Mechanical and Thermal ON–OFF Switching of the Vapochromic Behavior of a Luminescent Polymorphic Pt(II) Complex

Abstract

Vapochromic materials that exhibit color/luminescence changes induced by vapor exposure have attracted considerable attention. Herein, we report the grinding- and heating-induced ON–OFF switching of the vapochromic behavior of [Pt(ppyCl2)(Clacac)] (1; ppyCl2 = 2-(3-chlorophenyl)-4-chloropyridinato, Clacac = 3-chloroacetylacetonato). 1 formed yellow and orange polymorphs (1-Y and 1-O), and 1-Y could be converted to 1-Og, which showed a very similar crystal structure but with a broadened X-ray diffraction pattern compared with that of 1-O. Moreover, 1-Og can be reversibly transformed into 1-O via heating and grinding. Notably, 1-Og underwent a N,N-dimethylacetamide vapor-induced transformation to 1-Y, whereas 1-O did not undergo such a transformation. These results indicate the ON–OFF switching of vapochromic behavior induced via grinding and heating. This finding will be beneficial for developing intelligent molecular devices.

Chromic soft crystals based on luminescent platinum(II) complexes

“…Complicated changes often occur in chromic complexes that respond to weak stimuli. Recently, in-depth investigations of multi-stimuli responses and multi-chromic phenomena were reported (Ni et al, Martı ´nez- Junquera et al, 2022;Shigeta et al, 2023;Morimoto et al, 2023).…”

Pyridine-Triggered Fluorescent Switching in Coordination-Induced Allosteric Crystal Transformation

“…In order to enhance the discrimination ability of these sensor materials, a large number of chemically responsive sensing elements are necessary, which are usually obtained from unstable and expensive reagents. For example, thanks to the structural sensitivity, numerous Pt II complexes for humidity and volatile organic compounds sensing have been produced, by virtue of the weak intermolecular interactions. , From the standpoint of sustainable development, it is more economical to construct transition metal complexes with metals that are abundant in reserves, such as iron, nickel, and zinc . Fe II complexes possessing spin crossover (SCO) phenomena with FeN 6 or FeN 4 O 2 octahedral coordination environment are the most studied SCO systems and have been successfully applied to VOCs sensing.…”