G. Alpaslan, M. Macit / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 121 (2014) 372–380
373
interesting chemical properties, depending on the substituents
X-ray crystallography
suitable yellow prism-shaped crystal sample of size
0.71 ꢂ 0.35 ꢂ 0.15 mm was chosen for the X-ray study and then
carefully mounted on the goniometer. Data collection was per-
formed on a STOE IPDS II diffractometer by the w scan technique
with different electron-donating or electron-withdrawing groups
[12]. Therefore, non-linear properties of the Schiff bases use in
the design of various molecular electronic devices such as optical
switches and optical data storage devices [13,14].
In recently years, theoretical calculation methods are used to
describe the molecular structures and spectroscopic properties as
well as experimental studies. Density functional theory (DFT)
which is one of these methods have been widely used in literature
because of its great accuracy in reproducing the experimental val-
ues in molecule geometry, vibrational frequencies, atomic charges,
dipole moment, electronic properties, etc. [15–18].
In this paper, we have been reported the synthesis, character-
ization and crystal structure of (E)-1-((3-methoxyphenylimi-
no)methyl)naphthalen-2-ol, as well as theoretical studies on it
using the DFT/B3LYP/6-311++G(d,p) method. The aim of this study
is to investigate molecular structure, tautomeric forms, vibrational
frequencies and electronic absorption spectrum of the title com-
pound, both experimentally and theoretically. The properties of
the structural geometry, molecular electrostatic potential (MEP),
frontier molecular orbitals (FMOs), thermodynamic and non-linear
optical (NLO) properties for the compound at the B3LYP/6-
311++G(d,p) level were studied.
A
using graphite monochromated Mo K
a radiation (k = 0.71073 Å)
at 296 K. The systematic absences and intensity symmetries indi-
cate that crystal have to the monoclinic C2/c space group. A total
of 11843 reflection (2770 unique) with [1.4° < h < 26°] were col-
lected in the w scan mode and cell parameters were determined
by using X-AREA software [19]. Absorption correction
(l
= 0.09 mmꢁ1) was obtained by the integration method via
X-RED32 software [19]. The crystal structure was solved by direct
methods using SHELXS-97 [20]. The maximum peaks and deepest
hole observed in the final
D
q
map were 0.16 and ꢁ0.11 eÅ3,
respectively. The scattering factors were taken from SHELXL-97
[20]. The molecular graphics were done using Ortep-3 for Windows
[21]. The data collection conditions and parameters of refinement
process are listed in Table 1.
Computational procedures
Experimental and computational method
All theoretical computations were done by using Gaussian 03 W
program package [22]. For calculation of molecule geometry was
used the obtained atomic coordinates from X-ray geometry. Geom-
etry optimization of the title molecule was performed by using DFT
method with Becke’s three parameters hybrid exchange–correla-
tion functional (B3LYP) [23] at 6-311++G(d,p) basis set [24]. The
harmonic vibrational frequencies were calculated at the same level
of theory for the optimized structure. The assignments of vibra-
tional bands have been made by using GaussView molecular visu-
alization program [25]. Additionally, the calculated vibrational
frequencies were clarified by means of the potential energy distri-
bution (PED) analysis and assignments of all the fundamental
vibrational modes using VEDA 4 program [26].
Synthesis
The compound (E)-1-((3-methoxyphenylimino)methyl)naph-
thalen-2-ol was prepared by reflux a mixture of a solution contain-
ing 2-hydroxy-1-naphthaldehyde (17.2 mg; 0.1 mmol) in 20 ml
ethanol and a solution containing 3-methoxyaniline (12.3 mg,
0,1 mmol) in ethanol (20 ml). The reaction mixture was stirred
during 3 h under reflux. The crystals of (E)-1-((3-methoxyphenyli-
mino)methyl)naphthalen-2-ol for X-ray analysis were obtained
from ethanol solution by slow evaporation (yield 74%; m.p 368–
370 K).
The electronic absorption spectra of phenol-imine (OH) and keto-
amine (NH) forms were calculated using the time-dependent den-
sity functional theory (TD-DFT) method [27–30]. The tautomeric
stability, total energy, HOMO and LUMO energies for the OH and
NH forms of the compound were calculated at the 6-311++G(d,p)
level in the gas phase. Besides, the energetic and dipole moments
behavior in solvent media of the compound were carried out by
using Polarizable Continuum Model (PCM) [31–34]. To investigate
the reactive sites of the compound, the molecular electrostatic
potential was evaluated using the B3LYP/6-311++G(d,p) method.
The linear polarizability and first hyperpolarizability properties of
the compound were obtained from molecular polarizabilities based
on theoretical calculations. In addition, thermodynamic properties
of title compound were obtained by applying same level of theory.
Instrumentation
The FT-IR spectrum of the title compound was recorded in the
4000–400 cmꢁ1 region with a Shimadzu FTIR-8900 spectropho-
tometer using KBr pellet. Electronic absorption spectrum was mea-
sured on a Unicam UV–vis spectrophotometer in EtOH solvent. The
FT-IR spectrum of the title compound was recorded at room tem-
perature with scanning speed of 10 cm minꢁ1 and the spectral res-
olution of 4.0 cmꢁ1. The ultraviolet absorption spectrum of the title
compound was examined in the range 200–600 nm using a Unicam
UV–vis spectrophotometer equipped with a 10 mm quartz cell. The
UV pattern is taken from a 1.57 ꢂ 10ꢁ5 M solution of the title com-
pound, dissolved in ethanol at 20 °C.
Fig. 1. Tautomeric forms of the title compound.
Alpaslan, G?khan
