Chemistry Department, University of North Dakota, Grand Forks, North Dakota 58202-9024, USA.
J Phys Chem A. 2010 Aug 12;114(31):8119-25. doi: 10.1021/jp100457e.
The second-order generalized Van Vleck perturbation theory (GVVPT2) variant of multireference perturbation theory was used to investigate the ground and low-lying excited electronic states of [3,3'] bidiazirinylidene (C(2)N(4)). C(2)N(4) is arguably the simplest molecule with multiple CN(2) rings. Equilibrium geometries and adiabatic energy differences of the 1(1)A(g) ground state and 2 (1)A(g), 1(1)B(1g), 1(3)B(1g), 1(1)B(2g), 1(3)B(2g), 1(1)B(3g), 1(3)B(3g), 1(1)B(2u), 1(3)B(2u), 1(1)B(3u), and 1(3)B(3u) excited states of D(2h) symmetry were obtained. In addition, vertical excitation energies to and emission energies from the excited states were obtained. The 1(1)A(g) optimized geometry and harmonic frequencies for the CN(2) rings in C(2)N(4) are similar to those for the related difluorodiazirine molecule: R(CN), R(NN) bonds and the angleNCN angle are 0.012 and 0.006 A longer and 0.8 degrees smaller than that for the ring in F(2)CN(2). The NN stretch frequencies are 1470 and 1562 cm(-1), and CN stretches are 993 and 995 cm(-1). The similarity between the GVVPT2 results of C(2)N(4) and F(2)CN(2) suggests that C(2)N(4) might be sufficiently stable to be synthesized. The lowest-energy spin- and electric dipole-allowed vertical excitation, to the 1(1)B(2u) state, is predicted to occur in the visible (2.30 eV, 538.9 nm).
采用二阶广义范弗莱克微扰理论（GVVPT2）变体对多参考微扰理论进行了研究，研究对象是[3,3']双叠氮亚基（C2N4）的基态和低激发电子态。C2N4 可以说是具有多个 CN2 环的最简单分子。本文获得了 D2h 对称的 1(1)Ag 基态和 2(1)Ag、1(1)B1g、1(3)B1g、1(1)B2g、1(3)B2g、1(1)B3g、1(3)B3g、1(1)B2u、1(3)B2u、1(1)B3u 和 1(3)B3u 激发态的平衡几何形状和绝热能差。此外，还获得了垂直激发能和从激发态的发射能。C2N4 中 CN2 环的 1(1)Ag 优化几何形状和简正频率与相关的二氟代叠氮化物分子相似：R（CN）、R（NN）键和 NCN 角比环中 F2CN2 的长 0.012 和 0.006 A，小 0.8 度。NN 伸缩频率为 1470 和 1562 cm-1，CN 伸缩频率为 993 和 995 cm-1。C2N4 的 GVVPT2 结果与 F2CN2 的相似性表明，C2N4 可能足够稳定以进行合成。预测最低能量的自旋和电偶极允许垂直激发，到 1(1)B2u 态，发生在可见区（2.30 eV，538.9 nm）。
