The reaction of InCl3 with 2-formyl-8-hydroxyquinoline-4-nitroimidazole hydrazone (H2L1) in ethanol gave [In(H2L1)(HL1)Cl2], complex (1), as the product. Experimental data and theoretical DFT calculations suggested that complex (1) presents coordination number (CN) 8, with one neutral and one anionic ligand coordinated to the metal center through the ONpy-N tridentate chelating system together with two chloride ions. The reaction with 2-formyl-8-hydroxyquinoline-4-nitrobenzene hydrazone (H2L2) in methanol gave [In(HL2)Cl2(CH3OH)], complex (2), as the product while [In(HL2)Cl2]·CH3CH2OH, complex (3), was formed as the product using ethanol as solvent. Experimental data indicated that in complexes [In(HL2)Cl2(CH3OH)] (2) and [In(HL2)Cl2]·CH3CH2OH (3) one anionic ligand is attached to the indium(III) center through the ONpy-N-O tetradentate chelating system along with two chlorides. The crystal structure of the complex [In(HL2)Cl2(CH3OH)] (2) revealed that the indium(III) center presents CN 7. Calculated bond lengths in complex (2) were in accordance with the experimental values. The experimental and calculated electronic spectra of complexes (1) and (2) presented the same pattern and allowed the attribution of the absorption peaks to π - π* transitions.
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