Remarkable Sensing Behavior of Pyrazole-based Chemosensor Towards Cu(II) Ion Detection: Synthesis, Characterization and Theoretical Investigations

06 March 2018, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


We report the synthesis of a new imine based ligand, 3-((3-methoxybenzylidene)amino)-1H-pyrazol-5-ol (HL) and its Cu(II) complexes in 2:1 (HL:metal) and 1:1:1 (HL:metal:HQ) stoichiometric ratio using 8-hyroxyquinoline (HQ) as an additional bidentate ligand. The synthesized ligand (HL) and its Cu(II) complexes (1 and 2) are structurally characterized using FT-IR, electronic absorption and emission, NMR, MS and TGA techniques. Furthermore, the complexation of Cu2+ with HL leads to the immediate formation of brown colored solution which indicates that HL can act as simple colorimetric sensor for Cu2+ ions. We further investigated that the sensor could selectively bind to the Cu2+ ions even in the presence of competitive ions such as Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Ag+ and Na+ ions in aqueous solutions which was studied by electronic absorption spectroscopy. The HL ligand and corresponding Cu(II) complexes have been investigated for their reactive properties by density functional theory (DFT) calculations. Quantum molecular descriptors describing local reactive properties have been calculated in order to identify the most reactive molecule sites of title compounds. DFT calculations encompassed molecular electrostatic potential (MEP), local average ionization energies (ALIE), Fukui functions and bond dissociation energies for hydrogen abstraction (H-BDE).


Cu(II) complex
Fukui functions


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.