科研之友
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摘要
Reactions of ArCOCOCl (Ar = p-ClC(6)H(4), Ph) with Rh(acac)(CO)(2) proceeded readily to afford dimeric arylglyoxyl rhodium complexes [Rh(mu-Cl)(acac)(CO)(COCOAr)](2). [Rh(mu-Cl)(acac)(CO){COCO(p-ClC(6)H(4))}](2) was characterized by X-ray diffraction. Thermolysis of the products showed that [Rh(mu-Cl)(acac)(CO){COCO(p-ClC(6)H(4))}](2) was more stable than [Rh(mu-Cl)(acac)(CO)(COCOPh)](2). The reaction of p-CH(3)OC(6)H(4)COCOCl with Rh(acac)(CO)(2) did not form a similar dimeric complex as final product, but gave p-CH(3)OC(6)H(4)COCl as major product, showing thermal instability of corresponding arylglyoxyl and aroyl rhodium complexes. The reaction of C(6)F(5)CO-COCl did not form a simlar dimeric complex either, but a mononuclear complex RhCl(acac)(COCOC(6)F(5))(CO)(2) was generated as a transient intermediate, which was readily transformed to a furanone arising from reductive elimination of the acac ligand and C(6)F(5)COCO moiety followed by cyclization. In the thermolysis of [Rh(mu-Cl)(acac)(CO)(COCOAr)](2), only ArCOCl and Rh(acac)(CO)(2) were formed, and any ArCORh species could not be detected during the thermolysis process. However, the reaction of Rh(acac)(CO)(2) with PhCOCl formed RhCl(acac)(CO)(2)(COPh), albeit only to a small extent, suggesting that the reaction is not thermodynamically favored. The reaction of RhCl(CO)(PMe(3))(2) with p-ClC(6)H(4)COCOCl also proceeded cleanly to furnish p-ClC(6)H(4)COCORhCl(2)(CO)(PMe(3))(2). Thermolysis of the complex formed p-ClC(6)H(4)CORhCl(2)(CO)(PMe(3))(2), indicating slow reductive elimination of ClC(6)H(4)COCl as compared with the ArCORh species, generated in the thermolysis of [Rh(mu-Cl)(acac)(CO)(COCOAr)](2). Treatment of ClC(6)H(4)CORhCl(2)(CO)(PMe(3))(2) with carbon monoxide generates p-ClC(6)H(4)COCORhCl(2)(CO)(PMe(3))(2), although the yield was low.
- 出版日期2011-1-24
