Abstract
Four new compounds using 5-amino-3-methyl-1-phenylpyrazole were neatly prepared. A 2-((3-methyl-1-phenyl-1H-pyrazol-5-yl)diazenyl)benzene-1,3,5-triol (A1) and 2-((3-methyl-1-phenyl-1H-pyrazol-5-yl)diazenyl)benzene-1,3-diol (A2) were taken as examples of azo-dyes. Also, the two Schiff bases, 4-((3-Methyl-1-phenyl-1H-pyrazol-5-ylimino) methyl) benzene-1,3-diol (S1) and 4-Bromo-2-((3-methyl-1-phenyl-1H-pyrazol-5-ylimino) methyl) phenol (S2) were prepared and all these prepared compounds were isolated and purified. The synthesized reagents A1, A2, S1 and S2 were chelated with Cu(II) to form (1:1) (R:Cu(II)) solid complexes and well characterized using FT-IR, UV/visible and molar conductance. The conductivity studies revealed the electrolyte nature of all prepared copper complexes. From both electronic absorption spectra and cyclic voltammetry, the energy gaps for all free ligands and their copper complexes were determined. After a comparison of the representative IR bands of the free compound with the copper complexes formed, compounds were found to binding to the Cu(II) through phenolic OH and azomethine-nitrogen in S1 and S2 while in case in A1 and A2 chelation was taken place through OH and nitrogen of azo group. Furthermore, the date obtained from the electrochemical characterization indicated that these prepared Cu(II) complex can used as an inorganic dye sensitizers in dye-sensitized solar cells (DSSCs).