Syntheses and NMR behavior of calix[4]quinone and calix[4]hydroquinone

Coordination chemistry of calix[4]arene derivatives with lower rim functionalisation and their applications

“…In particular, amongst the functionalised calixarenes, the calixquinones are of particular interest because of their potential use as redox systems. Earlier work by Morita et al [144,145] and Gutsche and co-workers [146,147] had shown that chemical oxidation of calixarenes that contained unsubstituted phenol rings at the lower rim resulted in the formation of calix [4]arene-mono-, di-, triand tetra-quinones, the actual product depending on the number of free phenolic rings in the calixarene. Louati and co-workers in 2000 published a paper reporting the first electrochemical oxidation of calixarene diamide 162 leading to diquinone 163 in a final yield of 50% after column chromatography of bulk electrolysis products [148] (Fig.…”

First synthesis of a ‘1,2-diquinone-calix[4]arene’. Interaction of its reduced form with Ag+

“…Some of these compounds were employed for the study of interesting redox systems and charge-transfer complexes as well [18,19]. Most calixquinones have been synthesised by chemical oxidation of calixarenes that comprise unsub-stituted phenol rings [20][21][22][23]. It is noteworthy that to date no calixarene with adjacent quinone units has been reported.…”

Synthesis and Conformation of New Azo‐functionalized Calix[4]arenes†

“…Azo coupling reaction of calix [4]arenes 4a-4c was attempted to proceed with p-nitrobenzene-diazonium tetrafluoroborate according to the method described by Morita and Shinkai et al 16,17 But the reaction was not successful because p-nitrobenzene-diazonium salt only reacted with phenol or aromatic amine. Pentafluoroaniline 18 or tetrafluoro-4-pyridyldiazonium ion 19 were also tried as diazonium salt to react with calix [4]arenes 4a-4c.…”