1,3,6,8-Tetraazapyrenes: Synthesis, Solid-State Structures, and Properties as Redox-Active Materials

摘要

A series of new tetraazapyrene (TAPy)nderivatives has been synthesized by reducing 1,4,5,8-tetranitronaphthalenento its corresponding tin salt (I) and reacting itnwith perfluorinated alkyl or aryl anhydrides. The resulting 2,7-ndisubstituted TAPy molecules and the known parentncompound 1,3,6,8-tetraazapyrene (II) have been furthernderivatized by core chlorination and bromination. Thenbrominated compounds served as starting materials for Suzukincross-coupling reactions with electron-poor arylboronic acids.nSingle-crystal X-ray analyses established polymorphism fornsome TAPy compounds. The ground-state geometries of allnnew TAPy derivatives were modeled with DFT methodsn[B3PW91/6-31 g(d,p) and B3PW91/6-311+g(d,p)], especially focusing on the energies of the lowest unoccupied molecularnorbital (LUMO) and the electron affinities (EA) of the molecules. The results of the calculations were confirmed experimentallynby cyclic voltammetry to evaluate the substitution effects at the 2 and 7 position and the core positions, respectively, and gavenLUMO energy levels that range from −3.57 to −4.14 eV. Fabrication of organic field-effect transistors (OFETs) with several ofnthese tetraazapyrenes established their potential as organic n-type semiconductors.