A Hybrid Bronze Age: Progress and Potential in Mixed-Valence Organic–Inorganic Metal Oxides

Hybrid bronzes are mixed-valence organic-inorganic metal oxides that feature infinitely alternating 2D metal oxide layers and ordered arrays of molecular species. These modular crystalline materials possess untold potential as a nascent class of compounds that can deliver wide-ranging future technological impact, not to mention important fundamental chemical and physical knowledge. In this review, we highlight how hybrid bronzes allow synthetic chemists and materials scientists to simultaneously leverage the chemical functionality of organic or organometallic molecules along with the optical and electronic behaviors of extended inorganic solids. We briefly contextualize hybrid bronzes in terms of their inorganic parent metal oxides. We then present a condensed survey of the state-of-the field and a distillation of concepts we view as integral for motivating research to elevate the hybrid bronze platform, including their syntheses, structural motifs, characterization methods, electronic structures, resultant optical and electronic properties, and important knowledge gaps. We hope to introduce researchers unfamiliar with hybrid bronzes to this emerging and exciting system.