Ru alkylidene compounds bearing tridentate, dianionic ligands: Lewis acid activation and olefin metathesis†
Abstract
The series of tridentate complexes of Ru-alkylidenes (L)Ru(CHPh)(SCH2CH2)2E (E = O, L = SIMes 1, PCy32, E = S, L = SIMes 3, PCy34; E = PPh 7, L = PCy3), (L)Ru(CHPh)(SC6H4)2S (L = SIMes 5, PCy36), (L)Ru(CHPh) (OCH2CH2)2O (L = SIMes 8, PCy39) were prepared and shown to react with one equivalent of BCl3 to give the complexes (L)Ru(CHPh)Cl[E(CH2CH2S)2BCl2] (E = O, L = SIMes 10, PCy311, E = S, L = SIMes 12a/b, PCy313, E = PPh, L = PCy316) and (L)Ru(CHPh)(SC6H4)2O (L = SIMes 14, PCy315). In the case of 1 and 2 reaction with two equivalents of BCl3 affording the corresponding cation via chloride abstraction. These cations coordinate MeCN to give the six coordinate Ru cation salts [(L)Ru(CHPh)(NCMe)(O(CH2CH2S)2BCl2)][BCl4] L = SIMes 17, PCy318). The generated five coordinate cations derived from 2–9via addition of two equivalents of BCl3 were evaluated in standard preliminary tests for olefin metathesis catalysis.