X-ray crystal structure of the bis(dihydrogen) complex RuH2(H-2)(2)(PCy3)(2)

RuH2(H-2)(2)(PCy3)(2), the first reported stable bis (dihydrogen) complex c rystallizes in the P1 space group; the two dihydrogen ligands lie in the eq uatorial plane in a mutual cis position and are located trans to the hydrid e ligands; the H-H distances are ca. 0.85 Angstrom, in agreement with the p resence of unstretched dihydrogen ligands; these results are compared with previous theoretical calculations using density functional theory.