Molecular hydrogen, coordination compound

The main synthetic methods used in the preparation of the coordination compounds mentioned above are reactions of coordinatively unsaturated complexes with hydrogen, protonation of hydride complexes, and formation of complexes containing molecular hydrogen by a synthesis reaction under reducing conditions. 

Molecular hydrogen (H2) coordination compounds and a-bond complexes... 

This established C-H chemistry in molecular coordination compounds should have its formal analog in metal surface chemistry. Carbon-hydrogen bond-cleavage is a common reaction at metal surfaces but it does not comprise mechanistically the simple collision of a hydrocarbon such as methane with a metal surface vide infra). Methane neither reacts with nor is chemisorbed on a metal surface under moderate conditions. However, propylene does chemisorb, and then C-H bonds may be broken, depending upon the nature of the metal surface. Generally, the sequence at the surface comprises first the formation of a coordinate bond between a surface metal atom(s) and some functionality in the... 

Relatively few other compounds transfer growing polymer chains with coordination catalysts, but molecular hydrogen and its isotopes are effective. The transfer mechanism is... 

Hydrogen complexes form by reaction of transition metal compounds with molecular hydrogen or by protonation. The hydrogen in a transition metal complex may be bonded in the classical or nonclassical way. The complexes may interconvert, may be deprotonated, or may lose molecular hydrogen, generating vacant coordination sites. Thus, the picture of transition metal hydrogen complexes to-day is one of considerable complexity [1, 20, 24, 32, 33]. 

---