Experimental And Computational Evidence For A Stabilising C-Cl(Lone-Pair)Center Dot Center Dot Center Dot Pi(Chelate-Ring) Interaction

In addition to a variety of conventional non-covalent intermolecular interactions such as C-H center dot center dot center dot pi (arene), C-H center dot center dot center dot Cl and pi(arene)center dot center dot center dot pi(chelate-ring) contacts, the molecular packing in the crystal of an organotin dithiocarbamate compound, [SnCl(4-ClC6H4)(2){(S2CN(i-Pr)(2))}], exhibits evidence for a C-Cl center dot center dot center dot pi(chelate-ring) interaction. These interactions occur via a side-on approach of the chloride atom to the chelate-ring and therefore are characterised as C-Cl(lone-pair)center dot center dot center dot pi(chelate-ring) interactions, are shown to be attractive by NCl plots and QTAIM analysis, and are apparent in the calculated Hirshfeld surfaces. Theory suggests the energy of association provided by the C-Cl center dot center dot center dot pi(chelate-ring) interactions to be about 3-4 kcal mol(-1), a value greater than for analogous C-Cl center dot center dot center dot pi(arene) and C-H center dot center dot center dot pi(arene) interactions. A survey of the literature for related structures suggests that these interactions are not common. The newly described C-Cl(lone-pair)center dot center dot center dot pi(chelate-ring) interactions add to the variety of intermolecular interactions able to be formed by chelate-rings in the supramolecular chemistry of metal complexes.