Dehydro[12]- and -[18]Annulenes Fused with Tetrafluorobenzene:  Synthesis, Electronic Properties, Packing Structures, and Reactivity in the Solid State

• Published in: Journal of organic chemistry Vol. 67; no. 17; pp. 6091 - 6096
• Main Authors: Nishinaga, Tohru, Nodera, Nobutake, Miyata, Yasuo, Komatsu, Koichi
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 23.08.2002; Amer Chemical Soc
• Subjects: Alicyclic compounds; Alicyclic compounds, terpenoids, prostaglandins, steroids; Chemistry; Chemistry, Organic; Exact sciences and technology; Organic chemistry; Physical Sciences; Preparations and properties; Science & Technology; DEHYDROBENZOANNULENES; PERFLUOROPHENYL STACKING INTERACTIONS; CARBON; CRYSTAL-STRUCTURE; 2+2 CYCLOREVERSION; HIGHER OXIDES; GENERATION; POLYMERIZATION; ORGANOMETALLIC DEHYDROANNULENES; PRECURSORS; Differential scanning calorimetry; Electronic properties; Acetylenic compound; Theoretical study; Polymerization; Transition metal; Tetracyclic compound; Tricyclic compound; X ray diffraction; Chemical coupling; Macrocycle; Cyclic voltammetry; Solid state; Reactivity; Annulene; Density functional method; Benzenic compound; Oxidation; Fluorine Organic compounds; Conjugated compound; Copper; Chemical synthesis; Ultraviolet visible spectrometry; Crystalline structure
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo025786t

Dehydro[12]- and -[18]annulenes 3 and 4 fused with tetrafluorobenzene were newly synthesized by the copper-mediated oxidative coupling of 1,2-diethynyltetrafluorobenzene. The UV−vis spectra of 3 and 4 showed the maximum absorption to be almost identical to that of the corresponding unsubstituted benzodehydro[12]- and -[18]annulenes 1 and 2, respectively, while the reduction waves in cyclic voltammetry observed at potentials of −1.48 and −1.56 V vs Fc/Fc+ for 3 and 4 were less negative than those for 1 and 2. In agreement with these results, theoretical calculations (B3LYP/6-31G(d)) indicated that the HOMO−LUMO gap is similar for 1 and 3 and for 2 and 4 but that the LUMO levels of 3 and 4 are apparently lowered by the electronegative fluorine substituents. The X-ray crystallography of single crystals grown from 3 (crystal A), 3·C6H6 (crystal B), and a mixture of 1 and 3 (crystal C) demonstrated that the molecules of 3 are stacked in a slanted manner in crystals A and B, while those of 1 and 3 form sandwichlike 1:2 complexes (3·1·3) that are stacked in a columnar arrangement in crystal C. Despite the suitable packing for topochemical polymerization, crystals A−C were quite stable against photochemical reaction. In contrast, differential scanning calorimetry showed that the thermal polymerization occurred explosively at 120−135 °C.