Dinickel(II) complexes: preparation and catalytic activity.
Ligands (L(a-c)) based on 2,7-bis(3,5-di-R-pyrazol-1-yl)-1,8-naphthyridine (a, R = H; b, R = CH(3); c, R = Ph) were prepared for the construction of a series of dinickel complexes. Treatment of L(x) with NiCl(2) in an anhydrous methanol/THF solution resulted in the formation of dinuclear complexes [(L(x))(μ-Cl)(2)Ni(2)Cl(2)(CH(3)OH)(2)] (3, x = a; 4, x = b; 5, x = c). These new complexes were characterized by elemental analysis, IR and UV-Vis spectroscopic techniques. The structures of complexes 3 and 4 were further confirmed by X-ray diffraction studies. Interestingly, crystals of 4 were obtained as a co-crystallization of 4 and the methanol substituted species [{(L(b))(μ-Cl)(2)Ni(2)Cl(CH(3)OH)(3)}Cl] (4'). These dinickel complexes have been tested in the catalytic homo-coupling of terminal alkynes with the use O(2) as the oxidant, showing excellent activities. A clear improvement on the catalytic activity of these complexes is observed as compared to the mono-nuclear species.
Department of Chemistry, National Taiwan University, Taipei, Taiwan 106, ROC.
Ting-Peng
TP
Cheng
Bei-Sih
BS
Liao
Yi-Hung
YH
Liu
Shie-Ming
SM
Peng
Shiuh-Tzung
ST
Liu
D002384:Catalysis; D018360:Crystallography, X-Ray; D008024:Ligands; D000432:Methanol / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D013056:Spectrophotometry, Ultraviolet
D008024:Ligands; D009942:Organometallic Compounds; D009532:Nickel; D000432:Methanol