Synthesis, structure, and reactivity of peralkylcyclopentadienyl ansa-metallocenes of samarium:: Effect of steric crowding on the reactivity of tris(peralkylcyclopentadienyl)samarium complexes

被引：18

作者：

Evans, WJ ^{[1
]}

Cano, DA ^{[1
]}

Greci, MA ^{[1
]}

Ziller, JW ^{[1
]}

机构：

[1] Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA

来源：

ORGANOMETALLICS | 1999年 / 18卷 / 08期

关键词：

D O I：

10.1021/om980617d

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

Tris(peralkylcyclopentadienyl)samarium complexes containing two rings connected by a Me2Si group were synthesized for comparison with (C5Me5)(3)Sm. SmI3 reacts with Me2Si(C5Me4K)(2) in THF to make Me2Si(C5Me4)(2)SmI(THF) (1) in >90% yield. 1 reacts with KC5Me5 in toluene to make Me2Si(C5Me4)(2)Sm(C5Me5) (2a) and in THF to make Me2Si(C5Me4)(2)Sm(C5Me5)(THF) (2b). 1 reacts with KC5Me4Et, (KC5Me4Pr)-Pr-n, and (KC5Me4Pr)-Pr-i in toluene to make Me2Si(C5Me4)(2)Sm(C5Me4Et) (3), Me2Si(C5Me4)(2)Sm((C5Me4Pr)-Pr-n) (4), and Me2Si(C5Me4)(2)Sm((C5Me4Pr)-Pr-i) (5), respectively. In contrast to the reactivity of (C5Me5)(3)Sm, complexes 2a and 3-5 do not ring-open THF, do not reduce 1,3,5,7-C8H8 or Ph3P=Se, and do not polymerize ethylene at 50 psi. Structural data were obtained on 1, 2a, 2b, and 4. The (ring centroid)-metal-(ring centroid) angles of the Me2Si(C5Me4)(2) units in each structure range from 115.2 degrees (2b) to 123.3 degrees (1) and have average Sm-C(ring) distances of 2.70(6) Angstrom (1), 2.82(10) Angstrom (2a) 2.92(14) Angstrom (2b), and 2.83(10) Angstrom (4). The average Sm-C(C5Me4R) distance is 2.77(3) Angstrom in 2a, 2.82(4) Angstrom in 2b, and 2.78(3) Angstrom in 4. The beta-carbon of the propyl substituent in 4 is oriented toward samarium at a distance of 3.36 Angstrom.

引用

页码：1381 / 1388

页数：8

共 44 条

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