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首页> 外文期刊>Physical chemistry chemical physics: PCCP >Dissecting intermolecular interactions in the condensed phase of ibuprofen and related compounds: the specific role and quantification of hydrogen bonding and dispersion forces
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Dissecting intermolecular interactions in the condensed phase of ibuprofen and related compounds: the specific role and quantification of hydrogen bonding and dispersion forces

机译：对布洛芬和相关化合物的冷凝相中剖落分子间相互作用：氢键和分散力的具体作用和定量

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Ibuprofen is a well-established non-steroidal anti-inflammatory drug, inhibiting the prostaglandin-endoperoxide synthase. One of the key features defining the ibuprofen structure is the doubly intermolecular O-H center dot center dot center dot OQC hydrogen bond in cyclic dimers as know from carboxylic acids and confirmed by X-ray analysis. Until now, there was neither information about the vaporization enthalpy of ibuprofen nor about how this thermal property is determined by the subtle balance between different types of intermolecular interaction. In this study we derive the vaporization enthalpy of ibuprofen from thermochemical experiments to be Delta H-g(1)m degrees (298:15 K) = 89:4 +/- 0:8 kJ mol(-1). We dissected the hydrogen bond energy, E-HB = 45.0 kJ mol(-1), exclusively from measured vaporization enthalpies of related aliphatic carboxylic acids, their homomorph methyl esters and alkyl acetates, respectively. This contribution from hydrogen bonding could be confirmed almost quantitatively from quantum chemical calculations of ibuprofen clusters, which also suggest dispersion interaction of similar order (E-disp = 47 kJ mol(-1)). Following the full analysis of the gas-vapor transition enthalpy, we studied the changing structural components from the solid to the liquid phase of ibuprofen by means of Attenuated Total Reflection Infrared (ATR-IR) spectroscopy. The cyclic dimers as observed in the X-ray patterns are essentially preserved in the liquid state just above the melting point. However, with increasing temperature the doubly hydrogen-bonded cyclic dimers are replaced by singly hydrogen-bonded linear dimers in the liquid ibuprofen. The transfer enthalpy from the temperature-dependent equilibria of both dimers as obtained from the IR intensity ratios of the vibrational bands quantifies for the first time the energy of the released, single hydrogen bond to be E-HB = 21.0 kJ mol(-1). Overall, we show that a combination of thermodynamics, infrared spectroscopy and quantum chemistry provides quantification and detailed understanding of structure and molecular interaction in ibuprofen and related compounds.
机译：布洛芬是一种完善的非甾体抗炎药，抑制前列腺素 - 内甲氧化物合酶。定义布洛芬结构的关键特征之一是循环二聚体中的双分子O-H中心点中心点中心点中心点OQC氢键，如羧酸的知识，并通过X射线分析证实。到目前为止，既没有关于布洛芬的汽化焓的信息也没有关于这种热特性如何通过不同类型的分子间相互作用之间的细微平衡来确定的。在这项研究中，我们从热化学实验中得出了布洛芬的汽化焓，以ΔH-g（1）米（298：15 k）= 89：4 +/- 0：8kJ摩尔（-1）。我们分解了氢键能量，E-HB = 45.0kJ摩尔（-1），专门从相关脂族羧酸的测量蒸发焓，它们的同源物甲酯和烷基乙酸酯。可以几乎定量地从布洛芬簇的量子化学计算中数量地确认氢键的这种贡献，这也提出了类似订单的分散相互作用（E-DIPP = 47 kJ摩尔（-1））。在对气蒸气过渡焓的完全分析之后，我们通过减弱的全反射红外（ATR-IR）光谱研究了从固体到布洛芬的液相的改变的结构组分。如在X射线图案中观察到的环状二聚体基本上保存在熔点上方的液态中。然而，随着温度的增加，双氢键的环状二聚体由液体布洛芬的单氢键合的线性二聚体代替。从振动带的IR强度比获得的两倍二聚体的温度依赖性均衡的转移焓量量化了释放的单个氢键的能量，以E-Hb = 21.0kJ摩尔（-1） 。总的来说，我们表明热力学，红外光谱和量子化学的组合提供了对布洛芬和相关化合物的结构和分子相互作用的量化和详细了解。

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    Emelyanenko V. N.; Stange P.; Feder-Kubis J.; Verevkin S. P.; Ludwig R.;

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    Univ Rostock Inst Chem Abt Phys Chem Dr Lorenz Weg 2 D-18059 Rostock Germany;

    Univ Rostock Inst Chem Abt Phys Chem Dr Lorenz Weg 2 D-18059 Rostock Germany;

    Wroclaw Univ Sci &

    Technol Fac Chem Wybrzeze Wyspianskiego 27 PL-50370 Wroclaw Poland;

    Univ Rostock Inst Chem Abt Phys Chem Dr Lorenz Weg 2 D-18059 Rostock Germany;

    Univ Rostock Inst Chem Abt Phys Chem Dr Lorenz Weg 2 D-18059 Rostock Germany;

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  • 正文语种 eng
  • 中图分类 物理学;化学;
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