A Systematic Study of the Relationship between Molecular and Crystal Structure among 3,5-Diazabicyclo[2.2.2]octane-2,6-diones

A simple, convergent synthesis of 3,5-diazabicyclo[2.2.2]octane-2,6-diones (bicyclic N,N‘-diacylaminals)
has been developed, providing access to a large series of compounds differing only in their substituents at the
bridgehead positions. These compounds crystallize in several different forms, but always in such a way that each
molecule forms four hydrogen bonds. The sheer number of bicyclic amidals that can be synthesized and crystallized
provides an opportunity to elucidate crystal-engineering structure−structure relationship (SSR) principles.

本研究开发了一种简洁收敛的合成方法，用于制备3,5-二氮杂双环[2.2.2]辛烷-2,6-二酮（3,5-diazabicyclo[2.2.2]octane-2,6-diones，即双环N,N'-二酰基缩醛胺（bicyclic N,N‘-diacylaminals）），可得到一系列仅桥头位置取代基存在差异的化合物。此类化合物可结晶为多种不同晶型，但所有晶型中每个分子均形成四个氢键。可合成并结晶的双环缩醛胺数量极为可观，这为阐明晶体工程领域的结构-结构关系（structure−structure relationship, SSR）原理提供了绝佳契机。