Effect of M(CO)3 (M = Cr, Mn+) on aromatic C-Cl BDE in (eta6-ArCl)M(CO)3 complexes.
The coordination of Cr(CO)3 to chlorobenzenes significantly reduces the C-Cl bond dissociation energy. Treatment of chloroarene-Cr(CO)3 complexes with SmI2/HMPA at room temperature led to complete dechlorination. Reaction of o-allyloxychlorobenzene-Cr(CO)3 complexes with SmI2 at room temperature resulted in the corresponding dechlorinative cyclization products in good to excellent yields. Competition experiments indicated the following relative reactivities of dehalogenation by SmI2: PhI/PhCl-Cr(CO)3/PhBr/PhCl = 50:1:0.3:<0.001. On the other hand, the coordination of Mn(CO)3(+) to chlorobenzene showed a much smaller activation effect. Density functional theory calculations revealed that the spin delocalization effect of the metal center plays an important role in the C-Cl bond activation.
Lin
Hechun
H
Key State Laboratory of Applied Chemistry, Lanzhou University, Lanzhou, Gansu 730000, China.
Chen
Qian
Q
Cao
Lidong
L
Yang
Li
L
Wu
Yun-Dong
YD
Li
Chaozhong
C