Five-coordinate complex [RuHCl(CO)(PPr3i)(2)] as a precursor for the preparation of new cyclopentadienylruthenium compounds containing unsaturated eta(1)-carbon ligands

The five-coordinate complex [RuHCl(CO)(PPr3i)(2)] (1) reacts with cyclopentadiene in methanol under reflux to give [RuH(eta(5)-C5H5)(CO)(PPr3i)] (2) and [HPPr3i]Cl. The protonation of 2 in dichloromethane-d(2) leads to the dihydrogen complex [Ru(eta(5)-C5H5)(eta(2)-H-2)(CO)(PPr3i)]BF4 (3) in equilibrium with traces of the dihydrido tautomer [RuH2(eta(5)-C5H5)(CO)(PPr3i)]BF4 (4). The reaction of 2 with HBF4 . Et(2)O in acetone affords the solvated complex [Ru(eta(5)-C5H5)(CO){eta(1)-OC(CH3)(2)}(PPr3i)]BF4 (5), which reacts with CO, dimethyl acetylenedicarboxylate, and NaCl to give [Ru(eta(5)-C5H5)(CO)(2)(PPr3i)]BF4 (6), [Ru(eta(5)-C5H5){eta(2)-C-2(CO2CH3)(2)}(CO)(PPr3i)]BF4 (7), and [Ru(eta(5)-C5H5)Cl(CO)(PPr3i)] (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(eta(5)-C5H5)(C=C=CPh(2))(CO)(PPr3i)]BF4 (9), which affords [Ru(eta(5)-C5H5){C(OH)CH=CPh(2)}(CO)(PPr3i)]BF4 (10) by reaction with water. 10 is converted into the acyl derivative [Ru(eta(5)-C5H5){C(O)CH=CPh(2)}(CO)(PPr3i)] (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 alpha,beta-unsaturated hydroxycarbene complex [Ru(eta(5)-C5H5){C(OH)CH=CH2}(CO)(PPr3i)]BF4 (12). Similarly to 10, 12 is converted into [Ru(eta(5)-C5H5){C(O)CH=CH2}(CO)(PPr3i)] (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(eta(5)-C5H5){C(OH)CH=C(CH2)(4)CH2}(CO)(PPr3i)]BF4 (14). Chromatography of the mixture affords [Ru(eta(5)-C5H5){C(O)CH=C(CH2)(4)(CH2}(CO)(PPr3i)] (15) and [Ru(eta(5)-C5H5){C=CC=CH(CH2)(3)CH2}(CO)(PPr3i)] (16). 9 reacts with alcohols and thiols to give [Ru(eta(5)-C5H5){C(ER)CH=CPh(2)}(CO)(PPr3i)]BF4 (ER = OMe (17), OEt (18), SPrn (21)), which by treatment with NaOMe afford [Ru(eta(5)-C5H5){C(ER)=C=CPh(2)}(CO)(PPr3i)] (ER = OMe (19), OEt (20), SPrn (22)). Similarly, the reaction of 9 with benzophenone imine leads to [Ru(eta(5)-C5H5){C(CH=CPh(2))=N=CPh(2)}(CO)(PPr3i)]BF4 (23), which by reaction with NaOMe gives [Ru(eta(5)-C5H5){C(N=CPh(2))=C=CPh(2)}(CO)(PPr3i)] (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) Angstrom, while the C-N-C angle is 149.9(6)degrees.