Assessment of various density functionals for intermolecular N → Sn interactions: The test case of trimethyltin cyanide dimer

An assessment of the performance of various density functionals for describing structural and energetic properties of a model system exhibiting the intermolecular N → Sn interaction has been presented. A set of 20 density functionals belonging to several density functional theory (DFT) classes was used to predict the geometry and the interaction energy in the trimethyltin cyanide dimer, (Me3SnCN)2. The assessment of the density functionals was carried out by comparing the DFT results with the corresponding wave function theory (WFT) results. The combinations of the 20 density functionals with a few basis sets, as well as the dispersion-corrected variants of selected density functionals were included in the assessment. The representatives of modern DFT classess, such as those utilizing the long-range correction scheme and the range-separated hybrids, reproduce the reference results with great accuracy. A comparison of the DFT results for the dimer with the experimental data for crystalline trimethyltin cyanide was also made to evaluate the usefulness of the density functionals working with such a model system for reproducing the crystal structure of Me3SnCN and, generally, for the investigations of N → Sn contacts in crystals. A survey of the Cambridge Structural Database (CSD) was conducted to provide additional structural information for such contacts.