2
A. Mejri, K. Alouani / C. R. Chimie xxx (2016) 1e8
longueurs d'onde infrarouge. Ceci est dû ꢁa la coordination des groupements thio-
phosphoryles pr eꢀ sents dans la structure du ligand. Les eꢀ tudes eꢀ lectrochimiques et par UV
eVisible confirment que les complexes form eꢀ s ont une stœchiom eꢀ trie 1:2.
©
2016 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Cu2 in the same media induces a simultaneous anodic
shift in the potential of the oxidation peak. The electro-
chemical results were confirmed by the UVeVisible tech-
nique where we noticed a redshift behavior.
þ
1. Introduction
Exploration of chemosensors for bivalent cations,
particularly iron and copper, is an important research
subject attracting widespread attention due to the pivotal
roles of such species in several biological processes [1,2]. A
lack/surplus of these two trace essential elements in the
human body can induce some serious diseases such as
cancer and system perturbation [3,4].
2. Materials and methods
2.1. General
Although many analytical techniques were used to
detect metal cations including high performance liquid
chromatography (HPLC), fluorescence, inductively coupled
plasma mass spectrometry (ICP-MS) and atomic absorption
spectrometry (AAS) [5], this field still suffers many perfor-
mance limitations such as analysis time and high cost and
needs sophisticated equipments. For all these reasons, the
scientific community devoted huge interest to develop new
electrochemical sensors, which are considered economical,
easy to handle, and highly sensitive systems [6].
All reactions were carried out under a nitrogen atmo-
sphere in solvent dried by standard techniques and stored
over activated 3 Å molecular sieves. All reagents and sol-
vents were of analytical reagent grade, purchased from
Sigma-Aldrich and Acros and used without further purifi-
cation. Cadmium (II) perchlorate hydrate Cd(ClO ) $6H O,
4
2
2
4 2 2
copper (II) perchlorate hydrate Cu(ClO ) $6H O, cobalt(II)
perchlorate hydrate Co(ClO ) $6H O, iron (II) perchlorate
4
2
2
4 2 2
hydrate Fe(ClO ) $6H O, nickel(II) perchlorate hydrate
Ni(ClO ) $6H O and calcium (II) perchlorate hydrate
4
2
2
Ferrocene and rhodamine were widely used as electro-
chemical mediators to sense metallic cations. For instance,
P. Beer et al. employed a polyaza ferrocene macrocyclic
ligand to sensitively sense copper (II) ions by the formation
of a stable ferrocene based electrochemical complex in
polar organic solvent or even in water [7]. Moreover, R.
Ziessel's group has explored complexation properties to
detect various metals such as Cu (I), Cu(II), Fe(II) and Co(II)
Ca(ClO
4 2 2
) $4H O were used as received.
The NMR spectra were recorded on a Bruker AC-
300 MHz spectrometer. Chemical shifts for H and C NMR
1
13
31
were referenced to tetramethylsilane and P was refer-
enced to 85% H PO in D O. UVeVisible spectra were
measured in 1 cm quartz cells using a UNICO Spectro-Quest
2800 spectrophotometer. The IR spectrum was obtained on
a PerkineElmer alpha ATR apparatus.
3
4
2
[8,9]. Furthermore, rhodamine was also frequently involved
in metallic cation detection. Recently, dimethylimino-
cinnamyl based rhodamine has been explored by Kamal
2.2. Electrochemistry
2
þ
)
et al. as an electroactive compound to detect iron (Fe
10]. More recently, rhodamine hydrazide derivatives have
also been used as a highly sensitive and selective copper
The electrochemical experiments were conducted at
ambient temperature in 0.1 M tetrabutylammonium
[
perchlorate in acetonitrile solution with a three-electrode
glass cell controlled by MetrohmAutolab PGSTAT101 elec-
trochemical workstations. The cell was fitted with plat-
inum wire as the counter electrode and a platinum
electrode as the working electrode (1 mm diameter) which
was polished before each experiment. The Ag/AgCl (3 M
KCl) electrode was used as the reference electrode. Metal
cations were added as solutions of the corresponding
perchlorate salts in anhydrous acetonitrile.
2
þ
(
Cu ) electrochemical sensor in aqueous solution [11].
However, relatively few examples of phosphine chalco-
genides have been described as complexation agents for
the detection of metal cations [12e17]. Indeed, Bis-
(
diphenylthiophosphoryl)ferrocene (dptpf) and seleno
analogue (dpspf) were considered as the ferrocenyl ana-
logues of tetraphenylimidodiphosphinate ligands Ph P(E)-
NH-P(E)Ph
(E ¼ S, Se) [14] and their bonding ability to-
wards Cu(I) was reported [15]. Furthermore, the
P(S)(NMe Fe and (C P(S)(NEt Fe have been
2
2
(
C
5
H
4
2
)
2
)
2
5
H
4
2 2 2
) )
2 2 2
2.3. Preparation of chemosensor MeN[P(S)(NEt ) ]
developed by Nifant'ev and co-workers [16] to stabilize
different metallic cations [17].
MeN(PCl
2 2
) was obtained by the reaction between
In this work, we report the use of bis(tetraethylth-
methylammonium chloride and the excess of phosphorus
trichloride. MeN(PCl
dropwise to a solution of Et
ꢀ
2
iophosphoramidoyl)methylamine, MeN[P(S)(NEt
2
)
2
]
2
,
as
,
2 2
) (11.26 g, 4.8 10 mol) was added
2
þ
2þ
2þ
an electrochemical chemosensor to detect Ca , Ni , Cd
2
NH (40 ml, 0.38 mol) in
2
þ
2þ
2þ
Co , Cu and Fe bivalent cations and to sense simul-
ꢁ
anhydrous diethyl ether (150 ml) cooled at ꢀ78 C. The
taneously Fe2
þ
and Cu
2þ
.
The electrochemical in-
ꢁ
reaction mixture was stirred for 10 h at ꢀ78 C. After
vestigations reveal drastic changes in the potential of the
oxidation peak of the ligand in the presence of above cited
filtration, the obtained oil was dissolved in toluene
(
7
250 ml) and an equivalent amount of sulfur (2.35 g,
2þ
ꢀ
2
ꢁ
metallic cations. Furthermore, the presence of Fe and
.210 mol) was added at 0 C. The desired compound
Please cite this article in press as: A. Mejri, K. Alouani, Bis(tetraethylthiophosphoramidoyl)methylamine as an electrochemical
ligand for the simultaneous detection of iron and copper bivalent cations, Comptes Rendus Chimie (2016), http://dx.doi.org/
Mejri, Alma
