title: Structure and spectroscopic characterization of tetrathia- and tetraselena[8]circulenes as a new class of polyaromatic heterocycles.
abstract: The FTIR, Raman and UV-vis spectra of the recently synthesized tetrathia[8]circulene and tetraselena[8]circulene compounds have been measured and interpreted in details by the density functional theory (DFT) calculations taking into account the molecular symmetry constrains. The structural and electronic features of the studied compounds have also been discussed in connection with the observed spectroscopic characteristics. Particularly, we have found that despite a slightly non-planar conformation the neutral tetrathia[8]circulene and tetraselena[8]circulene molecules demonstrate bifacial aromatic/antiaromatic nature. The inner octatetraene core is characterized by the presence of paratropic ("antiaromatic") ring currents, whereas the outer macrocycle constructed of benzene, thiophene or selenophene rings possesses the strong magnetically-induced diatropic ("aromatic") ring current. This fact suggests the general electronic and magnetic similarity of the tetrathia- and tetraselena[8]circulenes with the strictly planar isoelectronic tetraoxa[8]circulene and related azaoxa-derivatives discussed earlier. However, the vibrational and UV-vis absorption spectra of the studied circulenes are rather different from those of the parent tetraoxa[8]circulene which indicates a clear manifestation of the symmetry selection rules.
authors.affiliation: Department of Organic Chemistry, Bogdan Khmelnitsky National University, blvd. Shevchenko 81, 18031 Cherkasy, Ukraine.
authors.forename: Valentina A
authors.initials: VA
authors.lastname: Minaeva
authors.affiliation: Department of Organic Chemistry, Bogdan Khmelnitsky National University, blvd. Shevchenko 81, 18031 Cherkasy, Ukraine. Electronic address: glebchem@rambler.ru.
authors.forename: Gleb V
authors.initials: GV
authors.lastname: Baryshnikov
authors.affiliation: Department of Organic Chemistry, Bogdan Khmelnitsky National University, blvd. Shevchenko 81, 18031 Cherkasy, Ukraine; Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, 100190 Beijing, China.
authors.forename: Boris F
authors.initials: BF
authors.lastname: Minaev
authors.affiliation: Department of Organic Chemistry, Bogdan Khmelnitsky National University, blvd. Shevchenko 81, 18031 Cherkasy, Ukraine.
authors.forename: Nataliya N
authors.initials: NN
authors.lastname: Karaush
authors.affiliation: Department of Chemistry, State Key Laboratory of Synthetic Chemistry, Center of Novel Functional Molecules, and Institute of Molecular Functional Materials, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Xiong
authors.affiliation: Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region.
authors.forename: Ming-De
authors.initials: MD
authors.lastname: Li
authors.affiliation: Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region.
authors.forename: David Lee
authors.initials: DL
authors.lastname: Phillips
authors.affiliation: Department of Chemistry, State Key Laboratory of Synthetic Chemistry, Center of Novel Functional Molecules, and Institute of Molecular Functional Materials, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region; Shenzhen Municipal Key Laboratory of Chemical Synthesis of Medicinal Organic Molecules & Shenzhen Center of Novel Functional Molecules, Shenzhen Research Institute, The Chinese University of Hong Kong, No. 10, Second Yuexing Road, Shenzhen 518507, China.
authors.forename: Henry N C
authors.initials: HN
authors.lastname: Wong
keywords: Circulene; DFT calculations; Electronic transition; FT-IR spectra; Raman spectra; UV–vis spectra