摘要
The structures and energies of the side-on complexes B2（N2）2 and monocyclic Bn（N2）nm （n = 3～6,m = -1～＋2） between N2 （1∑＋g） and B （2P） have been investigated by the DFT-B3LYP and MP2 methods at the 6-311＋G（2d） and aug-cc-pVTZ levels. The analyses of NICS （Nucleus Independent Chemical Shifts）,NBO （nature bond orbital）,AIM （atoms in molecules） and frontal orbitals have been used to reveal the origin of coordination bond between the π-electron donor N2 group and B atom,accompanied by the comparison with the end-on complexes. The results have indicated that the side-on coordination complexes can be formed due to the relative strong fluidity of the π-electrons,and the nature of the coordination bond has been exposed to be that the N2 group offers 1πu electron to the 2p orbital of boron. The coordinate energies of the side-on complexes are less than those of the end-on complexes. Furthermore,the aromaticity of side-on coordination complex is weaker than that of the corresponding end-on coordination complex.
The structures and energies of the side-on complexes B2（N2）2 and monocyclic Bn（N2）nm （n = 3～6,m = -1～＋2） between N2 （1∑＋g） and B （2P） have been investigated by the DFT-B3LYP and MP2 methods at the 6-311＋G（2d） and aug-cc-pVTZ levels. The analyses of NICS （Nucleus Independent Chemical Shifts）,NBO （nature bond orbital）,AIM （atoms in molecules） and frontal orbitals have been used to reveal the origin of coordination bond between the π-electron donor N2 group and B atom,accompanied by the comparison with the end-on complexes. The results have indicated that the side-on coordination complexes can be formed due to the relative strong fluidity of the π-electrons,and the nature of the coordination bond has been exposed to be that the N2 group offers 1πu electron to the 2p orbital of boron. The coordinate energies of the side-on complexes are less than those of the end-on complexes. Furthermore,the aromaticity of side-on coordination complex is weaker than that of the corresponding end-on coordination complex.
