Chiral Bimetallic Boronic Esters: A Donor–Acceptor Coexisting Receptor for Amines
作者:Kyoko Nozaki、Masanori Yoshida、Hidemasa Takaya
DOI:10.1246/bcsj.69.2043
日期:1996.7
A chiral bimetallic Lewis acid, 2,2′-(1,2-phenylene)bis[(4R,5R)-4,5-diphenyl-1,3,2-ioxaborolane] (1a), has been synthesized. The exceptionally strong binding of 1a with benzylamine was demonstrated by titrations. The complex formation ratio of 1a : amine = 1 : 2 was determined by a Job plot. The binding constants, K1 and K2, were determined by non-linear curve fitting to be K1 << K2. The results can be explained in terms of an allosteric effect. The first amine molecule coordinates with one of the two boron atoms of 1a; at the same time, one NH proton interacts with one of the two oxygen atoms in the other dioxaborolane ring to form a hydrogen bond. As a result, the two dioxaborolane rings are conformationally fixed by two-point binding to provide a preferable binding site for the second amine molecule. Although only a small chiral recognition of 1-phenylethylamine has been obtained with 1a, the clear separation of the peaks of the amine provides the possibility to use 1a as an NMR chiral-shift reagent.
合成了手性双金属路易斯酸2,2'-(1,2-亚苯基)双[(4R,5R)-4,5-二苯基-1,3,2-碘杂硼杂硼烷](1a)。滴定证明了 1a 与苄胺的异常强的结合。 1a:胺=1:2的复合物形成比例通过Job图确定。通过非线性曲线拟合确定结合常数K1和K2为K1<
Stoichiometric CO2 reductions using a bis-borane-based frustrated Lewis pair
作者:Michael J. Sgro、Johannes Dömer、Douglas W. Stephan
DOI:10.1039/c2cc33301e
日期:——
forms an adduct with PtBu(3), but is still capable of exhibiting FLP reactivity with THF and CO(2). The resulting CO(2) species is reduced by Me(2)NHBH(3) or [C(5)H(6)Me(4)NH(2)]X (X = [HB(C(6)F(5))(3)], [HB(C(6)F(5))(2)(C(7)H(11))]) followed by quenching with water to effect the stoichiometric conversion of CO(2) to methanol.
双硼烷1,2-C(6)H(4)(BCl(2))(2)与PtBu(3)形成加合物,但仍能显示与THF和CO(2)的FLP反应性。生成的CO(2)物种被Me(2)NHBH(3)或[C(5)H(6)Me(4)NH(2)] X还原(X = [HB(C(6)F( 5))(3)],[HB(C(6)F(5))(2)(C(7)H(11))]),然后用水淬灭以实现化学计量的CO(2)转化甲醇。
<i>ansa</i>-Bis(1-boratabenzene) Zirconium(IV) Complexes with Short Carbon Bridges to Boron
作者:Arthur J. Ashe、Jeff W. Kampf、Matthew W. Schiesher
DOI:10.1021/om020769f
日期:2003.1.1
(8) with 1,2-bis(dichloroboryl)benzene 9 affords exchange product 10, which on deprotonation followed by reaction with ZrCl4 gives the very labile o-phenylene-bridged bis(1-boratabenzene)zirconium dicholoride 6. A similar reaction sequence from 8 and 1,1-bis(dichloroboryl)-2-methyl-1-propene 11 affords the 1,1-isobutenyl-bridged bis(1-boratabenzene)zirconium dichloride 7. The X-ray structure of 7 is
1,1-二丁基-1-锡环六-2,5-二烯(8)与1,2-双(二氯硼基)苯9的反应生成交换产物10,该产物在去质子化后与ZrCl 4反应得到非常不稳定的邻苯撑桥联的双(1-硼酸苯)锆二胆酸盐6。来自8和1,1-双(二氯硼基)-2-甲基-1-丙烯11的相似反应序列提供了1,1-异丁烯基桥连的双(1-硼烷苯)二氯化锆7。描述了7的X射线结构。
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