Solid-state synthesis (S³) is an attractive approach to organic synthesis as in principle it offers minimal solvent waste and high yield. However, many functional groups are ill-suited for S³ reactions, which tend to only proceed when substrates are aligned in the solid-state according to the topochemical principle. The aim of this work is to use high yield, low-waste synthetic methods to develop a library of novel Schiff bases that can be utilized as linker ligands to prepare coordination networks. Herein, we report that eight pyridyl- and/or imidazolyl-substituted Schiff bases, 1–8, five of which are new chemical entities, can be prepared via reaction of an amine and an aldehyde without the use of solvent. All eight compounds were prepared via solvent-drop grinding (SDG) in multigram scale in >95% yield and each was characterized by FTIR, ¹H and ¹³C NMR spectroscopies and single crystal X-ray diffraction. One of the aldehydes used is a liquid under ambient conditions so its reactions to form 1–4 are not classified as S³ reactions whereas the other aldehydes are solids and 5–8 are therefore S³ reactions. The SDG solvents were selected in accordance with guidelines used by industry. 1–4 were also prepared quantitatively via addition of the liquid aldehyde (4-pyridinecarboxaldehyde) to a solution of the corresponding amine. That 1–8 contain functional groups suitable for coordinating with metal cations will enable 1–8 to serve as linker ligands in coordination networks as exemplified by 5, which forms a parallel interpenetrated coordination network with square lattice, sql, topology.

中文翻译：

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吡啶基和咪唑基取代的席夫碱连接基配体家族的高产率，低浪费合成

固态合成（S ³）是有机合成的一种有吸引力的方法，因为从原理上讲，它可减少溶剂浪费并提高收率。然而，许多官能团不适用于S ³反应，当根据拓扑化学原理将底物以固态排列时，S ³反应往往会继续进行。这项工作的目的是使用高收率，低浪费的合成方法来开发新型席夫碱的文库，该席夫碱可用作连接子配体来制备配位网络。在本文中，我们报道了8吡啶基-和/或咪唑基取代的席夫碱，1 - 8，其中五个是新的化学实体，可以通过胺和醛的反应制备，而无需使用溶剂。所有八种化合物均通过溶剂滴磨（SDG）以多克级制备，收率> 95％，并分别通过FTIR，¹ H和¹³ C NMR光谱学以及单晶X射线衍射进行表征。之一中使用的醛的是在环境条件下为液体，从而其反应以形成1 - 4不属于为S ^3个而其他醛是固体和反应5 - 8因此š ^3个反应。SDG溶剂是根据行业使用的准则选择的。1个- 4还制备通过加入液体醛（4-吡啶）为相应的胺的溶液的定量。即1 - 8包含适于与金属阳离子配位将使官能团1 - 8作为在协调网络连接基的配体通过所示例5，其形成与正方形晶格，并行互穿网络协调SQL，拓扑。