Labile silver(I) complexes with benzisothiazolinone anion and phosphines: Synthesis, characterization and hydrogen storage application

A silver complex was prepared with benzisothiazolinone ligand, which was used to prepare new phosphorus-rich complexes with dppe and dppp. All complexes were diagnosed by FTIR, 1H-NMR, 31P-NMR, CHN, and molar conductivity. The results proved that phosphines were labile, therefore 31P-NMR was measured by cryoprotection at different temperatures. As a promoted effort to obtain direct experimental proof for the dimeric and the labile nature of [Ag(bit)(diphos)]2 complexes in solution, the 31P{1H}-NMR spectrum of mixed (dppe/dppp) ligand complexes was measured. It was anticipated that an exchange of phosphines occurred between [Ag(bit)(dppe)]2 and [Ag(bit)(dppp)]2 complexes. However, a distribution of the dppp and dppe should result, and complex with compositions of [Ag2(bit)2(dppe)(dppp)] will be formed. The phosphine-containing complexes were used in hydrogen storage study. The results proved that hydrogen storage values were initially similar for [Ag(bit)(dppp)]2 and [Ag(bit)(dppe)]2, but increased significantly for [Ag(bit)(dppe)]2 at higher pressures to reach 4.35 wt% at 90 bar. The complex [Ag(bit)]n was used to synthesis [Ag(bit)(dppe)]2 and [Ag(bit)(dppp)]2. The resulting complexes were used as hydrogen storage materials.image