the only option to convey a clear image of each adduct (the 3D models are included
in the Supplementary Information).
3.2 Results for the Adducts of Arzanol with One Water
Molecule
Given the high number of conformers of the ARZ molecule, and the high number of
sites to which a water molecule can bind (including the possibility of simultaneous
binding to two geometrically suitable sites), considering all the possible adducts of
this type would be unaffordable. It was opted to calculate a selection of sufficiently
representative adducts for each binding site. While some sites (e.g., O14 or O23)
are accessible in all conformers, other sites are not available in some conformers,
and the combinations for simultaneous binding to two sites depend on the type of
conformer; therefore, only a limited number of adducts may be obtainable for
certain combinations. Changes during optimisation reduce the number of adducts
for some sites while increasing it for others (which informs that the former sites or
site-combinations are less favourable than others).
A total of more than 200 adducts were calculated. Figure 5 shows the main
geometries obtained, according to the type of conformer of the ARZ molecule and
to the site to which the water molecule binds. All the geometries are shown in the
Table 1 Symbols utilised to specify geometrical characteristics in the acronyms denoting the
conformers. The symbols d, s, r, w, u, η and ξ have the same meanings as in other studies on
ACPLs [6–10] and the symbols α, β, γ, δ, ε and τ had been introduced in [5]
Symbol
Meaning
d
The H15⋯O14 first IHB is present
s
The H17⋯O14 first IHB is present
r
H16 is oriented towards the α-pyrone ring
w
H16 is oriented towards the prenyl chain
u
H15 or H17, not engaged in the first IHB, is oriented toward the COR group
(‘upwards’)
η
Presence of O-H⋯π interaction between H16 and the C29=C30 double bond
ξ
Presence of O-H⋯π interaction between H17 and the C29=C30 double bond
a
No O-H⋯π interaction is present, and the prenyl chain is oriented ‘upwards’
b
No O-H⋯π interaction is present, and the prenyl chain is oriented ‘downwards’
α
The H27⋯O8 intermonomer hydrogen bond is present
β
The H15⋯O26 intermonomer hydrogen bond is present
γ
The H15⋯O23 intermonomer hydrogen bond is present
δ
The H16⋯O23 intermonomer hydrogen bond is present
ε
The H16⋯O26 intermonomer hydrogen bond is present
τ
The H27⋯O10 intermonomer hydrogen bond is present
π1
The C29=C30 double bond, when acting as binding site for a water molecule
Adducts of Arzanol with Explicit Water Molecules …
289
in the Supplementary Information).
3.2 Results for the Adducts of Arzanol with One Water
Molecule
Given the high number of conformers of the ARZ molecule, and the high number of
sites to which a water molecule can bind (including the possibility of simultaneous
binding to two geometrically suitable sites), considering all the possible adducts of
this type would be unaffordable. It was opted to calculate a selection of sufficiently
representative adducts for each binding site. While some sites (e.g., O14 or O23)
are accessible in all conformers, other sites are not available in some conformers,
and the combinations for simultaneous binding to two sites depend on the type of
conformer; therefore, only a limited number of adducts may be obtainable for
certain combinations. Changes during optimisation reduce the number of adducts
for some sites while increasing it for others (which informs that the former sites or
site-combinations are less favourable than others).
A total of more than 200 adducts were calculated. Figure 5 shows the main
geometries obtained, according to the type of conformer of the ARZ molecule and
to the site to which the water molecule binds. All the geometries are shown in the
Table 1 Symbols utilised to specify geometrical characteristics in the acronyms denoting the
conformers. The symbols d, s, r, w, u, η and ξ have the same meanings as in other studies on
ACPLs [6–10] and the symbols α, β, γ, δ, ε and τ had been introduced in [5]
Symbol
Meaning
d
The H15⋯O14 first IHB is present
s
The H17⋯O14 first IHB is present
r
H16 is oriented towards the α-pyrone ring
w
H16 is oriented towards the prenyl chain
u
H15 or H17, not engaged in the first IHB, is oriented toward the COR group
(‘upwards’)
η
Presence of O-H⋯π interaction between H16 and the C29=C30 double bond
ξ
Presence of O-H⋯π interaction between H17 and the C29=C30 double bond
a
No O-H⋯π interaction is present, and the prenyl chain is oriented ‘upwards’
b
No O-H⋯π interaction is present, and the prenyl chain is oriented ‘downwards’
α
The H27⋯O8 intermonomer hydrogen bond is present
β
The H15⋯O26 intermonomer hydrogen bond is present
γ
The H15⋯O23 intermonomer hydrogen bond is present
δ
The H16⋯O23 intermonomer hydrogen bond is present
ε
The H16⋯O26 intermonomer hydrogen bond is present
τ
The H27⋯O10 intermonomer hydrogen bond is present
π1
The C29=C30 double bond, when acting as binding site for a water molecule
Adducts of Arzanol with Explicit Water Molecules …
289