▎ 摘　　要

The development of alternate catalysts that utilize non-precious metal based electrode materials such as the first row transition metal complexes is an important goal for economic fuel cell design. In this direction, a new Fe4S4 cubane type cluster, [PPh4](2)[Fe4S4(DMET)(4)] (1) (DMET = cis-1,2-dicarbomethoxyethylene dithiolate) and its composite with functionalized graphene, (1@graphene) have been synthesized and characterized. The presence of nanocrystalline structures on graphene matrix in TEM and SEM images of 1@graphene indicate that the cluster (1) has been immobilized. The composite, 1@graphene evolves H-2 gas from p-toluene sulfonic acid (TsOH) in a mixture of H2O and CH3CN under ambient conditions with a significant turnover number of 3200. 1@graphene electrocatalyzes H-2 evolution at E-p, -1.2 V with remarkable throughput, catalytic efficiency and stability in only H2O or in only CH3CN. The Fe4S4 cluster (1) alone electro-catalyzes hydrogen evolution at Ep, -0.75 V from TsOH in CH3CN. The X-ray crystal structure of the Fe4S4 cluster (1) (lambda(max), CH2Cl2, 823 nm; epsilon, 2200 mol(-1) cm(-1)) shows that it is dianionic with a cumulative oxidation state of +2.5 for the iron centers and short C-S bond distances (ca., 1.712 angstrom & 1.727 angstrom) indicating the presence of sulfur based radicals.