Transition Metal Hydrides MH^+/0/-?M=Sc-Zn?:Benchmark Study And Periodic Trends

Transition metal hydride?TMH?plays a critical role in the field of catalytic transformations.Knowledge of enthalpies for cleaving metal hydride bonds enables the prediction of chemical reactivity,such as for the bond-forming and bond-breaking that occur in a catalytic reaction especially in the hydrogenation of carbon dioxide.Thermochemistry of the first row TMHs,MH^+/0/-?M=Sc-Zn?were calculated at the density functional theory?DFT?level as well as HF,MP2 and the CCSD?T?level.Hydricity is the energy required to cleave an M-H bond to generate a hydride ion?H–?.The heterolytic bond cleavage with proton dissociation is the acidity of the metal hydride.The homolytic bond-dissociation,involves formation H·.Periodic trends of H–,H+,H· donor ability are discussed and compared among the different elements and every MH^+/0/- systems.Note that,we can find suitable methods and avoid unfit methods for different element.It seems that ?B97XD and ?B97 are not suitable for calculating MH^+/0/-.Interestingly,BP86,TPSS,TPSSh and B3 LYP never appeared in the “worst column”.The study could give theoretical guidance on the catalysis of TMH.