Template reactions of (L)-3-acetyl-5-methyl-1-phenyl-4,5-dihydro-1,2,4-triazine-6-one (8a) or (L)-3-acetyl-5-benzyl-1-phenyl-4,5-dihydro-1,2,4-triazine-6-one (8b) with nickel(II) acetate in the presence of a suitable diamine such as: 1,3-diaminopropane, o-phenylenediamine, or ethylenediamine afforded square planar tetraaza nickel(II) complexes of the type 4N-M (Scheme 4). Single crystal Xray structural analysis of one of the complexes (9b) revealed square planar geometry around the nickel ion and symmetrical coordination of the triazinone moieties. The complexes were characterized by elemental analyses, magnetic measurements, and electrical conductivities.

Bu 2 Sn(O 2 AsMe 2 ) 2 ] (1) and [(Me 2 SnOSAsMe 2 ) 2 O] 2 (2) have been synthesized by reactions of Bu 2 SnO and Me 2 SnS, respectively, with HO 2 AsMe 2 in methanol. The complexes were characterized by elemental analyses, vibrational and mass spectra. X-ray diffraction studies show 1 to occur in an orthorhombic form with the space group Pbca at 273 K, whereas at 100 K it crystallizes triclinic in P1 (1, LT form) as twin of a twin. Cell parameters are a ϭ 10.