Phenylselenenylalkanes, their adducts with the dirhodium complex Rh2(MTPA)4 and ligand exchange mechanisms in solution as studied by 1H, 13C and 77Se NMR spectroscopy
Phenylselenenylalkanes, their adducts with the dirhodium complex Rh2(MTPA)4 and ligand exchange mechanisms in solution as studied by 1H, 13C and 77Se NMR spectroscopy
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通过 1H、13C 和 77Se NMR 光谱研究苯硒基烷烃、其与二铑配合物 Rh2(MTPA)4 的加合物以及溶液中的配体交换机制
DOI：
10.1002/mrc.1197
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发表时间：
2003
影响因子：
2
通讯作者：
H. Duddeck
中科院分区：
文献类型：
--
作者：
S. Malik;S. Moeller;G. Tóth;T. Gáti;M. Choudhary;H. Duddeck
在手性二铑配合物 Rh2[(R)-MTPA]4 [Rh-Rh; MTPA-H = (R)-(+)-甲氧基三氟甲基苯乙酸，莫舍酸]。低温下在溶液中鉴定出 1:1 和 2:1 加合物。对两种不同的配体交换机制“转换”和“替换”进行了表征，并讨论了交换转变期间的能量势垒和空间拥塞。配位引起的位移 Δδ(77Se) 通常为负（屏蔽）。对于薄荷酮双(苯基硒缩醛) (7)，这些值表明发生了两个硒原子的选择，表明 7 更喜欢在赤道硒原子处络合，而轴向硒原子几乎不涉及。版权所有 © 2003 约翰·威利父子有限公司
Twelve secondary phenylselenenylalkanes and ‐cycloalkanes were studied by 1H, 13C and 77Se NMR spectroscopy in the presence of the chiral dirhodium complex Rh2[(R)‐MTPA]4 [Rh–Rh; MTPA‐H = (R)‐(+)‐methoxytrifluoromethylphenylacetic acid, Mosher's acid]. The 1 : 1 and 2 : 1 adducts were identified in solution at low temperatures. Two different mechanisms of ligand exchange, ‘switch’ and ‘replacement,’ were characterized and their energy barriers estimated and steric congestion during the exchange transitions is discussed. Coordination‐induced shifts Δδ(77Se) are generally negative (shielding). For menthone bis(phenylselenoacetal) (7), these values indicate that a selection of the two selenium atoms occurs showing that 7 prefers complexation at the equatorial selenium atom whereas the axial selenium atom is hardly involved. Copyright © 2003 John Wiley & Sons, Ltd.