Abstract New compounds 5-benzyl-N-phenyl-1,3,4-thiadiazol-2-amine (Bptha, 1), 2-(5-phenyl-1,3,4-thiadiazol-2-yl) pyridine (Pthp, 2) and 2-(5-methyl-1,3,4-thiadiazole-2-ylthio)-5-methyl-1,3,4-thiadiazole (Mtmth, 3) have been synthesized and characterized with the aid of elemental analyses, IR, NMR and single crystal X-ray data. The structure of compounds 1, 2 and 3 are stabilized via intramolecular as well as intermolecular hydrogen bonding and crystallize in monoclinic system with space group P 1, P21/n and P 1, respectively. During the course of reaction, the substituted thiosemicarbazide/thiohydrazide get cyclized into the corresponding thiadiazole in the presence of manganese(II) nitrate via loss of H2O to yield compounds 1 and 2. However condensation occurred in the case of 5-methyl-1,3,4-thiadiazole-2-thiol which yielded 2-(5-methyl-1,3,4-thiadiazole-2-ylthio)-5-methyl-1,3,4-thiadiazole (3) by loss of one mole of H2S from two moles of 5-methyl-1,3,4-thiadiazole-2-thiol in the presence of manganese(II) acetate. The geometry optimization has been performed using DFT method and geometrical parameters thus obtained for the compounds have been compared with their single crystal X-ray data. The negative values of HOMO and LUMO energies for the molecules indicate that they are stable. The electronic transition from the ground state to the excited state due to a transfer of electrons from the HOMO to LUMO levels is mainly associated with the π⋯π transition.

中文翻译：

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5-苄基-N-苯基-1,3,4-噻二唑-2-胺，2-(5-苯基-1,3,4-噻二唑-2-基)的合成、光谱、X射线和DFT研究吡啶和2-(5-甲基-1,3,4-噻二唑-2-基硫基)-5-甲基-1,3,4-噻二唑通过Mn(II)催化反应获得

摘要 新化合物 5-benzyl-N-phenyl-1,3,4-thiadiazol-2-amine (Bptha, 1), 2-(5-phenyl-1,3,4-thiadiazol-2-yl)pyridine (Pthp , 2) 和 2-(5-methyl-1,3,4-thiadiazole-2-ylthio)-5-methyl-1,3,4-thiadiazole (Mtmth, 3) 已在元素的帮助下合成和表征分析、IR、NMR 和单晶 X 射线数据。化合物1、2和3的结构通过分子内和分子间氢键稳定，并分别在空间群为P 1 、P21/n 和P 1 的单斜晶系中结晶。在反应过程中，取代的氨基硫脲/硫酰肼在硝酸锰 (II) 存在下通过失去 H2O 环化成相应的噻二唑，生成化合物 1 和 2。 然而在 5-甲基-1 的情况下发生缩合， 3,4-噻二唑-2-硫醇生成 2-(5-methyl-1,3, 4-噻二唑-2-基硫基)-5-甲基-1,3,4-噻二唑 (3) 通过从 2 摩尔 5-甲基-1,3,4-噻二唑-2-硫醇中损失 1 摩尔 H2S乙酸锰（II）的存在。已使用 DFT 方法进行几何优化，并将由此获得的化合物的几何参数与其单晶 X 射线数据进行比较。分子的 HOMO 和 LUMO 能量为负值表明它们是稳定的。由于电子从 HOMO 到 LUMO 能级的转移，从基态到激发态的电子跃迁主要与 π⋯π 跃迁有关。已使用 DFT 方法进行几何优化，并将由此获得的化合物的几何参数与其单晶 X 射线数据进行比较。分子的 HOMO 和 LUMO 能量为负值表明它们是稳定的。由于电子从 HOMO 到 LUMO 能级的转移，从基态到激发态的电子跃迁主要与 π⋯π 跃迁有关。已使用 DFT 方法进行几何优化，并将由此获得的化合物的几何参数与其单晶 X 射线数据进行比较。分子的 HOMO 和 LUMO 能量为负值表明它们是稳定的。由于电子从 HOMO 到 LUMO 能级的转移，从基态到激发态的电子跃迁主要与 π⋯π 跃迁有关。