SELF-ASSEMBLY OF METHYL ZINC (31R)- AND (31S)-BACTERIOPHEOPHORBIDES D
SELF-ASSEMBLY OF METHYL ZINC (31R)- AND (31S)-BACTERIOPHEOPHORBIDES D
复制标题
甲基锌(31R)-和(31S)-细菌脱镁叶绿酸D的自组装
DOI：
10.1021/jp962872m
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发表时间：
1997
影响因子：
3.3
通讯作者：
K. Schaffner
中科院分区：
文献类型：
--
作者：
T. Balaban;H. Tamiaki;A. Holzwarth;K. Schaffner
光合细菌中捕光细菌叶绿素的甲基锌（3{sup 1}R）-和（3{sup 1}S）-[8 Et，12 Me]细菌脱镁叶绿酸d -类似物在非极性溶剂中自组装。而在稀二氯甲烷溶液中，两种差向异构体以其单体形式占优势，在较高浓度或较低温度下或用己烷稀释时形成具有逐渐红移的Q{sub y}选择的聚集体的复杂平衡。动态{sup 1}H-NMR和FT-IR光谱表明，3{sup 1}-羟基通过与锌的氧连接以及通过与中间体不对称二聚体中连接羟基的13{sup 1}-酮基的氢桥连直接参与自组装。基本单元，通过>C=O结合三个分子。哦... Zn键合，以及单体，二聚体和不同大小的低聚物之间的平衡的存在取决于平行的方案先前提出的细菌叶绿素C和D的条件。在某些方面，两种差向异构体的CD、{sup 1}H-NMR和IR光谱行为表明在二聚体和较大低聚物水平上存在非对映选择性构象和动力学差异。阿利亚，（3{sup 1}R）和（3{sup 1}S）差向异构体的1：1混合物的自组装比单独的差向异构体的自组装进行得更快。参考文献29篇，11图。
The methyl zinc (3{sup 1}R)- and (3{sup 1}S)-[8Et, 12Me] bacteriopheophorbides d - analogs of the light-harvesting bacteriochlorophylls in photosynthetic bacteria - self-assemble in nonpolar solvents. While in dilute dichloromethane solution both epimers prevail in their monomeric form, complex equilibria of aggregates with gradually red-shifting Q{sub y} absorptions are formed at either higher concentration or lower temperature or upon dilution with hexane. Dynamic {sup 1}H-NMR and FT-IR spectroscopies show that the 3{sup 1}-hydroxy group participates directly in the self-assembly through oxygen ligation to zinc and through hydrogen bridging to the 13{sup 1}-keto group of the ligated hydroxyls in intermediate unsymmetrical dimers. The basic unit, combining three molecules through >C=O...H-O...Zn bonding, and the existence of equilibria between monomers, dimers, and oligomers of varying size depending on the conditions parallel the scheme proposed previously for bacteriochlorophylls c and d. In some respects the CD, {sup 1}H-NMR, and IR spectral behavior of the two epimers indicates diastereoselective conformational and kinetic differences at the levels of dimers and larger oligomers. Inter alia, the self-assembly of a 1:1 mixture of the (3{sup 1}R) and (3{sup 1}S) epimers proceeds more rapidly than that of the separate epimers. 29 refs., 11 figs.