Microsolvation and solvent effects on molecular properties

A. F. MALDONADO; E. FLOREZ; S. P. BLATTER; G. MERINO; G. A. AUCAR

Marburg

Congreso; Relativistic Effects on Heavy Elements (REHE); 2017

REHE

All biomolecular phenomena take place in solution, as well as the vast majority of chemical processes. The environment modifies the properties of the system as compared to the isolated situation. Solvent effects, at least, can be included in three different ways: (i) by explicit inclusion of solvent molecules (microsolvation); (ii) by using a continuum solvation model (global solvation); (iii) by the combination of models (i) and (ii) (liquid phase). The advantage of the microsolvation model is its capacity to describe explicitly specific local interactions as hydrogen bonds, but it is size-limited and long-range effects of a polar solvent are absent. In this work we study the microsolvation process of heavy-iones (Br−, I− and Hg+2) as well as hydrogen halides HX (X = I, At) with water as solvent but also with methanol for the mercury case. We analized some intrinsic properties as well as response properties like NMR parameters, the nature of molecular bonding and relativistic effects on all of them as it was done in a previous work[1]. There exist important solvent effects on intrinsic and response properties in the systems under study. The nuclear magnetic shieldings of heavy-ions reduce their values up to 8% by solvent effects, as in the case of Hg+2 ion (sixth row of PT) with water as solvent while when the solvent is methanol, the effects are smaller. On the other hand, in the microsolvation process of hydrogen halides they are bonding to water molecues through hydrogen bond up to iodine atom, but for astatine atom such a bonding is through halogen bond. This change of the nature of the chemical bonding seems to be a purely relativistic effects.