Résumé
This chapter deals with many metal hydrides. These metal hydrides can be protonated to give dihydrogen complexes. In some cases, kinetic protonation takes place on an M–H bond of a complex to give an M–(H2) complex, even when the thermodynamically most favored protonation site is the metal itself. A combination of theoretical and experimental approaches provides an improved understanding of several aspects of hydride chemistry. A new type of hydrogen bond between a proton and a hydride is shown to influence the properties of a number of main group and transition-metal compounds. It seems to be important in case of protonation of hydrides by acids AH. The chapter also describes Pendant group effects that allow stabilization of an HF complex and observation of heterolytic H2 activation.