Spectroscopic, thermal and magnetic properties of some transition metal complexes derived from 1-Phenyl-3-Substituted-4-Nitroso-5-Pyrazolones

Abstract

Complexes derived from some 1-Phenyl-3-methyl -4-nitroso-5-pyrazolone (L1), 1,3-diphenyl-4-nitroso-5-pyrazolone (L2) and 1-phenyl-3-anilino-4-nitroso-5-pyrazolone (L3) with Mn 2+ , Co 2+ , Ni 2+ , Cu 2+ and Zn 2+ metal ions have been prepared. Structural investigation of the ligands and their complexes has been made based on elemental analysis, infrared (FT-IR), ultraviolet and visible spectra (UV-Vis.), proton nuclear magnetic resonance (1 H NMR), magnetic susceptibility ( eff.) and thermal analysis (TG and DTG). The effect of solvents has been carried out in organic solvents of varying polarity. The observed transition energy and oscillator strengths were also calculated. The data obtained show that all of the prepared complexes contain water molecules in their coordination sphere. The investigated ligands acts as neutral bidentate ligands bonded to the metal ions through the two oxygen atoms of the carbonyl and nitroso groups. The isolated complexes behave as non-electro-lyte in DMF solution. The Mn 2+ , Co 2+ , Ni 2+ and Cu 2+ complexes show high spin configurations as the ground state. The high spin values of magnetic susceptibility may be due to the ligands being weak ligands. The Mn 2+ , Co 2+ , Ni 2+ , Cu 2+ and Zn 2+ complexes exhibit an octahedral or distorted octahedral coordination with the investigated ligands.

Chiral two-dimensional metal–organic frameworks based on Zn(salen) ligands: subcomponent self-assembly and circularly polarised luminescence

“…The absorptions were probably ascribed to the π → π* transition of the salen ligands. 22 The solid-state ECD spectra (Fig. 3b) show that the MOF ( R )- 1 gave a negative Cotton effect located at 413 nm, while ( S )- 1 corresponded to a positive Cotton effect.…”