Journal of Molecular Liquids
Spectroscopic, computational and electrochemical studies on 2-(4-
nitrophenyl)-1H-benzo[d]imidazole and its interaction with cationic
surfactant cetyltrimethylammonium bromide
a
a
b
a,
Arup Datta , Sanjay Roy , Palash Mondal , Partha Sarathi Guin ⁎
a
Department of Chemistry, Shibpur Dinobundhoo Institution (College), 412/1 G. T. Road (South), Howrah 711 102, India
Department of Chemistry (UG & PG), Vivekananda Mahavidyalaya, Burdwan 713 103, India
b
a r t i c l e i n f o
a b s t r a c t
Article history:
2-(4-Nitrophenyl)-1H-benzo[d]imidazole (4-NBI) was prepared and characterized by experimental and compu-
Received 16 March 2016
Accepted 13 April 2016
Available online xxxx
tational methods. Electrochemical reduction of the compound was studied in dimethyl sulphoxide media which
showed that the nitro group of the molecule undergoes quasireversible three-step reduction producing –NH
2
while the imidazole nitrogen bonded to hydrogen undergoes an irreversible one-electron reduction. The elec-
tronic spectra were studied by TDDFT computational method and compared with the experimental results
which corroborated each other excellently. The interaction of 4-NBI with the cationic surfactant
cetyltrimethylammonium bromide (CTAB) was investigated in aqueous solution at physiological pH (7.4) by
UV–Vis spectroscopy. By using different nonlinear fitting methods binding parameters were evaluated for 4-
NBI – CTAB micelles interaction. The results showed that the electrostatic interaction plays a major role over hy-
drophobic interaction in the binding of 4-NBI to CTAB micelles. The electrostatic interaction has also an important
role in the distribution of 4-NBI between CTAB micelle–water phases. Gibbs free energy for the binding and dis-
tribution of 4-NBI between the bulk aqueous medium and surfactant micelles was calculated.
Keywords:
4-NBI
Computational method
UV–vis
CTAB micelles
Binding parameters
©
2016 Elsevier B.V. All rights reserved.
1
. Introduction
of this class of molecules bind a limit of their use [22–24]. Previous stud-
ies have shown that the formation of radicals and/or anions being re-
sponsible for toxic side effects as well as for drug action is related with
the electrochemical behavior of these molecules [25]. The electrochem-
ical property of a molecule is further related to the electronic behavior
as well chemical structure of the molecule. This makes the structural,
spectroscopic and electrochemical studies on such molecules to be
highly relevant to determine their structure–activity relationship.
Several studies explored that the mechanism of action of a biologi-
cally active molecule is related to its interaction with biological tissues
through its binding to membranes at the molecular level. Several bio-
logical processes have been observed to happen at the ionizable surface
of the biomembranes or along their hydrophobic area, leading to a com-
parative study on the interaction of such molecule with cationic,
zwiterionic, anionic and neutral surfactants to be important [26–28].
This provides helpful information on the nature of drug–membrane in-
teraction. This is why the studies on drug–surfactant interactions have
been carried out by several researchers using various models and tech-
niques owing to the extensive application of surfactants in the field
pharmaceutical research. Earlier studies established that micellar sys-
tems have the ability to solubilize hydrophobic drugs [29–32] which in-
creases their bioavailability and can be used as a model system for
biomembrane, as well as drug carriers in various drug delivery and
drug targeting systems [33–35]. The physicochemical interactions of a
Benzimidazole, its analogues and derivatives are a class of important
nitrogen-containing heterocyclic compounds which has been used in
biological and pharmaceutical chemistry for quite a long time. Imidazole
nucleus plays many vital roles in human physiology in the form amino
acid like histidine, vit-B12, nucleic acid bases, caffeine, biotin, etc.
Several studies showed that these molecules are effective as
antimicrobial, antihelminthic, antibacterial, anticonvulsant, anti-
inflammatory, antiarrythmic, antioxidant, androgen receptor antago-
nist, antiprotozoal, antitumour, antiviral, antihypertensives, antihista-
minics, antifolate, antifungal agents [1–18]. Their activity against
several viruses such as HIV, herpes (HSV-1), influenza and human
cytomegalovirus (HCMV) [19–21] draw an enormous attention of
researchers to work in this field. Some established medicines such as
astemizole, esomeprazole, albendazole, cimetidine, azomycin, metroni-
dazole, etc., also consist of imidazole ring as the centre of drug action.
It is important to note that although some nitroimidazoles have been
used successfully in treating various infections, some distinct toxicities
Abbreviations:
cetyltrimethylammonium bromide.
4-NBI,
2-(4-nitrophenyl)-1H-benzo[d]imidazole;
CTAB,
⁎
0167-7322/© 2016 Elsevier B.V. All rights reserved.