Determination of N-Heterocyclic Carbene (NHC) Steric and Electronic Parameters using the [(NHC)Ir(CO)₂Cl] System

Complexes of iridium bearing NHC (NHC = N-heterocyclic carbene) ligands were synthesized and fully characterized. The series [(NHC)Ir(cod)Cl] were obtained by simple cleavage of [Ir(cod)Cl]2. The [(NHC)Ir(cod)Cl] complexes were reacted with excess carbon monoxide, leading to [(NHC)Ir(CO)2Cl]. The infrared carbonyl stretching frequencies of these were recorded to quantify the electronic parameter of NHC ligands. X-ray diffraction study results allow for determination of NHC steric parameters within this series. These data allow for comparison with other ligand families.本研究合成并完整表征了一系列含氮杂环卡宾（N-heterocyclic carbene, NHC）配体的铱配合物。通过[Ir(cod)Cl]₂的简单裂解反应，获得了该系列的[(NHC)Ir(cod)Cl]配合物。将[(NHC)Ir(cod)Cl]配合物与过量一氧化碳进行反应，可得到[(NHC)Ir(CO)₂Cl]。记录该系列配合物的红外羰基伸缩振动频率，以量化NHC配体的电子参数。借助X射线衍射（X-ray diffraction）实验结果，可确定本系列NHC配体的空间位阻参数。上述数据可用于与其他配体家族进行对比研究。