand is proposed.