EPR Analysis of Cu2+ ion Doped Potassium borodicitrate Single Crystal

Abstract

In our present investigation single crystals of Potassium borodicitrate (KBDC) (for a fixed content- host lattice) with Cu²⁺, a guest species, as a dopant (at four 0.2, 0.5, 1 and 2 g) in weight ratio have been synthesized at room temperature by using slow evaporation method. These as-synthesized 4 crystals have been subjected to Electron Paramagnetic Resonance (EPR) studies. The EPR spectrum shows that 0.5 g dopant KBDC give a 4 equidistant hyperfine lines with the perfect symmetry confirms that the localization of Cu²⁺, a paramagnetic impurity, within it reveals that the maximum absorption of EPR signals happens at 0.5 g Cu²⁺ than any other concentrations with reference to 20° in horizontal plane than the normal and vertical recording in the same angular projection. The Spin Hamiltonian calculations are used to obtain spectroscopic field splitting factor g-tensor values, g_xx = 2.0421, g_yy = 2.1962, g_zz = 2.2827 and hyperfine splitting factor A-tensor values A_xx = 150, A_yy = 112 and A_zz   = 134. The K–O bond length associated with directional cosines of g_zz tensor reveal that the Cu²⁺ is located interstitially. This optimized single crystal has furtherance been subjected to Single cystal X-ray diffraction (SXRD), Fourier transform infrared Spectrascopy (FTIR).

Scanning electron microscope (SEM) Energy dispersive X-ray analysis (EDAX) and compared with pure KBDC single crystal. The XRD unit cell crystalline parameter variations reveal that there is doping effect of Cu²⁺ into the host lattice brings forth structural coordination of Cu²⁺ with KBDC. The FTIR confirms that complexation of host and guest through molecular interactions in the finger print region. The EDAX mapping shows Cu²⁺ presence in the crystal.

HIGHLIGHTS

• SXRD are taken to confirm that structure of pure KBDC and Cu²⁺ doped KBDC are same
• The spin Hamiltonian parameters of KBDC-Cu²⁺ single crystal are calculated through EPR spectra
• On analyzing the spectra, it is found that the doped ion site location symmetry is identified as interstitial and experience orthorhombic local field symmetry
• In addition to the above studies FTIR and EDX confirms the presence of Cu²⁺ ion

GRAPHICAL ABSTRACT