Double cyclometallation via carbon-silicon bond cleavage by palladium(II) acetate; X-ray structure of a cationic 1,4-dipalladated benzene ring and selective synthesis of heterobimetallic 1,4-phenylene bridged platinum(II)-palladium complexes

Abstract

The disilylated compound 1,4-bis(trimethylsilyl)-2,3,5,6-tetrakis((dimethylamino)methyl)benzene, (Me3Si)2C2N4, 4, can be electrophilically palladated selectively at the C-Si bonds to afford the neutral 1,4-bis(palladium) complex [(AcOPd)2(C2N4)], from which the dicationic [(LPd)2(C2N4)]2+ (L = MeCN) organometallic species are accessible. The monosilylated species (Me3Si)(H)C2N4, 5, can be used for the preparation of the dicationic heterodinuclear platinum(II)-palladium(II) species [(LPd)(LPt)(C2N4)]2+ (L = MeCN) via a sequence of transmetalation of the organolithium derivative of 5 with [PtCl2(SEt2)2], followed by a C-Si bond palladation reaction.