Photochromic Supramolecular Isomers Derived from Pb(II)-Bipyridinedicarboxylate Complexes

Abstract

Photochromic metal–organic complexes (PMOCs) have received huge attention of chemists, thanks to their diverse structural characteristic and various available photo-modulate physicochemical functionalities. The organic ligand plays a crucial role in the quest of PMOCs with specific photo-responsive functionalities. The multiple coordination modes of polydentate ligands also provide possibilities for forming isomeric MOCs, which may open a new perspective on the research of PMOCs. The exploration of suitable PMOC systems is significant for the yield of isomeric PMOCs. Taking into account extant PMOCs based on polypyridines and carboxylate as electron acceptors (EAs) and donors (EDs), the covalent fusion of suitable pyridyl and carboxyl species may produce single functionalized ligands bearing ED and EA moieties for the building of novel PMOCs. In this study, the coordination assembly of bipyridinedicarboxylate (2,2′-bipyridine-4,4′-dicarboxylic acid, H2bpdc) and Pb2+ ions generate two isomeric MOCs, [Pb(bpdc)]·H2O (1 and 2), which have the same chemical compositions with main discrepancies in the coordination mode of bpdc2– ligands. As expected, supramolecular isomers 1 and 2 exhibited different photochromic performance, thanks to the distinct microscopic functional structural units. A schematic encryption and anti-counterfeiting device based on complexes 1 and 2 has also been studied. Compared with the extensively studied PMOCs supported by photoactive ligands like pyridinium and naphthalimide-derivatives and PMOCs derived from mixed electron-accepting polydentate N-ligands and electron-donating ligands, our work provides a new idea for building PMOCs based on pyridinecarboxylic acid ligands.

Water-Stable Cd(II)-Based Metal–Organic Framework: Antibiotic Detection and Photochromism Behavior

“…The original state of the Cd-MOF presents a weak signal, which may be caused by the photo-sensitivity of solid 1 . Moreover, the crystal structure of 1 displays the short distances between the oxygen of nitrate groups and nitrogen of TBD moieties, which can be deemed as an advantage for the occurrence of PET from O to N atoms to generate radicals . Additionally, the maximum intensity of fluorescent emission exhibits a progressively declining trend along with the enhancement of photo-stimulus time, further confirming the existence of photogenerated radicals.…”

“…43 Moreover, the crystal structure of 1 displays the short distances between the oxygen of nitrate groups and nitrogen of TBD moieties, which can be deemed as an advantage for the occurrence of PET from O to N atoms to generate radicals. 44 Additionally, the maximum intensity of fluorescent emission exhibits a progressively declining trend along with the enhancement of photo-stimulus time, further confirming the existence of photogenerated radicals. The PXRD curve after photoirradiation reaches agreement with the simulated one (Figures S8), which excludes the possibility of photoinduced phase transition.…”

Polyoxometalate-based metal–organic supramolecular architectures derived from two new pyrimidine-amide ligands as supercapacitors and multifunctional electrochemical sensors

“…In addition, the synergistic effect between POM clusters and metal–organic units can also improve the stability and conductivity of these multifunctional materials, thereby further optimizing their electrochemical performance. 25–27…”

A Series of 9-Anthracene Carboxylic Acid-Based Lanthanide Binuclear Complexes: Construction, Magnetism, Photoluminescence, and Photochromism

“…Generally, the construction of electron transfer photochromic complexes requires both electron donor and electron acceptor components. − The electron-rich phosphate/phosphonate and carboxylate and electron-deficient polypyridine derivatives are the most studied as donors and acceptors, − respectively. However, a simpler approach should be promoted to assemble metal ions with a self-photochromic ligand such as a pyridinium salt and pyridine carboxylic acid.…”