Combined Experimental–Theoretical
Characterization
of the Hydrido-Cobaloxime [HCo(dmgH)<sub>2</sub>(P<i>n</i>Bu<sub>3</sub>)]
- Publication date
- Publisher
Abstract
A combined theoretical and experimental approach has
been employed
to characterize the hydrido-cobaloxime [HCo(dmgH)<sub>2</sub>(P<i>n</i>Bu<sub>3</sub>)] 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 <sup>1</sup>H 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)<sub>2</sub>(OH<sub>2</sub>)]<sup>2+</sup> (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