Espallargas Guillermo Mínguez, Hippler Michael, Florence Alastair J, Fernandes Philippe, van de Streek Jacco, Brunelli Michela, David William I F, Shankland Kenneth, Brammer Lee
Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom.
J Am Chem Soc. 2007 Dec 19;129(50):15606-14. doi: 10.1021/ja075265t. Epub 2007 Nov 23.
Hydrogen chloride gas (HCl) is absorbed (and reversibly released) by a nonporous crystalline solid, [CuCl2(3-Clpy)2] (3-Clpy = 3-chloropyridine), under ambient conditions leading to conversion from the blue coordination compound to the yellow salt (3-ClpyH)2[CuCl4]. These reactions require substantial motions within the crystalline solid including a change in the copper coordination environment from square planar to tetrahedral. This process also involves cleavage of the covalent bond of the gaseous molecules (H-Cl) and of coordination bonds of the molecular solid compound (Cu-N) and formation of N-H and Cu-Cl bonds. These reactions are not a single-crystal-to-single-crystal transformation; thus, the crystal structure determinations have been performed using X-ray powder diffraction. Importantly, we demonstrate that these reactions proceed in the absence of solvent or water vapor, ruling out the possibility of a water-assisted (microscopic recrystallization) mechanism, which is remarkable given all the structural changes needed for the process to take place. Gas-phase FTIR spectroscopy has permitted us to establish that this process is actually a solid-gas equilibrium, and time-resolved X-ray powder diffraction (both in situ and ex situ) has been used for the study of possible intermediates as well as the kinetics of the reaction.
在环境条件下，氯化氢气体（HCl）被一种无孔晶体固体[CuCl₂(3 - Clpy)₂]（3 - Clpy = 3 - 氯吡啶）吸收（并可逆释放），导致从蓝色配位化合物转变为黄色盐(3 - ClpyH)₂[CuCl₄]。这些反应需要晶体固体内的大量运动，包括铜配位环境从平面正方形变为四面体。这个过程还涉及气态分子（H - Cl）的共价键以及分子固体化合物（Cu - N）的配位键的断裂，以及N - H和Cu - Cl键的形成。这些反应不是单晶到单晶的转变；因此，晶体结构测定是使用X射线粉末衍射进行的。重要的是，我们证明这些反应在没有溶剂或水蒸气的情况下进行，排除了水辅助（微观重结晶）机制的可能性，鉴于该过程发生所需的所有结构变化，这一点很显著。气相傅里叶变换红外光谱使我们能够确定这个过程实际上是一种固 - 气平衡，并且时间分辨X射线粉末衍射（原位和非原位）已用于研究可能的中间体以及反应动力学。
