UC San Diego

Sustained interest in the unsaturated mononuclear cobalt carbonyls arises from their presumed role as reactive intermediates in industrial hydroformylation and carbonylation processes, yet their observations have been limited to low temperature matrix isolations. Herein, we report a full library of isolobal analogues of unsaturated cobalt carbonyl complexes by using sterically encumbering m-terphenyl isocyanides. A detailed mechanistic study on both the reactivity of Co(CNArMes2)4 along with the unique bond activation processes of (SiMe3)Co(CNArMes2)3 with N2O are presented. For the latter system, a demonstration of the catalytic capability of these cobalt complexes for the production of organoisocyanates is presented, which provides an exciting opportunity to produce value-added products using N2O as a terminal oxidant. Furthermore, a dispersion forced solid-state host-guest interaction with n-hexane is discussed with support of EDA (Energy Decomposition Analysis) calculation. A solution-phase persistence weakly coordinated 1,6-diaminohexane dimer complex, (μ2-N-(N2C6H18)[Co(SiMe3)(CNArMes2)3]2, was made and the CH/π interactions was monitored by VT-NMR (Variable Temperature Nuclear Magnetic Resonance), providing new insight into the existence of σ-alkane adducts of Co(SiMe3)(CNArMes2)3 forced by van der Waals (CH/π) interactions in the solid-state. Solution phase 2D-IR (Ultrafast Two-Dimensional Infrared Spectroscopy) data and DFT (Density Functional Theory) calculations presented to provide the direct observation of rapid isomerization of Co(CNArMes2)4 between the C3v and D2d isomers. Furthermore, for the first time, a controlled, stepwise cobalt phosphide cluster synthesis using cobalt metallates as building blocks is achieved.