Niedervalente Bismut-Organyle, chirale Stibane und Antimon-Analoge des Betains und Cholins

Abstract

The cyclobismuthanes (RBi):sub:n:/sub:, [R = 2-(Me:sub:2:/sub:NCH:sub:2:/sub:)C:sub:6:/sub:H:sub:4:/sub:, n = 3 (:b:1a:/b:), 4 (:b:1b:/b:)] were synthesized by reduction of RBiCl:sub:2:/sub: with Na in liquid ammonia or by reaction of R:sub:2:/sub:BiCl with LiAlH:sub:4:/sub: in ether. The reaction of :b:1a / b:/b: with W(CO):sub:5:/sub:THF (THF = tetrahydrofuran) gives the bismuthinidene complex RBi[W(CO):sub:5:/sub:]:sub:2:/sub: (:b:2:/b:). R:sub:2:/sub:BiCl reacts with Mg in THF to give R:sub:4:/sub:Bi:sub:2:/sub: (:b:3:/b:). X-ray structure analyses of :b:1b, 2:/b: and :b:3:/b: reveal intramolecular coordination of the pendant ligands on bismuth.:i:cyclo:/i:-(RBi):sub:n:/sub: [R = Me:sub:3:/sub:SiCH:sub:2:/sub:, Me:sub:3:/sub:CCH:sub:2:/sub:, n = 3 (:b:5a, 6a:/b:), n = 5 (:b:5b, 6b:/b:)] form by reaction of RBiCl:sub:2:/sub: with LiAlH:sub:4:/sub:. Equilibria between :b:1a:/b: and :b:1b, 5a:/b: and :b:5b:/b: or :b:6a:/b: and :b:6b:/b: favour the smaller rings at higher temperatures and dilution. Thermal decomposition of :b:5:/b: or :b:6:/b: leads to the corresponding dibismuthanes (:b:11, 12:/b:) and elemental Bi. Reaction of :b:5a,b:/b: or :b:6a,b:/b: with W(CO):sub:5:/sub:THF gives [{:i:m-h:sup:2:/sup:-cis:/i:-(RBi):sub:2:/sub:}{W(CO):sub:5:/sub:}:sub:2:/sub:] (:b:7, 8:/b:). Decomposition of :b:7:/b: leads to [:i:h:sup:2:/sup:-trans:/i:-(RBi):sub:2:/sub:W(CO):sub:5:/sub:] (:b:9:/b:). Reaction of :b:12:/b: with Fe:sub:2:/sub:(CO):sub:9:/sub: leads to R:sub:2:/sub:Bi:sub:2:/sub:Fe(CO):sub:4:/sub: (:b:13:/b:) and R:sub:2:/sub:Bi:sub:2:/sub:Fe:sub:2:/sub:(CO):sub:8:/sub: (:b:13:/b:).The syntheses of the antimony analogue of betaine and choline were achieved.