NMR AND PAC SPECTROSCOPIC DATA OF HG(II) COMPOUNDS: A COMPARISON OF FOUR- AND TWO-COMPONENT CALCULATIONS

S.P.A. SAUER; V. ARCISAUSKAITE; LARS HEMMINGSEN; S. KNECHT; J. I. MELO

Corrientes

Conferencia; International conference on relativistic effects in heavy elements - chemistry and physics; 2012

Universidad del Nordeste, IMIT Conicet

The coordination chemistry of Hg(II) is of great biological importance as mercury ions may substitute native metal ions in metalloproteins, probably giving rise to the well known toxic effects of this heavy metal ion. 199Hg NMR spectroscopy and 199mHg perturbed angular correlation (PAC) spectroscopy have become powerful tools in this context due to the sensitivity of the 199Hg NMR chemical shifts and electric field gradients to the first coordination sphere of Hg(II). The interpretation of these spectroscopic data for Hg(II) has until now almost exclusively relied on empirical comparison with data recorded for reference compounds. Although this is a useful approach in many cases, it may lead to incorrect conclusions, and completely lacks the full characterization of the electronic and molecular structure of the coordination compounds in question as can be obtained from quantum chemical calculations of the spectroscopic data. Relativistic and electron correlation effects play an important role for NMR and PAC properties of systems containing heavy elements, such as mercury. As four-componentcalculations for biological relevant Hg-complexes are still not possible, we will present results of recent studies, where we have benchmarked the two-component method ZORA against the four-component approach in calculations of chemical shifts and electric field gradients of the smaller HgL2 (L = Cl, Br, I, CH3) and [HgCl3]? compounds [1,2,3,4]. In addition we will discuss the effects of electron correlation both at DFT and Coupled Cluster level and the dependence of the NMR and PAC spectroscopic data on structural parameters. [1] V. Arcisauskaite, J. I. Melo, L. Hemmingsen, S. P. A. Sauer, J. Chem. Phys. 135, 044306 (2011).[2] V. Arcisauskaite, S. Knecht, S. P. A. Sauer and L. Hemmingsen, Phys. Chem. Chem. Phys. 14, 2651-2657 (2012)[3] V. Arcisauskaite, S. Knecht, S. P. A. Sauer and L. Hemmingsen, Phys. Chem. Chem. Phys. (submitted)[4] V. Arcisauskaite, S. Knecht, S. P. A. Sauer and L. Hemmingsen, to be published