Viability of half-sandwich complex of heavier group-14 elements (Si-Pb) with neutral Be-3 ring and its potential application as H-2 storage material

High level ab initio calculations were carried out to establish the half-sandwich structural behavior of heavier group-14 elements (Si-Pb) with neutral Be-3 ring fragment and their molecular hydrogen adsorption capacity. The proposed complexes are found to be global minima on the potential energy surface after a rigorous systematic isomeric search. Quantum chemical investigation revealed that the complexes found possess high bond dissociation energy and also favorable thermodynamics of their formation. The complexes were also found to possess significant aromatic behavior. Among all the complexes, gravimetric density reaches more than the target level by US DOE in case of Be3Si and Be3Ge system which makes them potential target for molecular H-2 storage. Furthermore, the average adsorption energy, E-ad for these two complexes ranges between physisorption and chemisorption process, thereby suggesting their reversible H-2 storage property.