Protonated bis(quinuclidine) included in a novel "bichannel" (urea)-chloride host: a very large urea channel

Abstract

The synthesis, crystal structure and properties of a novel ternary inclusion compound formed by protonated bis(quinuclidine) inserted in a urea-chloride anionic host, urea(5)[quinuclidine(2)H]Cl-+(-) (1), are reported. In the host structure each urea molecule interacts with adjacent urea molecules via N-H...O hydrogen bonds forming a channel arrangement. Each hexagonal channel is linked through halide ions by N-H...Cl hydrogen bonds forming a bichannel-like structure. The channel width of the host (14.32 Angstrom) is one of the largest known for a urea host derivative. The compound may be described as a commensurate species, c(g)/c(h) = 0.98. Conductivity determined for 1 at room temperature is 4.00 x 10(-6) (Omega cm)(-1) and it increases with temperature to 3.33 x 10(-4) (Omega cm)(-1) at 77degreesC. Aspects of the thermal stability of the product are discussed.