Synthese, Struktur und Reaktivität metallorganischer Verbindungen des Antimon mit Sb-Sb und Sb-H Bindungen und eines Dibismutans

Abstract

The reaction of RSbCl2 [R = (Me3Si)2CH] with LiAlH4 gives RSbH2 (1) and R(H)Sb-Sb(H)R (2) in good yields. In solution 1 and 2 were characterized by IR and NMR spectroscopy. The structure of 2 was determined by single crystal X-ray and neutron diffraction. 2 is present in the crystals as the meso isomer. 2 and 1 react with W(CO)5THF (THF = tetrahydrofuran) to give the complexes: meso-, d,l-(OC)5W[R(H)Sb-Sb(H)R]W(CO)5 (3), [R(H)2Sb]W(CO)5 (4) and [RSb=SbR]W(CO)5 (5). The complexes were characterized spectroscopically and crystallographically. The distibene complex 5 is formed in quantitative yield by heating a solution of d,l-3. The methylation of 2 and 1 with MeI / DBU leads to R(Me)Sb-Sb(Me)R (7) and RMeSbH (8). The reaction of 1 with SbCl3 in presence of pyridine gives R4Sb8 (9). Dehydrogenation of 2 with LiAlH4 leads to cis-trans-(RSb)4 (cis-trans-11). R2SbH (12) and R2BiH (13) [R = (Me3Si)2CH] are formed from the corresponding chlorides with LiAlH4. 12 is stable up to 100 °C, but 13 decompose at 20 °C to R2Bi-BiR2 (14). In solutions of 14 dimeric association was observed. In the crystal 14 is present as a dibismuthane in a near trans conformation. The reaction of (Me3SiCH2Sb)5 and (RSb)3 [R = (Me3Si)2CH] with W(CO)5THF gives µ-(Me3SiCH2Sb)5-Sb1,Sb3-[W(CO)5]2 (15) and [(Me3Si)2CHSb]3W(CO)5 (16). The insertion of Fe(CO)4 fragment into the Sb-Sb Bond was observed in the reaction of (RSb)3 [R = (Me3Si)2CH] with Fe2(CO)9. The complexes 15, 16 and 17 were characterized spectroscopically and crystallographically. The reduction of RSbCl2 [R = (Me3Si)2CH] with Na-K alloy gives R5Sb6Cl (18). In the crystals of 18, there is a folded Sb4-ring with a RSb-SbRCl side chain. In solution two rotation isomers were observed. The reduction of Me3CCH2SbBr2 with Mg gives (Me3CCH2Sb)5 (19). In the crystal there is an antimony five ring in a twist conformation. 19 is the first crystallographically characterized pentastibolane.