Dehalogenation of RSbBr2 (R = Me3CCH2) with Mg gives cyclo-(RSb) n (n = 4 (1a), 5 (1b)). The compounds cyclo-(RBi) n (R = Me3CCH2; n = 3 (2a), 5 (2b)) form by reaction of RBiCl2 with LiAlH4. Equilibria between 1a and 1b or between 2a and 2b favor the smaller rings at higher temperatures and dilution. Thermal reactions of 2a,b lead to R4Bi2 (3; R = Me3CCH2) and elemental bismuth. Reaction of 2a,b with W(CO)5(thf) (thf = tetrahydrofuran) gives [{μ-η 2-cis-(RBi)2}{W(CO)5}2] (4; R = Me3CCH2). Decomposition of [{μ-η 2-cis-(R‘Bi)2}{W(CO)5}2] (5; R‘ = Me3SiCH2) leads to [η 2-trans-(R‘Bi)2W(CO)5] (6). The crystal structures of 1b, 4, and 6 are reported.

CH 3 SbPh 2 reacts with HCl to give CH 3 SbCl 2 . CH 3 BiCl 2 and CH 3 BiBr 2 are formed by reaction of CH 3 -BiPh 2 with HCl or HBr. The adducts [CH 3 ECl 2 (bipy)] (E ) Sb, Bi, bipy ) 2,2′-bipyridine) are obtained by combining the components in diethyl ether or tetrahydrofuran. The crystal structures of CH 3 BiCl 2 and [CH 3 -ECl 2 (bipy)] (E ) Sb, Bi) have been determined by singlecrystal X-ray diffraction.