PREPARATION AND CHARACTERIZATION OF SOME CYCLOMETALATED PT(II) COMPLEXES FROM 2-PHENYLPYRIDINE AND 2-(2'-THIENYL)PYRIDINE

The preparation of cyclometalated Pt(II) compounds from 2-phenylpyridine, Hppy, and 2-(2'-thienyl)pyridine, Htpy, is considered. Salts of the monomeric [[N-C] PtCl2](-) anions are difficult to obtain in a pure state, but by addition of methanol to the reaction mixtures the dimers, [[N-C] PtCl](2), are precipitated in satisfactory yield. The dimers can then be transformed into pure Bu(4)N[[N-C] PtCl2] in close to quantitative yield by means of Bu(4)NCl in dichloromethane. The preparation of several derivatives of the general type [[N-C] PtX(2)]Z, Z being + 1, 0 and -1, and X(2) representing two monodentate or one bidentate ligand is described. The compounds have been characterized by IR and NMR and the H-1 and C-13 resonances have been completely assigned. The chlorides of the complex ions From 1,2-diaminoethane, [[N-C] Pten]Cl, are readily prepared both from the dimers, [[N-C] PtCl](2), and the monomers, [[N-C] PtCl2](-). These salts function as valuable precursors for [[N-C] PtX(2)]Z for reactions which have to be performed in aqueous solution. The reactions between [[N-C] PtCl2](-) and one equivalent of a monodentate ligand, L, lead to complexes in which L is trans to the nitrogen atom in the chelate ring.