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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

合成了一种新的手性2，2 ′-联吡啶配体R（+）-α-甲基苄胺，5，5 ′-二（-）-甲基苄氨基-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。利用这些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。最佳立体选择性为44%e. e当1在乙醇-水（75：25 v/v）中使用时。另一方面，立体选择性降低至约17%e.e.。当使用2。对[Co（edta）] ^-的猝灭实验表明，1的反应通过动态猝灭和静态猝灭机理进行，而2的反应仅通过静态猝灭机理进行。这些有趣的差异 ...更多信息 1和2之间的距离可以用静电相互作用来解释：由于1带正电，1可以很容易地与带负电的[Co（edta）] ^-形成加合物，并且由于静电吸引，[Cu^<11>（（-）-tmdcbpy）（PPh_3）_2] ^<2+>与[Co^<11>（edta）] ^的相互作用<2->很强。另一方面，负电荷2在基态不能形成稳定的加合物，且[Cu^<11>（（-）-tmdcbpy）（P（C_6H_4SO_3-m）Ph）_2]^0与[Co（edta）] ^<2->的相互作用也因缺乏静电引力而很弱，因此，在近紫外光照射下，以Co（OAc）_2和H_4edta或Na_4edta为原料，成功地进行了[Co（edta）] ^-的光不对称合成。在此光合反应中，当使用H_4edta时，产生过量的DELTA- [Co（edta）] ^-。该反应仅在DMSO中进行，且选择性明显取决于EDTA源、钴盐的抗衡阴离子的种类。少