Positional Isomerism Controlled Electronic and Photochromic Properties of Naphthalene Diimide-Based Chlorozincate Hybrids

Two organic–inorganic hybrids, [3-H2DPNDI][ZnCl4]·0.5H2O (1) and [4-H2DPNDI][ZnCl4]·0.5H2O (2) (3-H2DPNDI2+ = protonated N,N-di(3-pyridyl)-1,4,5,8-naphthalene diimide, 4-H2DPNDI2+ = protonated N,N-di(4-pyridyl)-1,4,5,8-naphthalene diimide), have been designed and prepared. Compounds 1 and 2 are constructed from typical [ZnCl4]2– inorganic clusters and positional isomeric organic cations of [H2DPNDI]2+, which are assembled into different three-dimensional supramolecular networks via different anion-π interactions and hydrogen-bonding interactions. Photochromism of 1 and non-photochromism of 2 are attributable to the usage of positional isomers, which leads to the different spatial stack of [ZnCl4]2– donors and [H2DPNDI]2+ acceptors, suggesting a delicate modulating effect of the distinct interfacial contacts on the intermolecular charge transfer/electron transfer and consequently photoresponsive behaviors.