Synthesis of [Ru(II)(Tp)(Cl)(PPh3)(CH3CN)] and its reactions with selected terminal alkynes: Experimental and computational studies

Abstract The ruthenium complex [Ru(II)(Tp)(Cl)(PPh 3 )(CH 3 CN)] ( 3 ) [Tp = hydrotris(pyrazolyl)borate] contains substitutional ligands, acetonitrile and chloride, and serves as a starting material for the synthesis of new ruthenium complexes. We found that water was also involved in reactions and formed the alkenyl ketone compound [Ru(Tp)(PPh 3 )(C(CH 2 Ph) = CHC(O)Ph)] ( 4 ) and the acyl complex [Ru(Tp)(PPh 3 )(C(O)CH 2 (C 6 H 5 )F)] ( 5 ). We suggest that water could be an impurity in the solvent, methanol. Methanol cannot be purified before a synthesis procedure, and water is more reactive than methanol. In order to have a better understanding on those new ruthenium complexes, the density functional theory (DFT) has been carried out at the PBE/DZVP level on the proposed mechanisms of the selected reactions. For the reactions of compound 3 with methyl propiolate or ethyl propiolate in the presence of methanol, the solvent can be the nucleophile, and a similar observation can be seen if methanol is replaced by ethanol.