Five-Coordinate Complex [RuHCl(CO)(PPrⁱ₃)₂] as a Precursor for the Preparation of New Cyclopentadienylruthenium Compounds Containing Unsaturated η¹-Carbon Ligands

Abstract

The five-coordinate complex [RuHCl(CO)(PPr i 3 ) 2 ] ( 1 ) reacts with cyclopentadiene in methanol under reflux to give [RuH(η 5 -C 5 H 5 )(CO)(PPr i 3 )] ( 2 ) and [HPPr i 3 ]Cl. The protonation of 2 in dichloromethane- d 2 leads to the dihydrogen complex [Ru(η 5 -C 5 H 5 )(η 2 -H 2 )(CO)(PPr i 3 )]BF 4 ( 3 ) in equilibrium with traces of the dihydrido tautomer [RuH 2 (η 5 -C 5 H 5 )(CO)(PPr i 3 )]BF 4 ( 4 ). The reaction of 2 with HBF 4 ·Et 2 O in acetone affords the solvated complex [Ru(η 5 -C 5 H 5 )(CO){η 1 -OC(CH 3 ) 2 }(PPr i 3 )]BF 4 ( 5 ), which reacts with CO, dimethyl acetylenedicarboxylate, and NaCl to give [Ru(η 5 -C 5 H 5 )(CO) 2 (PPr i 3 )]BF 4 ( 6 ), [Ru(η 5 -C 5 H 5 ){η 2 -C 2 (CO 2 CH 3 ) 2 }(CO)(PPr i 3 )]BF 4 ( 7 ), and [Ru(η 5 -C 5 H 5 )Cl(CO)(PPr i 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(η 5 -C 5 H 5 )(C C CPh 2 )(CO)(PPr i 3 )]BF 4 ( 9 ), which affords [Ru(η 5 -C 5 H 5 ){C(OH)CH CPh 2 }(CO)(PPr i 3 )]BF 4 ( 10 ) by reaction with water. 10 is converted into the acyl derivative [Ru(η 5 -C 5 H 5 ){C(O)CH CPh 2 }(CO)(PPr i 3 )] ( 11 ), when a CH 2 Cl 2 solution of 10 is passed through an Al 2 O 3 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(η 5 -C 5 H 5 ){C(OH)CH CH 2 }(CO)(PPr i 3 )]BF 4 ( 12 ). Similarly to 10, 12 is converted into [Ru(η 5 -C 5 H 5 ){C(O)CH CH 2 }(CO)(PPr i 3 )] ( 13 ), when the solutions of 12 are passed through an Al 2 O 3 column. Treatment of 5 with 1-ethynyl-1-cyclohexanol leads to a mixture of organometallic compounds including [Ru(η 5 -C 5 H 5 ){C(OH)CH C(CH 2 ) 4 CH 2 }(CO)(PPr i 3 )]BF 4 ( 14 ). Chromatography of the mixture affords [Ru(η 5 -C 5 H 5 ){C(O)CH C(CH 2 ) 4 CH 2 }(CO)(PPr i 3 )] ( 15 ) and [Ru(η 5 -C 5 H 5 ){C⋮CC CH(CH 2 ) 3 CH 2 }(CO)(PPr i 3 )] ( 16 ). 9 reacts with alcohols and thiols to give [Ru(η 5 -C 5 H 5 ){C(ER)CH CPh 2 }(CO)(PPr i 3 )]BF 4 (ER = OMe ( 17 ), OEt ( 18 ), SPr n ( 21 )), which by treatment with NaOMe afford [Ru(η 5 -C 5 H 5 ){C(ER) C CPh 2 }(CO)(PPr i 3 )] (ER = OMe ( 19 ), OEt ( 20 ), SPr n ( 22 )). Similarly, the reaction of 9 with benzophenone imine leads to [Ru(η 5 -C 5 H 5 ){C(CH CPh 2 ) N CPh 2 }(CO)(PPr i 3 )]BF 4 ( 23 ), which by reaction with NaOMe gives [Ru(η 5 -C 5 H 5 ){C(N CPh 2 ) C CPh 2 }(CO)(PPr i 3 )] ( 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) Å, while the C−N−C angle is 149.9(6)°.