Synthesis, Characterization, and Modeling of a Functional Conjugated Microporous Polymer: CO₂ Storage and Light Harvesting

Abstract

Rationalization of structure and properties of amorphous porous solids at the microscopic level is essential in developing advanced materials. We delineate the structural modeling of a designed tetraphenylethene-based amorphous conjugated microporous polymer TPE-CMP (1) and its gas storage and photophysical properties. The polymer 1 exhibits high specific surface area of 854 m2/g. 1 showed appreciable CO2 (32.4 wt %) uptake at 195 K up to 1 atm and 31.6 wt % at 273 K up to 35 bar. The structural model of 1 obtained through computational methods is quantitatively consistent with experimental observations. The microporous structural model of 1 was further validated by a calculation of CO2 adsorption isotherm obtained through GCMC simulations. Quantum chemical calculations were employed to understand the nature of interactions of CO2 with the constituents of the framework 1. π–π interaction with strength of 19 kJ/mol was observed between CO2 and the phenyl rings of TPE. 1 shows strong turn-on greenish-yellow emission due to the restriction of phenyl ring rotation of TPE node. This framework induced emission (FIE) of microporous polymer 1 is further exploited for light-harvesting applications by noncovalent encapsulation of a suitable acceptor dye, rhodamine B (RhB), in the framework.