Preparation and NMR studies of cobalt-containing diphosphine ligand chelated W, Ru, Au and Pd complexes: Suzuki cross-coupling reactions and carbonylation catalyzed by the Pd complex.
Treatment of a cobalt-containing diphosphine ligand, [[mu-P,P-PPh2CH2PPh2]Co2(CO)4[mu-PPh2C[triple bond]CPPh2]] 1 with metal complexes W(CO)6, Ru3(CO)12, AuCl(tht)(tht = tetrahydrothiophene) and (COD)PdCl2(COD = 1,5-cycloctadiene) gave 1-chelated metal complexes [(1)W(CO)4], [(mu-1)Ru3(CO)10] 4, [(1)(AuCl)2] 5 and [(1)PdCl2] 6, respectively. All these compounds were characterized by spectroscopic means whereas 3, 4 and 6 were also studied by X-ray diffraction. These compounds display chelating and bridging modes of metal-phosphine complexation. Variable-temperature 1H and 31P NMR experiments were carried out for 3-6 and revealed that the fluxional behavior of each individual bridging dppm fragment was affected greatly by the bite angle of 1 in each metal complex. Suzuki cross-coupling reactions were satisfactorily catalyzed by under mild conditions. The reactions of aryl halides or iodothiophenes with chloroform and alkali in biphasic solution utilizing a catalytic amount of result into the formation of benzoic and thiophenic acids, respectively.
Hong
Fung-E
FE
Department of Chemistry, National Chung-Hsing University, Taichung 40227, Taiwan. fehong@dragon.nchu.edu.tw
Chang
Yu-Chang
YC
Chang
Chin-Pei
CP
Huang
Yi-Luen
YL