Synthesis and Characterization of Manganese(II), Nickel(II) and Copper(II) Complexes of 4-(Arylideneamino)-3-Mercapto-6-Methyl-1,2,4-Triazin-5(4H)-Ones

Abstract

Manganese(II), nickel(II) and copper(II) complexes of 4-(2,6-dichlorobenzylidene-amino)-3-mercapto-6-methyl-1,2,4-triazin-5(4H)-one (HL1) and 4-(cinnamylideneamino)-3-mercaptc-6-inethyl-1,2,4-triazin-5(4H)-one (HL2) have been synthesized and characterized. The IR spectra indicate that both HL1 and HL2 act as neutral or monobasic bidentate ligands, coordinating to metal ions via azomethine-N and either carbony]-O or (thiolo or thiono)-S, depending on the metal ion. The magnetic and spectroscopic data suggest a distorted-octahedral geometry for the Ni(II) complexes, a square-planar geometry for [L1CuCl(H2O)] a dimeric distorted octahedral geometry for both [(L2)2Cu(H2O)]2 and [(HL)Mn(SO4)(H2O)2]2. Such dimeric structures have been revealed by the subnormally low μoff values for the Mn(II) complexes, due to antifenomagnetic coupling between the two Nm(II) centers, and the diamagnetism of [(L2 2Cu(H2O)]2 is due to a quenching mechanism. ESR parameters support the structures of the Mn(II) and Cu(II) complexes and that the two azomethine nitrogens are coordinated to the Cu(II) ion in the [(L2)2Cu(H2O)]2 complex. DTA studies of the maganese(II) and copper(II) complexes are also reported.