摘要:
The reactions of a range of coordinatively unsaturated sigma-organyl thiocarbony] complexes with 1,4,7-trithiacyclononane ([9]aneS(3)) have been investigated, leading in some but not all cases to migratory insertive coupling of thiocarbonyl and sigma-organyl ligands. Thus, under ambient conditions, the reaction of [RuR-Cl(CS)(PPh3)(2)] (R = C(CO2Me)=CHCO2Me, C(C C-CPh)=CHPh, C6H5) with [9]aneS(3) provides sigma-organyl complexes [RuR(CS)(PPh3)([9]aneS(3))](+). On heating, the species [Ru(C6H5)(CS)(PPh3)[9]aneS(3))](+) converts to the thiobenzoyl complex [Ru(eta(2)-SCPh)(PPh3)([9]aneS(3))](+). Similarly the silyl complex [RuCl(SiMe2OEt)-(CS)(PPh3)(2)] with [9]aneS3 provides [Ru(SiMe2OEt)(CS)(PPh3)([9]aneS(3))](+). However, the styryl and stilbenyl complexes [Ru(CR=CHPh)Cl(CS)(PPh3)(2)] (R = H, Ph) under similar conditions provide dihapto thioacyl derivatives [Ru(eta(2)-SCCR=CHPh)(PPh3)([9]aneS(3)](+). The osmium species [Os(CH=CHC6H4Me-4)Cl(CS)-(BTD)(PPh3)(2)] (BTD = 2,1,3-benzothiadiazole), however, yields only the nonmigrated product [Os(CH=CHC6H4Me-4)(CS)(PPh3)([9]aneS(3))](+). Migratory insertion is not induced by other sulfur donor ligands, e.g., CY3PCS2(Cy = cyclohexyl) and Na[S2CNMe2], which provide the complexes [Ru(CH=CH2)(S2CPCy3)-(CS)(PPh3)(2)](+) and [Ru(CH=CHPh)(S2CNMe2)(CS)(PPh3)(2)], respectively. The reactivity of different ligands (R) toward thiocarbonyl migratory insertion in [Ru(R)(CS)(PPh3)([9]aneS(3)](+) was analyzed through density functional theory. The calculated barriers agree qualitatively with experimental observations. In order to determine the electronic effect of substituents on the migrating ligand, a series of hypothetical systems with phenyl ligands varying only in the para-substituent was considered. A general trend that electron-releasing substituents on the migrating ligand promote reaction was observed. Through symmetry-adapted fragment orbital analysis, this phenomenon is determined to correlate well with the energy of the highest occupied,pi-orbital of the ligand.