A series of bis(pyrrolidone) and ε-caprolactam co-crystals of boric acid and 1,4-phenylenediboronic acid are reported. The high polarity of the lactam carbonyl group is highly complementary to the boronic acid hydrogen bond donor functionalities and co-crystals are based on cyclic boronic acid tape motifs, including an unusual donor–donor motif, with strong perpendicular interactions to the lactam functionalities. All of the co-crystals are able to act as a source of boric or boronic acid cross-linker in guar gelation.

中文翻译：

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瓜尔胶凝胶中的硼酸共晶体†

报道了硼酸和1，4-苯二硼酸的一系列双（吡咯烷酮）和ε-己内酰胺共晶体。内酰胺羰基的高极性与硼酸氢键供体官能团高度互补，共晶体基于环状硼酸带基序，包括不寻常的供体-供体基序，与内酰胺官能团之间具有很强的垂直相互作用。所有的共晶体都可以在瓜尔胶凝胶中充当硼或硼酸交联剂的来源。