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Effect of the Complexant Shape on the Large First Hyperpolarizability of Alkalides Li + (NH 3 ) 4 M −
Author(s) -
Jing YingQi,
Li ZhiRu,
Wu Di,
Li Ying,
Wang BingQiang,
Gu Feng Long,
Aoki Yuriko
Publication year - 2006
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600157
Subject(s) - alkali metal , hyperpolarizability , chemistry , natural bond orbital , inorganic chemistry , ion , electrochemistry , crystallography , analytical chemistry (journal) , molecule , computational chemistry , density functional theory , organic chemistry , electrode , polarizability
The effect of complexant shape effect on the first hyperpolarizability β 0 of alkalides Li + (NH 3 ) 4 M − (M=Li, Na, K) was explored. At the MP2/6‐311++G level, Li + (NH 3 ) 4 M − (M=Li, Na, K) have considerable β 0 values due to excess electrons from chemical doping and charge transfer. By comparison with the alkalides Li + (calix[4]pyrrole)M − , a complexant shape effect in Li + (NH 3 ) 4 M − is detected. The β 0 values of Li + (NH 3 ) 4 M − with the “smaller”, inorganic, T d ‐symmetric (NH 3 ) 4 complexant are more than four times larger than those of Li + (calix[4]pyrrole)M − with the “larger”, organic C 4 v ‐symmetric calix[4]pyrrole complexant. The ratios of the β 0 values of Li + (NH 3 ) 4 M − and Li + (calix[4]pyrrole)M − are 6.57 (M=Li ), 6.55 (M=Na), and 5.17 (M=K). In the Li + (NH 3 ) 4 M − systems, the NBO charge and oscillator strength are found to monotonically depend on the atomic number of the alkali metal anion. The order of the NBO charges of the alkali anions M − is −0.667 (M=Li )>−0.644 (M=Na)>−0.514 (M=K), while the order of the oscillator strengths in the crucial transition is 0.351 (M=Li )<0.360 (M=Na)<0.467 (M=K). This indicates that complexant shape effects are strong, and consequently the β 0 values of Li + (NH 3 ) 4 M − are found to be β 0 =70 295 (M=Li )<96 780 (M=Na)<185 805 a.u. (M=K). This work reveals that the use of a high‐symmetry complexant is an important factor that should be taken into account when enhancing the first hyperpolarizability of alkalides by chemical doping.