Effect of paramagnetic doping on an inorganic polymer triaquadipotassiumbis(malonato)zincate: spectroscopic investigation |
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Authors: | S Boobalan |
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Institution: | Department of Chemistry , Pondicherry University , Pondicherry, 605 014, India |
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Abstract: | Spectroscopic investigations on Mn(II)-doped triaquadipotassiumbis(malonato)zincate K2(H2O)3] Zn(mal)2], an inorganic polymer, have been carried out at room temperature using single crystal electron paramagnetic resonance (EPR), ultraviolet–visible, FT-IR and powder XRD techniques. Single crystal rotations along the three orthogonal axes show more than 30 lines of patterns in EPR spectra, indicating the presence of two sites, one with a large D value and the other with a smaller D value. The calculated spin-Hamiltonian parameters are as follows. Site 1: g xx =2.099, g yy =2.092, g zz =1.988, A xx =9.77, A yy =9.71, A zz =8.96 mT, D xx =?29.09, D yy =?11.90, D zz =40.99 mT; Site 2: g xx =2.040, g yy =1.995, g zz =1.924, A xx =9.51, A yy =9.09, A zz =8.80 mT, D xx =?11.94, D yy =?7.51 and D zz =19.45 mT. The direction cosines of g/A/D do not match with the direction cosines of Zn–O bonds in the host lattice for either site, suggesting that both the Mn(II) sites entered the lattice interstitially. Optical results indicate a strong covalent bonding between the metal ion and ligands, with site symmetry being primarily octahedral. The FT-IR and powder XRD data confirm the retention of the crystal structure, even after incorporating a paramagnetic probe. Various admixture coefficients, bonding and optical parameters have also been calculated. |
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Keywords: | chemistry defects doping EPR polymers |
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