Spectroscopic studies on Mn(II), Co(II), Ni(II), and Cu(II) complexes with N-donor tetradentate (N4) macrocyclic ligand derived from ethylcinnamate moiety

Spectral studies of transition metal complexes with 25, 26 dioxo1,6,12,17,23,24 hexaazacyclohexacosa 1,5,12,16 tetraene macrocyclic ligand (L)

“…Our results are in agreement with the complexes reported earlier [28]. The Nephelauzetic parameter β was readily obtained by using the relation: β = B (Complex)/B (free ion), where B (free ion) for Mn(II) is 786 cm −1 , for Ni(II) is 1041 and for Co(II) is 1120 cm −1 [29].…”

Synthesis and characterization of transition metal complexes of N′-[(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methylene]thiophene-2-carbohydrazide

“…Since the g || and g \ values are closer to 2 and g || [ g \ suggesting a tetragonal distortion around the copper(II) ions corresponding to elongation along the fourfold symmetry Z-axis [42]. The trend g || [ g \ [ g e (2.0023) shows that the unpaired electron is localized in the d x 2 Ày 2 orbital of the copper(II) ions in complexes [43].…”

“…If the value G [ 4.0, the exchange interaction is negligible which is typically the case for complex (2) (G = 5.7). When the G \ 4.0, a considerable exchange coupling is present in solid complex, which is typically the case for complexes (3) and (4) (G = 2.72, 2.6) [42,43]. Kivelson and Neiman showed that for an ionic environment g || is normally 2.3 or larger, but for covalent environment g || are less than 2.3.…”

“…This finding indicates that the two complexes are tetragonally distorted and the states are connected with spin orbit coupling. This situation leads to short relaxation times, where absorption is difficult to observe [42,44,45]. The ESR spectrum of the solid iron(III) complex [FeLCl 2 (H 2 O)] Á 2H 2 O at room temperature showed three bands at 1.9, 3.2, and 5.8.…”

Synthesis and Structural Aspect of Some Transition Metal Complexes with Schiff Base Ligand Derived from 2, 6 Diethyl 4-pyrone

“…complexes are of great significance on account of their unique coordination and structural properties and their utilities as bio-inorganic models [9][10][11][12][13] . In recent years, extensive research in chemistry of metal chelates involving chelating Schiff base containing nitrogen, oxygen and sulphur donor sites have steadily grown in many areas including synthesis, structure elucidation, reaction kinetics, redox behaviour and biological reactions.…”