Semi‐conductive Chiral MOFs with Helixes Based on Lactic Acid Derivatives for Photo‐catalytic Reaction

Abstract

AbstractA pair of new chiral Co(II) metal‐organic frameworks based on semi‐rigid lactic acid derivatives, namely, {[Co((R)‐CBA)(1,3‐DPP)(H2O)0.5] ⋅ H2O}n(1‐R) and {[Co((R)‐CBA)(1,3‐DPP)(H2O)0.5] ⋅ H2O}n (1‐S) (H2CBA=4‐(1‐carboxyethoxy) benzoic acid, 1,3‐DPP=1,3‐di(pyridin‐4‐yl)propane) were synthesized under hydrothermal conditions. The structures of complexes 1‐R and 1‐S were determined by single crystal X‐ray crystallography, revealing dinuclear cobalt units are connected through (R)‐ or (S)‐CBA2− anions that lead to the formation of enantiomeric helical chains. Helical chains are further linked together to build 3D Co‐(R)‐CBA (Co‐(S)‐CBA) framework in 1‐R(1‐S). Furthermore, more large helical chains are formed by Co(II) centers and 1,3‐DPP ligands in 1‐R and 1‐S. As a result, 1,3‐DPP ligands are introduced into complexes to stabilize the CBA−Co frameworks to obtain a four‐connected dia net. Apart from delicate structure, the UV‐vis sorption spectrum, Mott‐Schottky measurements and electrochemical impedance spectroscopy (EIS) demonstrated that complex 1‐R is a typical n‐type semiconductor with low resistance in charge transportation. Photo‐catalytic test result confirmed the complex 1‐R has catalytic activity for the degradation of RhB.