Chemists Synthesize Compound with Monovalent Carbon, Opening New Avenues in Chemistry

In a collaborative project, researchers from TU Dortmund and the Pantazis Group have achieved a milestone in chemistry by synthesizing an organic compound featuring a monovalent carbon atom in its ground state. This breakthrough expands the boundaries of carbon chemistry, which typically sees carbon atoms forming four bonds. The newly synthesized compound, Ph₃P→C, was created by irradiating a diazophosphorylide precursor with ultraviolet light at extremely low temperatures, causing nitrogen to split off. Electron paramagnetic resonance and electron-nuclear double resonance studies revealed that the compound possesses two unpaired electrons with parallel spin, indicating a spin-triplet state. Quantum chemical calculations confirmed the presence of a single dative bond between phosphorus and the terminal carbon. This marks the first known chemical species where a carbon center exists in the same electronic configuration and spin state as an isolated carbon atom in its ground state. This discovery opens up new possibilities for organic reactions, with potential applications in synthesis, catalysis, and material science.