Abstracts Book - IMRC 2018

• SF4-O007 Invited Talk
Au/H: THERE ARE ANALOGY BETWEEN BnHn+2 and BnAun+2 (n =
2-5) SERIES?
Edison Osorio 1 , Franklin Ferraro 1
1 Universidad Católica Luis Amigó, Ciencias Básicas, Colombia.
Over the past decades Boron-based materials, especially boron hydrides
(boranes), have been attracted considerable attention due to their ability to
store a good amount of hydrogen and release it upon chemical treatment when
needed. Those investigations have been inspired to scientific community to
understand the nature and the essential roles in some advancing chemical
bonding models. In 2012, we performed global minimum searches for the
BnHn+2 (n = 2-5) series and found that classical structures composed of 2c–2e
B–H and B–B bonds become progressively less stable along the series. We
believe this occurs because boron atoms in the studied molecules are trying to
avoid sp2 hybridization and trigonal structure at the boron atoms, as in that case
one 2p-AO is empty, which is highly unfavorable. Other interesting example
about the advancing chemical bonding corresponds to investigations about the
Au/H analogy in boron materials. Theoretical studies have showed that some
closo-auroboranes BxAux2– (x = 7–14) dianions possess structure and bonding
analogous to the famous deltahedral closo-borane cages, BxHx2–. Likewise,
theoretical studies in B10Au–, BAun0/- (n = 1–4) and B2Aun0/- (n = 1, 3, 5)
auroboranes have also been proved to possess similar geometrical structures
and bonding patterns with corresponding boron hydrides. With the idea of
understanding if there is some Au/H analogy between BnHn+2 and BnAun+2 (n
= 2-5) boron series, we performed the exploration on the potential energy
surfaces of BnAun+2 (n = 2-5) series using the gradient embedded genetic
algorithm and an adequate treatment of relativistic effects. Our results showed
that a geometrical similarity between these two series is not presented. The
global minima conformations reported here showed that the boron fragment
adopt a planar form, while the gold atoms were localized around of the boron
cluster as a planar form. Additionally, a completed study of the chemical
bonding pattern for the BnAun+2 (n = 2-5) series indicated the presence of
multiple forms of nc-2e B-Au chemical bonds.
Acknowledgment:
Universidad Catolica Luis Amigó