Et_2 NH_2[RE(S_2 CNEt_2)_4]的标准摩尔生成焓

Standard molar enthalpy of formation of Et_2 NH_2 [RE( S_2CNEt_2)_4]

目的合成、表征4种稀土与二乙氨基荒酸二乙铵(D-DDC)配合物并计算其标准摩尔生成焓。方法精密转动弹量热法。结果标题化合物的恒容燃烧热△cU分别为(-19 490．07±8．23),(- 19 391．14±10．72),(-19 208．32±8．99)和(-18 439．79±7．77)kJ／mol;计算了它们的标准摩尔燃烧焓△cHmθ和标准摩尔生成焓△fHmθ,分别为(-19 517．96±8．23),(-19 419．03±10．72),(- 19 236．21±8．99),(-18 467．68±7．77)kJ／mol和(-628．91±8．88),(-742．97±11．71),(- 918．15±9．59),(-1 690．32±8．50)kJ／mol;估算出未研究的同类配合物Et2NH2[Ce(S2CNEt2)4] 和Et2NH2[Pm(S2CNEt2)4]的△cHmθ和△fHmθ分别为-19 495,-18 930 kJ／mol和-673,-1 262 kJ／ mol。结论以配合物的△cHmθ和△fHmθ对轻稀土原子序数作图,得到一条曲线而非单向变化的直线, 说明配合物中RE3+与配体间的化学键有一定程度的共价性。

Ahn To synthesize and, characterize four complexes of RE （ RE = La, Pr, Nd, Sm） coordinated with diethylammonium diethyldinedithiocarbamate （D-DDC） and calculate their standard molar enthalpies of formation. Methods Using precise rotating-bomb calorimeter. Results The constant-volume combustion energies of title complexes, AcU, were determined as （ - 19 490.07 ± 8.23）, （ - 19 391.14 ±10.72）, （ - 19 208.32 ± 8.99） and （ - 18 439.79 ±7.77） kJ/mol, by a precise rotating -bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, △cHm^θ, and standard molar enthalpies of formation, △fHm^θ, were calculated as （ - 19 517.96 ±8.23）, （ - 19 419.03 ± 10.72）, （ - 19 236.21 ±8.99）, （ - 18 467.68 ±7.77） kJ/mol and （-628.91±8.88）, （ -742.97 ±11.71）, （ -918.15 ±9.59） , （ -1 690.32 ±8.50） kJ/mol. Furthermore, corresponding △cHm^θ and △fHm^θ of Et2NH2 [ Ce （ S2CNEt2 ）4 ] and Et2NH2 [ Pm （ S2CNEt2 ）4 ] were estimated as - 19 495, - 18 930 kJ/mol and -673, - 1 262 kJ/mol, respectively. Conclusion With increasing atomic number, △cHm^θ, and △fHm^θ of the complexes present non-linear change, showing that certain covalence exists in the coordination between RE^3＋ and ligands.