Combined Experimental–Theoretical Characterization of the Hydrido-Cobaloxime [HCo(dmgH)₂(P<i>n</i>Bu₃)]

A combined theoretical and experimental approach has been employed to characterize the hydrido-cobaloxime [HCo­(dmgH)₂(P<i>n</i>Bu₃)] compound. This complex was originally investigated by Schrauzer et al. [Schrauzer et al., <i>J. Am. Chem. Soc</i>. <b>1971</b>, <i>93</i>,1505] and has since been referred to as a key, stable analogue of the hydride intermediate involved in hydrogen evolution catalyzed by cobaloxime compounds [Artero, V. et al.<i> Angew. Chem., Int. Ed</i>. <b>2011</b>, <i>50</i>, 7238–7266]. We employed quantum chemical calculations, using density functional theory and correlated RI-SCS-MP2 methods, to characterize the structural and electronic properties of the compound and observed important differences between the calculated ¹H NMR spectrum and that reported in the original study by Schrauzer and Holland. To calibrate the theoretical model, the stable hydrido tetraamine cobalt­(III) complex [HCo­(tmen)₂(OH₂)]²⁺ (tmen = 2,3-dimethyl-butane-2,3-diamine) [Rahman, A. F. M. M. et al.<i> Chem. Commun</i>. <b>2003</b>, 2748–2749] was subjected to a similar analysis, and, in this case, the calculated results agreed well with those obtained experimentally. As a follow-up to the computational work, the title hydrido-cobaloxime compound was synthesized and recharacterized experimentally, together with the Co­(I) derivative, giving results that were in agreement with the theoretical predictions