This paper reports the crystal growth and structure of a newly synthesized hybrid organic-inorganic compound (CH 6 N 3 ) 2 [Co (NCS) 4 ].H 2 O by means of a joint experimental and theoretical study. Single-crystal X-ray diffraction reveals that this compound crystallizes in the noncentrosymmetric P2 1 2 1 2 space group. The 3D framework of the crystal structure is formed by hydrogen-bonded cations of (CH 6 N 3 ) + , [Co (NCS) 4 ] 2− anions and water molecules. UV-Visible reveals an indirect allowed optical transition with energy gap Eg = 3.41 eV. The optimized molecular structure, harmonic vibrational frequencies, static and frequency-dependent nonlinear optical (NLO) parameters were calculated by density functional theory with and without dispersion corrections. A good consistency for the structure, as well as IR and Raman spectra, is found between the calculated and experimental results. A detailed interpretation of the vibrational modes was carried out and a total assignment was performed on the basis of the potential energy distribution (PED) contribution. Moreover, the inter-ionic interaction energy was evaluated and a decomposition analysis was performed by localized molecular orbital energy decomposition analysis (LMO-EDA) method. The calculated NLO parameters compared to urea as a reference show that the title compound can be a good candidate for NLO applications.

中文翻译：

---

基于结构、DFT 的新型硫氰酸胍钴配合物的振动和非线性光学行为研究

本文通过联合实验和理论研究报告了一种新合成的杂化有机-无机化合物 (CH 6 N 3 ) 2 [Co (NCS) 4 ].H 2 O 的晶体生长和结构。单晶 X 射线衍射表明该化合物在非中心对称 P2 1 2 1 2 空间群中结晶。晶体结构的 3D 骨架由 (CH 6 N 3 ) + 、[Co (NCS) 4 ] 2- 阴离子和水分子的氢键阳离子形成。UV-Visible 揭示了一个间接允许的光学跃迁，能隙 Eg = 3.41 eV。优化的分子结构、谐波振动频率、静态和频率相关非线性光学 (NLO) 参数通过密度泛函理论计算，有和没有色散校正。结构的良好一致性，以及红外和拉曼光谱，介于计算结果和实验结果之间。对振动模式进行了详细解释，并根据势能分布 (PED) 贡献进行了总分配。此外，评价离子间相互作用能并通过局部分子轨道能量分解分析(LMO-EDA)方法进行分解分析。计算出的 NLO 参数与作为参考的尿素相比表明，标题化合物是 NLO 应用的良好候选者。评价离子间相互作用能并通过局部分子轨道能量分解分析（LMO-EDA）方法进行分解分析。计算出的 NLO 参数与作为参考的尿素相比表明，标题化合物是 NLO 应用的良好候选者。评价离子间相互作用能并通过局部分子轨道能量分解分析（LMO-EDA）方法进行分解分析。计算出的 NLO 参数与作为参考的尿素相比表明，标题化合物是 NLO 应用的良好候选者。