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Royal crown‐shaped electride Li 3 ‐N 3 ‐Be containing two superatoms: New knowledge on aromaticity
Author(s) -
Li ZhiRu,
Wang FangFang,
Wu Di,
Li Ying,
Chen Wei,
Sun XiaoYing,
Gu Feng Long,
Aoki Yuriko
Publication year - 2006
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.20408
Subject(s) - aromaticity , chemistry , nonmetal , ring (chemistry) , crystallography , molecule , metal , valence electron , electron , valence (chemistry) , computational chemistry , physics , organic chemistry , quantum mechanics
The structure and aromaticity of a royal crown‐shaped molecule Li 3 ‐N 3 ‐Be are studied at the CCSD(T)/aug‐cc‐pVDZ level. This molecule is a charge‐separated system and can be denoted as Li 3 2+ N 3 3− Be + . It is found that the Li 3 2+ ring exhibits aromaticity mainly because the Li 3 2+ ring can share the π‐electron with the N 3 −3 ring. The 4 n +2 electron counter rule can be satisfied for the Li 3 2+ subunit if the shared π valence electron of N 3 3− subunit is also taken into account. This new knowledge on aromaticity of a ring from the interactions between subunits is revealed first time in this paper. Li 3 ‐N 3 ‐Be can be also regarded as a molecule containing two superatoms (Li 3 and N 3 ), which may be named as a “superomolecule.” Li 3 ‐N 3 ‐Be is a new metal–nonmetal–metal type sandwich complex. The N 3 3− trianion in the middle repulses the electron clouds of the two metal subunits (mainly to the Li 3 superatom) to generate an excess electron, and thus Li 3 ‐N 3 ‐Be is also an electride. This phenomenon of the repulsion results in: (a) the HOMO energy level increased, (b) the electron cloud in HOMO distended, (c) the area of the negative NICS value extended, and (d) the VIE value lowered. So the superomolecule Li 3 ‐N 3 ‐Be is not only a new metal–nonmetal–metal type sandwich complex but also a new type electride, which comes from the interaction between the alkali superatom (Li 3 ) and the nonmetal superatom (N 3 ). © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 986–993, 2006