Quinone oligomerization, an x-ray study

On the structure of macromolecules obtained by oxidative polymerization of polyhydroxyphenols and quinones

“…24 Among the side products formed simultaneously with SHA we should mention hydroxyphenol dimers10,23 in alkaline solutions, and benzofuran and dibenzofuranbased oligomers when polymerization reaction is conducted in the presence of protic acids. 10,17 Notwithstanding this relative abundance of work on NHAs and SHAs, some confusion remains in the literature concerning the way in which each monomeric unit of hydroxylated phenol is connected with the others. As shown in Scheme 1, two possible isomeric polymers can be expected from BQ or HQ polymerization, one having a poly(ortho-phenylene) backbone and the other one having the poly(para-phenylene) main chain.…”

DFT and QTAIM study of the tetra-tert-butyltetraoxa[8]circulene regioisomers structure

“…The symmetric tetraoxa [8]circulenes [1][2][3][4][5][6][7] attract the research interest as a promising electroluminescent material for organic light-emitting diodes (OLEDs) [8][9][10][11]. The first reliable structure description of the simplest symmetric tetraoxa [8]circulene (Fig.…”

Organic Light‐Emitting Diodes from Symmetrical and Unsymmetrical π‐Extended Tetraoxa[8]circulenes

“…[7] The structure of the tetraoxa[8]-circulene framework was deduced by means of mass spectrometry of the all-naphthalene tetraoxa [8]circulene (4 N) by Erdtman and Hçgberg, and was later confirmed by single-crystal X-ray crystallography. [8][9][10][11] It became clear that when one side of the 1,4-benzoquinone was substituted, either by using 1,4-naphthoquinone or a 2,3-disubstituted-1,4-benzoquinone, the tetraoxa [8]circulene was a major product upon acid treatment. More recently a series of liquid-crystalline tetraoxa [8]circulenes were synthesised by attachment of linear alkyl chains to the tetraoxa [8]circulene framework.…”