Tsipis Athanassios C
Laboratory of Inorganic and General Chemistry, Department of Chemistry, University of Ioannina, 451 10 Ioannina, Greece.
Phys Chem Chem Phys. 2009 Oct 1;11(37):8244-61. doi: 10.1039/b903677f. Epub 2009 Jun 30.
In the present study it was demonstrated that the NICS(zz)-scan patterns along with symmetry-based selection rules can unequivocally probe the antiaromaticity in a wide range of antiaromatic organic and inorganic rings/cages. The NICS(zz)-scan profiles typical of antiaromaticity correspond to symmetric curves around the axis perpendicular to the ring plane with the positive NICS(zz)(R) values decaying rapidly and monotonically with respect to the distance R from the ring center. The magnitude of the induced paratropic ring currents is determined by the magnitude of the excitation energies of the rotationally (R(z)) allowed HOMO --> LUMO transitions. The appearance of the NICS(zz)-scan curves in conjunction with the symmetry-based selection rules constitute a powerful magnetic criterion of antiaromaticity capable of predicting the antiaromaticity in the realm of antiaromatic organic, inorganic and "all-metal" molecules lifting up all controversies with respect to the aromaticity/antiaromaticity for some peculiar aromatic/antiaromatic molecules.
在本研究中，已证明NICS(zz)-扫描模式以及基于对称性的选择规则能够明确探测广泛的反芳香族有机和无机环/笼中的反芳香性。典型的反芳香性NICS(zz)-扫描轮廓对应于垂直于环平面的轴周围的对称曲线，正的NICS(zz)(R)值相对于距环中心的距离R迅速且单调衰减。诱导的抗磁环电流的大小由旋转（R(z)）允许的HOMO→LUMO跃迁的激发能大小决定。NICS(zz)-扫描曲线与基于对称性的选择规则相结合，构成了一个强大的反芳香性磁判据，能够预测反芳香族有机、无机和“全金属”分子领域中的反芳香性，消除了一些特殊芳香/反芳香分子在芳香性/反芳香性方面的所有争议。
