Stereoselective synthesis, optical characterization, DFT, and metal ion detection of tetra p-tert-butylthiacalix[4]arene derivatives containing amide and thiamide fragments at lower rim

P-tolylacetamide and p-tolylthioacetamide fragments are present in new p-tert-butylthiacalix[4]arenes at lower rims. P-tert-butylthiacalix[4]arene1reacted with 2-chloro (p-tolyl)acetamide to produce acetamide derivatives of thiacalixarene2–3, which are then thionated with Lawesson's reagent to produce thiacetamidethiacalixarenes derivatives 4–5. FT-IR, NMR, metal ion detection, and the optical absorption spectrum characteristics of the novel thiacalixarenes derivative have all been used to analyze their structures. Density Functional Theory calculations revealed critical insights into the electronic, structural, and reactive properties of thiacalixarene derivatives (2–5). Compound 2 exhibited the highest nucleophilicity, lowest energy gap, and greatest reactivity towards metal uptake, underscoring its suitability for coordination chemistry. Computational analyses using the B3lyp/6-311++G** method matched well with experimental data, confirming the theoretical models. The IR spectra showed good agreement between experimental and theoretical results. Molecule electrostatic potential mapping highlighted possible sites for electrophilic interactions and stable metal-ligand bonding.