Synthesis of Type B Tetrazolylidene–Palladium Complexes and Comparative Analysis with a Type A Analog

Abstract

Type B mesoionic carbenes (^BMICs) have rarely been studied experimentally, despite their strong donor potential. The tetrazolylidene scaffold allows for the investigation of substituent effects on nitrogen atoms without altering the heterocyclic structure. However, previous reports on tetrazolo-^BMIC have been limited to labile lithium complexes, detectable only by ¹³C NMR at –100 °C, which decompose at room temperature. Herein, we present the synthesis of stable 2,3-diaryltetrazolylidene–Pd complexes as ^BMICs complexes, which are compared with known NHC–Pd complexes using ¹³C NMR, ³¹P NMR, single-crystal X-ray diffraction, catalytic activity analyses, and computational analysis.