Multi-Zinc-Expanded Oligoacenes: An Intriguing Class of Well-Defined Open-Shell Singlet Diradicals
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- 作者：Hongfang Yang ; Qisheng Song ; Wenchao Li ; Xinyu Song ; Yuxiang Bu
- 刊名：The Journal of Physical Chemistry C
- 出版年：2012
- 出版时间：March 8, 2012
- 年：2012
- 卷：116
- 期：9
- 页码：5900-5907
- 全文大小：377K
- 年卷期：v.116,no.9(March 8, 2012)
- ISSN：1932-7455
文摘
Two classes of multi-Zn-expanded oligoacenes from benzene to pentacene are computationally designed through introducing a Zn array into acene rings in two ways: acene-chain axial versus single-ring quasi-transversal direction. Combined density functional theory, CASSCF, and CCSD calculations predict that all these multi-Zn-expanded oligoacenes have the open-shell singlet diradical ground states, in contrast with the common fact that their parent oligoacenes are closed-shell systems or may have a triplet ground state and only acenes larger than octacene have open-shell singlet diradical ground states. These results offer the first theoretical prediction that the multi-Zn introduction into the acene ring(s), forming the Zn-expanded oligoacenes, can lead them to diradical structures. The diradical character of the ground states of these molecules arises from the Zn-participation-induced disjoint nature of the nonbonding molecular orbitals that are singly occupied in the diradicals. This work provides a strategy to design perfect and stable singlet diradicals from oligoacenes or their derivatives.