TY - JOUR
T1 - Organoactinides promote the dimerization of aldehydes
T2 - Scope, kinetics, thermodynamics, and calculation studies
AU - Sharma, Manab
AU - Andrea, Tamer
AU - Brookes, Nigel J.
AU - Yates, Brian F.
AU - Eisen, Moris S.
PY - 2011/2/9
Y1 - 2011/2/9
N2 - Surprising catalytic activities have been found for the actinide complexes Cp*2ThMe2 (1), Th(NEtMe)4 (2), and Me2SiCp″2Th(C4H9) 2(3) toward oxygenated substrates. During the catalytic dimerization of benzaldehydes to their corresponding esters, complexes 1 and 2 gave 65 and 85% yield in 48 h, respectively, while the geometry-constrained complex 3 gave 96% yield in 24 h. Exploring the effect of substituents on benzaldehyde, it has been found that, in general, electron-withdrawing groups facilitate the reaction. Kinetic study with complexes 1 and 3 reveals that the rate of the reaction is first order in catalyst and substrate, which suggests the rate equation "rate = k[catalyst]1[aldehyde]1". The activation energy of the reaction was found to be 7.16 ± 0.40 and 3.47 ± 0.40 kcal/mol for complexes 1 and 3 respectively, which clearly indicates the advantage of the geometry-constrained complex. Astonishing are the reactivity of the organoactinide complexes with oxygen-containing substrates, and especially the reactivity of complex 3, toward the dimerization of substrates like p-methoxybenzaldehyde, m/p-nitrobenzaldehyde, and furanaldehyde and the reactivity toward the polymerization of terephthalaldehyde. Density functional theory mechanistic study reveals that the catalytic cycle proceeds via an initially four-centered transition state (+6 kcal/mol), followed by the rate-determining six-centered transition state (+13.5 kcal/mol), to yield thermodynamically stable products.
AB - Surprising catalytic activities have been found for the actinide complexes Cp*2ThMe2 (1), Th(NEtMe)4 (2), and Me2SiCp″2Th(C4H9) 2(3) toward oxygenated substrates. During the catalytic dimerization of benzaldehydes to their corresponding esters, complexes 1 and 2 gave 65 and 85% yield in 48 h, respectively, while the geometry-constrained complex 3 gave 96% yield in 24 h. Exploring the effect of substituents on benzaldehyde, it has been found that, in general, electron-withdrawing groups facilitate the reaction. Kinetic study with complexes 1 and 3 reveals that the rate of the reaction is first order in catalyst and substrate, which suggests the rate equation "rate = k[catalyst]1[aldehyde]1". The activation energy of the reaction was found to be 7.16 ± 0.40 and 3.47 ± 0.40 kcal/mol for complexes 1 and 3 respectively, which clearly indicates the advantage of the geometry-constrained complex. Astonishing are the reactivity of the organoactinide complexes with oxygen-containing substrates, and especially the reactivity of complex 3, toward the dimerization of substrates like p-methoxybenzaldehyde, m/p-nitrobenzaldehyde, and furanaldehyde and the reactivity toward the polymerization of terephthalaldehyde. Density functional theory mechanistic study reveals that the catalytic cycle proceeds via an initially four-centered transition state (+6 kcal/mol), followed by the rate-determining six-centered transition state (+13.5 kcal/mol), to yield thermodynamically stable products.
UR - http://www.scopus.com/inward/record.url?scp=84961979590&partnerID=8YFLogxK
U2 - 10.1021/ja105696p
DO - 10.1021/ja105696p
M3 - 文章
AN - SCOPUS:84961979590
SN - 0002-7863
VL - 133
SP - 1341
EP - 1356
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 5
ER -