Exploring Mesoionic Imine‐Carbodiimide (MII‐CDI) Adducts: 1,3 H‐Shift, N(I) Compounds and Guanidinate‐Type Ligands

Abstract

Abstract 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 NHC‐CDI adducts, formed by the reactions of N ‐heterocyclic carbene ( NHC ) with CDI , these zwitterionic compounds undergo a spontaneous 1,3‐hydrogen shift (1,3‐H shift), resulting in guanidine‐type compounds. The mechanism of this 1,3‐H shift has been investigated through quantum chemical calculations. 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 behavior of these nitreone ( N(I) ) compounds. 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 N ‐heterocyclic imine ( NHI ) congeners.