Theoretical investigation of aromaticity and charge transfer in emission process of triarylmethyl radicals as OLED materials. Issue 6 (28th October 2020)

• Record Type: Journal Article
• Authors: Sang, Shenglong; Chen, Fei; Zhang, Cong
• Is Part Of: International journal of quantum chemistry. Volume 121:Issue 6(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-28
• Subjects: charge transfer -- local excitation -- nucleus independent chemical shift -- spin density -- triarylmethyl radicals; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.26522
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: Four different kinds of triarylmethyl radicals (TAMs)— tris(2, 4, 6‐trichlorophenyl)methyl radical (TTM), perchlorotriphenyl methyl radical (PTM), (3, 5‐dichloro‐4‐pyridyl)bis(2, 4, 6‐trichlorophenyl)methyl radical (PyBTM), and (N‐carbazolyl)bis(2, 4, 6‐tirchlorophenyl)methyl radical (CzBTM)—are investigated theoretically with regard to their structures and electron transition behaviors. Linear correlation has been found between the spin density of α‐C and the averaged cosine of the torsion angle, with the correlation coefficient satisfied by R 2 = .96 by applying the Becke method. The emission energies predicted by PCM‐UBMK/6‐311++G(d, p)//PCM‐UM06‐2X/6‐31+G(d, p) are reliable for TAMs. Interfragment charge transfer (IFCT) analysis reveals the charge transfer behavior during the excitation. The aromaticity of TAMs is evaluated by NICS(1)zz for the first time. Combined with the IFCT analysis results, the NICS(1)zz values of the acceptor on the ground states are found to be highly correlated with the emission wavelength, and R 2 is .98 at the PCM‐UB3LYP/6‐31+G(d, p) level, which can be used for emission spectra prediction and molecular design. Abstract : The detail of charge transfer during the excitation has been explored for the highly stable Triarylmethyl radicals (TAMs). Aromatic index NICS(1)zz of acceptor in TAMs is highly correlated with emission energy and the linear correlation can be used for TAMs molecular design.