Synthesis and characterization of MH···HOR dihydrogen bonded ruthenium and osmium complexes（η~5-C_5H_4CH_2OH）MH（PPh_3）_2（M = Ru, Os）

Treatment of RuCl2（PPh3）3 with 6-dimethylaminopentafulvene in THF in the presence of water produced（η5-C5H4CHO） RuCl（PPh3）2, which was reduced by NaBH4 to give the Ru-H···HO dihydrogen bonded complex（η5-C5H4CH2OH） RuH（PPh3）2. The dihydrogen bonded complex（η5-C5H4CH2OH）RuH（PPh3）2 could also be synthesized by the reduction of complex（η5-C5H4CHO）RuH（PPh3）2, which was obtained by the reaction of RuHCl（PPh3）3 with 6-dimethylaminopentafulvene in the presence of water. The analogous dihydrogen bonded osmium complex（η5-C5H4CH2OH）OsH（PPh3）2 was similarly prepared. Single crystal structures and DFT calculations support the presence of intra-molecular H···H interaction, with separations of around 1.9 to 2.0 .