氮分子与过渡金属中心钼、铁、钒相互作用的理论研究

通过密度泛函理论计算研究了过渡金属模型体系的二氮复合物(N2)M(NH2)3(NH3)和(N2)M(SH)3(NH3)(-OCH2COO-)(M=Mo,V,Fe),预测了质子-电子还原二氮过程的能量变化.计算结果表明,对于单过渡金属中心体系,钼与N2存在强的相互作用,钒与N2相互作用较弱,铁不能有效地结合N2.通过质子化过渡金属模型体系中高柠檬酸二齿配体的羧基氧,并改变金属中心的价态和体系的自旋态,可以调控羧基氧与金属配位键的生成与断裂.两类模型体系的计算结果显示,对于单过渡金属中心的钼、钒、铁体系,钼是结合N2最有效的活性位.

Spectroscopic Investigation of New Room-temperature Molten Salt Based on LiTFSI with Acetamide

Complexes of the transition met al-containing model compounds with dinitrogen (N2)M(NH2)3(NH3) and (N2)M(SH)3(NH3)(-OCH2COO-) MMo,V, Fe] were studied by the density functional theory. The relative energetics of the reduction of N2 to ammonia by the proton-electron transfer to the dinitrogen derivative was predicted. The calculated results show that there is a strong interaction between the Mo center and dinitrogen and the V…NN interaction is relatively weak, whereas the Fe center cannot bind N2. The homocitrate ring opening in the simplified Mo-containing fragment in the FeMoco was predicted to be manipulable by controlling the spin multiplicity and oxidation state of the transition met al complex. The present results from both models indicate that the Mo is the most efficient active site for the dinitrogen binding and reduction among the single transition-met al centers Mo, V and Fe.