Cupric chloride dihydrate

Cupric chloride dihydrate (CuCl₂·2H₂O, 99%, Sigma Aldrich), sodium sulphide (Na₂S, 70%, Merck), polyethylene glycol-400 (PEG-400, Merck), nitromethane (CH₃NO₂, 98%, TCI), nitroethane (C₂H₅NO₂, 98%, Spectrochem), sodium azide (NaN₃, 99%, Spectrochem). EDTA (disodium salt dihydrate, 99.5%), NH₄OH solution, methylene blue (MB), and potassium dichromate (K₂Cr₂O₇, 99.9%) were purchased from Rankem, benzyl alcohol (99%) and all the related substrates were purchased from TCI. All aldehydes were purchased from Spectrochem with 98% purity. All chemicals were used as received without further purification. The products were isolated by column chromatography (60–200 mesh) over silica gel. Thin-layer chromatography was performed using silica gel 60F₂₅₄ plates and visualized under UV light.

Chitosan (degree of deacetylation ≥ 75%, viscosity 20–300 cps), anhydrous calcium chloride granules (7.0 mm, 93.0%), ferric chloride hexahydrate (ACS reagent, 97%), montmorillonite, cupric chloride dihydrate (ACS reagent, ≥ 99.0%) were purchased from Sigma-Aldrich, Mumbai, India. Sodium alginate (pure) from Sisco laboratories, Chennai and carboxymethyl cellulose from Molychem, Mumbai, were obtained. Norfloxacin (C₁₆H₁₈FN₃O₃, Analytical standard, ≥98%) purchased from Merck, Mumbai. Distilled deionized water (Millipore system) was used in all experiments, and all other chemicals were directly utilized with no additional purification.