Synthesis, structural, spectral (FT-IR, FT-Ra, and UV–Vis), thermal, and density functional studies on p-methylaniline complexes of Mn(II), Co(II), and Ni(II) bromides

• Synthesis and characterization of Mn(II), Co(II), Ni(II) bromide complexes of p-methylaniline.
• Elemental and thermogravimetric analyses, magnetic moment, UV–vis, FT-IR, and FT-Raman studies.
• Density functional studies on the molecular structures and vibrational spectra.
• The effects of complex formation on vibrational bands.

Transition metal complexes of the form MBr2L2, where M = Mn(II), Co(II) and Ni(II); L = p-methylaniline, were prepared and characterized by elemental and thermogravimetric analyses, magnetic moment measurements, and UV–vis, FT-IR and FT-Raman spectral studies. Geometries, spin-state energetics, and vibrational spectra of the complexes were obtained at the B3LYP/def2-TZVP level. The present experimental and theoretical data suggest 5-coordinate polymeric bromide bridged structure for the Mn complex, distorted tetrahedral structure for the Co complex, and distorted octahedral coordination site for the Ni complex. The experimental FT-IR and FT-Raman bands of the complexes were assigned based on the computational results expressed in terms of internal coordinates with percent potential energy distributions. The vibrational spectra suggest that the coordination occurs via nitrogen atom of p-methylaniline. The thermal characteristics of the complexes indicate that their decompositions start through p-methylaniline.

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