Relativistic Effects on the Nuclear Spin-Spin Coupling Polarizability Tensor of Chiral Molecules

G. I. PAGOLA, ...; M. A. B. LARSEN ; M. B. FERRARO; S. A. SAUER

Santiago

Congreso; XLIV Congreso de Químicos Teóricos de Expresión Latina (QUITEL); 2018

In this work, relativistic and non-relativistic calculations have been performed on hydrogen peroxide, dihydrogen disulfide, dihydrogen diselenide and dihydrogen ditelluride, H2X2 (X = O, S, Se, Te), in order to investigate the consequences of relativistic effects on their structures as well as their nuclear magnetic resonance (NMR) spin-spin coupling constants and spin-spin coupling constant polarizabilites. The study has been performed using both one-component non-relativistic and four-component relativistic calculations at the density functional theory (DFT) level with the B3LYP exchange-correlation functional. The calculation of nuclear spin-spin coupling constant polarizabilities has been performed by evaluating the components of the third order tensor, nuclear spin-spin coupling polarizability, using quadratic response theory. From this the pseudoscalar[1] associated with this tensor has also been calculated. The results show that relativistic corrections become very important for H2Se2 and H2Te2 and for the pseudoscalar their importance in these molecules with is remarkable. This pseudoscalar becomes 5 times as large for H2Se2 and 20 times as large for H2Te2 from a non-relativistic to the relativistic calculation. It hint that a new chiral discrimination technique via NMR spectroscopy might be possible for molecules containing elements like Se or Te. Figure: The pseudoscalar associated with the reduce spin-spin coupling polarisability tensor (in 108 T2 m J-1 V-1), which is important for the discrimination of chiral molecules by NMR. The trend of an increasing pseudoscalar in this series of molecules, in particular after considering relativistic effects, hints that the suggested chiral discrimination might be possible in compounds containing Se and Te.Acknowledgments: This work was developed with financial support from Universidad de Buenos Aires (UBACYT 20020130100039BA and 20020130200096BA), CONICET (PIP 11220130100377). References:[1] H. Kjær, M. R. Nielsen, G. I. Pagola, M. B. Ferraro, P. Lazzeretti and S. P. A. Sauer, J. Comput. Chem. 33 (2012) 1845.