Conformation Restriction of Nonplanar Di-2-pyrimidyl Sulfide with Intramolecular N•••C Interaction and Its Supramolecular Silver(I) Complexes

A series of silver(I) complexes with semirigid di-2-pyrimidyl sulfide (DprS), namely, {[Ag-2(DprS)(2)(CF3CO2)](CF3CO2)center dot 2H(2)O}(infinity) (1), {[Ag-6(DprS)(6)(CF3SO3)(5)](CF3SO3)center dot 3.5H(2)O}(infinity) (2), {[Ag-2(DprS)(C2F5CO2)(2)]}(infinity), (3), [Ag(DprS)(NO3)(infinity) (4), and {[Ag-3(DprS)(3)](ClO4)(3)}(infinity) (5), have been synthesized and characterized by single-crystal X-ray analysis. The silver(I) complexes 1-2 and 4-5 exhibit one-dimensional tape-like coordination polymers with different topological structures, while complex 3 has a two-dimensional coordination network. In these complexes, the two pyrimidyl rings of each DprS are almost in an orthogonal orientation, a rigid nonplanar conformation, and the multidentate ligand adopts an unvaried N,N',N ''-mu(3) ligation mode despite the different anions (CH3COO- in 1, CF3SO3- in 2, C2F5COO- in 3, NO3- in 4, and ClO4- in 5). Attractive intramolecular N-pyrimidyl center dot center dot center dot C-pyrimidyl interaction between a 1-positional N atom of one pyrimidyl ring and an electrophilic 2-positional C atom of the other ring of DprS is a common dominant interaction, which drives and stabilizes the nonplanar ligand conformation in these crystalline structures. Calculation through the self-consistent field crystal orbital method based on density functional theory indicates the presence of the N center dot center dot center dot C contact, a nucleophile-electrophile affinity. Unconventional anion-pi(pyrimidyl) interactions engaged in the construction of the supramolecular architectures of 1-5 also are presented and discussed.