Five- and six-membered platinacycles derived from phenantryl and anthracenyl imines

The reaction of Pt₂Me₄(μ-SMe₂)₂] with ligands Me₂NCH₂CH₂NCHAr (2a, Ar=9-phenantryl; 2b, Ar=9-anthracenyl) carried out in acetone at room temperature produced the corresponding compounds PtMe₂{9-(Me₂NCH₂CH₂NCH)C₁₄H₉}] (3) in which the imines act as bidentate N,N^′] ligands. Refluxing toluene solutions of compounds 3 gave cyclometallated C,N,N^′] compounds PtMe{9-(Me₂NCH₂CH₂NCH)C₁₄H₈}] (4) as a mixture of two isomers containing either a five- or a six-membered metallacycles for 3a and as a single isomer containing a six-membered metallacycle for 3b. The reactions of compounds 4 with acetyl chloride and with methyl iodide produced, respectively, compounds PtCl{9-(Me₂NCH₂CH₂NCH)C₁₄H₈}] (5) and PtMe₂I{9-(Me₂NCH₂CH₂NCH)C₁₄H₈}] (6). All compounds were characterised by NMR spectroscopies and analytical data.