Syntheses, structures and redox properties of tris(pyrazolyl)borate-capped ruthenium vinyl complexes

Abstract

Reaction of RuHCl(CO)(PPh3)3 with aryl alkynes HCCC6H4R-4 [1: R = N(C6H4Me-4) 2 (a), OMe (b), Me (c), CO2Me (d), NO2 (e)] gives the five-coordinate vinyl complexes Ru(CHCHC6H 4R-4)Cl(CO)(PPh3)2 (2a-e). Reaction of 2a with excess PMe3 gives crystallographically characterised Ru{CHCHC 6H4N(C6H4Me-4)2-4}Cl(CO) (PMe3)3 (3a), whilst reaction of 2a-e with KTp affords Ru(CHCHC6H4R-4)(CO)(PPh3)Tp (4a-e) bearing the facially capping Tp- ligand. Electrochemical and spectroelectochemical properties of 4a-e are consistent with substantial redox activity associated with the vinyl ligand, and these properties have been satisfactorily modelled by DFT based calculations of electronic structure. Show more