The C—C cross coupling reaction catalyzed by palladium complexes represents one of the most important C—C bond formation reactions. Traditionally, organo phosphines are used as the ligands to modify the catalytic properties of palladium complexes. However, most of them are air-sensitve, Labile to be oxidized and to dissociate in solution. Therefore, excess phosphorous ligands are needed to keep the catalytic activities. N-Heterocyclic carbene (NHC) reported since 1991 has been a focus in organometallic chemistry and catalysis because of its strong electronic donor properties, versatile structures that can be readily modified, and excellent coordinative ability to metal. The Pd-NHC compound has emerged as an al-ternative of Pd-phosphine compound in the promotion of C—C bond coupling reactions. In this paper, the application of the Pd-NHC complexes derived from mono-ligated NHC, chelate NHC to Heck reaction and Suzuki reaction was summarized.

Key words: Pd, NHC, Heck reaction, Suzuki reaction, catalysis