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

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.