13C NMR Spectroscopic Determination of Ligand Donor Strengths Using N-Heterocyclic Carbene Complexes of Palladium(II)

摘要: The electronic parameters of 25 Werner-type and organometallic ligands have been experimentally determined ranked on a unprecedented unified 13C NMR scale using safe easily obtainable complexes the type trans-[PdBr2(iPr2-bimy)L]n− (iPr2-bimy = 1,3-diisopropylbenzimidazolin-2-ylidene; L ligand in question) as spectroscopic probes. methodology is based sensitivity constant iPr2-bimy carbene signal to donor strengths varying co-ligands, which even allows detection backbone substituent effects more accurately than previous carbonyl-based systems. For evaluation N-heterocyclic carbenes (NHCs), one-pot approach novel hetero-bis(carbene) bearing two different NHCs introduced. Furthermore, first complex strongly donating indazolin-3-ylidene presented. molecular structures 10 probes characterized by single-crystal X-ray diffraction analyses.