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

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.