Anion-induced two stable isostructural Cd(ii) LMOFs based on benzotriazole with the highly selective detection of Fe3+ ions

Abstract

Two new LMOFs, [Cd₉(BTA)₆(5-tbuip)₆O₂]_n (LMOF-1) and [Cd₃(BTA)₂(5-tbuip)₂]_n (LMOF-2) (BTA = 1H-benzotriazole, 5-tbuip = 5-tert-butylisophthalic acid), have been synthesized by a solvothermal method. The different anions of cadmium salts lead to two isostructural LMOFs. Fe³⁺ could be detected by LMOF-1 with N-rich sites, which possessed a high quenching coefficient (K_sv) of up to 1.87 × 10⁵ M⁻¹. The K_sv value for the detection of Fe³⁺ is better than or comparable to those reported in the literature. Since LMOF-2 had a larger pore size compared to that of LMOF-1, it could detect Cr₂O₇²⁻ with a higher K_sv than LMOF-1. In addition, LMOF-1 is closer to white light, which means that it has potential application in white light-emitting diodes (WLEDs).