Dihydrobis(methimazolyl)borato complexes of ruthenium and osmium

The reaction of Na[H2B(mt)2] (mt = 2-mercapto, 3-methylimidazol-1-yl, methimazolyl) with [Ru(X)Cl(CO) (PPh3)n] (n = 3 X = H; n = 2 BO2C6H4, SiCl3, SiMe3) affords the complexes [Ru(X)(CO)(PPh3){κ2-H,S,S’-H2B (mt)2}]. Evidence is presented to also support the transient formation of [Ru(X)(CO)(PPh3){κ2-H,S,S’-H2B (mt)2}] (X = CHvCHPh, Ph) via a similar strategy, although these are unstable. The osmium complex [OsH (CO)(PPh3){κ2-H,S,S’-H2B(mt)2}] is similarly obtained from [OsHCl(CO)(PPh3)3] or [OsH(NCMe)2(CO)(PPh3)2]BF4. The reaction of [RuH(CO)(PPh3){κ2-H,S,S’-H2B(mt)2}] with chloroform or diphenyldiselenide provides [Ru(X)(CO)(PPh3){κ2-H,S,S’-H2B(mt)2}] (X = Cl, SePh), the latter reaction also providing traces of[Ru(SeH)(CO)(PPh3){κ2-H,S,S’-H2B(mt)2}]. Spectroscopic and structural data for the series [Ru(X)(CO)(PPh3) {κ2-H,S,S’-H2B(mt)2}] are discussed in terms of perturbations on the B–H–Ru interaction by the transligand X.This work was supported by the Australian Research Council (DP130102598 and DP110101611). We thank the University of Botswana for a studentship (to N. T.)