Adducts of Arzanol with Explicit Water
Molecules: An Ab Initio and DFT Study
Liliana Mammino
Abstract Arzanol (C 22 H 26 O 7 ) is a naturally occurring acylphloroglucinol present
in Helichrysum italicum. It is the major responsible of its medicinal properties,
which include anti-oxidant properties. In the arzanol molecule, the R of the COR
group characterising acylphloroglucinols is a methyl group, and the two substituents in meta to COR are an α-pyrone ring, bonded to the benzene ring through a
methylene bridge, and a prenyl chain. The high number of hydrogen bond donor
and acceptor sites in the molecule entails an investigation taking into account
solute-solvent hydrogen bonds in an explicit manner. The current work considers
adducts of arzanol with explicit water molecules for a representative selection of its
conformers. Adducts with one water molecule attached in turn to each of the
H-bond donors or acceptors were calculated to estimate the strength with which
each site can bind a water molecule. Adducts with varying numbers of water
molecules were calculated to identify preferred arrangements of the water molecules around the various sites and around the molecule as a whole. These adducts
also suggest possible geometries for the first solvation layer. All the adducts were
calculated at the HF/6-31G(d, p) and the DFT/B3LYP/6-31+G(d, p) levels, with
fully relaxed geometry.
Keywords Acylphloroglucinols ⋅ Adducts with explicit water molecules
Arzanol ⋅ Hydrogen bonding ⋅ Solute-solvent interactions
Electronic supplementary material The online version of this chapter (https://doi.org/10.1007/
978-3-319-74582-4_16) contains supplementary material, which is available to authorized users.
L. Mammino ( ✉ )
Department of Chemistry, University of Venda, P/Bag X5050, Thohoyandou 0950,
South Africa
e-mail: sasdestria@yahoo.com
© Springer International Publishing AG, part of Springer Nature 2018
Y. A. Wang et al. (eds.), Concepts, Methods and Applications of Quantum Systems
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 31,
https://doi.org/10.1007/978-3-319-74582-4_16
281
Molecules: An Ab Initio and DFT Study
Liliana Mammino
Abstract Arzanol (C 22 H 26 O 7 ) is a naturally occurring acylphloroglucinol present
in Helichrysum italicum. It is the major responsible of its medicinal properties,
which include anti-oxidant properties. In the arzanol molecule, the R of the COR
group characterising acylphloroglucinols is a methyl group, and the two substituents in meta to COR are an α-pyrone ring, bonded to the benzene ring through a
methylene bridge, and a prenyl chain. The high number of hydrogen bond donor
and acceptor sites in the molecule entails an investigation taking into account
solute-solvent hydrogen bonds in an explicit manner. The current work considers
adducts of arzanol with explicit water molecules for a representative selection of its
conformers. Adducts with one water molecule attached in turn to each of the
H-bond donors or acceptors were calculated to estimate the strength with which
each site can bind a water molecule. Adducts with varying numbers of water
molecules were calculated to identify preferred arrangements of the water molecules around the various sites and around the molecule as a whole. These adducts
also suggest possible geometries for the first solvation layer. All the adducts were
calculated at the HF/6-31G(d, p) and the DFT/B3LYP/6-31+G(d, p) levels, with
fully relaxed geometry.
Keywords Acylphloroglucinols ⋅ Adducts with explicit water molecules
Arzanol ⋅ Hydrogen bonding ⋅ Solute-solvent interactions
Electronic supplementary material The online version of this chapter (https://doi.org/10.1007/
978-3-319-74582-4_16) contains supplementary material, which is available to authorized users.
L. Mammino ( ✉ )
Department of Chemistry, University of Venda, P/Bag X5050, Thohoyandou 0950,
South Africa
e-mail: sasdestria@yahoo.com
© Springer International Publishing AG, part of Springer Nature 2018
Y. A. Wang et al. (eds.), Concepts, Methods and Applications of Quantum Systems
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 31,
https://doi.org/10.1007/978-3-319-74582-4_16
281