Structural Diversity of Cadmium Complexes with N‐Heterocyclic Carbene‐Isothiocyanate Zwitterionic Ligand

Abstract In this study, we discuss the synthesis and structural characterization of three N‐heterocyclic carbene isothiocyanate zwitterionic ligands, 1,3‐bis(2,6‐diisopropylphenyl)‐2‐N‐phenyl‐thiocarbamoyl imidazolium (Im Dipp ‐CSNPh, L1) , 1,3‐bis( tert ‐butyl)‐2‐N‐phenylthiocarbamoyl imidazolium (Im t Bu ‐CSNPh, L2) and 1,3‐bis(2,4,6‐trimethylphenyl)‐2‐N‐phenylthiocarbamoyl imidazolium (Im Mes ‐CSNPh, L3) and their cadmium complexes, [(Im Dipp ‐CSNPh) 2 CdCl][CdCl 3 ] ( 1 ) and [(Im t Bu ‐CSNPh)Cd(μ‐Cl)Cl] 2 ( 2 ). Both bench‐stable cadmium complexes were synthesized by directly reacting the corresponding NHC‐CSNPh adducts with anhydrous cadmium chloride. The solid‐state structures of zwitterionic NHC‐isothiocyanate betaine adducts ( L1 ‐ L3 ) and cadmium complexes ( 1 and 2 ) were investigated with the assistance of single crystal X‐ray diffraction analysis. A steric modification of N‐substituent on NHC governs a unique structural change from betaine Im Dipp ‐CSNPh coordinated cationic cadmium complex to neutral dimeric cadmium complex with Im t Bu ‐CSNPh.