Loureiro Rui M S, Johnstone Robert A W, Labat Gaël
University of Liverpool, Department of Chemistry, Crown Street, Liverpool L69 7ZD, England.
Acta Crystallogr C. 2008 Jun;64(Pt 6):o306-8. doi: 10.1107/S0108270108011530. Epub 2008 May 6.
Fusion of 4-nitrophenol and acetamide in a 1:1 molar ratio gives the title product, C6H5NO3.C2H5NO, (III), which has the character of a pure covalently bonded compound, having a high sharp melting point. Complex (III) (m.p. 371.9-372.9 K) can be recrystallized from various solvents and forms eutectics with either acetamide or 4-nitrophenol. Similar fusion of mixtures of acetamide and 2-nitrophenol yields no complex similar to (III) and mixtures of acetamide and 3-nitrophenol produce only a weak low-melting complex. The significance of this study lies in its demonstration, via graph set analysis, that some of the patterns found individually in crystalline acetamide or 4-nitrophenol have been preserved in crystals of complex (III), while several higher order graph sets are produced in (III) due to new hydrogen bonds involving the nitro group. In particular, large hydrogen-bonded rings are formed together with helical chains.
4-硝基苯酚与乙酰胺按1:1摩尔比熔融得到标题产物C6H5NO3·C2H5NO，即(III)，它具有纯共价键化合物的特性，熔点高且尖锐。配合物(III)（熔点371.9 - 372.9 K）可从多种溶剂中重结晶，并与乙酰胺或4-硝基苯酚形成低共熔物。乙酰胺与2-硝基苯酚的混合物进行类似熔融不会产生类似于(III)的配合物，而乙酰胺与3-硝基苯酚的混合物仅产生一种微弱的低熔点配合物。本研究的意义在于通过图集分析表明，在结晶乙酰胺或4-硝基苯酚中单独发现的一些模式在配合物(III)的晶体中得以保留，而由于涉及硝基的新氢键，在(III)中产生了几个更高阶的图集。特别是，形成了大的氢键环以及螺旋链。
