首页> 美国卫生研究院文献>Proceedings of the National Academy of Sciences of the United States of America >Donor properties of the three carbonyl groups of chlorophyll a: ab initio calculations and 13C magnetic resonance studies.
【2h】

Donor properties of the three carbonyl groups of chlorophyll a: ab initio calculations and 13C magnetic resonance studies.

机译:叶绿素a的三个羰基的给体性质:从头算和13 C磁共振研究。

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

The relative donor properties of the three carbonyl groups of chlorophyll a have been studied theoretically by a series of ab initio molecular fragment, floating spherical Gaussian orbital, self-consistent field calculations on ethyl chlorophyllide a and experimentally through a 13C magnetic resonance study on chlorophyll a. The approximate ground state electronic wavefunction of ethyl chlorophyllide a was perturbed by monopole and dipole point charges whose signs, magnitudes, and positions were chosen to mimic the coulombic interactions associated with carbonyl coordination to Mg. Because the polarizability of the ring V keto carbonyl binding site is substantially greater than that for the ester carbonyl binding sites, the ring V keto binding site binds with smallest binding energy for weak perturbations and with largest binding energy for strong perturbations. A comparison of 13C magnetic resonance chemical shifts in chlorophyll a monomer and dimer provides new experimental evidence that the donor-acceptor interactions that bind the chlorophyll dimer together involve a substantial participation by the ring V keto carbonyl and minimal participation by the two ester carbonyl groups, and thus are in agreement with conclusions derived from the ab initio calculations.
机译:通过一系列从头算分子片段,浮动球形高斯轨道,对叶绿素a的自洽场计算,以及通过对叶绿素a的13C磁共振实验,对叶绿素a的三个羰基的相对供体性质进行了理论研究。 。叶绿素a的近似基态电子波函数受到单极点和偶极点电荷的干扰,其电荷,符号和位置被选择来模拟与羰基配位到Mg的库仑相互作用。由于环V酮羰基结合位点的极化率实质上大于酯羰基结合位点的极化率,因此对于弱扰动,环V酮结合位点具有最小的结合能,对于强扰动,具有最大结合能。叶绿素a单体和二聚体中13 C磁共振化学位移的比较提供了新的实验证据,表明将叶绿素二聚体结合在一起的供体-受体相互作用包括V环酮羰基的大量参与和两个酯羰基的最小参与,因此与从头算计算得出的结论一致。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号