A New Combined Computational and Experimental Approach to Characterize Photoactive Conjugated 3D Polymers

Mollart, Catherine and Heasman, Patrick and Sherrett, Ellena and Fletcher, Peter A. T. J and Fayon, Pierre and Thomas, Jens M. H. and Franckevičius, Villius and Peach, Michael J. G. and Trewin, Abbie (2025) A New Combined Computational and Experimental Approach to Characterize Photoactive Conjugated 3D Polymers. Small, 21 (9): e2407187. ISSN 1613-6810

Abstract

A tractable new computational protocol is proposed to elucidate oligomeric‐scale detail from experimental spectra, providing insight into the local and longer‐range electronic and molecular structures of amorphous materials. The protocol uses an in‐house code Ambuild to grow kinetically‐controlled representative oligomeric clusters of an amorphous polymeric material. Generating many clusters, the statistical prevalence of different structural motifs is identified, and used to develop a ‘subset’ of structures that capture a broad range of important morphologies. Subsequent electronic structure calculations allow the prediction of IR, NMR, and UV–vis spectra of the bulk materials, providing significant insight into oligomeric scale topologies and helping develop structure–property relationships by identifying the underlying structural origins of different spectral features observed experimentally. Two known, and two novel, pyrene‐based conjugated microporous polymers (CMPs) are synthesized and characterized as a test bed for this newly‐proposed protocol. Meaningful IR, NMR, and UV–vis absorption spectral data, and experimentally comparable computationally derived spectra are obtained. Whilst IR and NMR reliably probe the local environment, UV–vis absorption spectroscopy is found to be particularly sensitive to the longer‐range structural motifs observed on an oligomeric scale, providing significant structural insight into the synthesized materials with reasonable computational cost.