Danten Y, Tassaing T, Besnard M
Laboratoire de Physico-Chimie Moléculaire (U.M.R C.N.R.S 5803), Université Bordeaux I, 351, Cours de la Libération, 33405 Talence, France.
J Phys Chem A. 2006 Jul 20;110(28):8986-9001. doi: 10.1021/jp061845l.
We have investigated the infrared (IR) vibrational spectra of acetaminophen (N(4-hydroxyphenyl) acetamide or paracetamol) complexes formed with ethanol and acetone in relation to the nature of the specific intermolecular interactions involved in the stabilization of the complexes. The structures and binding energies of the complexes have been determined using Hartree-Fock (HF) and DFT-B3PW91 procedures and different Pople's basis sets as well. The main results are presented and discussed by considering the hydroxyl (OH), amino (NH), and carbonyl (CO) chemical groups of acetaminophen interacting with the acetone or ethanol molecules either separately or in conjunction in the complex formation. The frequency shifts and IR intensity variations associated with the internal modes of acetaminophen (namely nu(OH), nu(NH), and nu(CO)) as well as the most pertinent vibrational probes of ethanol (nu(OH)) and acetone (symmetric nu(CO) and nu(CCC) stretching modes) interacting with acetaminophen have been analyzed. The predicted spectral changes have been critically discussed in comparison with IR absorption measurements of acetaminophen dissolved as a solute in ethanol or acetone CO2 expanded solutions. It is argued that the exchange-correlation contribution taken into account in DFT calculations is likely significant in determining the main IR spectral features of acetaminophen complexes formed with acetone or involving hydrogen-bonded as with ethanol.
我们研究了对乙酰氨基酚（N-(4-羟基苯基)乙酰胺或扑热息痛）与乙醇和丙酮形成的配合物的红外（IR）振动光谱，这与配合物稳定化过程中特定分子间相互作用的性质有关。配合物的结构和结合能已使用哈特里-福克（HF）和密度泛函理论B3PW91方法以及不同的波普尔基组进行了测定。通过考虑对乙酰氨基酚的羟基（OH）、氨基（NH）和羰基（CO）化学基团在配合物形成过程中单独或共同与丙酮或乙醇分子相互作用的情况，呈现并讨论了主要结果。分析了与对乙酰氨基酚的内禀模式（即ν(OH)、ν(NH)和ν(CO)）以及与对乙酰氨基酚相互作用的乙醇（ν(OH)）和丙酮（对称ν(CO)和ν(CCC)伸缩模式）最相关的振动探针相关的频率位移和红外强度变化。与对乙酰氨基酚作为溶质溶解在乙醇或丙酮CO2膨胀溶液中的红外吸收测量结果相比，对预测的光谱变化进行了严格讨论。有人认为，在密度泛函理论计算中考虑的交换相关贡献在确定与丙酮形成的对乙酰氨基酚配合物或与乙醇形成的涉及氢键的配合物的主要红外光谱特征方面可能具有重要意义。
