Novel Electron Acceptors Bearing a Heteroquinonoid System. I. Synthesis and Conductive Complexes of 5,5′-Bis(dicyanomethylene)-5,5′-dihydro-Δ2,2′-bithiophene and Related Compounds

Abstract

Novel electron acceptors bearing a heteroquinonoid system, 5,5′-bis(dicyanomethylene)-5,5′-dihydro-Δ2,2′-bithiophene, its 3,3′-dichloro, 3,3′-dibromo, and 3,3′,4,4′-tetrabromo derivatives, and 5,5″-bis(dicyanomethylene)5,5″-dihydro-Δ2,2′:5′,2″-terthiophene were synthesized by the action of tetracyanoethylene oxide or by Pd(0)-catalyzed substitution reactions with sodium dicyanomethanide on the corresponding α,α′-dihalogenoheteroaromatics. They showed very small on-site Coulomb repulsion as expected, and afforded several highly conductive molecular complexes with electron donors such as hexamethylenetetratellurafulvalene.

Spider‐Like Oligothiophenes

“…T14 6 was analogously synthesized starting from hexabromo-2,2'-bithiophene (65 % yield). [11] Much more laborious was the preparation of T19 7 . We found it very difficult to attain the substitution of all the bromine atoms of octabromo-a-terthiophene [12] with bithienyl units.…”

Dielectric tensor and optical spectra of quaterthiophene crystals

“…4T was synthesized and purified according to one of the standard procedures [11,20]. Single crystals of the low-temperature polymorph of 4T were grown from solution at room temperature as thin flakes, few mm 2 in size with thickness ranging from few hundreds of nm to few mm [21].…”

Synthesis and polymerization of 2,5-dimethylene-2,5-dihydrothieno[3,2-b]thiophene derivatives: The structure and reactivity of quinonoid monomers

“…4a was synthesized in a 42% yield as red-brown needles from 2,5-dibromothieno[3,2-b]thiophene (5) 19 and tetracyanoethylene oxide (TCNEO) 20 according to the method reported by Yui et al 18 and purified by a silica gel column treatment using dichloromethane as an eluent, followed by recrystallization from acetonitrile: mp Ͼ 300°C. IR (KBr): COH After stirring for 30 min at room temperature, 30 mL of THF was added and then cooled to 0°C.…”

“…The NMR tubes were set in a bath thermostated at 60°C, and the NMR spectra were measured at room temperature in each reaction time. The amounts of 1c, 2c, and 4c consumed in each reaction time were calculated on the basis of the change in the ratio of proton peak area at 2-, 3-, 5-, and 6-positions (a singlet peak at ␦ 7.18 ppm) for 1c, at 3-and 4-positions (a singlet peak at ␦ 7.23 ppm) for 2c, and at 3-and 6-positions (a singlet peak at ␦ 6.90 ppm) for 4c, to proton peak area of chloroform (␦ 19 4a was prepared in a 42% yield as red-brown needles by the reaction of 5 with TCNEO according to the method reported by Yui et al 18 However, characterization of 4a was limited to IR and UV-Vis spectroscopy and elemental analysis because of its extreme insolubility. 4a is insoluble in chloroform, acetone, dimethyl sulfoxide, ethyl acetate, hexane, methanol, and benzene, and slightly soluble in dichloromethane, acetonitrile, and 1,2-dichloroethane.…”

“…Preparation and polymerization of TT have not been reported yet. 2,5-Dis(dicyanomethylene)-2,5-dihydrothieno [3,2-b]thiophene (4a) 18 was prepared as one of the TT derivatives isolable at room temperature. Synthesis and polymerization behavior of these TT derivatives are of interest for comparison with NQ, QM, and DT derivatives, especially for understanding the relationship between structure and reactivity (polymerizability) for the family of quinonoid compounds.…”