Some organic molecules encapsulate solvents upon crystallization. One class of compounds that shows a high propensity to form such crystalline solvates are tetraaryladamantanes (TAAs). Recently, tetrakis(dialkoxyphenyl)-adamantanes have been shown to encapsulate a wide range of guest molecules in their crystals, and to stabilize the guest molecules against undesired reactions. The term ‘encapsulating organic crystals’ (EnOCs) has been coined for these species. In this work, we studied the behavior of three TAAs upon exposition to different guest molecules by means of sorption technique. We firstly measured the vapor adsorption/desorption isotherms with water, tetrahydrofuran and toluene, and secondly, we studied the uptake of methane on dry and wet TAAs. Uptake of methane beyond one molar equivalent was detected for wet crystals, even though the materials showed a lack of porosity. Thus far, such behavior, which we ascribe to methane hydrate formation, had been described for porous non-crystalline materials or crystals with detectable porosity, not for non-porous organic crystals. Our results show that TAA crystals have interesting properties beyond the formation of conventional solvates. Gas-containing organic crystals may find application as reservoirs for gases that are difficult to encapsulate or are slow to form crystalline hydrates in the absence of a host compound.

Wet tetraaryladamantane crystals take up methane in form of methane hydrate structure I, even though they appear non-porous to argon.

一些有机分子在结晶时将溶剂包封。一类显示出形成这种结晶溶剂化物的高倾向性的化合物是四芳基金刚烷（TAA）。近来，四（二烷氧基苯基）-金刚烷已显示在其晶体中包封了多种客体分子，并稳定了客体分子以防止不希望的反应。这些物种被称为“封装有机晶体”（EnOCs）。在这项工作中，我们通过吸附技术研究了三种TAA在暴露于不同的客体分子时的行为。我们首先测量了水，四氢呋喃和甲苯的蒸气吸附/解吸等温线，其次，我们研究了干和湿TAAs上甲烷的吸收。检测到湿晶体中甲烷的吸收量超过一摩尔当量，即使材料显示缺乏孔隙。迄今为止，已经描述了这种可归因于甲烷水合物形成的行为，是针对具有可检测孔隙率的多孔非晶体材料或晶体，而非非多孔有机晶体。我们的结果表明，TAA晶体具有超越常规溶剂化物形成的有趣特性。含气体的有机晶体可以用作在没有主体化合物的情况下难以包封或缓慢形成结晶水合物的气体的储存器。我们的结果表明，TAA晶体具有超越常规溶剂化物形成的有趣特性。含气体的有机晶体可以用作在没有主体化合物的情况下难以包封或缓慢形成结晶水合物的气体的储存器。我们的结果表明，TAA晶体具有超越常规溶剂化物形成的有趣特性。含气体的有机晶体可以用作在没有主体化合物的情况下难以包封或缓慢形成结晶水合物的气体的储存器。

湿的四芳基金刚烷晶体以甲烷水合物结构I的形式吸收甲烷，即使它们对氩气无孔。