Intermolecular Re–H···H–N and Re–H···base hydrogen bonding estimated in solution by a UV-VIS spectroscopic method

Hydrogen bonding (Re–H···H–N) is estimated in solution between ReH5(PPh3)2L (L=pyridine, 4-picoline, 4-dimethylaminopyridine, and 4-carbomethoxypyridine), as hydrogen bond acceptor, and indole, as hydrogen bond donor. Re–H···base hydrogen bonding between [Re(PPh3)2(MeCN)4H][BF4]2 as hydrogen bond donor and various amines as hydrogen bond acceptors is much weaker. The binding strengths are estimated by UV-VIS spectroscopy.