| 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 ωB97XD and ωB97 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. |
