These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
Manuscript_ChemRxiv.pdf (1.55 MB)

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

submitted on 06.03.2018 and posted on 06.03.2018 by Nagaraj Nayak, Shiva Prasad Kollur, Renjith Raveendran Pillai, Stevan Armaković, Sanja J. Armaković
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).


Manipal Academy of Higher Education and Ministry of Education, Science and Technological Development of Serbia (OI 171039 and TR 34019)


Email Address of Submitting Author


Manipal Academy of Higher Education



ORCID For Submitting Author


Declaration of Conflict of Interest

No conflict of interest.