Rylene Ribbons with Unusual Diradical Character Wangdong Zeng, Hoa Phan, Tun Seng Herng, Tullimilli Y. Gopalakrishna, Naoki Aratani, Zebing Zeng, Hiroko Yamada, Jun Ding, Jishan Wu  Chem  Volume 2, Issue 1, Pages 81-92 (January 2017) DOI: 10.1016/j.chempr.2016.12.001 Copyright © 2017 Elsevier Inc. Terms and Conditions

Chem 2017 2, 81-92DOI: (10.1016/j.chempr.2016.12.001) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 1 Structures of Armchair Graphene Nanoribbons and Their Model Compounds (A) The network skeleton of an AGNR, where N is the width of the ribbon. (B) Resonance structures of teranthene and quarteranthene, the model compounds for N-AGNR with N = 7. (C) Resonance structures of new rylene molecules reported in this work, the model compounds for 5-AGNR. Chem 2017 2, 81-92DOI: (10.1016/j.chempr.2016.12.001) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 2 Optical and Electrochemical Properties of the Rylene Molecules (A) UV-vis-NIR absorption spectra in DCM. (B) Plots of HOMO, LUMO, EgOpt, and EgEC versus the reciprocal of the number naphthalene units (1/n). Chem 2017 2, 81-92DOI: (10.1016/j.chempr.2016.12.001) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 3 Magnetic Properties of CP-HR (A) Variable-temperature 1H-NMR spectra of CP-HR in d8-tetrahydrofuran (183–328 K). (B) Chemical structure and labeling of CP-HR. (C) EPR spectrum of CP-HR recorded at room temperature in powder form. (D) χM T-T curves in the SQUID measurements for the powder of CP-HR. The solid line is the fitting curve according to the Bleaney-Bowers equation; the g factor was taken to be 2.0. Chem 2017 2, 81-92DOI: (10.1016/j.chempr.2016.12.001) Copyright © 2017 Elsevier Inc. Terms and Conditions

Figure 4 Geometric and Electronic Structures of the Rylene Molecules (A) The optimized structures of CP-Per to CP-DoR. θ is the bending angle. (B) Spin-density distribution of CP-HR, CP-OR, CP-DeR, and CP-DoR in the open-shell singlet diradical ground state. The branched alkyl chains were replaced by methyl groups during the calculations. The hydrogen atoms are omitted for clarity. Chem 2017 2, 81-92DOI: (10.1016/j.chempr.2016.12.001) Copyright © 2017 Elsevier Inc. Terms and Conditions

Scheme 1 Synthetic Route of the Rylene Molecules Reagents and conditions: (a) 1.0 equiv NBS, 0°C, 20 min; (b) NBS (2.1 equiv for 2b and 1.1 equiv for 4 and 8), room temperature, 20–30 min; (c) Pd(PPh3)4, 2-(3,5-di-tert-butylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, Na2CO3 (2M), toluene, 80°C, overnight; (d) PdCl2(dppf), pinacolborane, 1,2-dichloroethane, Et3N, 2 hr, 80°C; (e) NIS, TFA, DCM; (f) Pd2(dba)3, Sphos, Na2CO3 (2 M), toluene/EtOH = 20:1, 110°C, 36 hr; (g) DDQ, Sc(OTf)3, toluene, reflux. Chem 2017 2, 81-92DOI: (10.1016/j.chempr.2016.12.001) Copyright © 2017 Elsevier Inc. Terms and Conditions