溶液相机理学研究和三 (二) 基离子) 含复合物的固态结构
Albert C Fahrenbach1, Jonathan C Barnes, Don Antoine Lanfranchi
1Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|December 14, 2011
概括
循环 (((帕拉奎特-p-) (CBPQT (((2(•+))) 环与1.1′-二甲基-4,4′-双基离子 (BIPY (((•+)) 形成稳定的包容复合体. 这种激进-激进的识别促进了对分子相互作用和机械互锁分子的理解.
科学领域:
- 超分子化学 超分子化学
- 材料科学 材料科学 材料科学
- 有机化学 有机化学
背景情况:
- 循环 (((帕拉克瓦特-p-) (CBPQT ((2(•+))) 是一个二根的二元环.
- 1,1′-dialkyl-4,4′-bipyridinium基离子 (BIPY(•+)) 是宿主-客人化学中的常见客人.
研究的目的:
- 在机理和定量上研究CBPQT ((2(•+)) 和BIPY ((•+) 客人之间形成的包容综合体.
- 阐明这些三根复合体的结构,热力学和运动性质.
主要方法:
- 单晶X射线晶体学用于确定复杂结构.
- 量子力学计算以支持结构发现.
- 异热定位热度计 (ITC) 和紫外线/紫外线光谱检测热力学稳定性.
- 停止流光谱用于协会和解离的动力学研究.
- 可变扫描速率循环电压测量 (CV) 用于电化学机制的细节.
主要成果:
- 形成了两个三基复合体,即CBPQT(2(•+)) MV(•+) 和CBPQT(2(•+)) V(•+).
- X射线结晶学揭示了CBPQT2的CBPQT2腔内MV的中心对称排列,形成连续的基离子堆.
- 量子力学计算表明,由于激素配对相互作用,SOMO中的电子不对称性在溶液中持续存在.
- ITC和UV/vis光谱学为CBPQT提供了 (5.0 ± 0.6) × 10^4 M−1和 (7.9 ± 5.5) × 10^4 M−1的约束常数.
- 停止流量光谱测定了CBPQT的关联率 (k_f = (2.1 ± 0.3) × 10^6 M−1 s−1) 和解离率 (k_b = 250 ± 50 s−1) 的相关性.
- 电化学研究揭示了一种双根的四化中间体,对V的客体进行缓慢解离合 (k_b = 10 ± 2 s-1).
结论:
- CBPQT2+) 戒指对BIPY2+) 基离子和潜在的π电子丰富的客体都有独特的识别能力.
- 这些发现为利用在机械互锁分子中激素对激素的识别奠定了基础.
- 这项研究增强了对BIPY ((•+) 激素-激素相互作用在溶液和固体状态的基本理解.
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