Synthesis, Spectroscopic and Thermodynamic Studies of Metal Complexes with Schiff Bases Derived from 2-[5-(Pyridin-2-Ylmethylene)-amino] 1,3,4-Oxadiazol-2-yl-Phenol

Abstract

New metal complexes of the ligand 2-[5-(Pyridin-2-ylmethylene)-amino] 1,3,4-thiadiazol-2-ylphenol (L) with the metal ions Co(II), Ni(II), Cu(II) and Zn(II) were prepared in alcoholic medium. The Schiff base was condensed [2-pyridine carbxaldehyde] with [2-amino-5-(phenyl-1,3,4oxadiazole] in alcoholic medium. Two tetradentate Schiff bases ligand were used for complexation upon two metal ions of Co 2+, Ni 2+, Cu 2+ and Zn 2+ as dineucler formula M2L2. The synthesized compound and their metal complexes were characterized by FTIR Spectroscopy, electronic spectroscopy, Elemental analysis, magnetic susceptidbility measurements, thermal analysis , 1 H-NMR spectra, and mass spectra. The activation thermodynamic parameters such as ΔE * , ΔH * , ΔS * and ΔG * were calculated from the TGA curve using Coats-Red fern method. From the measurements, structures of the complexes were proposed.

Preparation and Characterization of New Tetra-Dentate N₂O₂ Schiff Base with Some of Metal Ions Complexes

“…The spectra of the chromium complex observed two (428 nm, 608 nm) in Table 3, attributed to the allowed transfer 4 A 2 g → 4 T 1 g (F) and 4 A 2 g → 4 T 1 g (F) respectively [19]. It has been observed that the electron spectrum is complex cobalt(II) low spin octahedral (t 2 g 6 eg 1 ), one permissible transition 500 nm, which is 2 Eg 2 T 2 g (20).…”

Preparation, Spectroscopy, Biological Activities and Thermodynamic Studies of New Complexes of Some Metal Ions with 2-[5-(2-Hydroxy-Phenyl)- 1,3,4-Thiadiazol-2-Ylimino]-Methyl-Naphthalen-1-Ol]

“…The linked nitrogen atom of thiadiazol ring shows shifted absorption bands of ligand range 1174 -1303 cm -1 in complexes which confirms the metal's binding to the group (= N-N =) 17 . For all complexes, a new beam appeared in the range 586-590 cm -1 due to the vibrations of the group stretch (M-O) 18 and showed a stretching of the group (M-N) of the prepared complexes in the bounded region between 458-495cm -1 , confirming the metal's association via the (N) atom 19 . All the infrared spectrum values for the complexes are shown in Tab.2.…”

“…Positive values for (∆H) indicate that the reactions are endothermic. The negative values indicate that the reactions are heat-emitting and the small values of the Arrhenius factor (Z) indicate that the reactions of the decomposition of ligand (LH 2 ) are fast, while the large and positive values in the state of transition can be classified as slow reactions [7][8][9]19 .…”