Some new dicationic dihydrogen complexes of ruthenium

A series of new dicationic dihydrogen complexes of ruthenium of the type tr ans-[(dppe)(2)Ru(eta (2)-H-2)(RCN)][BF4](2) [dppe = Ph2PCH2CH4PPh2; R = CH3 , CH3CH2, CH3CH2CH2, CH2=CH, p-CH3-C6H4-CH2, C6H5, and (CH3)(2)N] have been prepared by the protonation reaction of the precursor hydrides, trans-[(dp pe)(2)Ru(H)(RCN)][BF4] using HBF4. OEt2, The variable temperature spin-latt ice relaxation times (T-1, ms) and the H, D coupling constants of the eta ( 2)-HD isotopomers indicate the intact nature of the H-H bond in these compl exes. It was found that the spectroscopic and chemical properties of these derivatives are not very sensitive to the change in the trans nitrile Ligan d. The pK(a) values of the dihydrogen complexes have been determined using the equilibrium: trans-[(dppe)(2)Ru(H)(RCN)][BF4] + HBF4. OEt2 reversible a rrow trans-[(dppe)(2)Ru(eta (2)-H-2)(RCN)][BF4](2) + Et2O by H-1 NMR spectr oscopy.