Protonation of triosmium clusters Os3(CO)9(μ−CO)(μ3−2σ,η2−HCCR) and Os3(μ−H)(CO)9(μ3−σ,2η2−CCR) (R = CH2OH, CMe2OH, C(Me) = CH2

Transition Metal Complexes Containing Allenylidene, Cumulenylidene, and Related Ligands

“…In the osmium series, protonation (TfOH) of Os 3 (μ 3 -C 2 R)(CO) 9 (R = CH 2 OH, CMe 2 OH, CMeCH 2 ) gave [Os 3 (μ-H)(μ 3 -CCCR‘ 2 )(CO) 9 ] + ( 126 , R‘ = H, Me), containing the μ 3 -η 3 -( 6e )-allenylidene ligand found in the WRe 2 complexes 112 (Scheme ) . They show similar dynamic behavior with Δ G ⧧ 55.6 kJ mol -1 .…”

“…The μ 3 -( 6e )-allenylidene ligand can also be considered to be another example of an α-carbonium ion stabilized by interaction with metal centers . The complexes are fluxional by a process which involves movement of the CMe 2 group from one Re atom to the other; for 112 (R = Et), Δ G ⧧ is 59 kJ mol -1 .…”

Preparation and structural characterisation of some ruthenium cluster carbonyls containing allenylidene ligands †

“…Mild heating (refluxing hexane, 15 min) results in decarbonylation and formation of the hydrido-alkynyl complexes Ru 3 (µ-H){µ 3 -C 2 CAr 2 (OH)}(CO) 9 [Ar = Ph (9), tol (10)]. Again, 9 has been reported on an earlier occasion.…”

“…A solution of Ru 3 {µ 3 -HC 2 CPh 2 (OH)}(µ-CO)(CO) 9(7) (130 mg, 0.164 mmol) in hexane (20 ml) was heated at reflux point for 1 h, after which the colour had paled to yellow. Purification by preparative tlc (acetone-hexane 3 : 7) gave pale yellow crystals (pentane) of Ru 3 (µ-H){µ 3 -C 2 CPh 2 (OH)}(CO) 9 (9) (108 mg, 86%) obtained from the band with R f 0.54.Preparation of Ru3 ( -H){ 3 -C 2 C(tol) 2 (OH)}(CO) 9(10). A solution of Ru 3 {µ 3 -HC 2 C(tol) 2 (OH)}(µ-CO)(CO) 9 (8) (450 mg, 0.55 mmol) in hexane (50 ml) was heated at reflux point for 1 h, the colour gradually changing to yellow.…”

“…A solution of Ru 3 {µ 3 -HC 2 C(tol) 2 (OH)}(µ-CO)(CO) 9 (8) (450 mg, 0.55 mmol) in hexane (50 ml) was heated at reflux point for 1 h, the colour gradually changing to yellow. Preparative tlc (acetone-hexane 1 : 4) gave a single yellow band (R f 0.66), which after extraction and crystallisation (pentane) afforded pale yellow crystals of Ru 3 (µ-H){µ 3 -C 2 C(tol) 2 (OH)}(CO) 9(10) (383 mg, 88%).Preparation of Ru 3 ( -H){ 3 -C 2 CH 2 (OH)}(CO) 9 (13).A solution of Ru 3 {µ 3 -HC 2 CH 2 (OH)}(µ-CO)(CO) 9 (11) (100 mg, 0.156 mmol) in hexane (20 ml) was heated at reflux point for 15 min, after which time tlc showed complete disappearance of starting material. Purification by preparative tlc (silica gel, acetonehexane 1 : 4) gave yellow crystals (CHCl 3 ) of Ru 3 (µ-H){µ 3 -C 2 CH 2 (OH)}(CO) 9 (13) (68 mg, 71%).Preparation of Ru 3 ( -H){ 3 -C 2 CMe 2 (OH)}(CO) 9 (14).A solution of Ru 3 {µ 3 -HC 2 CMe 2 (OH)}(µ-CO)(CO) 9(12) (84 mg, 0.126 mmol) in hexane (15 ml) was heated at reflux point for 15 min, after which time the colour had changed from orange to pale yellow.…”