A series of ruthenium(ii) complexes containing the bulky, functionalized trialkylphosphines tBu2PCH2XC6H5 as ligands

Abstract

The monomeric ruthenium(II) complexes [(η⁶-C₆H₅XCH₂PtBu₂-κ-P)RuCl₂] 3, 4 were prepared either on a reductive route from RuCl₃·3H₂O and tBu₂PCH₂XPh (X = CH₂  1, OCH₂  2) or by ligand replacement reactions from [(p-cym)RuCl₂]₂ and the phosphine via the p-cymene compounds [(p-cym)(C₆H₅XCH₂PtBu₂-κ-P)RuCl₂] 6, 7 as intermediates. Abstraction of one chloro ligand from 3 with AgPF₆ led to the formation of the dinuclear complex [{(η⁶-C₆H₅CH₂CH₂PtBu₂-κ-P)RuCl}₂](PF₆)₂  8, which reacts with acetone, CH₃CN and PMe₃ by bridge cleavage to afford the mononuclear compounds [(η⁶-C₆H₅CH₂CH₂PtBu₂-κ-P)RuCl(L)]PF₆  9, 10, 12. Both 10 and 11 (the latter containing 2 as chelating ligand) were also obtained from 3, 4 and AgPF₆ in the presence of acetonitrile. Hydridoruthenium(II) complexes [(η⁶-C₆H₅XCH₂PtBu₂-κ-P)RuHCl] 13, 14, [RuHCl(H₂)(L)₂] 15 (L = 1), 16 (L = 2) and [RuHCl(CO)(2)₂] 17 could be prepared from RuCl₃·3H₂O and 1 or 2 in the presence of NEt₃ under reductive conditions. Insertion, substitution and addition reactions of compound 17 led to the formation of [Ru(CHCH₂)Cl(CO)(2)₂] 18, [RuHF(CO)(2)₂] 19, and [RuHCl(CO)₂(2)₂] 20, respectively. The cationic allenylidene complexes [(η⁶-C₆H₅XCH₂PtBu₂-κ-P)RuCl(CCCPh₂)]A 22a,b (X = CH₂; A = BF₄, PF₆) and 23 (X = OCH₂; A = PF₆) were prepared from 3, 4 or 13, HCCC(OH)Ph₂ and either one equiv. of AgPF₆ or an equivalent amount of HBF₄ in diethyl ether. Treatment of 15 and 16 with acetylene afforded the five-coordinate vinylideneruthenium(II) compounds [RuHCl(CCH₂)(L)₂] 24, 25 which in the presence of HBF₄ are highly efficient catalysts for the Ring Opening Metathesis Polymerization (ROMP) of cyclooctene. The molecular structures of 10 and 17 were determined crystallographically.