Synthesis and Reactivity of Coordination and Six-Membered, Cyclometalated Platinum Complexes Containing a Bulky Diimine Ligand

The reaction of [Pt₂Me₄(μ-SMe₂)₂] with ligand (9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₉) (L) gives initially the platinum(II) complex [PtMe₂{(9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₉)}], 1, which contains a chelate dinitrogen ligand. Compound 1 was reacted with MeI to give the related six-coordinate platinum(IV) compound [PtMe₃I{(9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₉)}], 2, by oxidative addition. Compound 1, when refluxed in toluene, gave the monometalated complex [PtMe{(9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₈)}], 3, with a six-membered, cyclometalated, anthryl ring. When compound 1 was reacted with acetyl chloride, the dicyclometalated compound [Pt{(9-C₁₄H₈)CHNCH₂CH₂NCH(9-C₁₄H₈)}], 4, with two six-membered cyclometalated anthryl rings, was formed. Similarly, cis-[PtCl₂(dmso)₂] was reacted with ligand L to afford the platinum(II) compound [PtCl₂{(9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₉)}], 5. This compound, when left in solution at room temperature, gave the monometalated compound [PtCl{(9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₈)}], 6, but under no conditions tried was the dimetalated species obtained. The structures of [PtCl₂{(9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₉)}], 5, [PtMe₃I{(9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₉)}], 2, and [PtCl{(9-C₁₄H₉)CHNCH₂CH₂NCH(9-C₁₄H₈)}], 6, were determined by X-ray diffraction.