Octahedral alkynylphosphine Ruthenium(II) complexes: synthesis, structure, and electrochemistry

Reaction of [RuCl2(PPh3)3] with excess of PPh2C≡CFc (Fc = ferrocenyl) proceeds with formation of [trans-RuCl2(PPh2C≡CFc)4] (3), which reacts with HC≡CR (R = Ph, Tol) via dissociative loss of one PPh2C≡CFc ligand to yield vinylidene complexes [mer,cis-RuCl2(C═CHR)(PPh2C≡CFc)3] (R = Ph 4a, Tol 4b). Reported herein also is the preparation of a series of trans/cis bis(alkynyl)tetrakis(alkynylphosphine) derivatives [Ru(C≡CR′)2(PPh2C≡CR)4] (R′ = Ph, Tol; R = Ph, trans/cis-5a, 5b; R = Tol, trans/cis-6a, 6b; R = Fc, trans/cis-7a, 7b), synthesized by reaction of [trans-RuCl2(PPh2C≡CR)4] (R = Ph 1, Tol 2, Fc 3) with an excess of HC≡CR′ (R′ = Ph, Tol) and NEt3, in the presence or absence of NaPF6. In the preparation of cis-5a, the ketovinyl derivative [mer-Ru{κC,O-C(CH2COCH3)═CHPh}Cl(PPh2C≡CPh)3] (8) was obtained as a byproduct in the presence of acetone. The solid-state structures of complexes 3, trans-5a, trans-7a, and 8 have been determined by X-ray diffraction studies, showing the presence of several types of we...