Mesoionic Imines (MIIs): Strong Donors and Versatile Ligands for Transition Metals and Main Group Substrates

We report the synthesis and reactivity of 1,2,3-triazolin-5-imine type mesoionic imines (MIIs). The MIIs are accessible by a base-mediated cycloaddition between substituted acetonitrile an aromatic azide, methylation established routes subsequent deprotonation. C=O-stretching frequencies in MII-CO2 Rh(CO)2Cl complexes were used to determine overall donor strength. stronger donors than N-heterocyclic (NHIs). excellent ligands for main group elements transition metals which they display substituent-induced fluorine-specific interactions undergo C-H activation. DFT calculations gave insights into frontier orbitals MIIs. predict relatively small HOMO-LUMO gap compared other related ligands. potentially able act as both π-donor π-acceptor This highlights potential exciting properties with huge future development.