SYNTHESES AND STRUCTURES OF NIS2N2 COMPOUNDS - [N,N'-BIS(O-MERCAPTOBENZYLIDEN)ETHYLENEDIAMINATO]NICKEL(II), NI(TSALEN), AND [N,N'-BIS(O-MERCAPTOBENZYL)ETHYLENEDIAMINATO]NICKEL(II), NI(EBMBA)

The syntheses, structures, absorption spectra, and redox potentials of Ni(tsalen), H-2tsalen=N,N'-bis(o-mercaptobenzyliden)ethylenediamine, and Ni(ebmba), H-2ebmba=N,N'-bis(o-mercaptobenzyl)ethylenediamine, are described. Ni(tsalen) was prepared directly from N,N'-bis(o-t-buthylthiobenzyliden)ethylenediamine, from which H-2ebmba and, subsequently, Ni(ebmba) were also prepared. The crystal data for these two complexes are as follows: 1) Ni(tsalen); space group Pna2(1) with the unit-cell dimensions a = 8.929(1), b = 22.603(2), c = 7.4841(1) angstrom, Z = 4, 2) Ni(ebmba); space group P2(1)/c, a = 13.324(5), b = 7.9263(8), c = 15.262(3) angstrom, beta = 101.23(2)degrees. Ni(tsalen) and Ni(ebmba) adopt squareplanar geometries with average Ni-S distances of 2.157 and 2.165 angstrom, respectively. The Ni-N distances of these complexes are 1.85(5) and 1.945 angstrom, respectively. These values, as well as the redox potentials and absorption maxima, ware compared with those of another type of NiS2N2 compound, [Ni(ebtsa)]2-; H-4ebtsa=N,N'-bis(o-mercaptobenzol)ethlenediamide.