Abstract Gas phase vacuum deposition processes such as chemical vapor deposition or molecular layer deposition can be used to deposit conformal thin films of organic polymers. Urea and urethane are typical products in such vacuum thin film deposition methods that are obtained from spontaneous, catalyst- and solvent-free reactions between isocyanates/isothiocyanates and amines/diols/thiols. In this work, the thermochemistry of the urea/urethane coupling reactions between homobifunctional reactants is analyzed using double-hybrid density functional theory calculations. The reactant pairs are chosen such that the molecular backbone structures are either aromatic (-C6H4-) or aliphatic (-(CH2)4-) in both reactants. It is observed that the activation energies of the reactions can be correlated with the basicity of the amines/alcohol/thiol species. Furthermore, since the chemical properties are dependent on the structure of the molecular backbone, the molecular reactivity of the aliphatic reactant pairs are suggested to be higher than aromatic ones.

中文翻译：

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分子骨架结构对二异（硫）氰酸酯与二胺、二醇和二硫醇之间气相偶联反应的影响

摘要 气相真空沉积工艺如化学气相沉积或分子层沉积可用于沉积有机聚合物的保形薄膜。尿素和氨基甲酸酯是此类真空薄膜沉积方法中的典型产品，它们是通过异氰酸酯/异硫氰酸酯和胺/二醇/硫醇之间的自发、无催化剂和无溶剂反应获得的。在这项工作中，使用双杂化密度泛函理论计算分析了同双功能反应物之间尿素/氨基甲酸酯偶联反应的热化学。选择反应物对，使得两种反应物中的分子主链结构都是芳香族 (-C6H4-) 或脂肪族 (-(CH2)4-)。据观察，反应的活化能与胺/醇/硫醇物质的碱度有关。