Modelling doped (Ni, Pd, Pt) sulfur-nitrolic systems as new motifs for storage of hydrogen

Quantum chemical calculations have been performed on a series of cyclic rings (S(2)N(2) and S(3)N(3)(-)) with and without doping of transition metals (TM = Ni, Pd and Pt) to study their ability to store hydrogen. Calculations show that S(2)N(2) is planar while S(3)N(3)(-) is puckered to C(3v) symmetry. Undoped SN rings and chains are predicted to have dispersive interactions with H(2) with endothermic binding energies and significant contributions from entropy at room temperature. However, doping with TM increases the number of binding hydrogens. Binding of the TM with the rings shows interesting diversity in structures. Strategies are proposed for the storage of hydrogen in this interesting class of molecular materials.