XIV
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International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
331
T9: P–5
Spectroscopic (IR and UV-Vis) and molecular docking studies on
1,1’-diethyldicarboxilat-3,3’-bis(3,4-dihydroxy)-7,7’-bisindolizine
Gosav Steluta
1
, Maftei Dan
2
, Dediu Andreea
1
, and Dinica Rodica Mihaela
1
1
Chemistry, Physics and Environment Department, "Dunarea de Jos" University, Domneasca St. 47,
800008 Galati, Romania, e-mail: Steluta.Gosav@ugal.ro
2
Chemistry Department, "Al.I. Cuza" University, 11 Carol I Bldv. RO-700506, Iasi, Romania
In the present paper, a bisindolizinic compound i.e. 1,1’-diethyldicarboxilat-3,3’-bis(3,4-
dihydroxy)-7,7’-bisindolizine [1] was investigated from a structural and a vibrational point of
view at DFT/B3LYP/6-311G(d,p) level of theory. The equilibrium geometry of the most stable
conformer of the title molecule was determined. The complete vibrational assignments of
wavenumbers for the most stable conformer were made on the basis of potential energy
distribution (PED). The observed and calculated IR frequencies are found to be in good
agreement.
UV-Vis absorption spectrum was recorded for 1,1’-diethyldicarboxilat-3,3’-bis(3,4-
dihydroxy)-7,7’-bisindolizine in chloroform, and the observed absorption bands were assigned
to electronic transitions computed at TD-DFT/6-31+G(d) level in solution using PBE0 and
CAM-B3LYP exchange-correlation functionals. Solvent effect on the lowest excited state of
studied compound was modeled using the corrected Linear Response solvation (cLR) approach.
Analysis of electron density reorganization in the lowest ππ* excited singlet of 1,1’-
diethyldicarboxilat-3,3’-bis(3,4-dihydroxy)-7,7’-bisindolizine is performed. Also, the molecular
electrostatic potential (MEP) maps in ground and excited states were used to further rationalize
the effect of substitution on optical spectral properties.
Docking of ligand molecule i.e. 1,1’-diethyldicarboxilat-3,3’-bis(3,4-dihydroxy)-7,7’-
bisindolizine, onto the ATP-binding site (Fig. 1) of PI3Kα isoform has performed using
AutoDock Vina software. The inhibition potency of ligand molecules is compared with that of a
standard ligand [2] which has a moderate potency of PI3Kα inhibition i.e. IC50 = 23µM.
Fig. 1. Molecular surface view of ligand compound docked in the active site of PI3Kα kinase.
Keywords: bisindolizine; FTIR; B3LYP; TD-DFT
References
[1] I.I. Druta, R.M. Dinica, E. Bacu, I. Humelnicu, Tetrahedron 54 (36) (1998) 10811.
[2] H. Park, H. Choi, S. Hong, D. Kim, D.S. Oh, S. Hong, Bioorg.&Med. Chem. Lett. 21 (2011) 2021.
XIV
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International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
332
T9: P–6
Vibrational assignment and the effect of α-methyl and ethyl
substitutions on the Cu-O strength in bis-(3-alkylpentane-2,4-
dionato)copper(II): an experimental and DFT study
Seyedabdollah Seyedkatouli
1
, Mohammad Vakili
1
, and Sayyed Faramarz Tayyari
1
1
Department of Chemistry, Ferdowsi University of Mashhad, Mashhad 91775-1436, Iran,
e-mail: s.a.seyedkatouli@mail.um.ac.ir
We subsisted methyl and Ethyl groups in α-position of copper (II) acetylacetonate, Cu(acac)
2
, see
Fig .1. From the theoretical point of view, by considering the conformations of α substitutions, with
respect to the plane of the molecule and each other, 2 stable conformers can be obtained for each
molecule, Cu(3-Meacac)
2
and Cu(3-Etacac)
2
. Our calculations in the gas phase indicate that the
energy difference between the mentioned forms are negligible, about 0.01-0.07 kcal.mol
-1
. A
complete assignment of the observed IR and Raman band frequencies of title molecules has been
done, and compared to those in bis(acetylacetonato)Cu(II) [1].
Fig. 1. Figure The structure of bis-(3-alkylpentane-2,4-dionato)copper(II).
Some optimized geometrical and topological parameters at the bond critical point (BCP) of the
Cu-O bonds, calculated at the B3LYP/6-311G* level by Gaussian 09 and AIM 2000 softwares, and
experimental and theoretical vibrational band frequencies related to the Cu-O bond strength for above
complexes are shown in Table 1. According to this Table, the following trend in Cu-O bond strength
is concluded: Cu(3-Etacac)
2
≥Cu(3-Meacac)
2
>Cu(acac)
2
. According to the pairwise exchange steric
energies, calculated by NBO 5.0 program, the steric effect could be a good reason for the above trend.
Table 1: Comparing selected parameters related to the Cu-O bond strength for title molecules.
a
Cu(3-Etacac)
2
Cu(3-Meacac)
2
b
Cu(acac)
2
b
R(Cu–O)
1.914
1.915(1.908)
1.925(1.921,1923)
R(C–O)
1.273
1.272(1.285)
1.270(1.268)
R(C–C
α
)
1.415
1.413(1.409)
1.403(1.404,1407)
ρ (e.au
-3
)
0.0919
0.0917
0.0894
∇
2
(e.au
-5
)
-0.1311
-0.1307
-0.1256
ν
s
O-Cu-O
469(468)
469(467)
466(450)
ν
a
O-Cu-O
640(625)
641(623)
620(613)
a
Bond lengths are in Ǻ, the experimental values of ν are in parentheses(in cm
-1
).
b
The experimental values of bond lengths are in parentheses. Data from [2, 3].
Keywords: bis-(3-alkylpentane-2,4-dionato)copper(II); vibrational assignment; DFT.
Acknowledgment
This work was supported by the Ferdowsi University of Mashhad, Grant No. 42561.
References
[1] M. Vakili, S.F. Tayyari, M. Hakimi-Tabar, A.-R. Nekoei, S. Kadkhodaei, J. Mol. Struct. 1058 (2014) 308.
[2] H. Golchoubian, Asian J. Chem. 20 (2008) 5834.
[3] lnge Robertson, Mary R. Truter, J. Chem. Soc. A (1967) 309.
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