Coordination Networks of a Ditopic Macrocycle Exhibiting Anion-Controlled Dimensional Changes and Crystal-to-Crystal Anion Exchange

Abstract

A rationally designed NO2S2-donor macrocycle L was synthesized, and anion variation (PF6(-), CF3CO2(-), NO3(-), and CF3SO3(-)) of its silver(I) complexes was employed as a strategy for controlling their coordination modes and network dimensions. The assembly reactions of L with four silver(I) salts afforded the complexes [Ag2L2](PF6)2 (1), [Ag4L2(CF3CO2)4]n (2), [Ag4L2(NO3)4]n (3), and {[Ag3L2(CF3SO3)2]CF3SO3}n (4) that adopt cyclic dimer, 1D, 2D, and pseudo 3D network structures, respectively, with the structure adopted depending on the coordination ability and coordination modes of the anion used. Interestingly, quantitative anion exchange accompanying an irreversible structural conversion from 2, 3, or 4 to 1 was observed in the crystalline state by powder X-ray diffraction (PXRD) and IR spectroscopy. A stepwise mechanistic process from 2 (CF3CO2(-), 1D) to 3 (NO3(-), 2D) by anion exchange was also proposed.