Hydrogen Bonds Involving Metal Centers

Hydrogen bonds involving metal center as a hydrogen donor or hydrogen acceptor are only a specific type of metal-hydrogen interactions; it is therefore not easy to differentiate hydrogen bond from other metal-hydrogen interactions, especially agostic ones. The first part of the review is therefore devoted to the results of structural chemistry and molecular spectroscopy (NMR, IR), as a tool for differentiating hydrogen bondings from other hydrogen interactions. The classical examples of Pt center dot center dot center dot H-N, Pt center dot center dot center dot H-O, Pt center dot center dot center dot H-C, and Pd center dot center dot center dot H-N hydrogen bonds were discussed as well as hydrogen bonds involving half-sandwich complexes (eta(5)-C5R5)ML2, where M stays for Co, Ir or Rh, R for H or CH3, and L for CO, PMe3 or C2H4. The paper deals also with metal donating (M-H center dot center dot center dot A) and bifurcated hydrogen bonds. The hydrogen interactions in complexes of other heavy metals (Ni, Cu, Ag, Os) were also briefly discussed.