Inorganic Chemistry, Vol.51, No.23, 13017-13022, 2012
Interaction of In(I) and Tl(I) Cations with 2,6-Diaryl Pyridine Ligands: Cation Encapsulation within a Very Weakly Interacting N/Arene Host Environment
The interaction of 2,6-dimesitylpyridine with Tl(I) and In(I) cations has been investigated with a view to developing tractable molecular M(I) compounds which are soluble in organic media. In stark contrast to isosteric and isoelectronic terphenyl systems, complexes featuring the [(2,6-Mes(2)py)M](+) fragment feature very weak metal-ligand interactions in the solid state, as revealed by M-N distances of the order of 2.45 angstrom (M = In) and 2.64 angstrom (M = Tl). While additional weak pi interactions are observed with arene solvate molecules in these systems, the related 2:1 complex [(2,6-Mes(2)py)(2)In][BAr4f] features an In(I) center wholly encapsulated by the bulky Mes(2)py donors, and even longer In-N distances [2.586(6) and 2.662(5) angstrom]. These contacts are about 0.5 angstrom greater than the sum of the respective covalent radii (2.13 angstrom) and provide evidence for an effectively "naked" In(I) cation stabilized to a minor extent by orbital interactions.