Direct Observation of Intermediates in a Thermodynamically Controlled Solid-State Dynamic Covalent Reaction

详细信息    查看全文

• 作者：Ana M. Belenguer ; Giulio I. Lampronti ; David J. Wales ; Jeremy K. M. Sanders
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：November 19, 2014
• 年：2014
• 卷：136
• 期：46
• 页码：16156-16166
• 全文大小：949K
• ISSN：1520-5126

文摘

We present the first polymorph interconversion study that uses solid-state dynamic covalent chemistry (DCC). This system exhibits unexpected and rich behavior, including the observation that under appropriate conditions the polymorph interconversion of a heterodimer proceeds through reversible covalent chemistry intermediates, and this route is facilitated by one of the two disulfide homodimers involved in the reaction. Furthermore, we demonstrate experimentally that in all cases a dynamic equilibrium is reached, meaning that changing the milling conditions affects the free energy difference between the two polymorphs and thus their relative stability. We suggest that this effect is due to the surface solvation energy combined with the high surface to volume ratio of the nanocrystalline powder.