Alkali Metals-Substituted Adamantanes Lead to Visible Light Absorption: Large First Hyperpolarizability

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• 作者：Heng-Qing Wu ; Rong-Lin Zhong ; Shi-Ling Sun ; Hong-Liang Xu ; Zhong-Min Su
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：April 3, 2014
• 年：2014
• 卷：118
• 期：13
• 页码：6952-6958
• 全文大小：295K
• 年卷期：v.118,no.13(April 3, 2014)
• ISSN：1932-7455

文摘

Adamantane (Ad) is the parent molecule of diamondoids, which has been the subject of much chemical interest because of its highly symmetric cage structure. Many valuable papers demonstrated that the H atom of the methine position in Ad is highly reactive. Compared with highly symmetric carbon structures such as graphene and single-walled carbon nanotubes (SWCNTs), Ad only possesses 蟽 bonds. In this work, we report a quantum chemical calculation on three complexes (Ad-Li, Ad-Na, and Ad-K), which were obtained by substituting the H atom of methine position in Ad with alkali metal (Li, Na, and K). Interestingly, the substitution by alkali metals leads to absorption within the visible region. The maximum absorption wavelengths of the complexes show a red shift trend from the Li to the K complex. This trend indicates that the crucial transition energy becomes smaller, which might lead to a larger nonlinear optical response. Among the three structures, the largest first static hyperpolarizability (尾_tot) of the K complex was 76626 au, which is about 45 times larger than a prototypical second-order nonlinear optical (NLO) molecule of p-nitroaniline (尾_tot = 1679 au). Therefore, our results show that alkali metal substituted Ads may be novel potential candidates for high-performance NLO materials.