Molecular insight into a disulfonimide-bearing diol: synthesis, characterisation and access to poly(disulfonimide)s

Abstract

Control over interchain interactions plays a pivotal role in the design of high-performance polymeric materials. Aromatic polyimides exemplify this principle but still suffer from several inherent limitations in applications requiring high permeability and processability due to dense chain packing. To broaden the design space for advanced polymer architectures, we explore non-planar benzene-1,2-disulfonimide as a promising structural alternative to the conventional imide fragment. This work aims to establish a synthetic and theoretical foundation for the exploration of poly(1,2-disulfonimides) as promising candidates for next-generation high-performance polymers. Here, we perform a comprehensive investigation of the synthetic route to aromatic N-substituted cyclic 1,2-disulfonimides and polymers on this basis. The vibrational and geometric features of the disulfonimide fragment were elucidated through a combination of quantum-mechanical calculations and spectroscopic methods, confirming its distinctive structural identity. A synthetic platform for disulfonimide-bearing diols was designed and applied to obtain the first dihydroxy-terminated cyclic 1,2-disulfonimide, which underwent successful model polycondensation. Molecular-dynamics simulations qualitatively indicate that incorporation of the disulfonimide fragment into a polyester backbone leads to a pronounced increase in glass-transition temperature without a corresponding increase in packing density compared to a homologous polyimide.