M. Alyapyshev et al. / Polyhedron 29 (2010) 1998–2005
1999
were proposed for Am/lanthanides separation from acidic
solutions [15,16]. Diamides of dipicolinic acid were also tested in
the presence of CCD. It was found that DPA–CCD system selectively
extract Am over lanthanides from 1 to 5 M nitric acid with high
separation factors of Am from light lanthanides (La–Gd). The selec-
tivity of extraction tends to decrease with increasing of metal
atomic number: DAm/DLa is >100; while DAm/DEu does not exceed
168.68, 154.63, 153.92, 137.65, 123.45, 121.30, 48.69, 45.66,
31.11, 29.63, 20.29, 19.76, 13.90, 13.55.
2.2. Dynamic NMR experiments
1
The H NMR spectra were recorded at 400.13 MHz on a BRUKER
‘
‘Avance400” instrument in approximately 0.2 mol/l solutions in
toluene-d and CD CN in 5 mm probe tubes at different tempera-
tures (deuteriated solvent as internal lock).
4
[17].
8
3
New selective sensors for rare earths elements determination
have been nowadays widely developed and tested [18,19]. The
ion–ligand interaction in the liquid–liquid extraction system has
much in common with an interaction of metal ion with ionophore
in the sensor membrane, so it is worth to use the ligands studied in
liquid-liquid extraction as ionophores. It was shown in some pa-
pers [20,21] and also in our previous works [22–24] that such ap-
proach allows to reach good results in many cases.
2.3. Extraction experiments
1
,2-Dichloroethane and polar fluorinated solvents (meta-nitro-
benzotrifluoride (F-3) and phenyltrifluoromethyl sulfone (FS-13))
were used as diluents for synthesised diamides.
The present work is devoted to the new type of ‘‘soft-hard hy-
þ
ꢁ
For the preparation of H BCl solution, a cesium salt of chlori-
6
0
0
brid donor” ligands – diamides of 2,2 -dipyridyl-6,6 -dicarboxylic
nated cobalt dicarbollide was used. The exact weighted amount of
cesium salt of CCD dissolved in a desired diluent was contacted
twice with 4 M perchloric acid solution. The aqueous phase and ce-
sium perchlorate sediment were thrown away and a solution of
0
0
acid. If compare with DPA, diamides of 2,2 -dipyridyl-6,6 -dicar-
boxylic acid possess in their structure additional pyridine ring,
and should complex metal as tetradentate compounds. Moreover
the introducing of the additional ‘‘soft donor” (nitrogen of pyridine
ring) to the structure is to increase the selectivity of the ligand to-
ward americium.
þ
ꢁ
H BCl in a diluent was filtered through a paper filter. The con-
6
centration of CCD in the solution was determined by titration of
the aliquots with NaOH solution using bromcresol green as an indi-
cator and by Co-analysis.
The aim of the present work was the study of extraction and
separation of Am and lanthanides from nitric acid solution with
The extraction experiments were carried out in 5 ml polypro-
pylene vials. One ml of organic phase and one ml of aqueous phase
0
0
new diamides of 2,2 -dipyridyl-6,6 -dicarboxylic acid both alone
and in the presence of CCD, and development of new ion selective
sensors on the base of studied diamides.
ꢁ3
were placed in vials. An aqueous phase contained 10 M euro-
pium nitrate in nitric acid of desired concentration spiked with
2
41
152
either
Am or
Eu. The samples were vigorously agitated for
3
min at room temperature (21 ± 1 °C). Phases were separated after
2
. Experimental
a short centrifugation for 5–10 min, and aliquots (0.4 ml) were
taken for analysis. The distribution ratios were determined radio-
metrically using a DeskTop InSpector-1270 scintillation
2.1. Synthesis of Dyp-1 and Dyp-2
c-spec-
trometer designed on the base of a well-type NaI-detector
0
0
1
0 ml of SOCl
2
, 2.0 g (8.2 mmol) of 2,2 -dipyridyl-6,6 -dicarbox-
5
1
1 ꢀ 51 mm ‘‘Canberra” Co. The measurement error was less than
ylic acid and one drop of DMF were refluxed for 3 h. Excess of SOCl
2
5%.
was removed under reduced pressure and the resulting solid finely
dried. The solid residue was dissolved in dry THF (120 ml). This
solution was added dropwise to a mixture of 2.22 ml (17.2 mmol)
The extraction of lanthanides and fission products was studied
by ICP-MS method. The initial solution contained 22 metals (La,
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, Cu, Zn, Cd,
Pb, Pd, Zr and Mo) in nitric acid of desired concentration. The
0
0
00
HNR R” (HNR R : N-ethylaniline for Dyp-1; dibutylamine for
Dyp-2), 8.3 ml (59 mmol) NEt and THF (20 ml) at 50 °C. The
resulting mixture was stirred overnight at this temperature, then
poured into water (70 ml) and extracted with CHCl
(2 ꢀ 150 ml).
The combined organic extracts were washed with water
2 ꢀ 120 ml) and dried over NaSO . Rotary evaporation of the or-
ganic solution yielded 74% Dyp-1 or 80% Dyp-2.
Dyp-1: mp. 182–184 °C. Anal Calc. for C28
.82; N, 12.44. Found: C, 74.50; H, 5.90; N, 12.32%. H NMR
400 MHz, CDCl ) d: 7.63 (d, 1H), 7.46 (t, 1H), 7.17 (d, 1H), 7.07
m, 5H, Ph), 4.01 (q, 4H, CH
3
ꢁ4
concentration of each metal in initial solution was 1 ꢀ 10 M.
3
2.4. Sensors experiments
(
4
The new sensors on the base of Dyp-1 diamide were prepared
and tested in accordance with the procedure described previously
in [24]. Sensor membranes consist of high molecular weight poly-
vinyl chloride (PVC) as a polymer, o-nitrophenyloctyl ether (NPOE)
as a solvent-plasticizer, potassium tetrakis[3,5-bis(trifluormeth-
yl)phenyl] borate (KTFB) and chlorinated cobalt(III) dicarbollide
(CCD) were used as an ion-exchanger, Dyp-1 was used as neutral
ligand with cadmium selectivity. The polymeric sensor membranes
were produced according to the following standard procedure.
Weighed amounts of membrane components were dissolved in
freshly distilled tetrahydrofuran (THF) and stirred for 20 min on
a magnet stirrer. Once the components were dissolved in the
THF, the membrane cocktail was poured into a flat bottom teflon
beaker and allowed to stand overnight at room temperature to
evaporate the solvent. Disks 8 mm in diameter and 0.5 mm thick
were cut from the parent membranes and attached with PVC glue
onto the end of PVC tubes (10 mm in diameter) used as electrode
bodies.
26 4 2
H N O : C, 74.65; H,
1
5
(
(
(
(
7
1
3
1
2 3
), 1.24 (t, 6H, CH ). H NMR
400 MHz, ACETONITRILE-d3) d ppm: 1.18 (t, J = 6.97 Hz, 3H) 3.94
d, J = 6.97 Hz, 2H) 7.04–7.34 (m, 5H) 7.57 (d, J = 7.34 Hz, 2H)
C NMR (CDCl ) d: 153.57, 143.43,
3
36.88, 128.77, 127.55, 126.44, 124.21, 121.53, 45.51, 12.77. IR
13
.74 (t, J = 7.34 Hz, 1H).
ꢁ1
(
KBr), cm : 1639 (amide I).
42 4 2
Dyp-2: m.p. 66–68 °C. Anal. Calc. for C28H N O : C, 72.07; H,
1
9
.07; N, 12.01. Found: C, 72.15; H, 9.18; N, 12.19%. H NMR (CDCl
d: 8.42 (d, 1H), 7.89 (t, 1H), 7.60 (d, 2H), 3.54 (t, 2H, cis-CH ), 3.36
t, 2H, trans-CH ), 1.69 (m, 4H), 1.44 (q, 2H, cis-CH ), 1.11 (q, 2H,
trans-CH ), 1.00 (t, 3H, cis-CH ), 0.74 (t, 3H, trans-CH
400 MHz, TOLUENE-d ) d ppm: 0.67 (t, J = 7.34 Hz, 3H) 0.86–1.05
m, 5H) 1.35 (tq, J = 7.43 Hz, 2H) 1.54 (tt, J = 7.80, 7.58 Hz, 2H)
3
)
2
(
2
2
1
2
3
3
). H NMR
(
(
1
3
0
8
.67 (tt, J = 7.80, 7.58 Hz, 2H) 3.14–3.32 (m, J = 7.58, 7.58 Hz, 2H)
.50 (t, J = 7.34 Hz, 2H) 7.30 (t, J = 7.70 Hz, 1H) 7.55 (dd, J = 7.82,
Electrochemical measurements were carried out in the follow-
ing galvanic cell (in case of liquid contact sensors):
.98 Hz, 1H) 8.31 (dd, J = 7.83, 0.98 Hz, 1H); 13C NMR (CDCl
) d:
3