Investigation of ligand steric effect on the hydrogen gas produced via a nickel-catalyzed dehydrogenation of ammonia-borane utilizing unsymmetrical triazolylidene ligands

Seven new unsymmetrical triazolylidene ligands 4-(4-R-phenyl)-1-R′-1,2,4-triazoly-1-lidene (where R = H, CH3, CF3, F; and R′ = CH3, iPr, Bzl, methylcyclohexane) were employed in a nickel-catalyzed dehydrogenation of ammonia borane. The ligand's reactivity is correlated to the steric bulk associated with the different R′ substitutions of the triazole using the solid angle G-parameter.46