Disilaferra- and disilaruthenacyclic complexes containing mesityl isocyanide as a ligand, 3' and 4', were synthesized and characterized by spectroscopy and crystallography. Both 3' and 4' showed excellent catalytic activity for the hydrogenation of alkenes. Compared with iron and ruthenium carbonyl analogues, 1' and 2', the isocyanide complexes 3' and 4' were more robust under the hydrogenation conditions, and were still active even at higher temperatures (∼80 °C) under high hydrogen pressure (∼20 atm). The iron complex 3' exhibited the highest catalytic activity toward hydrogenation of mono-, di-, tri-, and tetrasubstituted alkenes among currently reported iron catalysts. Ruthenium complex 4' catalyzed hydrogenation under very mild conditions, such as room temperature and 1 atm of H. The remarkably high catalytic activity of 4' for hydrogenation of unfunctionalized tetrasubstituted alkenes was especially notable, because it was comparable to the activity of iridium complexes reported by Crabtree and Pfaltz, which are catalysts with the highest activity in the literature. DFT calculations suggested two plausible catalytic cycles, both of which involved activation of H assisted by the metal-silicon bond through σ-bond metathesis of late transition metals (oxidative hydrogen migration). The linear structure of M-C≡N-C (ipso carbon of the mesityl group) played an essential role in the efficient hydrogenation of sterically hindered tetrasubstituted alkenes.

SUMMARYThe purpose of the present study was to find the possibility of a glucose-protein interaction using phydroxyacetophenone (p-HAP)-Sepharose resin. Additionally, two proteins were identified as p-HAP-Sepharose binding proteins. In this study, seven polypeptides were found to have an affinity with p-HAP in the liver cytosolic fraction. More specifically, this study demonstrated that the four polypeptides from the seven also have an affinity with glucose. Moreover, to confirm the results from this experiment using a p-HAP affinity column, a commercially available horse liver alcohol dehydrogenase (HLADH) was examined. HLADH bounded to a p-HAP affinity column was eluted by both glucose and p-HAP. The in vitro enzymatic activity of the HLADH, in the presence of ethanol as a substrate, was significantly decreased by incubation with glucose (up to 250 mM). These results suggested that glucose has an affinity with HLADH and decreases its activity in vitro.