DFT calculations of 119Sn chemical shifts for organometallic cyanides

Density functional theory (B3LYP) calculations have been carried out for Sn-119 isotropic chemical shifts for a grouping C-N-Sn(CH3)(3)-N-C characteristic of a series of solid organometallic compounds. A strong influence of the Sn-N-C bond angle was found. Computations were then made for seven model groupings of this type with geometries found for four iron-based heterobimetallic systems. A good correlation was found between calculated and observed chemical shifts. The trends are well reproduced in spite of the lack of relativistic terms in the computations. The correlation was used to assign three additional Sn-119 resonances for one of the compounds to the relevant crystallographic sites. The methods are shown to have predictive value.