The coordination chemistry of iminooxosulphuranes VIII. The coupling of tosyliminooxosulphurane with ethylene, allene, and alkynes coordinated to osmium

Abstract

The reactions of the zerovalent osmium nitrosyl complexes [OsCl(NO)(PPh3)2(L)] (L CH2CH2, CH2CCH2, PhCCPh, PhCCH, CH3CCCH3 and CF3CCCF3) with toluene sulphonyliminooxo-λ4-sulphurane, OSNSO2C6H4Me-4 (OSNSO2R) have been investigated. The ethylene complex reacts either by ethylene substitution to provide [OsCl(NO)(PPh3)2(OSNSO2R)] or by formation of the metallacyclic complex [Os{CH2CH2S(NSO2R)O}Cl(NO)(PPh3)2], which has been crystallographically characterised. The allene complex reacts in a similar manner, also forming a metallacycle [Os{C(CH2)CH2S(NSO2R)O}Cl(NO)(PPh3)2]. The reactivity of the alkyne complexes depends upon the nature of the alkyne substituents: the strongly bound hexafluorobut-2-yne complex is unreactive, the but-2-yne complex reacts by alkyne substitution (i.e., formation of [OsCl(NO)(PPh3)2(OSNSO2R)]), and the aryl alkyne complexes react by metallacycle formation to give [Os{CPhCR′S(NSO2R)O}Cl(NO)(PPh3)2] (R′ H, Ph). The metallacyclic derivatives are readily and reversibly protonated (HBF4) at the exocyclic sulphimine substituent. Show more