Synthesis and characterization of mixed ligands of copper(II)-terephthalate complexes

In this study, mixed ligand complexes of Cu(II) metal and terephthalic acid (H2tf) were synthesized. 2-aminomethylpyridine (amp), 1,8-diaminonaphthaline (dan), N,N-diethylethylenediamine (deen), N,N-dimethylethylenediamine (dmen), 2,2-dimethyl-1,3-propanediamine (dmpd), 8-hydroxyquinoline (hk), N-methyl-1,3-propanediamine (mpen) and 1,3-propanediamine (pen) were used as secondary ligands in the complexes. The structural properties of complexes were characterized by using elemental and thermal analyses (TG, DTA and DTG), magnetic susceptibilities, FT-IR, UV-Vis., Atomic Absorption and Mass Spectroscopy techniques. Formulas of complexes were recommended [Cu(tf)(amp)2]·3H2O (1), {[Cu(tf)(H2O)(dan)]·H2O}n (2), [Cu(tf)(deen)2]·4H2O (3), [Cu(dmen)2(tf)] (4), [Cu(tf)(dmpd)2] (5), {[Cu(tf)(H2O)(hk)]·H2O}n (6), [Cu(tf)(mpen)2]·2H2O (7) ve [Cu(tf)(pen)2] (8). In 1, 3, 4, 5, 7 and 8 complexes, terephthalate is coordinated to metal ion as monodentate with oxygen atom of first carboxylate group and the other carboxylate group isn't coordinated. In 2 and 6 complexes, two carboxylate group of terephthalate are coordinated to metal ions as bidentate bridges ligand and they are polymeric complexes. In electronic spectrum of 1, 3, 4, 5, 7 and 8 complexes, d-d band at range of 564-626 nm (ε = 53-256 Lmol-1cm-1), n-π* and π-π* bands at range of 240-362 nm (ε =10520-19920 Lmol-1cm-1) appeared. Cu(II) ion in all complexes is paramagnetic and has got one unpaired electron. All of the experimental magnetic momentum values and calculated values were found to be in coherence. Crsytal water molecules and aqua ligand are separated from the structure at the first stage in TGA curves, the following stage, respectively auxiliary ligand and terephthalate ligand are separated from structure.