(NHC)-Pd(II) complexes with hydrophilic nitrogen ligands: catalytic properties in neat water

Authors : Hayati TÜRKMEN, Lütfiye GÖK, İbrahim KANİ, Bekir ÇETİNKAYA

Pages : 633-642

Doi:10.3906/kim-1302-75

View : 15 | Download : 7

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The cleavage reactions of the dimers [insert ignore into journalissuearticles values(NHC);PdX2]2 with hydrophilic N-donors, L, afforded the mixed-ligand complexes of the type trans-[insert ignore into journalissuearticles values(NHC);LPdX2] insert ignore into journalissuearticles values(X = Cl or Br; NHC = 1,3-dialkylbenzimidazol-2-ylidene insert ignore into journalissuearticles values(BIm); or bisinsert ignore into journalissuearticles values(imino);acenaphthene-annulated bisinsert ignore into journalissuearticles values(2,6-diisopropylphenyl);imidazol-2-ylidene insert ignore into journalissuearticles values(BIAN-IPr);; L = diethanolamine insert ignore into journalissuearticles values(DEA);, morpholine insert ignore into journalissuearticles values(MOR);, and 3-pyridinecarboxylic acid insert ignore into journalissuearticles values(3-PCA););. The new complexes insert ignore into journalissuearticles values(1--3); were characterized by elemental analysis and spectroscopic methods and the molecular structure of 1a was determined by X-ray diffraction studies. These complexes were applied in the Suzuki--Miyaura cross-coupling reaction of phenylboronic acid with aryl halides in neat water. The activities of catalysts were monitored by gas chromatography--flame ionization detector and nuclear magnetic resonance. Whereas the complexes with DEA or 3-PCA ligands did not show significant difference in the activity, the BIAN-IPr complexes 1b and 3b bearing DEA and 3-PCA, displayed the highest catalytic activity at 100 °C.
Keywords : Palladium, diethanolamine, N heterocyclic carbene, water soluble complexes, cross coupling