ISSN : 0970 - 020X, ONLINE ISSN : 2231-5039
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Abstract

Predicting ESR Peaks in Titanium (III), Vanadium (IV) and Copper (II) Complexes of Halo Ligands by NMR, ESR and NQR Techniques: A DFT Study

Harminder Singh1, A. K. Bhardwaj2, M. L. Sehgal2, Mehjbeen Javed3 and Irshad Ahmad4*

DOI : http://dx.doi.org/10.13005/ojc/310325


Abstract:

15 halo (I≥1/2) complexes of Ti (III), V (IV) and Cu (II) each possessing one unpaired electron were studied using DFT implemented in ADF.2010.02. Aten, NQCC and h parameters of metal ions and ligands were obtained from ESR/EPR program while their σ and δ parameters were given by NMR/EPR program after optimization of complexes. Ligands having same values of these 5 parameters were spatially equivalent and, thus, would undergo same hyperfine interaction. Experimental determination of ESR lines in Cu (II) complexes became erroneous because the presence of both the large Jahn-Teller effect and the high value of its spin-orbit coupling constant   (λ Cu (II) = -830 cm-1) affect the A ten parameter adversely. Cryoscopic conditions, generally required, in ESR experiments of Ti (III)and V (IV)complexes were difficult to obtain and cumbersome to maintain.

Keywords:

Jahn-Teller; Chemical Shift; Shielding Constant

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