Stability and structure of Co(2), Ni(2), Cu(2), Zn(2) and Cd(2) complexes with substituted pyridines

Studies have been carried out on complexation of Co(2), Ni(2), Cu(2), Zn(2) and Cd(2) with a variety of 3-substituted pyridines, py-R, with R=C2H5, CH2OH, (CH2)3OH, NHCOCH3, N(CH3)2, and CONH2. The effect of the nature of the substituent R on the π-acceptor capacity of the ligands has been discussed. The weakening of π-acceptor capacity of the derivatives with simultaneous increase in the basicity of the ligands has been shown to be favourable for formation of tetrahedral Zn(2) and Cd(2) complexes. (author)