Formation and Reactivity with (BuCN)-Bu-t of a Thorium Phosphinidiide through a Combined Experimental and Computational Analysis
Résumé
An investigation of the formation of a thorium phosphinidiide reveals that changing from a 2,4,6-(Pr3C6H2)-Pr-i (Tipp)-substituted phosphido ligand to a 2,4,6-Me3C6H2 (Mes) ligand forms a similar product, [(C5Me5)(2)Th](2)(P-2,6-CH2C6H2-4-CH3), but via a different sequence of bond activations. The resulting phosphinidiide was reacted with 1 and 2 equiv of (BuCN)-Bu-t, leading to mono(ketimide), [(C5Me5)(2)Th](2)[mu(2)-P-(2-CH2-6-(N=C(Bu-t)(CH2))-4-Me-C6H2)], and bis(ketimide), [(C5Me5)(2)Th](2)[mu(2)-P-(2-CH2-6-(N=C(Bu-t)(CH2))-4-Me-C6H2)], complexes, respectively, through insertion into the thorium- carbon bonds. An analysis of the Th-P-Th moiety showed a correlation of decreased Th-P-Th bond angle and upheld P-31 NMR chemical shift with decreasing Th-P covalent bond character.