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)(PPri 3)2] (1) reacts with cyclopentadiene in methanol under reflux to give [RuH(η5-C5H5)(CO)(PPri 3)] (2) and [HPPri 3]Cl. The protonation of 2 in dichloromethane-d 2 leads to the dihydrogen complex [Ru(η5-C5H5)(η2-H2)(CO)(PPri 3)]BF4 (3) in equilibrium with traces of the dihydrido tautomer [RuH2(η5-C5H5)(CO)(PPri 3)]BF4 (4). The reaction of 2 with HBF4·Et2O in acetone affords the solvated complex [Ru(η5-C5H5)(CO){η1-OC(CH3)2}(PPri 3)]BF4 (5), which reacts with CO, dimethyl acetylenedicarboxylate, and NaCl to give [Ru(η5-C5H5)(CO)2(PPri 3)]BF4 (6), [Ru(η5-C5H5){η2-C2(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CPh2)(CO)(PPri 3)]BF4 (9), which affords [Ru(η5-C5H5){C(OH)CHCPh2}(CO)(PPri 3)]BF4 (10) by reaction with water. 10 is converted into the acyl derivative [Ru(η5-C5H5){C(O)CHCPh2}(CO)(PPri 3)] (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CH2}(CO)(PPri 3)]BF4 (12). Similarly to 10, 12 is converted into [Ru(η5-C5H5){C(O)CHCH2}(CO)(PPri 3)] (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)(PPri 3)]BF4 (14). Chromatography of the mixture affords [Ru(η5-C5H5){C(O)CHC(CH2)4CH2}(CO)(PPri 3)] (15) and [Ru(η5-C5H5){C⋮CCCH(CH2)3CH2}(CO)(PPri 3)] (16). 9 reacts with alcohols and thiols to give [Ru(η5-C5H5){C(ER)CHCPh2}(CO)(PPri 3)]BF4 (ER = OMe (17), OEt (18), SPrn (21)), which by treatment with NaOMe afford [Ru(η5-C5H5){C(ER)CCPh2}(CO)(PPri 3)] (ER = OMe (19), OEt (20), SPrn (22)). Similarly, the reaction of 9 with benzophenone imine leads to [Ru(η5-C5H5){C(CHCPh2)NCPh2}(CO)(PPri 3)]BF4 (23), which by reaction with NaOMe gives [Ru(η5-C5H5){C(NCPh2)CCPh2}(CO)(PPri 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)°.

Formation of Oxaphosphacarbenes by Reaction of [RuTpCl(PPh3)(thp)] with Terminal Alkynes and a Propargylic Alcohol

“…Such a small singlet may be attributable to the carbonyl compound [RuTpCl(CO)(thp)], [20] presumably produced by reaction of the allenylidene with water released from Selegue's reaction. Similar addition reactions of water have already been described for other cationic [21] and neutral [22] ruthenium(II) allenylidene complexes. Compound 11 was characterised by NMR spectroscopy.…”

Nucleophilic addition reactions to the allenylidene complex [Cp∗RuCCCPh2(CO)(PMeiPr2)]+: X-ray crystal structures of , , and

“…The angle C12-N1-C14 has a value of 168.7(5)°, which indicates an essentially linear C‚N‚C C assembly. In the related complex [CpRu{C(N‚CPh 2 ) CH‚CPh 2 }(CO)(P i Pr 3 )] + [29], this angle has a value of 149.9(6)°, being therefore more deviated from linearity. The IR spectrum of 2 displays one strong band at 1796 cm À1 ascribed to the C‚N‚C group.…”

Activation of alkynes by {[Cp∗Ru(CO)(PMeiPr2)]+}: X-ray crystal structures of and

“…In this work we report the outcome of our investigations on the activation of alkynes by the fragment {[Cp * Ru(CO)(PMe i Pr 2 )] + }. Here, we compare the results with those previously obtained with the {[Cp * Ru(P) 2 ] + } ((P) 2 = dippe [6,7,11], (PEt 3 ) 2 [7,8,10], (PMe i Pr 2 ) 2 [9]) fragments and the analogous less electron rich {[CpRu(CO)(P i Pr 3 )] + } fragment [13].…”

“…In neutral ruthenium allenylidene complexes (i.e., [Cp * Ru‚C‚C‚CPh 2 (Cl)(PPh 3 )] [2]) this band also appears below 1900 cm À1 , whereas the related derivative [CpRu‚C‚C‚CPh 2 (CO)(P i Pr 3 )][BF 4 ] [23] displays the band at 2002 cm À1 .This indicates that 7 contains an electron-poor ruthenium centre due to the presence of the carbonyl ligand in the coordination sphere. As a result, the reactivity patterns of the allenylidene complex 7 are expected to be remarkably different to those of the Cp * Ru bis(phosphine) allenylidene derivatives that we have studied in the past, but very close to the reactivity patterns displayed by the electron-poor system [CpRu‚C‚C‚CPh 2 (CO)(P i Pr 3 )] + [13]. The nucleophilic addition reactions to the allenylidene complex 7 will be reported in a forthcoming paper.…”