Three-dimensional Cd(ii) porphyrin metal–organic frameworks for the colorimetric sensing of Electron donors

Abstract

Metalloporphyrins are promising colorimetric sensors for a wide range of small molecule analytes. Three 3D metal–organic frameworks containing metallated 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) with Cd(II) and 1,2-bis(4-pyridyl)ethylene (bpe) or 1,2-bis(4-pyridyl)diazene (bpaz) featured open square 1D channels decorated with metalloporphyrin units. Exposure of the frameworks to amine vapours resulted in significant shifts in the metalloporphyrin Soret bands, enabling the colorimetric detection of amines. The electron-accepting properties of metalloporphyrin units were additionally exploited for the colorimetric detection of electron-rich species.