Protonation of cationic hydride and alkyl complexes of Ir(III)

Abstract

Reaction of HBF 4·OEt 2 with IrH 2(MeCN)P 3 + ( 1) (P = PMe 2Ph) in the presence of MeCN gives rapid conversion to cis, mer-IrH(MeCN) 2P 3 2+ and H 2. The corresponding reaction with cis, mer-IrMe 2(MeCN)P 3 + is much slower, but gives the corresponding product, cis, mer-IrMe(MeCN) 2P 3 2+. In the absence of added MeCN, HBF 4·OEt 2 transforms the dihydride cation 1 to equimolar cis, mer-IrH(MeCN) 2P 3 2+ and IrH 4P 3 +; 0.5 mol of acid suffices to effect this reaction. In the absence of added MeCN, the protonation of the dimethyl cation leads to the ether complex mer-IrMe(Et 2O)(MeCN) P 3 2+, which is subsequently scavenged by adventitious water to yield mer-IrMe(H 2O)MeCN)P 3 2+. The crystal structure of this aquo complex, as its BF 4 salt, shows a chain of BF 4 − /IrMe(H 2O)(MeCN)P 3 2+ units held together by two hydrogen bonds to each water molecule. Crystallographic data for [IrMe(H 2O)(NCMe)(PMe 2Ph) 3](BF 4) 2 (at − 169°C): a = 10.709(3) Å, b = 15.645(4), c = 10.481(2), β = 106.49(1)° with Z = 2 in space group P 1 .