The synthesis of porous coordination materials with tunable composition, available active centers, and adequate crystallinity poses challenges since the structural and morphological features of metal-organic frameworks (MOFs) largely depend on metalligand complexes and synthesis conditions. In spite of the possibility of using calixarene ligands due to their macrocycles, numerous oxygen donor sites, and adjustable coordination sphere, the study of cobalt-calixarene MOFs is still understudied with regard to the combination of their spectroscopic, morphological, elemental, and crystallographic characterization. In this paper, the synthesis and characterization of a cobalt-calixarene MOF (Co–CAR–MOF) are described. The material was synthesized by using a functionalized 4-tert-butylcalixarene, cobalt(II) chloride, and benzene-1,3,5-tricarboxylic acid in dimethylformamide at 40 °C at 30 kHz for 60 min in an ultrasonic sonicator. For characterization, Fourier-transform infrared spectroscopy, scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, and powder X-ray diffraction were utilized. FTIR results have shown the existence of the calixarene-derived organic framework and the interaction of Co with oxygen atoms. SEM has shown that the material has irregular, rough, and agglomerated particles. Meanwhile, EDX has indicated that the framework consists of carbon, oxygen, and cobalt atoms. The existence of distinct PXRD reflections shows that there is an ordered, partly crystalline material, with an estimated crystallite size of 40.8 nm. It is apparent from the data that there has been a successful synthesis of a nanocrystalline cobalt-calixarene coordination material. This opens up a possibility for studying its porosity, stability, and possible applications in adsorption, catalysis, sensing, and environmental remediation.

Onyeka Wilson Akabuogu, Nikechukwu Nike Omosun, Innocent Ajah Okoro, Ifeanyi Edozie Otuokere,"Sonochemical Synthesis, FTIR, SEM–EDX, and XRD Characterization of a Calixarene-Based Cobalt Metal–Organic Framework" International Journal of Advanced Multidisciplinary Research and Educational Development, V2(4): Page(600-606) July - August 2026. ISSN: 3107-6513. www.ijamred.com. Published by Scientific and Academic Research Publishing.