In-situ spectroscopic studies of rhodium catalyzed production of hydrogen from dimethylamine borane: Homogeneous or heterogeneous catalysis?

The mechanism of catalytic B-N bond formation in amine borane complexes was studied as potential new materials for hydrogen storage. Results using 11B NMR spectroscopy to monitor the kinetics of hydrogen release and in situ XAFS to characterize the active catalyst species in the Rh catalyzed dehydrocoupling reaction of dimethylamine borane complex in toluene were presented. dimethylamine borane was rapidly converted to the cyclic dimer with concurrent lose of hydrogen at room temperature with a half-life of ∼ 30 min using [Rh(cod)Cl]₂ as the catalyst precursor. The EXAFS results suggested that the predominate transition metal species is a Rh(0) cluster with no more than 4-6 core Rh atoms with strongly ligands. This is an abstract of a paper presented at the 228th ACS National Meeting (Philadelphia, PA, 8/22-26/2004).