Activation of Propargyl Alcohols by TpRu Complexes Bearing a Bidentate NHC Ligand

作者：Jimenez Tenorio Manuel^*; Puerta M Carmen; Valerga Pedro

来源：Organometallics, 2016, 35(3): 388-399.

DOI：10.1021/acs.organomet.5b00964

The complex [TpRuCl(COD)] reacts with L center dot Ag2Cl2 (L = bis(3-methylimidazol-2-ylidene)) in dichloroethane at 120 degrees C for a period of 20 h, furnishing the bis(carbene) derivative [TpRuCl(L)] (1). This compound reacts with NaBAr4' in FPh under dinitrogen to yield the cationic dinitrogen complexes [TpRu(N-2)(L)][BAr4'] (2') and [{TPRu(L)/(mu-N-2)][BAr4'](2) (2). The terminal dinitrogen complex 2' is labile and spontaneously converts into 2, which was structurally characterized. The reaction of 2 with CO is slow and affords [TpRu(CO)(L)][BAr'4] (3). The kinetics of the substitution of coordinated dinitrogen in 2 by CD3CN has been studied. The value of 25 +/- 4 kcal mol(-1) determined for Delta G(298)(double dagger) for the substitution reaction is consistent with the observation that the dinitrogen ligand is strongly bound to ruthenium in 2. Complex 1 reacts with propargyl alcohols HC equivalent to CC(OH)RR' (RR' = Me-2, (CH2)(5), MePh, HPh) and NaBPh4 in MeOH at 50-60 degrees C, yielding the corresponding gamma-methoxyvinylidene complexes [TpRu=C=CHC(OMe)RR'(L)][BPh4] (RR' = Me-2 (4a), (CH2)(5) (4b), MePh (4c), HPh (4d)). The reaction of 1 with HC equivalent to CCH2OH under the same conditions led to the gamma-hydroxyvinylidene derivative [TpRu=C=CHCH2OH(L)][BPh4] (5), whereas the reaction with HC equivalent to CC(OH)Ph-2 resulted in the formation of the deep purple allenylidene complex [TpRu=C=CCPh2(L)][BPh4] (6). A series of N- and S-donor molecules such as pyrazole, piperidine, 2-pyridinethiol, and 1,3-benzenedithiol add to the C-alpha atom of the allenylidene ligand in 6 to yield the corresponding diphenylvinylcarbene species [TpRu=C(X)CH=CPh2(L)][BPh4] (X = C3H3N2 (7), N(CH2)(4)CH2 (8), SC5H4N (9), SC6H4SH (10)), of which compound 7 was structurally characterized. The reaction of 6 with KOBut in acetone produced the neutral sigma-alkynyl derivative [TpRuCE equivalent to CC(CH2COCH3)Ph-2(L)] (11), resulting from the addition of acetone enolate to the C-gamma of the allenylidene ligand.

• 出版日期2016-2-8