论文部分内容阅读
In this work, we report a theoretical exploration of the ground-state electronic struc- tures and molecular vibrational properties of a series of binuclear zirconium complexes in the framework of density functional theory (DFT) employing the B3LYP hybrid functional. The calculated results reveal that the electronic structure of the complex [(η5-C5Me5)2Zr]2(μ2,η2,η2-N2) is unfavorable for hydrogenation due to the exclusion of side-on dinitrogen in the LUMO+1 molecular orbital as compared with the reactant 1 [(η5-C5Me4H)2Zr]2(μ2,η2,η2-N2). Besides, the structural feature of the hypothetical intermediate 1?, [(η5-C5Me4H)2Zr]2(μ2,η2,η2-N2)-H2, clearly implies the possibility of further hydrogenation. In addition, the distinguishing of vibrational modes of experimental intermediate 2, [(η5-C5Me4H)2ZrH]2(μ2,η2,η2-N2H2), indicates that the asymmetric stretching of Zr–N and Zr–H leads to dissociation. Moreover, the vibrational intensity of Zr–H is stronger than that of Zr–N. Therefore, it can be predicted that excess hydrogen atmosphere is necessary to ensure the dissociation of Zr–N bonds.
In this work, we report a theoretical exploration of the ground-state electronic struc- tures and molecular vibrational properties of a series of binuclear zirconium complexes in the framework of density functional theory (DFT) employing the B3LYP hybrid functional. The calculated results reveal that the electronic structure of the complex [(η5-C5Me5) 2Zr] 2 (μ2, η2, η2-N2) is unfavorable for hydrogenation due to the exclusion of side-on dinitrogen in the LUMO + 1 molecular orbital as compared with the reactant 1 [(η5-C5Me4H) 2Zr] 2 (μ2, η2, η2-N2). Further, the structural feature of the hypothetical intermediate 1? H2, clearly distinguishing the possibility of further hydrogenation. In addition, the distinguishing of vibrational modes of experimental intermediate 2, [(η5-C5Me4H) 2ZrH] 2 (μ2, η2, η2-N2H2) N and Zr-H leads to dissociation. Moreover, the vibrational intensity of Zr-H is stronger than that of Zr -N. Therefore, it can be predicted that excess hydrogen atmosphere is necessary to ensure the dissociation of Zr-N bonds.