Exploring MII-CDI Adducts: 1,3 H-Shift, N(I) Compounds and Guanidinate-Type Ligands

In this study, we report our recent findings on the synthesis and reactivity of a novel 1,2,3-triazolin-5-imine type mesoionic imine-carbodiimide (MII-CDI) adduct. Unlike reported reactions of N-heterocyclic imines (NHI) with CDI, these zwitterionic compounds undergo a spontaneous 1,3 H-shift, resulting in guanidine-type compounds. The MII-CDI adduct serves as a valuable synthon for the synthesis of mesoionic carbene-acyclic diamino carbene (MIC-ADC)-based nitreone (N(I)) compounds. We have conducted a detailed investigation into the electronic properties, chemical reactivity, and electrochemical behaviour of this nitreone (N(I)). Additionally, the potential of these MII-CDI adducts as guanidinate ligands is explored. Our investigations here display the distinct reactivities of MII in contrast to their NHI congeners.