Five-coordinate complex [RuHCl(CO)(PPri3)2] as a precursor for the preparation of new cyclopentadienylruthenium compounds containing unsaturated η1-carbon ligands

Article abstract of DOI:10.1021/om960124d

The five-coordinate complex [RuHCl(CO)(PPrⁱ₃)₂] (1) reacts with cyclopentadiene in methanol under reflux to give [RuH(η⁵-C₅H₅)(CO)(PPrⁱ ₃)] (2) and [HPPrⁱ₃]Cl. The protonation of 2 in dichloromethane-d₂ leads to the dihydrogen complex [Ru(η⁵-C₅H₅)(η₅-H ₂)(CO)(PPrⁱ₃)]-BF₄ (3) in equilibrium with traces of the dihydrido tautomer [RuH₂(η⁵-C₅H₅)(CO)(PPr ⁱ₃)]-BF₄ (4). The reaction of 2 with HBF₄·Et₂O in acetone affords the solvated complex [Ru(η⁵-C₅H₅)(CO){η ¹-OC(CH₃)₂}(PPrⁱ ₃)]BF₄ (5), which reacts with CO, dimethyl acetylenedicarboxylate, and NaCl to give [Ru(η⁵-C₅H₅)(CO)₂(PPr ⁱ₃)]BF₄ (6), [Ru(η⁵-C₅H₅){η²-C ₂(CO₂CH₃)₂}(CO)(PPrⁱ ₃)]-BF₄ (7), and [Ru(η⁵-C₅H₅)Cl(CO)(PPrⁱ ₃)] (8), respectively. Complex 5 also reacts with alkyn-1-ols. The reaction with 1,1-diphenyl-2-propyn-1-ol leads to the allenylidene complex [Ru(η⁵-C₅H₅)(C=C=CPh ₂)(CO)(PPrⁱ₃)]BF₄ (9), which affords [Ru(η⁵-C₅H₅){C(OH)CH=CPh ₂}-(CO)(PPrⁱ₃)]BF₄ (10) by reaction with water. 10 is converted into the acyl derivative [Ru-(η⁵-C₅H₅){C(O)CH=CPh ₂}(CO)(PPrⁱ₃)] (11), when a CH₂Cl₂ solution of 10 is passed through an Al₂O₃ column. The structure of 11 was determined by an X-ray investigation. The reaction of 5 with 2-propyn-1-ol leads to the α,β-unsaturated hydroxycarbene complex [Ru-(η⁵-C₅H₅){C(OH)CH=CH ₂}(CO)(PPrⁱ₃)]BF₄ (12). Similarly to 10, 12 is converted into [Ru-(η⁵-C₅H₅){C(O)CH=CH ₂}(CO)(PPrⁱ₃)] (13), when the solutions of 12 are passed through an Al₂O₃ column. Treatment of 5 with 1-ethynyl-1-cyclohexanol leads to a mixture of organometallic compounds including [Ru(η⁵-C₅H₅){C(OH)CH=C(CH₂) ₄CH₂}(CO)(PPrⁱ₃)]BF₄ (14). Chromatography of the mixture affords [Ru(η⁵-C₅H₅){C(O)CH=C(CH₂) ₄CH₂}(CO)-(PPrⁱ₃)] (15) and [Ru(η⁵-C₅H₅){C≡CC=CH(CH ₂)₃CH₂}(CO)(PPrⁱ₃)] (16). 9 reacts with alcohols and thiols to give [Ru(η⁵-C₅H₅){C(ER)CH=CPh ₂}(CO)(PPrⁱ₃)]BF₄ (ER = OMe (17), OEt (18), SPrⁿ (21)), which by treatment with NaOMe afford [Ru(η⁵-C₅H₅){C(ER)=C=CPh ₂}(CO)-(PPrⁱ₃)] (ER = OMe (19), OEt (20), SPrⁿ (22)). Similarly, the reaction of 9 with benzophenone imine leads to [Ru(η⁵-C₅H₅){C(CH=CPh ₂)=N=CPh₂}(CO)(PPrⁱ₃)]BF₄ (23), which by reaction with NaOMe gives [Ru(η⁵-C₅H₅){C(N=CPh ₂)=C=CPh₂}(CO)(PPrⁱ₃)] (24). The structure of 23 was also determined by an X-ray investigation. The C=N bond lengths are 1.283(9) and 1.252(9) A?, while the C-N-C angle is 149.9(6)°.