Ethanol

All chemicals and regents used for this study were analytical grade and used without further purification. 1,10-phenanthroline monohydrate (BDH chemical Ltd., Poole, England), copper (II) acetate monohydrate [Cu(CO₂CH₃)₂·H₂O], triethylamine, NaHCO₃, NaOH, and Mueller-Hinton agar were purchased from Loba Chemie PVT Ltd., Addis Ababa. Metformin hydrogen chloride (Met.HCl) and ciprofloxacin hydrogen chloride (Cip.HCl) were obtained from Cadila Pharmaceuticals PLC, Ethiopia. Methanol, ethanol, HCl, DMSO, ethyl acetate and dichloromethane (DCM) were purchased from Alpha Chemika, Addis Ababa, Ethiopia. Thin Layer Chromatography (MERCK Silica gel 60 F254) together with UV Cabinet (UV-Vis lamp at 254 and 365 nm) were used to monitor the progress of the chemical reactions. The melting points of the complexes were determined using capillary tubes (Thiele tube). UV-Vis spectrophotometer (SM-1600 Spectrophotometer), FTIR (Perkin-Elmer BX spectrometer, Shimadzu Corporation, Japan), TGA/DTC (DTG-60H SHIMADZU thermal analyzer) and High resolution mass spectra (Waters-LCT-Premier mass spectrometer) were used to characterize the synthesized metal complexes.

Materials used and their commercial sources are as follows: Anhydrous Ferric chloride FeCl₃; 96% (ADVENT Chem Bio), Zinc chloride ZnCl₂; 98% (ADVENT Chem Bio), Sodium hydroxide (Alpha Chemika), p-Nitrophenyl Palmitate (PNPP); (Thermo Fisher Scientific), Aspergillus niger lipase (LOBA Chemie, India), Tris buffer superior extra pure 99.9% (Srichem), p-Nitro phenol (MERCK), Isopropyl alcohol 99% (Alpha Chemika), 1,1-diphenyl-2-picryl hydrazyl (DPPH) (Sigma Aldrich), Hydrochloric acid (Alpha Chemika), Methylene Blue dye (Alpha Chemika), Crystal violet (Alpha Chemika), Sodium Chloride (Alpha Chemika), Ethanol 99% (Alpha Chemika) and Gentamycin (GEN) Antibiotic disc (Oxoid). All the chemicals utilized were of reagent grade and employed without undergoing additional purification. All experiments were conducted using Ultrapure Milli-Q water.