实验确定Cr-C(2)Cl(4) 键解离在Cr(CO)(5)(C(2)Cl(4) 中的Cr-C(2)Cl(4) 键解离:量化金属-烯结合相互作用
1Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA.
Journal of the American Chemical Society
|December 26, 2001
概括
在有机金属复合体中,Cr-C键被烯变形所削弱,而不仅仅是电子相互作用. 这种变形能量显著影响金属-烯结合强度.
科学领域:
- 有机金属化学 有机金属化学
- 计算化学计算化学
- 频谱学是一种光谱学.
背景情况:
- 德沃-查特-肯森模型描述了通过西格玛捐赠和反向结合的金属-氨酸结合.
- 了解影响金属-烯结合强度的因素对于预测反应性和稳定性至关重要.
研究的目的:
- 确定气相中Cr-C((2)Cl(4) 键的键解离. 在气相中Cr(CO) (((5) ((C(2)Cl(4)).
- 用密度函数理论 (DFT) 进行能量分解分析来量化金属-烯结合相互作用.
- 为了研究保利排斥和变形能量的对金属-烯键强度的影响.
主要方法:
- 暂时的红外光谱学被用来测量债券解离度.
- 基于密度函数理论 (DFT) 的能量分解分析被用来剖析结合相互作用.
- 通过一系列复合体 (Cr(CO) ((5) ((C(2)X(4) 的键比较,X = H,F,Cl).
主要成果:
- 确定Cr-C(2)Cl(4) 键解离的度为12.8 +/- 1.6 kcal/mol. 这是一个非常好的结果.
- 金属-烯酸结合强度受到保利排斥和变形金属和烯酸部分所需的能量的影响.
- 由于金属-烯背接,由重混合驱动的烯变形是整体变形能量的主要贡献者.
结论:
- 变形能量,特别是烯酸,是决定金属烯酸键度趋势的主要因素.
- 德沃-查特-肯森模型为理解这些相互作用提供了一个框架,但定量分析揭示了变形的重要性.
- 这些发现提供了对有机金属烯复合物的结合性质的更深入的见解.
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