UNSYMMETRICAL 1,4-DIAZABUTADIENE COMPLEXES OF PLATINUM(II)

The new unsymmetrical 1,4-diazabutadiene ligand glyoxal (2-(methoxymet hyl)-4,6-di-tert-butylphenyl)diimine (L) and its reduced analog (LH4) were synthesized. The reactions of both ligands with bis(benzonitrile) complexes of palladium and platinum, MCl2(PhCN)(2), were investigated . Two isomers of formula MCl2L were isolated from the reaction of L wi th MCl2(PhCN)(2) (1a and Pk, for Pd, 2a and 2b for Pt), while only a s ingle product, MCl2(LH4), formed in the reaction with LH4 (3 for M = P d, 4 for M = Pt). All new compounds were characterized by elemental an alyses and IR and NMR spectroscopies, The molecular structures for L, LH4, 2b, 3, and 4 were determined by single-crystal X-ray diffraction. The metal complexes exhibit distorted square-planar geometry. The ary l groups of the L and LH4 Ligands lie out of the coordination plane in a manner that blocks potential axial ligation sites. Ligand L crystal lizes in the triclinic space group <P(1)over bar> with a = 5.760(1) An gstrom, b = 9.383(2) Angstrom, c = 14.954(3) Angstrom, alpha = 89.38(2 )degrees, beta = 79.67(2)degrees, gamma = 88.14(2)degrees, and Z = 1. The reduced ligand LH4 crystallizes in the monoclinic space group P2(1 ) with a = 5.9758(1) Angstrom, b = 17.4272(2) Angstrom, c = 15.6222(1) Angstrom, beta = 99.063(1)degrees, and Z = 2. Complex 2b crystallizes in the monoclinic space group P2(1)/c with a = 16.9599(2) Angstrom, b = 18.4985(2) Angstrom, c = 12.4976(0) Angstrom, beta = 100.945-(0)deg rees and Z = 4, Complex 3 crystallizes in the monoclinic space group C 2/c with a = 36.1506(8) Angstrom, b = 8.0904 (2) Angstrom, c = 15.5671 (1) Angstrom, beta = 113.988(1)degrees, and Z = 4. Complex 4 crystalli zes in the monoclinic space group C2/c with a = 36.0649(3) Angstrom, b = 8.1787(2) Angstrom, c = 15.7585(3)Angstrom, beta = 112.610(1)degree s, and Z = 4.