Zn, Cd and Cu Coordination Polymers for Metronidazole Sensing and for Ullmann and Chan‐Lam Coupling Reactions

• Published in: Chemistry, an Asian journal an Asian journal, 2024-10, Vol.19 (19), p.e202400501-n/a
• Main Authors: Manna, Krishna, Boruah, Rishika, Natarajan, Srinivasan
• Format: Article
• Language: English
• Subjects: Aniline; Aqueous solutions; Aromatic compounds; Cadmium; chan-lam coupling; Chemical reactions; Coordination polymers; Ethane; Ethanol; heterogeneous catalysis; Hydrazines; Ligands; luminescence sensing; metal organic framework; metronidazole; Recyclability; Single crystals; Terephthalic acid; Transition metals; ullmann coupling reaction
• ISSN: 1861-4728; 1861-471X; 1861-471X
• DOI: 10.1002/asia.202400501

Five compounds, [Zn2(bpe)(BPTA)2(H2O)2] ⋅ 2H2O (1); [Zn(bpe)(BPTA)] (2); [Cd(bpe)(BPTA)H2O] (3); [Cd(BPTA) (bpmh)] ⋅ 2H2O (4); and Cu2(BPTA)2(bpmh)3(H2O)2] ⋅ 2H2O (5) were prepared employing 2,5‐bis(prop‐2‐yn‐1‐yloxy)terephthalic acid (2, 5 BPTA) as the primary ligand and 1,2‐di(pyridin‐4‐yl)ethane (4, 4′ bpe) (1–3) and 1,2‐bis(pyridin‐3‐ylmethylene)hydrazine (bpmh) (4–5) as the secondary ligands. Single crystal studies indicated that the compounds 1, 3 and 5 have two‐dimensional layer structures and compounds 2 and 4 three‐dimensional structures. The luminescence behaviour of the compounds 2 and 3 were explored for the sensing of metronidazole in aqueous medium. The studies indicated that the compounds can detect metronidazole in ppm level both in solution as well as simple paper strips. The Cu compound 5 was found to lose the coordinated water molecule at 100 °C without any structural change. The coordinatively unsaturated Cu‐centre were examined towards the Lewis acidic character by carrying out the Ullmann type C−C homocoupling reaction of the aromatic halide compounds. The compounds, 4 and 5, also have the Lewis basic functionality arising out the =N−N=, aza groups. The bifunctional nature of the coordination polymers (CP) was explored towards the Chan‐Lam coupling reaction between phenyl boronic acid and aniline derivatives in the ethanol medium. In both the catalytic reactions, good yields and recyclability were observed. The present studies illustrated the rich diversity that the transition metal containing compounds exhibit in extended framework structures. The synthesis, structure, single crystal to single crystal transformation of a series of Zn, Cd and Cu‐based metal–organic framework compounds is described. The Zn and Cd compound with 2,5‐BPTA as primary ligand and 1,2‐di(pyridin‐4‐yl)ethane (4,4′ bpe) as secondary ligand exhibited blue luminescence under UV light, which was exploited towards the sensing of metronidazole in aqueous medium. The coordinatively unsaturated Cu‐centres were utilized for the Lewis acidic Ullmann type C−C homocoupling reaction of the aromatic halide compounds.