首次直接对同一金属碎片复合物的结构进行比较,以C,C-和C,O-结合模式的基结合
D B Grotjahn1, L S Collins, M Wolpert
1Department of Chemistry, 5500 Campanile Drive, San Diego State University, San Diego, CA 92182-1030, USA.
Journal of the American Chemical Society
|August 23, 2001
概括
这项研究揭示了 (Ir) 和 (Rh) 基复合体中的金属联体结合如何根据基结合方式不同. 它突出了Ir复合体中更大的trans影响和背接,有助于理解基因连接体化学.
科学领域:
- 有机金属化学 有机金属化学
- 协调化学 协调化学
- 频谱学是一种光谱学.
背景情况:
- 基联体在协调化学中具有根本性的重要性.
- 了解金属烯复合物的结构和粘合细微差别至关重要.
- 之前的研究并没有广泛地将不同结合方式的基因与同一金属碎片进行比较.
研究的目的:
- 阐明 (Ir) 和 (Rh) 基复合物的结构和结合.
- 为了比较基与金属中心的eta(2) - ((C,C) 和eta(2) - ((C,O) 结合方式.
- 调查这些复合体中的反向影响和背接效应.
主要方法:
- 新型Ir(I) 和Rh(I) 基因复合物的合成,包括同位素标记的变体 (例如,Ph2C=(13) C=O,Ph2C=C=(18) O).
- 进行X射线衍射分析以确定精确的结构参数,包括金属结合体键距离和角度.
- 红外 (IR) 光谱学用于研究同位素置换的影响,并分析振动模式,特别是C-O伸展频率.
- 为最终的光谱分配进行初步的正常坐标模式分析.
- 核磁共振 (NMR) 光谱法用于分析C-C合常量.
主要成果:
- X射线结构揭示了eta(2) - ((C,C) 和eta(2) - ((C,O) 结合模式的明显的Ir-Cl键距离,这表明C=C结合基的转子影响更大.
- 对Ir (I) 和Rh (I) 复合物的比较显示,Ir (I) 的反结略大,由系统C=C=O的变形表明.
- 同位素替代为协调基的红外吸收数据提供了新的见解,使得C-O伸展频率的分配成为可能.
- 在基复合体中, (13) C-(13) C 合的大小和碳-碳键距离之间建立了相关性.
结论:
- 联体的结合方式显著影响了Ir和Rh复合物的电子和结构性质.
- 与相比,在这些凯复合体中表现出更大的反影响和反结合能力.
- 光谱方法,特别是具有同位素标记的红外线方法,对于表征金属-基因相互作用和赋予振动模式是有效的.
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