Lande Dipali N, Gejji Shridhar P, Pathak Rajeev K
Department of Chemistry, Sir Parshurambhau College, Tilak Road, Pune, 411030, MH, India.
Department of Chemistry, Savitribai Phule Pune University, Pune, 411007, MH, India.
J Mol Model. 2024 Nov 26;30(12):415. doi: 10.1007/s00894-024-06193-8.
Oxirene, surmised to exist in the interstellar medium, was synthesized in the laboratory only recently. The present study investigates theoretically to what extent the two exotic molecules, oxirene and its thia-analogue thiirene, are capable of forming molecular self-aggregates and undergo micro-hydration under cooperative hydrogen bonding as the tour de force. Cogent molecular descriptors, such as binding energies for cluster formation, molecular electrostatic potential (MESP), effective atomic charges, infrared spectroscopic response, criticality profiles from the quantum theory of atoms in molecules (QTAIM), hydrogen bond energies, and reduced density gradient (RDG) maps identifying non-covalent interactions (NCI), all in unison confirm theoretically the existence and characterize the aggregates. In particular, infrared spectra display frequency down-shifts for the hydrogen bonded C-H vibrations in aggregates and for O-H in hydrated complexes. This work carried out in silico, should furnish credible tenets toward identification of oxirene and thiirene self-aggregates and their micro-hydrated complexes that potentially exist in the interstellar medium.
By means of a molecular modeling program AVOGADRO, a multitude of initial-guess clusters under universal force field (UFF) were generated, which were subsequently optimized employing the GAUSSIAN16 suite of programs with the tightest convergence criterion, at the ωB97xD level of density functional theory embodying long-range dispersion effects, in conjunction with a reliable basis set 6-311 ++ G(2d,2p). The versatile package GAUSSVIEW yields the structures, vibrational frequencies, and criticality information, respectively.
氧杂环丙烯被推测存在于星际介质中，直到最近才在实验室中合成。本研究从理论上探究了两种奇异分子——氧杂环丙烯及其硫类似物硫杂环丙烯——在协同氢键作用下形成分子自聚集体并发生微水合作用的能力。有说服力的分子描述符，如团簇形成的结合能、分子静电势（MESP）、有效原子电荷、红外光谱响应、分子中原子量子理论（QTAIM）的临界性分布、氢键能以及识别非共价相互作用（NCI）的密度降低梯度（RDG）图，都一致从理论上证实了聚集体的存在并对其进行了表征。特别是，红外光谱显示聚集体中氢键合的C-H振动以及水合配合物中O-H的频率下移。这项在计算机上进行的工作应为识别可能存在于星际介质中的氧杂环丙烯和硫杂环丙烯自聚集体及其微水合配合物提供可靠的原则。
借助分子建模程序AVOGADRO，在通用力场（UFF）下生成了大量初始猜测团簇，随后使用GAUSSIAN16程序套件，在体现长程色散效应的ωB97xD密度泛函理论水平下，结合可靠的基组6-311++G(2d,2p)，以最严格的收敛标准对其进行优化。多功能软件包GAUSSVIEW分别给出结构、振动频率和临界性信息。
