Four new symmetrical Schiff bases derived from 2,2′-diamino-6,6′-dibromo-4,4′-dimethyl-1,1′-biphenyl or 2,2′-diamino-4,4′-dimethyl-1,1′-biphenyl, and 3,5-dichloro- or 5-nitro-salicylaldehyde, were synthesized and reacted with copper-, iron- and zinc-acetate, producing the corresponding complexes. The Schiff bases and their metal complexes were characterized by ¹H-, ¹³C-NMR, IR and UV-Vis spectroscopy and elemental analysis. The structures of one Schiff base and the two zinc complexes were resolved by X-ray structure determination. Density functional theory (DFT) calculations at the B3LYP/6-31G(d) level of the latter compounds were carried out to optimize and examine their molecular geometries. The biomedical applications of the Schiff bases and their complexes were investigated as anticancer or antimicrobial agents.

New photophysical and antioxidant materials of trimesic trihydrazide derivatives were synthesized by one-pot stage of trimesic trihydrazide and different aromatic aldehydes. All compounds were characterized by spectroscopic techniques (NMR, MS, and IR) and elemental analysis. The absorption and emission spectral characteristics of hydrazone derivatives were investigated. The absorption maxima showed red shift relative to the starting compound. While the emission maxima showed clear dependent on the type of substituents. The electron donating and electron withdrawing showed red and blue shifts relative to the starting compound, respectively. The compounds’ effectiveness as antioxidant was estimated by DPPH radical scavenging and ABTS radical cation assays in vitro which indicated that the derivatives could be used as potential antioxidants. In addition, compounds 3g, and 3i showed strong antioxidant activities according to the DPPH assay and compounds 3c and 3m exhibited good antioxidant activities in ABTS assay. Antimicrobial activity of the derivatives was estimated using a micro-broth dilution method. Furthermore, molecular geometries of all prepared derivatives were fully optimized using density functional theory (DFT) calculations at the 6-31G(d)/B3LYP level of theory.

A new open-chain ether-linked polymer has been prepared via nucleophilic aromatic substitution reaction on a C-F bond of 1,4-dibromo-2,5-difluorobenzene by using 2,2-bis(4-hydroxyphenyl) hexafluoropropane (bisphenol AF or BAF). The new polymer (PE-AF) has shown a good solubility in non-polar solvents, good thermal stability (up to 300 °C) and random surface morphology. Tailoring these properties has been achieved by utilizing the post-modification synthetic methodology on the bromo-sites of the polymer backbone via the application of an Ullmann coupling reaction with aniline to form the polymer (PE-Sec-NHPh). The successful synthesis of the polymers has been confirmed by elemental analysis, infrared spectroscopy (IR), ¹H- and ¹³C-NMR and ¹³C CP-MAS solid state. Upon incorporation of the aniline linker, the nitrogen content increased when compared with the parent polymer chain, and thus PE-Sec-NHPh revealed a higher thermal stability up to 350 °C and a more uniformly aggregated morphology (spherical particles ca. 0.3–0.1 µm). A further evaluation has been conducted on the polymers by measuring their surface tendency toward carbon dioxide capture. Interestingly, despite their non-porous nature, the polymers demonstrated a reasonable amount of gas capture that reached 90.0 and 41.0 mg/g for PE-Sec-NHPh and PE-AF, respectively. Furthermore, the calculated CO₂ binding affinities of the polymers are consistent with data reported previously in the literature.

This study reports on the synthesis and characterization of novel perfluorinated organic polymers with azo- and azomethine-based linkers using nucleophilic aromatic substitution. The polymers were synthesized via the incorporation of decafluorobiphenyl and hexafluorobenzene linkers with diphenols in the basic medium. The variation in the linkers allowed the synthesis of polymers with different fluorine and nitrogen contents. The rich fluorine polymers were slightly soluble in THF and have shown molecular weights ranging from 4886 to 11,948 g/mol. All polymers exhibit thermal stability in the range of 350–500 °C, which can be attributed to their structural geometry, elemental contents, branching, and cross-linking. For instance, the cross-linked polymers with high nitrogen content, DAB-Z-1h and DAB-Z-1O, are more stable than azomethine-based polymers. The cross-linking was characterized by porosity measurements. The azo-based polymer exhibited the highest surface area of 770 m²/g with a pore volume of 0.35 cm³/g, while the open-chain azomethine-based polymer revealed the lowest surface area of 285 m²/g with a pore volume of 0.0872 cm³/g. Porous structures with varied hydrophobicities were investigated as adsorbents for separating water-benzene and water-phenol mixtures and selectively binding methane/carbon dioxide gases from the air. The most hydrophobic polymers containing the decafluorbiphenyl linker were suitable for benzene separation, while the best methane uptake values were 6.14 and 3.46 mg/g for DAB-Z-1O and DAB-A-1O, respectively. On the other hand, DAB-Z-1h, with the highest surface area and being rich in nitrogen sites, has recorded the highest CO₂ uptake at 298 K (17.25 mg/g).

The Schiff base ligand 3,5-diiodosalicylideneamino-4,4′-dimethyl-1,1′-biphenyl was synthesized and reacted with manganese, cobalt, iron and copper acetate producing the corresponding complexes, which were characterized by IR, UV-Vis spectroscopy and elemental analysis. The structure of copper complex Cu(II)L was resolved by single crystal X-ray diffraction. The biological efficacy of the Schiff base and the corresponding complexes were examined in their capacity as antimicrobial agents. Density functional theory calculations were carried out to optimize and examine the molecular geometry of Cu(II)L complex.