Conical conformationed tetra-alkyl substituted p-tert-butylcalix[4]arene derivatives: thermal, spectral, and physical properties

Abstract

Tetra-Alkyl Substituted p-tert-butylcalix[4] arene derivatives were synthesized with the reaction of p-tert-butylcalix[4] arene and alkylbromide derivatives (1-bromobutane, 1-bromopentane, 1-bromohexane, and 1-bromodecane) in strong basic medium. The obtained compounds were characterized using ¹H NMR, ¹³C{H} NMR, FT-IR, elemental analysis, TG/DTA/DTG, DSC, XRD, and UV-Vis. techniques. Thermal and spectral properties were also investigated and evaluated. Compared to the literature, all the hydroxyl groups of p-tert-butylcalix[4] arene were reacted to the related alkylbromide derivatives and originally synthesized the conical type tetra-substituted p-tert-butylcalix[4] arene compounds. It is important to emphasize that the evidence of tetra-substitution of calix[4] arene according to the synthesis method is very important in the literature. It was noted that well crystallization in polycrystalline form was diminished upon introducing attachments of alkyl groups. On the other hand, compared to the determined optical bandgap value of 4.36 eV of p-tert-butylcalix[4] arene, 1 eV decreasing of this value by attached four decyl groups on the calixarene backbone is critically important. These materials were evaluated as wide bandgap semiconductors with bandgap values ​​determined on the basis of optical absorption. Such a significant reduction in the band gap could make tetra-alkyl substituted p-tert-butylcalix[4] arene derivatives suitable for optical and electronic applications, offering enhanced physical properties by tuning the band gap.