Molecular Dynamics-simulated OH···O bonded-cyclic dimer structure, called D_c, has been proposed for 2,5-Dihydroxyterephthalic acid a potential organic linker in Hydrogen-bonded Organic Frameworks (HOF). Among many dimer species bound by inter-molecular OH···O bonds, D_c was chosen because of its relatively highest lifetime of 18.3 ps as indicated by the radial distribution functions (RDF). Experimentally observed intense but broad down-shifted IR absorptions peak at ∼ 3023 cm⁻¹ and bands near 2556 cm⁻¹ combined with staggered occurrence of IR and Raman bands in other spectral regions suggested that the proposed cyclic dimer appeared to possess an extended quasi-centrosymmetric configuration. Upon optimization of D_c at B3LYP/6-311++G(d,p) level, it yielded geometry and vibrational spectra in agreement with experimental spectra. Further, we have characterized both intra- and inter-molecular OH···O bonds in D_c using stabilization energy E⁽²⁾ and other molecular orbital (MO) properties from NBO analysis. Bond critical points (BCPs) and ring critical points (RCPs) deduced from electron density (ρ(r)), its laplacian (${\nabla }^2\rho \left(r\right)$) and potential energy density (v(r)) using AIM calculations have provided complementary perspectives. Additionally, a combination of quantitative analysis and graphical visualization of the charge regions where non-covalent interactions occur in real space intra- and inter-molecular OH···O bonds, van der Waals and repulsive steric clash interactions have been obtained from NCI calculations.

分子动力学模拟的 O H···O 键合环状二聚体结构，称为D _c，已被提议用于 2,5-二羟基对苯二甲酸，它是氢键有机框架 (HOF) 中的潜在有机连接剂。在许多由分子间 O H···O 键结合的二聚体中，选择D _c是因为其相对最高的寿命为 18.3 ps，如径向分布函数 (RDF) 所示。实验观察到的强烈但广泛的下移红外吸收峰在~ 3023 cm ^-1和 2556 cm ^-1附近的波段结合其他光谱区域中交错出现的 IR 和拉曼波段表明所提出的环状二聚体似乎具有扩展的准中心对称配置。在 B3LYP/6-311++G(d,p) 水平上优化D _c后，它产生了与实验光谱一致的几何和振动光谱。此外，我们使用来自 NBO 分析的稳定能E ⁽²⁾和其他分子轨道 (MO) 特性表征了D _c中分子内和分子间的 O H···O 键。由电子密度 ( ρ ( r ) ) 推导出的键临界点 (BCPs) 和环临界点 (RCPs )，其拉普拉斯算子 (${\nabla }^2\rho \left(r\right)$) 和势能密度 (v( r )) 使用 AIM 计算提供了互补的观点。此外，从 NCI 获得了在实际空间中发生非共价相互作用的电荷区域的定量分析和图形可视化的组合，分子内和分子间 O · H···O 键、范德华和排斥性空间冲突相互作用计算。