Binding Modes and Reactivity of Pyrido[2,1‑a]isoindole as a Neutral Carbon Donor with Main-Group and Transition-Metal Elements

Various binding modes of pyrido­[2,1-a]­isoindole with main-group and transition-metal elements have been established. The carbon atom at position 6 of pyrido­[2,1-a]­isoindole is highly nucleophilic, forming a σ complex with Pt­(II) ion. The benzene ring of pyrido­[2,1-a]­isoindole forms an η⁶-π complex with Cr(0). The reaction of pyrido­[2,1-a]­isoindole with PPh₂Cl in the presence of Proton Sponge leads to a PPh₂-functionalized product, which can further react with a BH₃ molecule, forming a P→B adduct. Pyrido­[2,1-a]­isoindole was also found to undergo a dehydrogenative C–C coupling reaction in the presence of Cu­(I) ions, forming a dimer. These interesting reactivities and binding modes demonstrate the rich chemistry of pyrido­[2,1-a]­isoindole, as well as its potential application in main-group and transition-metal chemistry.