Stereoselective Photoreactions With New Coppe (1) Complexes Possessing A Chiral Conjugate Ligand

具有手性共轭配体的 New Coppe (1) 配合物的立体选择性光反应

基本信息

批准号：
06640729
负责人：
SAKAKI Shigeyoshi
金额：
$ 1.15万
依托单位：
KUMAMOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640729/
关键词：
Chiral Copper (I) Complex Photo-asymmetric reduction Cobalt (III) Complex Photo-asymmetric synthesis Excited state lifetime Solvent effects Photoinduced electron transfer Reaction mechanism

项目摘要

We synthesized a new chiral 2,2'-bipyridine ligand possessing R (+) -alpha-methylbenzyeamine, 5,5'-di (-) -methylbenzylamido-4,4'-6,6'-tetramethyl-2,2'-bipyridine (-) -tmdcbpy, and its Cu (I) complexes, [Cu ( (-) -tmdcbpy) (PPh_3) _2] 1, [Cu ( (-) -tmdcbpy) (P (C_6H_4-SO_3-m) Ph_2) _2] ^-2, [Cu ( (-) -tmdcbpy) ( (+) -diop) ] ^+3, and [Cu ( (-) -tmdcbpy) ( (-) -diop) ] ^+ 4. Using these Cu (I) complexes, stereoselective photoreduction of [Cu (edta) ] ^-was successfully carried out upon irradiation of near UV light corresponding to the MLCT absorption band of these Cu (I) complexes. The best stereoselectivity was 44%e.e. when 1 was used in ethanol-water (75 : 25 v/v). On the other hand, the stereoselectivity decreases to about 17%e.e. when 2 was used. The quenching experiments with [Co (edta) ] ^-indicated clearly that the reaction of 1 proceeds through dynamic and static quenching mechanism but the reaction of 2 takes place only through static quenching mechanism. These interesting diff … More erences between 1 and 2 are interpreted in terms of the electrostatic interaction : because 1 is positively charged, 1 can easily form an adduct with negatively charged [Co (edta) ] ^-and the interaction of [Cu^<11> ( (-) -tmdcbpy) (PPh_3) _2] ^<2+> with [Co^<11> (edta) ] ^<2->is strong due to the electrostatic attraction. On the other hand, the negatively charge 2 can not form a stable adduct in the ground state, and also the interaction of [Cu^<11> ( (-) -tmdcbpy) (P (C_6H_4SO_3-m) Ph) _2] ^0with [Co (edta) ] ^<2->is weak because of the lack of electrostatic attraction.Then, photo-asymmetric synthesis of [Co (edta) ] ^-was successfully carried out from Co (OAc) _2and H_4edta or Na_4edta, using these Cu (I) complexes with oxygen gas under upon irradiation of near UV light., In this photosynthetic reaction, DELTA- [Co (edta) ] ^-was produced in the excess when H_4edta was used. This reaction was possible only in DMSO,and the selectivity significantly depends on the kind of edta source, counter anion of Co salt. Less

我们合成了一种新的手性2,2'-联吡啶配体，其具有R(+)-α-甲基苯甲胺，5,5'-二(-)-甲基苯甲酰氨基-4,4'-6,6'-四甲基-2,2' -联吡啶 (-) -tmdcbpy 及其 Cu (I) 配合物，[Cu ( (-) -tmdcbpy) (PPh_3) _2] 1, [Cu ( (-) -tmdcbpy) (P (C_6H_4-SO_3-m) Ph_2) _2] ^-2, [Cu ( (-) -tmdcbpy) ( (+) -diop) ] ^+3 ，和 [Cu ( (-) -tmdcbpy) ( (-) -diop) ] ^+ 4. 使用这些 Cu (I) 配合物，在对应于这些 Cu (I) 配合物的 MLCT 吸收带的近紫外光照射下，成功地进行了 [Cu (edta) ] ^- 的立体选择性光还原，当 1 在乙醇-水中使用时，最佳立体选择性为 44%e.e.。 (75：25 v/v)，当使用 2 时，立体选择性降低至约 17%e.e.。 [Co (edta) ] ^ 的实验清楚地表明 1 的反应通过动态和静态猝灭机制进行，但 2 的反应仅通过静态猝灭机制发生。 1 和 2 之间的这些有趣的差异在中进行了解释。静电相互作用方面：由于1带正电，1很容易与带负电的[Co(edta)]^-形成加合物，与[Cu^<11>((-) -tmdcbpy) (PPh_3) _2] ^<2+> 与 [Co^<11> (edta) ] ^<2-> 由于静电引力而较强，另一方面，负电荷 2 不能形成电荷。基态下的稳定加合物，以及 [Cu^<11> ( (-) -tmdcbpy) (P (C_6H_4SO_3-m) Ph) 的相互作用_2]^0与[Co(edta)]^<2->由于缺乏静电引力而很弱。然后，从Co(OAc)_2成功地进行了[Co(edta)]^-的光不对称合成H_4edta或Na_4edta，在近紫外光照射下使用这些Cu(I)与氧气的络合物。，在该光合作用反应中，DELTA-[Co(edta)当使用H_4edta时，该反应只能在DMSO中产生，并且选择性显着取决于edta源、Co盐抗衡阴离子的种类。