Cycloparaphenylenes and Carbon Nanorings

Shigeru Yamago, Bichi Kayahara, and Sigma Hashimoto 

Polycyclic Arenes and Heteroarenes Synthesis, Properties, and Applications, First Edition. Edited by Qian Miao. 2016 Wiley-VCH Verlag GmbH Co. KGaA. Published 2016 by Wiley-VCH Verlag GmbH Co. KGaA. 

The first synthetic study regarding [2]CPP was reported in 1935 [13]. However, it took nearly 40 years to realize the synthesis of a [2] CPP derivative, namely 9,9, 10,10 -tetradehydrodianthracene (1), from 9,10 -dibromodianthracene (2) 

An obvious drawback in the synthesis of CPPs and related tubular compounds is the strain energy, which relates to the bending of linear Jt-conjugated molecules into rings. In addition, the effects of bending on the physical properties of CPPs, compared to the linear compounds, are interesting. Therefore, the strain and electronic properties of [ ]CPPs ( = 4-20) will be briefly discussed based on density functional theory (DPT) calculations. 

Orbital energies (HOMO-1, HOMO, LUMO, and LUMO+1 energies) of [n]CPPs (n = 4-20). Data taken from Ref. [28]. 

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Matsui K, Segawa Y, Kami K (2012) Synthesis and properties of cycloparaphenylene-2,5-pyridylidene a nitrogen-containing carbon nanoring. Org Lett 14(7) 1888-1891... 

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