Reactions of benzophenone imine complex [Tp(NH═CPh2)(PPh3)Ru–Cl] with alkyne and dimerization of terminal alkynes in the presence of Et3N

Abstract Treatment of benzophenone imine complex [Tp(PPh 3 )(NH═CPh 2 )Ru–Cl] ( 1 ) {Tp═HB(pz) 3 , pz = pyrazolyl} with 4-Ethynyltoluene in the presence of H 2 O in distilled ethanol afforded the chelate alkenyl ketone complex [Tp(PPh 3 )RuCCH 2 ( p -MeC 6 H 4 )═CHC(O)( p -MeC 6 H 4 )] ( 2 ). On the other hand, reaction of 1 with HC≡C(O)OR 1 in R 2 OH produced the chelate vinyl ether complexes [Tp(PPh 3 )Ru–C(OR 2 )═CHC(O)OR 1 ] ( 3a , R 1  = Me, R 2  = Me; 3b , R 1  = Et, R 2  = Me; 3c , R 1  = Et, R 2  = Et; 3d , R 1  = Me, R 2  = Et), respectively. Preliminary results on the catalytic activity of 1 are also presented. Intriguingly, complex 1 is found to catalyze the dimerization of terminal alkynes HC≡CR (R =  p -MeC 6 H 4 , C(O)OCH 3 ) in the presence of Et 3 N to give eynes. The structures of 3c and 3d have been determined by X-ray diffraction analysis.