Anion-Controlled Architecture and Photochromism of Naphthalene Diimide-Based Coordination Polymers.

Three new cadmium coordination polymers, namely [Cd(NO₃)₂(DPNDI)(CH₃OH)]·CH₃OH (), [Cd(SCN)₂(DPNDI)] (), and [Cd(DPNDI)₂(DMF)₂]·2ClO₄ () (DPNDI = ,-di(4-pyridyl)-1,4,5,8-naphthalene diimide, DMF = ,-dimethylformamide) have been synthesized by reactions of DPNDI with Cd(NO₃)₂, Cd(SCN)₂, and Cd(ClO₄)₂, respectively. Compound is a one-dimensional coordination polymer with strong lone pair-π interactions between the coordinated NO₃ anions and the imide ring of DPNDI; while is a two-dimensional network with a (4, 4) net topology. In the case of , due to the presence of uncoordinated perchlorate counter ions, it exhibits a non-interpenetrated square-grid coordination polymer containing one-dimensional rhomboid channels. The structural diversity in these compounds is attributed to different coordination abilities and geometries of counter anions. Due to the presence of electron-deficient NDI moiety, the photochromic behavior of these compounds was studied. Interestingly, only compounds and exhibit color changes under light irradiation. The influence of the anions on the photochromism process of the NDI-based materials has been discussed.