Selective chemochromic and chemically-induced photochromic response of a metal-organic framework

The Zn( ii ) MOF with a tripyridinium-based hexacarboxylate shows direct color change on exposure to small primary amines and UV-assisted color response on exposure to small alcohols. The reversible, group-specific and size-selective chemochromic/chemophotochromic behaviours are ascribed to spontaneous/photoinduced guest-to-host electron transfer within the unique confined space furnished with electron-deficient sites. The MOF provides unique confined space furnished with electron acceptor sites, and exposure to amines/alcohols causes specific and size-selective direct/UV-assisted color change owing to spontaneous/photoinduced electron transfer.