Low-valent organobismuth compounds with intramolecular coordination:: cyclo-R3Bi3, cyclo-R4Bi4, RBi[W(CO)5]2, and R4Bi2 [R=2-(Me2NCH2)C6H4]

The cyclobismuthanes RnBin, [R = 2-(Me2NCH2)C6H4; n = 3 (1a), 4 (1b)] have been synthesised by reduction of RBiCl2 with Na in liquid NH3 or by reaction of R2BiCl with LiAlH4 in Et2O. The reaction of 1a/b with W(CO)5-THF afforded the bismuthinidene complex RBi[W(CO)(5)](2). (2). R2BiCl reacts with Mg in THF to give the dibismuthane R4Bi2 (3). Single-crystal X-ray structure analyses of 1b, 2, and 3 reveal intramolecular coordination of the pendant CH2NMe2 groups to the bismuth atom.