Metal ion transport through bulk liquid membrane mediated by cationic ligand surfactants

Article abstract of DOI:10.1135/cccc20050441

A series of N,N,N-trialkyl-2-(hydroxyimino)-2-(pyridin-2-yl)ethan-1-aminium nitrates 3a-3h and N,N,N-trialkyl-4-(hydroxyimino)-4-(pyridin-2-yl)butan-1- aminium nitrates 3i-31 representing cationic surfactants with a powerful 1-(hydroxyimino)-1-(pyridin-2-yl)alkyl chelating subunit were prepared as potential selective metal ion extractants. Their extraction ability was tested in transport of Cu²⁺, Ni²⁺, Co²⁺, and Pd ²⁺ through a bulk liquid membrane. The introduction of the cationic group into the extractant molecule increases the selectivity and facilitates the metal ion transport as shown by comparing the transports carried out with ligand surfactants 3 and lipophilic alkyl pyridin-2-yl ketoximes 2. The efficiency and selectivity of the metal ion transport mediated by ligand surfactants 3 depends predominantly on their structure and lipophilicity, i.e. on the number and length of hydrophobic alkyl chains and on the length of the spacer connecting the chelating moiety with the cationic head group of the surfactant.

Full text of DOI:10.1135/cccc20050441

Metal Ion Transport Through Bulk Liquid Membrane
441
METAL ION TRANSPORT THROUGH BULK LIQUID MEMBRANE
MEDIATED BY CATIONIC LIGAND SURFACTANTS
1
2
3,
4
Eva SVOBODOVÁ , Radek CIBULKA , František HAMPL *, Jan ŠMIDRKAL and
František LIŠKA5
Department of Organic Chemistry, Institute of Chemical Technology, Prague,
1
2
Technická 5, 166 28 Prague 6, Czech Republic; e-mail: svobodoe@vscht.cz, cibulkar@vscht.cz,
3
4
5
hamplf@vscht.cz, smidrkal@sas.upenn.edu, liskaf@vscht.cz
Received Decem ber 20, 2004
Accepted February 21, 2005
A series of N,N,N-trialkyl-2-(h ydroxyim in o)-2-(pyridin -2-yl)eth an -1-am in ium n itrates 3a–3h
an d N,N,N-trialkyl-4-(h ydroxyim in o)-4-(pyridin -2-yl)butan -1-am in ium n itrates 3i–3l repre-
sen tin g cation ic surfactan ts with a powerful 1-(h ydroxyim in o)-1-(pyridin -2-yl)alkyl ch elatin g
subun it were prepared as poten tial selective m etal ion extractan ts. Th eir extraction ability
2
+
2+
2+
2+
was tested in tran sport of Cu , Ni , Co , an d Pd th rough a bulk liquid m em bran e. Th e
in troduction of th e cation ic group in to th e extractan t m olecule in creases th e selectivity an d
facilitates th e m etal ion tran sport as sh own by com parin g th e tran sports carried out with
ligan d surfactan ts 3 an d lipoph ilic alkyl pyridin -2-yl ketoxim es 2. Th e efficien cy an d selec-
tivity of th e m etal ion tran sport m ediated by ligan d surfactan ts 3 depen ds predom in an tly
on th eir structure an d lipoph ilicity, i.e. on th e n um ber an d len gth of h ydroph obic alkyl
ch ain s an d on th e len gth of th e spacer con n ectin g th e ch elatin g m oiety with th e cation ic
h ead group of th e surfactan t.
Keyw ord s: Ligan ds; Liquid m em bran es; Metal ion tran sport; Oxim es; Pyridin e derivatives;
Surfactan ts; Copper; Palladium ; Quatern ary am m on ium salts; Extraction s.
Im portan t in dustrial processes like h ydrom etallurgy, recovery of precious
m etals, waste water treatm en t, an d isolation an d separation of radio-
1
n uclides utilize solven t extraction or m etal ion tran sport th rough liquid
1
b,2
m em bran e
.
Liquid m em bran e stan ds for an organ ic solven t im m iscible with water
separatin g source an d receivin g aqueous ph ases. Metal ion tran sport
th rough liquid m em bran e from th e source ph ase in to receivin g ph ase is
m ediated by a lipoph ilic ligan d dissolved in th e m em bran e. So far, th ree
types of liquid m em bran es differin g in th e th ickn ess of organ ic layer an d
m utual position s of all ph ases h ave been described2
b–2f
: bulk, supported,
an d em ulsion liquid m em bran es. From th e th eoretical poin t of view, m etal
ion tran sport th rough liquid m em bran e provides a useful tool for th e in ves-
Collect. Czech. Chem. Commun. (Vol. 70) (2005)
doi:10.1135/cccc20050441

4
42
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
tigation of in teraction s between m etal ion s an d ligan ds at th e aqueous/
organ ic in terface, wh ich en ables explorin g an d ch aracterizin g th e stren gth
an d selectivity of h ost–guest in teraction s an d oth er features as well as
studyin g th e prin ciples of specific m etal ion tran sport an d partition in g in
1
b,2d
livin g system s
.
Num erous m etal ion carriers derived for exam ple from crown eth ers an d
th eir aza an alogues (azacrown s, cyclen s an d cyclam s), lariate eth ers, an d
calixaren es h ave been reported in coun tless papers over th e years (see, e.g.,
2
b,2d,2f,3a–3c
3d–3i
reviews
an d several recen tly publish ed papers
). Various lig-
an ds of m uch sim pler structures h ave been design ed for in dustrial applica-
tion s. Clearly, both th e efficien cy an d selectivity of th ese extractan ts are
usually lower com pared to th e above-m en tion ed ligan ds tailored often as
4
selective cation receptors. Oxim es of α-h ydroxyketon es, e.g. LIX 63 (lit. ),
5
oxim es of o-h ydroxyacetoph en on es, e.g. LIX 84 (lit. ), 7-alkyl-8-h ydroxy-
6
quin olin es, e.g. Kelex 100 (lit. ), an d dialkyl ph osph ates, e.g. sodium
7
bis(2-eth ylh exyl)ph osph ate (D2EHPA) can be given as exam ples of in dus-
8
trial extractan ts. Tetraazadiol 1 prepared by Men ger seem s to be on e of th e
2
+
m ost efficien t Cu carriers so far reported.
OH
NOH
CH3
NOH
n-C9H19
OH
LIX 63
LIX 84
C2H5
O
O
O
C2H5
n-C4H9
n-C4H9
P
-
n-C4H9
N
O Na+
CH3 OH
Kelex 100
C2H5
D2EHPA
OH
HO
N
N
NH HN
n-C16H33
n-C16H33
1
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
443
To disclose th e m ech an ism of m etal ion tran sfer across th e aqueous/
organ ic in terface as well as th e factors govern in g th is process, Ton dre an d
co-workers in vestigated com plexation an d m etal ion tran sport in m icelles
6
a,9
6a,9e
an d m icroem ulsion s . In several cases
th ey observed rem arkable dif-
feren ces in th e rates of various m etal ion extraction by th e sam e ligan d.
Sim ilar kin etic selectivity h as been reported for lipoph ilic alkyl pyridin -2-yl
2
+
2+
2+
ketoxim es 2 an d Cu , Co , an d Ni ion s in m icelles of cetyltrim eth yl-
1
0
am m on ium brom ide .
Despite its poten tial, th e focus on surfactan t-like m etal ion carriers h as
been low so far. On ly a few exam ples of lipoph ilic ligan ds possessin g an
ion ic h ead group h ave been reported1
b,2d
. Th e ion ic h ead group in th ese
ligan d surfactan ts is usually form ed by protolytic reaction s. Ligan ds com -
8
,11
12
prisin g am in o
an d carboxylic fun ction s serve as exam ples. If th ese
types of ligan ds are em ployed in m etal ion tran sport th rough liquid m em -
bran e, th e uph ill tran sport (i.e. tran sport again st th e con cen tration gradi-
en t) an d th e sh uttle effect (i.e. tran sport of m ore th an stoich iom etric
am oun t of th e m etal ion ) can be observed. Th ere are two essen tial prerequi-
sites for successful uph ill tran sport (Sch em e 1): (i) m etal ion tran sport from
th e source ph ase is com pen sated by proton coun ter-tran sport from th e re-
ceivin g ph ase; th e con stan t differen ce in pH values of th e source an d re-
ceivin g ph ases is a drivin g force of th e process, (ii) an ion izable fun ction
participates in coordin ation to m etal ion .
source
phase
liquid
membrane
receiving
phase
Mn+
HL+
Mn+
H+
MLn+
H+
pHsource
>
pHreceiving
SCHEME 1
N,N,N-Trialkyl-ω-(h ydroxyim in o)-ω-(pyridin -2-yl)alkan -1-am in ium salts 3
possessin g a cation ic h ead group an d 1-(h ydroxyim in o)-1-(pyridin -2-yl)-
alkyl ch elatin g subun it are oth er exam ples of ligan d surfactan ts. Origin ally,
1
2
we h ave syn th esized eth an -1-am in ium salts 3a–3c (R = CH , R = alkyl
3
1
3a
C –C ) to serve as ligan ds for m etallom icellar h ydrolytic catalysts . In pi-
8
12
lot experim en ts, we h ave also exam in ed th eir ability to extract m etal ion s
from aqueous ph ase in to organ ic solven ts; two-ch ain salts 3f an d 3h were
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
44
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
in volved in th is study as well13b. Th e efficien cy of th e carrier 3f in Cu2+
tran sport th rough liquid m em bran e was com parable to th at of Men ger’s
“
m agic” tetraazadiol 1.
2
a
b
c
d
e
f
R
CH3
n-C3H7
n-C6H13
n-C8H17
n-C10H21
n-C12H25
R
N
NOH
3
a
b
c
d
e
f
n
1
1
1
1
1
1
1
1
3
3
3
3
R1
R2
CH
CH
CH
CH
3
3
3
3
8 17
n-C H
n-C10
n-C12
n-C16
H
21
25
33
H
H
R1
(
2 n
CH )
n-C
n-C
6
H
H
13
n-C
n-C
6
H
13
N
N+ R2 NO -
3
H
17
NOH
8
17
8
CH
3
g
h
i
n-C10
n-C16
H
21 n-C10
33 n-C16
H
21
H
H
33
n-C
n-C
6
H
13
n-C
n-C
6
H
13
j
8
H
17
8
H
17
k
l
n-C10
H
21 n-C10
H
21
n-C12
H
25 n-C12
H
25
Prom isin g results of our prelim in ary tran sport experim en ts with eth an -
am in ium salts1 3a–3c, 3f, an d 3h en couraged us to perform m ore detailed
an d system atic in vestigation of th e extraction ability in a series of N,N,N-
trialkyl-ω-(h ydroxyim in o)-ω-(pyridin -2-yl)alkan -1-am in ium salts 3. We
con sidered th e ligan d surfactan ts 3 to be prospective m etal ion carriers:
th eir am ph iph ilic n ature allows th em to orien t th em selves on th e ph ase in -
terface an d pen etrate with th eir ch elatin g subun it in to aqueous ph ase as
sh own sch em atically in Fig. 1. Proton ation of n itrogen atom of pyridin e fa-
3b
aqueous phase
N
HON
(CH2)n
CH3
N+
R1
R2
3
organic phase
FIG. 1
Expected orien tation of th e ligan d surfactan ts 3 at th e aqueous/organ ic in terface
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
445
cilitates m etal ion release at th e liquid m em bran e/receivin g ph ase in terface
an d allows coun ter-tran sport of proton s.
Th is paper is focused on th e in fluen ce of th e quatern ary am m on ium m oi-
ety structure an d th e len gth of th e spacer between th e ion ic h ead group
an d th e ch elatin g fun ction on th e extraction ability of cation ic ligan d sur-
factan ts. Besides, th e efficien cy of lipoph ilic alkyl pyridin -2-yl ketoxim es 2
in m etal ion tran sport th rough liquid m em bran e was exam in ed as well.
Th ese experim en ts served as a referen ce in th e evaluation of th e in fluen ce
of th e cation ic h ead group in th e m olecule of th e carrier on th e m etal ion
tran sport rate an d selectivity.
RESULTS AND DISCUSSION
Syntheses of Metal Ion Carriers 2 and 3
Th e n ew eth an am in ium ligan ds 3d , 3e, an d 3g em ployed in th is study were
prepared usin g th e described procedure1 : 2-(brom oacetyl)pyridin e an d
correspon din g lipoph ilic tertiary am in es afforded quatern ary 2-oxo-
3b
2
-(pyridin -2-yl)eth an -1-am in ium salts 4. Salts 4 were tran sform ed to ligan d
surfactan ts 3d , 3e, an d 3g by th e reaction with h ydroxylam in e utilizin g th e
2
+
13b
stabilizin g effect of Ni ion s
followed by an ion exch an ge (Sch em e 2).
R1
CH
3
N
R1
N+ R2
R2
N
Br
Br
-
N
O
O
CH
3
4
1
2
3
4
. NH
2
OH·HCl, pyridine, Ni2+
-EDTA
. Amberlite IRA 400 (OH-)
. HNO
. Na
2
R1
3
N+ R2 NO
NOH CH
-
4
N
a–3h
3
3
3
SCHEME 2
Two syn th etic routes for th e preparation of keton es 5, th e key in term edi-
ates in th e syn th esis of butan am in ium ligan ds 3i–3l, were con sidered. Th e
first in volved th e addition of th e 3-(dialkylam in o)propylm agn esium h alide
to pyridin e-2-carbon itrile, th e oth er th e addition of (pyridin -2-yl)lith ium to
4
3
-(dialkylam in o)butan en itriles 6 (Sch em e 3). Alth ough th e addition of
-(dialkylam in o)propylm agn esium ch lorides to pyridin e-2-carbon itrile
seem ed to be th e m eth od of ch oice (various 4-(dialkylam in o)butan -2-on es
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
46
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
1
4
h ave been prepared usin g th e procedure ), th e preparation of lipoph ilic
-(dialkylam in o)propylm agn esium ch lorides (R = n-C H an d h igh er
3
6
13
h om ologues) failed in our h an ds. Th e altern ative path way, i.e. th e addition
of (pyridin -2-yl)lith ium to n itriles 6, afforded keton es 5. Nitriles 6 were pre-
pared from com m ercially available 4-brom obutan en itrile an d correspon d-
1
5
in g dialkylam in es in th e presen ce of th e Hün ig base (Sch em e 3).
Mg
Cl
NR2
ClMg
NR2
N
CN
N
NR2
O
5
N
Li
R2NH
i-Pr2NEt
NC
Br
NC
NR2
6
SCHEME 3
Quatern ization of keton es 5 with m eth yl iodide followed by th e reaction
of salts 7 with h ydroxylam in e an d an ion exch an ge in th e obtain ed iodides
8
afforded th e desired ligan d surfactan ts 3i–3l in good yields (Sch em e 4).
Th e reverse order of th ese reaction s, i.e. th e reaction of keton es 5 with
h ydroxylam in e followed by quatern ization of th e obtain ed oxim es, led to
com plex m ixtures of products. Dich lorom eth an e was foun d to be a satisfac-
tory solven t for quatern ization of am in o group in lipoph ilic keton es 5. Th e
reaction tim e in th is case (ten s of h ours) can be reduced to 10 m in wh en
th e reaction is perform ed in m icrowave oven usin g toluen e as a solven t.
Th e iodides 8 were con verted to n itrates 3i–3l to preven t air oxidation of
iodide ion durin g th e m etal ion tran sport experim en ts. Th e an ion exch an ge
usin g Am berlite IRA 400 gave h igh er yields (ligan ds 3i–3k) th an th at per-
form ed with silver n itrate (ligan d 3l).
I-
CH3I
+
N
NR2
N
NR2
O
O
5
7
CH3
1
. NH2OH
NO3-
2. anion exchange
7
+
N
NR2
NOH
CH3
3i–3l
SCHEME 4
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
447
All th e prepared salts 3 were of un iform con figuration sin ce on ly on e set
of sign als was foun d in th eir 1H an d C NMR spectra. In th e case of
eth an am in ium salt 3a, irradiation of m eth ylen e proton s at C-1 affords NOE
tran sferred to proton of th e h ydroxyim in o group th us givin g eviden ce of
E con figuration at th e C=N bon d (Fig. 2). We assum e th at all th e oth er
in vestigated salts 3 were of th e sam e con figuration sin ce th e ch em ical
sh ifts of correspon din g h eteroarom atic proton s were practically th e sam e.
13
1
6
It is kn own th at ch em ical sh ifts of h eteroarom atic proton s in alkyl or aryl
pyridin -2-yl ketoxim es are stron gly in fluen ced by th e C=N bon d con figura-
tion – th e differen ces in ch em ical sh ifts of th e correspon din g h etero-
1
6a
arom atic proton s in E an d Z isom ers bein g up to 0.28 ppm (lit. ).
Alkyl pyridin -2-yl ketoxim es 2 were prepared from pyridin e-2-carbo-
n itriles an alogously to th e described procedure1
0a
.
Transport of Metal Ions
Th e extraction ability of th e prepared m etal ion carriers 2 an d 3 was exam -
in ed in tran sport of m etal ion s th rough bulk liquid m em bran e. Th e tran s-
port cell used (Fig. 3) was con structed to follow th e design of apparatus de-
2
a–2c,8
scribed elsewh ere
. Ch loroform layer (70 m l) con tain in g th e tested
ligan d 2 or 3 (70 µm ol) was used as th e liquid m em bran e wh ich separated
th e source (50 m l, pH 4.6) an d th e receivin g (25 m l, pH 1.0) ph ases. Th e ex-
perim en ts were in itiated by ch argin g th e apparatus with th e source ph ase
con tain in g th e total m etal ion am oun t to be tran sported (250 µm ol). Th e
2
:1 ratio of th e source an d receivin g ph ase volum es was ch osen to keep a
substan tial part of th e tran sport experim en t un der uph ill con dition s (as-
sum in g n egligible accum ulation of th e m etal ion in th e m em bran e, th e up-
h ill tran sport starts at th e m om en t wh en on e th ird of th e m etal ion
am oun t h as been tran sferred in to receivin g ph ase). Durin g th e tran sport ex-
perim en ts, th e m etal ion con ten t was m on itored in all th e ph ases – source
an d receivin g, an d in th e m em bran e. To get a better in sigh t in to th e tren ds
Me
Me
n-C8H17
N+
H
H
N
N
3a
OH
FIG. 2
NOE of salt 3a
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
48
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
of th e structure/tran sport ability relation sh ip, th e results of our previously
1
3b
perform ed experim en ts with ligan d surfactan ts
also in cluded in th e discussion given below.
3a–3c, 3f, an d 3h were
Rigorous an alysis of th e obtain ed m etal ion con cen tration vs tim e data
in all th e ph ases is rath er com plex an d lies beyon d th e scope of th is work.
Exact m ath em atical m odel sh ould take in to con sideration – besides th e
m etal ion tran sport from th e source in to receivin g ph ase – also th e n on -
productive proton tran sport from th e receivin g in to source ph ase an d th e
distribution of th e ligan d between th e m em bran e an d aqueous ph ases,
wh ich can be sign ifican t especially in tran sport experim en ts in volvin g
ligan ds of lower lipoph ilicity. Th erefore, we n eeded sim ple an d readily
available criteria allowin g a com parison of th e tran sport effectivity of th e
in vestigated ligan ds. In our opin ion , th e am oun t of m etal ion tran sferred
from th e source ph ase in to m em bran e (sh own as th e percen tage of th e total
m etal ion am oun t in th e experim en t) durin g th e first 24 h of th e tran sport
can be con sidered as a plausible approxim ation of th e in itial tran sport rate
across th is in terface. Th e m etal ion am oun t tran sferred in to receivin g ph ase
durin g th is period is an approxim ation of th e in itial overall m etal ion tran s-
port rate wh ich can serve as a m easure of th e ligan d efficien cy.
2
+
Cu Transport
No Cu2+ tran sport occurred in th e absen ce of th e carrier. All th e in vesti-
2
+
gated types of ligan ds m ediated uph ill tran sport of Cu with th e on ly ex-
ception of ligan d 3a (n o tran sport occurred). Th e tran sport rates in experi-
receiving
phase
source
phase
membrane
FIG. 3
Tran sport cell
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
449
m en ts m ediated by sh ort-ch ain ligan ds 2a an d 3i were very low. Th e stoi-
2
+
ch iom etry of Cu com plexes with sim ilar types of ligan ds was reported to
1
7a–17c
17b,17d,17e
be both 1:1 (lit.
) an d 1:2 (lit.
). Takin g in to con sideration an y
of possible stoich iom etries (both 1:2 an d 1:1) th e occurren ce of th e sh uttle
2
+
effect in all tran sports is un question able (Table I). Th e course of th e Cu
tran sports m ediated by ligan ds 3e an d 3k (Fig. 4) can be given as typical ex-
am ples. In all cases, th e rates of th e Cu2 tran sfer across both in terfaces
were sim ilar sin ce n o substan tial accum ulation of th e m etal ion in th e
m em bran e was observed.
+
1
–3
It is gen erally kn own
th at lipoph ilicity of th e ligan d in fluen ces sign ifi-
can tly its tran sport or extraction ability. Th erefore, we plotted th e observed
2
+
in itial Cu tran sfer rate in to m em bran e as well as th e in itial overall tran s-
port rate again st log P values (logarith m of th e partition coefficien t between
octan -1-ol an d water) for all th e in vestigated ligan ds (Fig. 5). Values of log P
1
8
were calculated usin g a software package Pallas 1.2 (lit. ).
All th e in vestigated carriers (two ch ain am m on ium salts with m on o-
m eth ylen e spacer 3e–3h , two ch ain salts with trim eth ylen e spacer 3i–3l,
an d alkyl pyridin -2-yl ketoxim es 2) exh ibit sim ilar depen den ces of th e in i-
2
+
tial Cu tran sfer rate in to m em bran e as well as th e depen den ce of th e in i-
tial overall tran sport rate on th eir lipoph ilicity. In tran sports m ediated by
alkyl pyridin -2-yl ketoxim es 2, th e Cu2 extraction from th e source ph ase is
som ewh at faster th an its release from th e m em bran e in to receivin g ph ase.
+
1
00
a
100
80
b
8
6
0
0
60
4
0
4
2
0
0
20
0
0
0
20
40
60
80
100
t, h
0
20
40
60
80
100
t, h
FIG. 4
Th e course of th e Cu tran sport m ediated by ligan d 3e (a) an d 3k (b). Cu2+ con ten t in th e
2+
source ph ase (em pty sym bols), receivin g ph ase (full sym bols), an d in th e m em bran e (asterisks)
2
+
is given as a percen tage of th e total Cu am oun t ch arged in to tran sport cell
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
50
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
TABLE I
Cu2+ tran sport m ediated by ligan ds 2 an d 3
Cu2+ am oun t in aqueous ph ases after 24 h ,
Cu2+ am oun t in receiv-
in g ph ase after 100 h ,
a
%
Ligan d
log P
a
%
source ph ase
receivin g ph ase
2
2
2
2
2
2
3
3
3
3
3
3
3
3
a
b
c
d
e
f
0.83
2.03
3.56
4.58
5.60
6.62
5.47
2.87
4.91
6.95
3.21
5.33
7.37
9.41
88
40
36
39
44
61
43
90
21
41
94
38
10
42
7
57
38
38
34
20
34
10
70
54
3
69b
81
88
82
87
86
51
94
84
97
17c
94
90
85
d
e
f
g
i
j
51
74
42
k
l
a
Relative to in itial am oun t. b After 600 h . c After 200 h .
1
00
a
100
80
b
8
0
6
4
0
0
60
40
2
0
0
20
0
0
2
4
6
8
10
0
2
4
6
8
10
log P
log P
FIG. 5
2
+
In itial Cu tran sfer rate from th e source ph ase in to m em bran e vs lipoph ilicity of th e ligan d
(
3
log P) (a). Overall tran sport rate vs lipoph ilicity of th e ligan d (log P) (b). Ligan ds: 3e–3g (᭿),
i–3l (᭹), 2 (ꢀ). Th e dash ed lin es sh ould on ly h elp th e eyes to follow th e poin ts
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
451
Neverth eless, even in th ese cases th e m axim um Cu2+ accum ulation in th e
m em bran e in th e in itial ph ase of th e experim en t did n ot exceed 20% of th e
total m etal ion am oun t. For each structural type, th e carrier efficien cy vs
log P profile sh ows a m arked optim um (Fig. 5). Th is optim um lipoph ilicity
in creases wh en goin g from ketoxim es 2 to salts 3i–3l possessin g tri-
m eth ylen e spacer. Th e m axim um observed Cu2 tran sport rate in creases
in th e sam e order. A com parison of th e m ost efficien t ligan ds from each se-
ries of h om ologues (eth an am in ium salt 3f, butan am in ium salt 3k, an d pro-
pyl pyridin -2-yl ketoxim e 2b) clearly dem on strates th at th e presen ce of th e
quatern ary am m on ium group in th e carrier m olecule in creases th e rate of
th e m etal ion tran sport. Apparen tly, th e presen ce of cation ic h ead group in
th e ligan d m olecule facilitates its adsorption on th e in terface in proper ori-
en tation for th e m etal ion with drawal from th e source ph ase or for its re-
lease in to receivin g ph ase. Of th e two ch ain m on om eth ylen e ligan ds 3e–3h
+
2
+
an d trim eth ylen e ligan ds 3i–3l, th e m ost efficien t Cu carriers were salts 3f
an d 3k. Most likely, th e h igh er efficien cy of ligan d 3k com pared with th at
of ligan d 3f is a con sequen ce of its lon ger spacer between th e quatern ary
n itrogen an d pyridin e m oiety. It is reason able to assum e th at h igh er flexi-
bility of th e ch elatin g fun ction at th e in terface an d th e possibility of its
deeper pen etration in to aqueous ph ase facilitates th e com plexation an d
decom plexation at th e source ph ase–m em bran e an d m em bran e–receivin g
ph ase in terfaces.
In th e case of salts 3, a question also appeared about th e in fluen ce of th e
n um ber of lipoph ilic alkyl ch ain s attach ed to quatern ary n itrogen on th e
2
+
tran sport efficien cy. A com parison of th e rates of Cu tran sport m ediated
by two ch ain salt 3f (th e m ost efficien t two ch ain carrier with m on om eth yl-
en e spacer) an d by an alogous sin gle ch ain salt 3d of sim ilar lipoph ilicity
(
Table I) provides eviden ce of h igh er efficien cy of two ch ain ligan ds.
Other Metal Ion Transport
Majority of tran sport experim en ts perform ed with ligan ds 2 an d 3 did n ot
sh ow detectable ch an ges of th e Ni2 an d Co con ten t in th e source ph ase.
+
2+
Th e on ly exception s were sin gle ch ain decyl an d dodecyl salts 3b an d 3c
wh ich slowly tran sported Ni2 ion s in to receivin g ph ase . In terestin gly,
+
13b
2
+
th e m ore lipoph ilic dodecyl ligan d 3c is a worse Ni carrier th an th e decyl
salt 3b. Slow Ni tran sport occurred also in th e case of sh ort-ch ain ligan ds
a–2c. Sim ilarly to salts 3b an d 3c, th e Ni2+ tran sport rate decreases with
2
+
2
th e ligan d lipoph ilicity (Table II).
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
52
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
Wh at is th e source of th e observed selectivity in m etal ion tran sport
m ediated by ligan ds 2 an d 3? Wh ile Cu2 usually form s square-plan ar
+
2
+
2+
com plexes, th e m etal ion s th at are n ot tran sported (Co an d Ni ) h ave
octah edral coordin ation sph ere. As drawn sch em atically in Fig. 6, lipoph ilic
ch elatin g ligan ds in square-plan ar com plexes can be arran ged at th e in ter-
face in such a way th at all h ydroph obic alkyl ch ain s are orien ted in to or-
gan ic ph ase. On th e oth er h an d, th is is n ot possible for lipoph ilic ligan ds
form in g octah edral com plexes. Th erefore, th e form ation of octah edral com -
plex at aqueous/organ ic in terface is disfavoured alth ough un der n orm al
circum stan ces (i.e. in h om ogen eous solution s) ligan ds possessin g
TABLE II
Ni2+ tran sport m ediated by ligan ds 2 an d 3
Ni2+ am oun t in aqueous ph ases after 24 h ,
Ni2+ am oun t in receiv-
in g ph ase after 100 h ,
a
%
Ligan d
log P
a
%
source ph ase
receivin g ph ase
2
2
2
3
3
a
b
c
b
c
0.83
2.03
3.56
2.41
3.43
77
94
78
90
94
10
4
29
21
8
59b
28b
8
10
6
a
Relative to in itial am oun t. b After 200 h .
aqueous phase
phase interface
organic phase
FIG. 6
Arran gem en t of th e square-plan ar an d octah edral m etal ion com plexes with lipoph ilic ligan ds
at th e aqueous/organ ic in terface
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
453
1
-(h ydroxyim in o)-1-(pyridin -2-yl)alkyl ch elatin g un it readily form stable
1
9
com plexes of NiL stoich iom etry . Th e orien tation of h ydroph obic alkyl
ch ain s of th e ligan d disadvan tagin g th e form ation of Ni com plexes at th e
aqueous/organ ic in terface explain s also th e above-m en tion ed order of th e
3
2
+
2
+
Ni tran sport rates m ediated by ligan ds 2a–2c, 3b, an d 3c.
To verify th is h ypoth esis we decided to test our carriers 3 in palladium
tran sport. In addition to th e fact th at palladium form s square-plan ar com -
plexes, it is worth y of atten tion for its scarcity an d h igh price. Surprisin gly,
2
+
on ly a sm all n um ber of papers dealin g with Pd tran sport th rough liquid
2
0
m em bran e h as been publish ed so far .
2
+
In our prelim in ary experim en ts with Pd tran sport we em ployed salts 3f
an d 3k, th e m ost successful Cu2 carriers. Th e first experim en ts were carried
out with ligan d 3f un der th e sam e con dition s as th e above-m en tion ed
+
2
+
2+
2+
Cu , Co , an d Ni tran sports. However, th e results were disappoin tin g:
2
+
Pd was accum ulated in th e m em bran e on ly (ca. 30% of th e total m etal
am oun t) but n o m etal was detected in th e receivin g ph ase. On ly after in -
creasin g th e h ydroch loric acid con cen tration in th e receivin g ph ase (to
–
1
2+
5
m ol l ), th e tran sfer of Pd ion s across th e m em bran e-receivin g ph ase in -
terface occurred13b. Most likely, th e Pd2+ tran sfer from th e m em bran e de-
pen ds on sufficien t con cen tration of ch loride an ion s in th e receivin g ph ase
2
–
due to th e form ation of [PdCl ] . To verify th is h ypoth esis we perform ed
4
2
+
Pd tran sport usin g a 4.9 M NaCl solution in 0.1 M HCl as a receivin g ph ase
i.e. we kept th e sam e total con cen tration of ch lorides as in th e previous
(
2
+
case). As expected, both th e in itial Pd tran sfer rate in to m em bran e an d
th e in itial overall rate of th e tran sport did n ot differ sign ifican tly in both
2
+
cases. Com parable results were obtain ed with th e Pd tran sport m ediated
by ligan d 3k un der th e sam e con dition s (Table III).
TABLE III
Pd2+ tran sport m ediated by ligan ds 2 an d 3
Pd2+ am oun t in aqueous ph ases after 24 h , %a
Pd2+ am oun t in receivin g
Ligan d
a
ph ase after 100 h , %
source ph ase
receivin g ph ase
3
3
3
3
fb
kb
fc
42
15
21
41
27
55
47
25
57
71
74
70
kc
a
Relative to in itial am oun t. b 5 M HCl as a receivin g ph ase. c 4.9 M solution of NaCl in 0.1 M
HCl.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
54
Conclusion
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
Com parison of tran sport experim en ts perform ed with ligan ds 2 with out
ion ic h ead group an d ligan ds 3 possessin g a quatern ary am m on ium m oiety
dem on strates th at ligan d surfactan ts are prom isin g agen ts in m etal ion ex-
traction s from aqueous solution s in to organ ic solven ts. Th e results of th e
tran sport experim en ts provide eviden ce of both th e lipoph ilic part of th e
ligan d (i.e. th e n um ber an d len gth of th e h ydroph obic alkyl ch ain ) an d th e
distan ce between th e ch arged h ead group an d th e ch elatin g un it stron gly
in fluen cin g th e efficien cy of th e m etal ion carrier an d th eir usefuln ess in
design in g n ew ligan d surfactan ts for m etal ion extraction s. Obviously, a
successful extractan t of th is type sh ould con tain a flexible spacer allowin g
deeper pen etration of th e ch elatin g un it in to aqueous ph ase. Con siderin g
th e lipoph ilic part of th e m olecule, two sh ort h ydroph obic alkyl ch ain s
seem to be m ore useful th an on e lon g ch ain providin g th e sam e lipo-
ph ilicity. Most likely, two ch ain ligan d surfactan t m olecules are able to ar-
ran ge m ore favourably at th e ph ase in terface th an th e sin gle-ch ain on es as
2
1
a con sequen ce of th e h ydroph ilic/lipoph ilic balan ce .
Gen erally, th e selectivity of m etal ion extraction s with lipoph ilic ligan ds
is con trolled predom in an tly by th e stability of th e resultin g com plex. Nev-
erth eless, th is is n ot th e case of ligan d surfactan ts wh ose m obility at th e in -
terface is restricted. Depen din g on th e com plex stoich iom etry som e coordi-
n ation sites in th e coordin ation sph ere of th e m etal ion m igh t be in accessi-
ble to don or atom s of th e ligan d. Th is circum stan ce can be utilized in de-
sign in g n ew m etal ion extractan ts with en h an ced selectivity.
EXPERIMENTAL
Gen eral
Tem perature data are un corrected. NMR spectra were recorded on Varian Gem in i 300
300.08 MHz for 1H) an d Bruker AMX3 400 (400.13 MHz for H an d 125.77 MHz for C)
1
13
(
spectrom eters. Ch em ical sh ifts are given in ppm relative to an in tern al stan dard tetra-
–
1
m eth ylsilan e (δ 0.0), couplin g con stan ts, J, are given in Hz. In frared spectra (ν in cm ) were
taken on an FTIR spectrom eter Nicolet 740. TLC an alyses were carried out on DC Alufolien
Kiesegel 60 F254 (Merck). Preparative colum n ch rom atograph y was perform ed on silica gel
Kieselgel 60 0.040–0.063 m m (Merck). Elem en tal an alyses were perform ed on a Perkin –Elm er
2
40 an alyser.
Ch em icals
All solven ts were purified by stan dard procedures. Dih exylam in e (purum ), dioctylam in e
(
purum ), didecylam in e (purum ), N-eth yldiisopropylam in e (purum ), 4-brom obutan en itrile
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
455
(
purum ), butyllith ium (2.5 M solution in h exan e), h ydroxylam in e (purum ), an d 2-acetyl-
pyridin e (purum ) were obtain ed from Aldrich , 2-brom opyridin e (purum ) an d m eth yl iodide
(
purum ) were products of Fluka. Cu(NO3)2 an d Ni(NO3)2 (an alytical grade), an d oth er auxil-
2
2
iary ch em icals an d solven ts were obtain ed from Lach em a Brn o. Didodecylam in e
dih exadecylam in e , N-m eth yldih exylam in e , N-m eth yldioctylam in e , N-m eth yldidecyl-
am in e , N-m eth yldih exadecylam in e , N,N-dim eth ylh exadecylam in e , an d 2-(brom o-
acetyl)pyridin e h ydrobrom ide
,
2
2
22
22
2
2
22
13a
1
3a
were prepared usin g th e described procedures.
Alkyl Pyridin -2-yl Ketoxim es (2). Gen eral Procedure
Aqueous solution of h ydroxylam in e (50%) or aqueous solution of h ydroxylam in e h ydro-
ch loride an d potassium carbon ate were added in several portion s to a stirred refluxin g solu-
tion of keton e in eth an ol un til th e startin g com poun d was com pletely con verted to oxim e.
Th e con version of th e reaction was m on itored by TLC with eluen t ch loroform –m eth an ol
1
00:1. After evaporation of solven ts, th e obtain ed crude oxim e was purified by crystalliza-
tion from eth an ol–water or by colum n ch rom atograph y.
Methyl pyridin-2-yl ketoxime (2a). Yield 80%, m .p. 122–123 °C (lit.
1
0b
120–122 °C). 1H NMR
CDCl ): 2.41 s, 3 H (CH ); 7.26 dd, 1 H, J(5,4) = 2J(5,6) = 6.6 (H-5); 7.68 td, 1 H, J(4,3) =
2
2
(
2
3
3
J(4,5) = 7.7, J(4,6) = 1.7 (H-4); 7.84 d, 1 H, J(3,4) = 7.9 (H-3); 8.64 d, 1 H, 2J(6,5) = 4.4
3
2
(
H-6).
Propyl pyridin-2-yl ketoxime (2b). Yield 62%, m .p. 46–49 °C (lit. 48 °C). 1H NMR (CDCl ):
2
3
3
2
2
2
0
.98 t, 3 H, J(3′,2′) = 7.7 (CH ); 1.63 qi, 2 H, J(2′,1′) = J(2′,3′) = 7.7 (O=CCH CH ); 2.98 t,
3 2 2
H, J(1′,2′) = 7.7 (O=CCH ); 7.26 m , 1 H (H-5); 7.69 ddd, 1 H, J(4,3) = J(4,5) = 7.7,
2
J(4,6) = 1.7 (H-4); 7.80 dd, 1 H, J(3,4) = 8.2, J(3,5) = 1.1 (H-3); 8.63 dd, 1 H, J(6,5) = 4.9,
J(6,4) = 1.1 (H-6).
Hexyl pyridin-2-yl ketoxime (2c). Yield 90%, m .p. 71–75 °C. 1H NMR (CDCl ): 0.87 t, 3 H,
2
2
2
2
3
2
3
2
3
3
2
2
2
J(6′,5′) = 5.9 (CH ); 1.30 m , 6
HON=CCH CH ); 2.98 t, 2 H, J(1′,2′) = 7.7 (HON=CCH ); 7.26 m , 1 H (H-5); 7.69 ddd, 1 H,
J(4,3) = J(4,5) = 8.0, 3J(4,6) = 1.5 (H-4); 7.8 d, 1 H, 2J(3,4) = 7.8 (H-3); 8.62 d, 1 H, J(6,5) =
H ((CH ) ); 1.58 qi, 2 H, J(2′,1′) = J(2′,3′) = 7.8
2 3
3
2
(
2
2
2
2
2
2
3
9
.3 (H-6). For C12H18N O (206.3) calculated: 69.87% C, 8.79% H, 13.58% N; foun d: 69.94% C,
2
.08% H, 13.52% N.
Octyl pyridin-2-yl ketoxime (2d ). Yield 45%, m .p. 38–42 °C (lit.
1
0a
38–40 °C). 1H NMR
2
2
(
2
CDCl ): 0.86 t, 3 H, J(8′,7′) = 6.7 (CH ); 1.25 m , 10 H ((CH ) ); 1.57 qi, 2 H, J(2′,1′) =
J(2′,3′) = 7.5 (HON=CCH CH ); 2.97 t, 2 H, J(1′,2′) = 7.8 (HON=CCH ); 7.26 m , 1 H (H-5);
3
3
2 5
2
2
2
2
2
2
2
2
7
8
.67 ddd, 1 H, J(4,3) = J(4,5) = 7.6, J(4,6) = 1.7 (H-4); 7.80 d, 1 H, J(3,4) = 7.9 (H-3);
.62 d, 1 H, 2J(6,5) = 4.7 (H-6).
1
Decyl pyridin-2-yl ketoxime (2e). Yield 92%, m .p. 52–54 °C. H NMR (CDCl ): 0.87 t, 3 H,
3
2
2
2
J(10′,9′) = 7.0 (CH ); 1.24 m , 14 H ((CH ) ); 1.57 qi, 2 H, J(2′,1′) = J(2′,3′) = 7.7
3
2 7
2
2
(
2
HON=CCH CH ); 2.98 t, 2 H, J(1′,2′) = 7.9 (HON=CCH ); 7.26 ddd, 1 H, J(5,4) = 8.0,
2 2 2
J(5,6) = 4.9, J(5,3) = 1.2 (H-5); 7.68 ddd, 1 H, J(4,3) = J(4,5) = 7.9, J(4,6) = 1.9 (H-4);
3
2
2
3
.80 dd, 1 H, 2J(3,4) = 8.0, J(3,5) = 1.0 (H-3); 8.62 dd, 1 H, J(6,5) = 4.7, J(6,4) = 1.7 (H-6).
3
2
3
7
For C16H26N O (262.4) calculated: 73.24% C, 9.99% H, 10.68% N; foun d: 73.40% C, 10.50% H,
2
1
0.32% N.
1
0b
58–63 °C). 1H NMR
Dodecyl pyridin-2-yl ketoxime (2f). Yield 75%, m .p. 59–63 °C (lit.
2
2
(
CDCl ): 0.87 t, 3 H, J(12′,11′) = 6.6 (CH ); 1.24 m , 18 H ((CH ) ); 1.57 qi, 2 H, J(2′,1′) =
J(2′,3′) = 7.6 (HON=CCH CH ); 2.97 t, 2 H, J(1′,2′) = 7.7 (HON=CCH ); 7.25 ddd, 1 H,
3
3
2 9
2
2
2
2
2
2
2
3
2
2
3
J(5,4) = 8.0, J(5,6) = 4.9, J(5,3) = 1.1 (H-5); 7.67 ddd, 1 H, J(4,3) = J(4,5) = 7.7, J(4,6) =
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
56
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
1
1
.8 (H-4); 7.80 dd, 1 H, 2J(3,4) = 8.2, 3J(3,5) = 1.1 (H-3); 8.62 dd, 1 H, 2J(6,5) = 5.2, 3J(6,4) =
.4 (H-6).
N,N-Dialkyl-2-(h ydroxyim in o)-N-m eth yl-2-(pyridin -2-yl)eth an -1-am in ium Nitrates (3d –3h ).
Gen eral Procedure
–
1
Aqueous solution of n ickel n itrate (1.3 m ol l ) was m ixed with pyridin e an d eth an ol (1:2:2
2
+
2+
v/v). A blue Ni com plex of pyridin e appeared im m ediately. Salt 4 (2 m ol/m ol Ni ) an d
2
+
h ydroxylam in e h ydroch loride (4 m ol/m ol Ni ) were added an d th e reaction m ixture was
stirred at 60 °C for 45 h . Pyridin e was rem oved in vacuo an d th e residue was dissolved in
2
+
5
0% aqueous eth an ol. Th en Na -EDTA dih ydrate (6 m ol/m ol Ni ) was added to th is solu-
2
tion an d stirred at 60 °C for 3 h . Th e solid was filtered off an d wash ed with 50% aqueous
eth an ol. Th e filtrate was extracted with ch loroform , th e extract dried with an h ydrous so-
dium sulfate an d th e solven t was evaporated. Th e crude product was dissolved in m eth an ol
–
an d th en treated with Am berlite IRA 400 (OH ), n eutralized with n itric acid, evaporated an d
purified by colum n ch rom atograph y or crystallization .
N-Hexadecyl-2-(hydroxyimino)-N,N-dimethyl-2-(pyridin-2-yl)ethan-1-aminium nitrate (3d ). Ni-
trate 3d was prepared from th e salt 4d (0.900 g, 2.12 m m ol) an d h ydroxylam in e h ydroch lo-
ride (0.870 g, 12.45 m m ol) in th e presen ce of Ni(NO3)2 (1.55 m m ol). Colum n ch rom atogra-
ph y with eluen t ch loroform –m eth an ol–aceton e–water 15:5:5:1. Pure product was obtain ed as
1
2
a yellow viscous liquid (0.750 g, 76%). H NMR (CDCl ): 0.88 t, 3 H, J(16′′,15′′) = 6.5 (CH );
3
3
+
+
1
(
.27 m , 26 H ((CH ) ); 1.87 m , 2 H (N CH CH ); 3.18 s, 6 H (N CH ); 3.46 m , 2 H
2 13 2 2 3
N CH ); 4.82 s, 2 H (N CH C=NOH); 7.28 m , 1 H (H-5′); 7.71 dd, 1 H, J(4′,3′) = J(4′,5′) =
2 2
.8 (H-4′); 8.10 d, 1 H, J(3′,4′) = 7.7 (H-3′); 8.52 d, 1 H, 2J(6′,5′) = 4.9 (H-6′). C NMR
+
+
2
2
2
13
6
(
CDCl ): 14.1 (C-16′′); 22.6 (C-15′′); 23.3 (C-14′′); 24.3 (C-13′′); 26.4 (C-12′′); 26.5 (C-11′′);
3
2
9.0 (C-10′′); 29.1 (C-9′′); 29.3 (C-8′′); 29.4 (C-7′′); 29.5 (C-6′′); 29.6 (C-5′′); 29.7 (C-4′′); 31.9
+
(
C-3′′); 43.1 (N CH ); 52.1 (C-2′′); 53.7 (C-1); 58.3 (C-1′′); 120.9 (C-5′); 124.3 (C-4′); 137.2
3
(
C-3′); 149.4 (C-2′); 146.4 (C-6′); 152.2 (C=NOH). For C25H46N O (466.7) calculated: 64.35% C,
4
4
9
.94% H, 12.01% N; foun d: 63.78% C, 10.06% H, 11.74% N.
N,N-Dihexyl-2-(hydroxyimino)-N-methyl-2-(pyridin-2-yl)ethan-1-aminium nitrate (3e). Nitrate
e was prepared from th e salt 4e (2.000 g, 4.92 m m ol) an d h ydroxylam in e h ydroch loride
3
(
2.040 g, 29.52 m m ol) in th e presen ce of Ni(NO3)2 (3.69 m m ol). Colum n ch rom atograph y
with eluen t ch loroform –m eth an ol 10:1. Pure product was obtain ed as a yellow viscous liq-
1
uid (0.900 g, 46%). H NMR (CDCl ): 0.87 m , 6 H (CH ); 1.29 m , 12 H ((CH ) ); 1.77 m , 4 H
3
3
2 3
+
+
+
+
(
7
8
(
(
N (CH CH ) ); 3.09 s, 3 H (N CH ); 3.29 m , 4 H (N (CH ) ); 4.79 s, 2 H (N CH C=NOH);
2 2 2 3 2 2 2
.38 dd, 1 H, J(5′,4′) = J(5′,6′) = 4.5 (H-5′); 7.71 dd, 1 H, J(4′,3′) = J(4′,5′) = 7.5 (H-4′);
.08 d, 1 H, 2J(3′,4′) = 4.4 (H-3′); 8.50 d, 1 H, J(6′,5′) = 3.9 (H-6′). C NMR (CDCl ): 13.8
2
2
2
2
2
13
3
+
C-6′′); 22.8 (C-5′′); 25.9 (C-4′′); 31.1 (C-3′′); 49.9 (N CH ); 51.4 (C-2′′); 56.4 (C-1); 63.9
C-1′′); 121.0 (C-5′); 124.2 (C-4′); 137.1 (C-3′); 146.4 (C-2′); 148.3 (C-6′); 152.6 (C=NOH). For
3
C20H36N O (396.5) calculated: 60.58% C, 9.15% H, 14.13% N; foun d: 59.90% C, 9.23% H,
4
4
1
4.43% N.
2
-(Hydroxyimino)-N-methyl-N,N-dioctyl-2-(pyridin-2-yl)ethan-1-aminium nitrate (3f). Nitrate
3
f was prepared from th e salt 4f (1.045 g, 2.22 m m ol) an d h ydroxylam in e h ydroch loride
(
0.309 g, 4.44 m m ol) in th e presen ce of Ni(NO3)2 (1.11 m m ol). Crystallization from eth an ol–
1
eth er afforded 3f as a wh ite solid (0.221 g, 29%), m .p. 81–83 °C. H NMR (DMSO-d ): 0.87 t,
6
(
6
2
+
H, J(8′′,7′′) = 6.5 (CH ); 1.20 m , 20 H ((CH ) ); 1.69 m , 4 H (N (CH CH ) ); 2.93 s, 3 H
3 2 5 2 2 2
+
2
+
+
N CH ); 3.22 t, 4 H, J(1′′,2′′) = 8.2 (N (CH ) ); 4.70 s, 2 H (N CH C=NOH); 7.50 dd, 1 H,
3
2
2
2
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
457
2
J(5′,4′) = 7.3, 2J(5′,6′) = 5.2 (H-5′); 7.95 m , 2 H (H-3′, H-4′); 8.63 d, 1 H, 2J(6′,5′) = 4.4 (H-6′).
1
3
C NMR (CDCl ): 14.0 (C-8′′); 22.6 (C-7′′); 22.8 (C-6′′); 26.3 (C-5′′); 29.0 (C-4′′); 31.6 (C-3′′);
3
+
4
1
1
9.5 (N CH ); 52.8 (C-2′′); 55.7 (C-1); 62.6 (C-1′′); 121.1 (C-5′); 126.4 (C-4′); 137.1 (C-3′);
3
41.3 (C-2′); 142.8 (C-6′); 152.6 (C=NOH). For C24H45N O (515.7) calculated: 55.91% C, 8.79% H,
5
7
3.58% N; foun d: 55.10% C, 8.32% H, 13.56% N.
N,N-Didecyl-2-(hydroxyimino)-N-methyl-2-(pyridin-2-yl)ethan-1-aminium nitrate (3g). Nitrate
g was prepared from th e salt 4g (4.200 g, 8.20 m m ol) an d h ydroxylam in e h ydroch loride
3
(
2.540 g, 36.60 m m ol) in th e presen ce of Ni(NO3)2 (6.10 m m ol). Colum n ch rom atograph y
with eluen t ch loroform –m eth an ol 10:1. Pure product was obtain ed as a yellow viscous liq-
1
uid (3.680 g, 88%). H NMR (CDCl ): 0.87 m , 6 H (CH ); 1.27 m , 28 H ((CH ) ); 1.83 m , 4 H
3
3
2 7
+
+
+
+
(
7
N (CH CH ) ); 3.14 s, 3 H (N CH ); 3.37 m , 4 H (N (CH ) ); 4.81 s, 2 H (N CH C=NOH);
2 2 2 3 2 2 2
.28 m , 1 H (H-5′); 7.68 dd, 1 H, J(4′,3′) = J(4′,5′) = 7.7 (H-4′); 8.13 d, 1 H, J(3′,4′) = 8.2
H-3′); 8.48 d, 1 H, 2J(6′,5′) = 3.8 (H-6′). 13C NMR (CDCl ): 14.1 (C-10′′); 22.6 (C-9′′); 23.0
2
2
2
(
(
(
3
+
C-8′′); 23.7 (C-7′′); 26.3 (C-6′′); 6.8 (C-5′′); 29.2 (C-4′′); 31.8 (C-3′′); 50.3 (N CH ); 52.1
C-2′′); 55.8 (C-1); 63.9 (C-1′′); 21.2 (C-5′); 24.1 (C-4′); 37.0 (C-3′); 145.8 (C-2′); 148.1 (C-6′);
3
1
6
52.7 (C=NOH). For C28H52N O (508.5) calculated: 66.14% C, 10.31% H, 11.02% N; foun d:
4 4
7.04% C, 10.50% H, 11.32% N.
N,N-Dihexadecyl-2-(hydroxyimino)-N-methyl-2-(pyridin-2-yl)ethan-1-aminium nitrate (3h ). Ni-
trate 3h was prepared from th e salt 4h (1.134 g, 1.49 m m ol) an d h ydroxylam in e h ydroch lo-
ride (0.410 g, 5.88 m m ol) in th e presen ce of Ni(NO3)2 (0.75 m m ol). Colum n ch rom atogra-
ph y with eluen t ch loroform –m eth an ol 100:5. Crystallization from petroleum eth er afforded
1
2
3
6
2
1
1
h as a wh ite solid (0.220 g, 22%), m .p. 93–94 °C. H NMR (CDCl ): 0.88 t, 6 H, J(16′′,15′′) =
3
+
+
.6 (CH ); 1.25 m , 52 H ((CH ) ); 1.79 m , 4 H (N (CH CH ) ); 3.08 s, 3 H (N CH ); 3.26 m ,
3
2
13
2
2
2
3
+
+
+
H (N CH ); 3.38 m , 2 H (N CH ); 4.79 s, 2 H (N CH C=NOH); 7.29 m , 1 H (H-5′); 7.70 td,
2
2
2
2
2
3
2
H, J(4′,3′) = 8.2, J(4′,5′) = 7.7, J(4′,6′) = 1.7 (H-4′); 8.11 d, 1 H, J(3′,4′) = 8.2 (H-3′); 8.49 d,
H, 2J(6′,5′) = 4.4 (H-6′). 13C NMR (CDCl ): 14.1 (C-16′′); 22.5 (C-15′′); 22.7 (C-14′′); 26.2
3
(
(
(
C-13′′); 27.4 (C-12′′); 29.1 (C-11′′); 29.2 (C-10′′); 29.3 (C-9′′); 29.4 (C-8′′); 29.5 (C-7′′); 29.5
+
C-6′′); 29.6 (C-5′′); 29.7 (C-4′′); 31.9 (C-3′′); 49.7 (N CH ); 53.4 (C-2′′); 57.0 (C-1); 62.0
3
C-1′′); 121.4 (C-5′); 125.0 (C-4′); 137.4 (C-3′); 149.4 (C-2′); 149.6 (C-6′); 152.6 (C=NOH). For
C40H76N O (677.1) calculated: 70.96% C, 11.31% H, 8.27% N; foun d: 70.94% C, 10.80% H,
4
4
8
.27% N.
N,N-Dialkyl-4-(h ydroxyim in o)-N-m eth yl-4-(pyridin -2-yl)butan -1-am in ium Nitrates (3i–3l).
Gen eral Procedure
Aqueous solution of h ydroxylam in e (50%) was added in several portion s to a stirred reflux-
in g solution of salt 7 in eth an ol un til th e startin g keton e 7 was com pletely con verted to
oxim e 8. Th e con version of th e reaction was m on itored by TLC with eluen t ch loroform –
m eth an ol–aceton e–water 15:5:5:1. After evaporation of solven ts, th e obtain ed crude iodide 8
was purified by colum n ch rom atograph y with eluen t ch loroform –m eth an ol–aceton e–water
1
5:5:5:1 an d th en con verted to n itrate 3.
Anion exchange, method A: Saturated solution of iodide 8 in m eth an ol was passed th rough
–
–
a colum n packed with Am berlite IRA 400 (OH form , five-fold excess of OH to 8). Th e re-
sultin g solution of quatern ary am m on ium h ydroxide was n eutralized with dilute n itric acid
(
1:1). Evaporation of solven ts afforded th e n itrate 3.
Anion exchange, method B: Equal volum es of aqueous solution of silver n itrate (0.2 m ol l–1)
–
1
an d a solution of iodide 8 in dich lorom eth an e (0.04 m ol l ) were vigorously stirred at room
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
58
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
tem perature overn igh t. Th en , silver iodide was filtered off an d a saturated aqueous solution
of Na -EDTA was added to th e filtrate. Th is m ixture was vigorously stirred overn igh t. Or-
2
gan ic ph ase was wash ed with water an d dried with an h ydrous m agn esium sulfate. Evapora-
tion of dich lorom eth an e afforded th e n itrate 3.
N,N-Dihexyl-4-(hydroxyimino)-N-methyl-4-(pyridin-2-yl)butan-1-aminium nitrate (3i). Oxim e 3i
was prepared from keton e 7i (0.620 g, 1.31 m m ol). Meth od A was used for an ion exch an ge.
1
Pure product was obtain ed as a wh ite solid (0.465 g, 84%), m .p. 55–60 °C. H NMR (CDCl ):
3
.84 t, 6 H, 2J(6′′,5′′) = 6.3 (CH ); 1.23 m , 12 H ((CH ) ); 1.60 m , 4 H (N (CH CH ) );
.09 m , 2 H (HON=CCH CH ); 3.05 t, 2 H, J(3,2) = 6.6 (HON=CCH ); 3.09 s, 3 H (N CH );
+
0
2
3
2
3
2
2 2
2
+
2
2
2
3
+
+
3
2
.22 m , 4 H (N (CH ) ); 3.42 m , 2 H (CH N (C H ) ); 7.24 m , 1 H (H-5′); 7.66 td, 1 H,
2 2 2 6 13 2
J(4′,3′) = 8.3, J(4′,5′) = 7.7, J(4′,6′) = 1.7 (H-4′); 7.97 d, 1 H, J(3′,4′) = 8.3 (H-3′); 8.52 d,
2
3
2
2
13
1
2
H, J(6′,5′) = 4.9 (H-6′); 10.95 s, 1 H (NOH). C NMR (CDCl ): 13.7 (C-6′′); 19.4 (C-5′′);
0.8 (C-4′′); 22.0 (C-3′′); 22.2 (C-2′′); 25.7 (C-2); 30.9 (N CH ); 48.3 (C-3); 60.7 (C-1); 61.7
3
+
3
(
C-1′′); 120.7 (C-5′); 123.5 (C-4′); 136.3 (C-3′); 148.4 (C-6′); 153.6 (C-2′); 156.2 (HON=C). For
C22H40N O (424.6) calculated: 62.24% C, 9.50% H, 13.20% N; foun d: 61.97% C, 9.82% H,
4
4
1
2.97% N.
4
-(Hydroxyimino)-N-methyl-N,N-dioctyl-4-(pyridin-2-yl)butan-1-aminium nitrate (3j): Oxim e 3j
was prepared from keton e 7j (3.085 g, 5.81 m m ol). Meth od A was used for an ion exch an ge.
1
Pure product was obtain ed as a yellow solid (2.145 g, 77%), m .p. 60–64 °C. H NMR (CDCl ):
3
.86 t, 6 H, 2J(8′′,7′′) = 7.1 (CH ); 1.21 m , 20 H ((CH ) ); 1.58 m , 4 H (N (CH CH ) );
.08 m , 2 H (HON=CCH CH ); 3.03 t, 2 H, J(3,2) = 6.6 (HON=CCH ); 3.09 s, 3 H (N CH );
+
0
2
3
2
5
2
2 2
2
+
2
2
2
3
+
+
3
2
.21 m , 4 H (N (CH ) ); 3.41 m , 2 H (CH N (C H ) ); 7.23 m , 1 H (H-5′); 7.67 t, 1 H,
2 2 2 8 17 2
J(4′,5′) = 7.7 (H-4′); 7.97 d, 1 H, J(3′,4′) = 8.3 (H-3′); 8.52 d, 1 H, J(6′,5′) = 4.9 (H-6′).
2
2
1
3
C NMR (CDCl ): 13.8 (C-8′′); 19.3 (C-7′′); 20.7 (C-6′′); 22.0 (C-5′′); 22.3 (C-4′′); 26.1 (C-3′′);
8.8 (C-2′′); 31.4 (C-2); 48.3 (N CH ); 52.7 (C-3); 60.7 (C-1); 61.6 (C-1′′); 120.7 (C-5′); 123.4
3
+
2
3
(
C-4′); 136.3 (C-3′); 148.3 (C-6′); 153.5 (C-2′); 156.5 (HON=C). For C26H48N O (480.7) cal-
4 4
culated: 64.97% C, 10.07% H, 11.66% N; foun d: 64.66% C, 10.53% H, 11.09% N.
N,N-Didecyl-4-(hydroxyimino)-N-methyl-4-(pyridin-2-yl)butan-1-aminium nitrate (3k). Oxim e 3k
was prepared from keton e 7k (2.044 g, 3.48 m m ol). Meth od A was used for an ion exch an ge.
1
Pure product was obtain ed as a wh ite solid (1.490 g, 80%), m .p. 75–77 °C. H NMR (CDCl ):
3
2
+
0
2
3
5
8
.87 t, 6 H, J(10′′,9′′) = 6.6 (CH ); 1.23 m , 28 H ((CH ) ); 1.60 m , 4 H (N (CH CH ) );
3 2 7 2 2 2
.09 m , 2 H (HON=CCH CH ); 3.04 t, 2 H, J(3,2) = 6.1 (HON=CCH ); 3.09 s, 3 H (N CH );
2
+
2
2
2
3
+
+
2
2
.22 m , 4 H (N (CH ) ); 3.42 m , 2 H (CH N (C10H21)2); 7.23 td, 1 H, J(5′,4′) = 2.2, J(5′,6′) =
.0 (H-5′); 7.66 td, 1 H, J(4′,3′) = 7.7, J(4′,5′) = 1.7 (H-4′); 7.97 d, 1 H, J(3′,4′) = 7.7 (H-3′);
.52 d, 1 H, 2J(6′,5′) = 5.5 (H-6′); 11.02 s, 1 H (NOH). C NMR (CDCl ): 14.1 (C-10′′); 19.7
2
2
2
2
2
2
13
3
(
(
(
C-9′′); 20.9 (C-8′′); 22.3 (C-7′′); 22.6 (C-6′′); 26.3 (C-5′′); 29.1 (C-4′′); 29.3 (C-3′′); 29.4
+
C-2′′); 31.8 (C-2); 48.5 (N CH ); 52.8 (C-3); 61.1 (C-1); 61.7 (C-1′′); 120.9 (C-5′); 123.6
3
C-4′); 136.4 (C-3′); 148.3 (C-6′); 153.8 (C-2′); 156.5 (HON=C). For C30H56N O (536.8) cal-
4
4
culated: 67.13% C, 10.52% H, 10.44% N; foun d: 66.92% C, 10.74% H, 10.65% N.
N,N-Didodecyl-4-(hydroxyimino)-N-methyl-4-(pyridin-2-yl)butan-1-aminium nitrate (3l). Oxim e 3l
was prepared from keton e 7l (2.775 g, 4.32 m m ol). Meth od B was used for an ion exch an ge.
1
Pure product was obtain ed as a wh ite solid (0.400 g, 16%), m .p. 65–68 °C. H NMR (CDCl ):
3
.87 t, 6 H, 2J(12′′,11′′) = 6.5 (CH ); 1.24 m , 36 H ((CH ) ); 1.59 m , 4 H (N (CH CH ) );
.08 m , 2 H (HON=CCH CH ); 3.03 t, 2 H, J(3,2) = 6.6 (HON=CCH ); 3.08 s, 3 H (N CH );
.20 m , 4 H (N (CH ) ); 3.41 m , 2 H (CH N (C12H25) ); 7.21 t, 1 H, J(5′,4′) = 7.4, J(5′,6′) =
.0 (H-5′); 7.63 t, 1 H, J(4′,3′) = 7.7 (H-4′); 7.94 d, 1 H, J(3′,4′) = 8.0 (H-3′); 8.50 d, 1 H,
+
0
2
3
3
2
9
2
2 2
2
+
2
2
2
3
+
+
2
2
2
2
2
2
2
2
5
2
13
J(6′,5′) = 4.4 (H-6′); 11.02 s, 1 H (NOH). C NMR (CDCl ): 14.1 (C-12′′); 19.7 (C-11′′); 20.9
3
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
459
(
(
(
C-10′′); 22.3 (C-9′′); 22.7 (C-8′′); 26.3 (C-7′′); 29.1 (C-6′′); 29.3 (C-5′′); 29.4 (C-4′′); 29.5
+
C-3′′, C-2′′); 29.6 (C-3); 31.9 (C-2); 48.5 (N CH ); 61.1 (C-1); 61.7 (C-1′′); 120.9 (C-5′); 123.6
3
C-4′); 136.4 (C-3′); 148.6 (C-6′); 153.8 (C-2′); 156.5 (HON=C). For C34H64N O (592.9) cal-
4
4
culated: 68.88% C, 10.83% H, 9.45% N; foun d: 68.22% C, 11.13% H, 9.56% N.
N,N-Dialkyl-N-m eth yl-2-oxo-2-(pyridin -2-yl)eth an -1-am in ium Brom ides (4)
Brom ides 4 were prepared usin g th e previously described procedure13a. Th e differen ces from
th is procedure (con cern in g isolation an d purification on ly) are given below.
N-Hexadecyl-N,N-dimethyl-2-oxo-2-(pyridin-2-yl)ethan-1-aminium bromide (4d ). Salt 4d was
prepared from h exadecyldim eth ylam in e (1.150 g, 4.23 m m ol) an d 2-(brom oacetyl)pyridin e
h ydrobrom ide (4.89 g, 17.78 m m ol). Crude product was purified by colum n ch rom atogra-
ph y with eluen t ch loroform –m eth an ol 100:15. Pure product was obtain ed as a yellow vis-
1
cous liquid (0.950 g, 53%). H NMR (CDCl ): 0.87 m , 3 H (CH ); 1.26 m , 26 H ((CH )13);
3
3
2
+
+
+
1
(
.70 m , 4 H (N (CH CH ) ); 3.74 s, 6 H (N CH ); 3.86 m , 2 H (N CH ); 5.76 s, 2 H
2 2 2 3 2
N CH C=O); 7.58 m , 1 H (H-5′); 7.91 dd, 1 H, J(4′,5′) = J(4′,3′) = 7.1 (H-4′); 8.03 d, 1 H,
J(3′,4′) = 7.7 (H-3′); 8.68 d, 1 H, 2J(6′,5′) = 4.5 (H-6′).
+
2
2
2
2
N,N-Dihexyl-N-methyl-2-oxo-2-(pyridin-2-yl)ethan-1-aminium bromide (4e). Salt 4e was pre-
pared from dih exylm eth ylam in e (2.600 g, 12.83 m m ol) an d 2-(brom oacetyl)pyridin e h ydro-
brom ide (14.320 g, 51.33 m m ol). Crude product was purified by colum n ch rom atograph y
with eluen t ch loroform –m eth an ol–aceton e–water 15:5:5:1. Pure product was obtain ed as a
1
2
yellow viscous liquid (3.820 g, 78%). H NMR (CDCl ): 0.87 t, 6 H, J(6′′,5′′) = 6.8 (CH );
3
3
+
+
1
(
.31 m , 12 H ((CH ) ); 1.66 m , 4 H (N (CH CH ) ); 3.68 s, 3 H (N CH ); 3.78 m , 2 H
2 3 2 2 2 3
N CH ); 3.96 m , 2 H (N CH ); 5.69 s, 2 H (N CH C=O); 7.59 dd, 1 H, J(5′,4′) = J(5′,6′) =
2 2 2
.8 (H-5′); 7.92 dd, 1 H, J(4′,3′) = J(4′,5′) = 7.6 (H-4′); 8.03 d, 1 H, J(3′,4′) = 7.7 (H-3′);
.68 d, 1 H, 2J(6′,5′) = 3.3 (H-6′).
+
+
+
2
2
2
2
2
6
8
N-Methyl-N,N-dioctyl-2-oxo-2-(pyridin-2-yl)ethan-1-aminium bromide (4f). Salt 4f was pre-
pared from m eth yldioctylam in e (5.180 g, 20.00 m m ol) an d 2-(brom oacetyl)pyridin e h ydro-
brom ide (6.720 g, 24.09 m m ol). Crude product was purified by colum n ch rom atograph y
with eluen t ch loroform –m eth an ol–aceton e–water 35:5:5:1. Pure product was obtain ed as a
1
2
yellow viscous liquid (4.32 g, 46%). H NMR (CHCl ): 0.84 t, 6 H, J(8′′,7′′) = 6.6 (CH );
3
3
+
+
1
.24 m , 20 H ((CH ) ); 1.69 m , 4 H (N (CH CH ) ); 3.66 s, 3 H (N CH ); 3.76 m , 2 H
2 5 2 2 2 3
N CH ); 3.91 m , 2 H (N CH ); 5.63 s, 2 H (N CH C=O); 7.50 dd, 1 H, J(5′,4′) = 7.8,
2 2 2
J(5′,6′) = 4.7 (H-5′); 7.91 dd, 1 H, J(4′,3′) = J(4′,5′) = 7.6 (H-4′); 8.03 d, 1 H, J(3′,4′) = 8.3
H-3′); 8.67 d, 1 H, 2J(6′,5′) = 5.0 (H-6′).
+
+
+
2
(
3
2
2
2
(
N,N-Didecyl-N-methyl-2-oxo-2-(pyridin-2-yl)ethan-1-aminium bromide (4g). Salt 4g was pre-
pared from didecylm eth ylam in e (2.580 g, 8.28 m m ol) an d 2-(brom acetyl)pyridin e h ydrobro-
m ide (6.080 g, 21.64 m m ol). Crude product was purified by colum n ch rom atograph y with
eluen t ch loroform –m eth an ol 10:1. Pure product was obtain ed as a yellow viscous liquid
2
(
1
(
(
5.400 g, 90%). 1H NMR (CDCl ): 0.87 t, 6 H, J(10′′,9′′) = 7.1 (CH ); 1.23 m , 28 H ((CH ) );
3
3
2 7
+
+
+
.66 m , 4 H (N (CH CH ) ); 3.68 s, 3 H (N CH ); 3.80 m , 2 H (N CH ); 3.95 m , 2 H
2 2 2 3 2
+
+
2
2
N CH ); 5.68 s, 2 H (N CH C=O); 7.60 m , 1 H (H-5′); 7.91 dd, 1 H, J(4′,3′) = J(4′,5′) = 7.4
2 2
H-4′); 8.05 d, 1 H, J(3′,4′) = 6.3 (H-3′); 8.69 d, 1 H, 2J(6′,5′) = 3.9 (H-6′).
2
N,N-Dihexadecyl-N-methyl-2-oxo-2-(pyridin-2-yl)ethan-1-aminium bromide (4h ). Salt 4h was
prepared from dih exadecylm eth ylam in e (2.870 g, 5.60 m m ol) an d 2-(brom acetyl)pyridin e
h ydrobrom ide (2.300 g, 8.25 m m ol). Crude product was purified by colum n ch rom atogra-
ph y with eluen t ch loroform –m eth an ol 10:1. Pure product was obtain ed as a yellow viscous
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
60
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
1
liquid (1.290 g, 32%). H NMR (CDCl ): 0.87 m , 6 H (CH ); 1.30 m , 52 H ((CH )13); 1.70 m ,
3
3
2
+
+
+
+
4
2
H (N (CH CH ) ); 3.67 s, 3 H (N CH ); 3.80 m , 2 H (N CH ); 3.94 m , 2 H (N CH ); 5.66 s,
2 2 2 3 2 2
H (N CH C=O); 7.59 dd, 1 H, J(5′,4′) = J(5′,6′) = 6.4 (H-5′); 7.91 dd, 1 H, J(4′,3′) =
J(4′,5′) = 7.8 (H-4′); 8.03 d, 1 H, J(3′,4′) = 7.8 (H-3′); 8.68 d, 1 H, 2J(6′,5′) = 4.9 (H-6′).
+
2
2
2
2
2
2
4
-(Dialkylam in o)-1-(pyridin -2-yl)butan -1-on es (5). Gen eral Procedure
A solution of 2.5 M butyllith ium in h exan e (10.0 m m ol) was added dropwise at –25 °C un -
der n itrogen with in 20 m in to a stirred solution of 2-brom opyridin e (10.1 m m ol) in eth er
(
85 m l). Th e obtain ed dark-red solution was cooled to –78 °C an d stirred for 5 m in . Th en , a
solution of butan en itrile 6 (7.6 m m ol) in eth er (15 m l) was added dropwise. After stirrin g at
78 °C (2 h ) an d at am bien t tem perature (4 h ), th e reaction m ixture was quen ch ed with 1 M
–
h ydroch loric acid (150 m l). Organ ic layer was wash ed with water (5 × 150 m l). Aqueous
ph ase was alkalin ized with potassium carbon ate an d th en extracted with eth er (9 × 100 m l).
Th e com bin ed organ ic layers were dried with an h ydrous m agn esium sulfate. Evaporation of
solven ts afforded crude product wh ich was purified by colum n ch rom atograph y.
4
-(Dihexylamino)-1-(pyridin-2-yl)butan-1-one (5i). Keton e 5i was prepared from 2-brom o-
pyridin e (1.600 g, 10.13 m m ol) an d n itrile 6i (1.905 g, 7.55 m m ol). Gradien t elution with
dich lorom eth an e–m eth an ol from 100:1 to 10:1. Pure product was obtain ed as a reddish vis-
1
2
cous liquid (0.950 g, 39%). H NMR (CDCl ): 0.86 t, 6 H, J(6′′,5′′) = 6.6 (CH ); 1.24 m , 12 H
3
3
(CH ) ); 1.39 m , 4 H (N(CH CH ) ); 1.89 qi, 2 H, J(2,1) = 2J(2,3) = 7.3 (COCH CH ); 2.40 t,
2
(
4
2 3 2 2 2 2 2
2
2
2
H, J(1′′,2′′) = 7.4 (N(CH ) ); 2.51 t, 2 H, J(1,2) = 7.4 (CH N(C H13)2); 3.22 t, 2 H, J(3,2) =
2 2 2 6
.4 (CH CO); 7.45 ddd, 1 H, J(5′,4′) = 7.7, J(5′,6′) = 4.7, J(5′,3′) = 1.1 (H-5′); 7.82 td, 1 H,
2
J(4′,3′) = J(4′,5′) = 7.7, J(4′,6′) = 2.2 (H-4′); 8.03 d, 1 H, J(3′,4′) = 7.7 (H-3′); 8.67 d, 1 H,
J(6′,5′) = 4.9 (H-6′). C NMR (CDCl ): 13.9 (C-6′′); 21.3 (C-5′′); 22.5 (C-4′′); 26.6 (C-3′′);
2
2
3
7
2
2
3
2
2
13
3
2
(
7.1 (C-2); 31.7 (C-2′′); 35.4 (C-3); 53.3 (C-1); 53.8 (C-1′′); 121.5 (C-5′); 126.8 (C-4′); 136.6
C-3′); 148.7 (C-6′); 153.5 (C-2′); 201.6 (C=O). IR (CHCl ): 1696 (CO).
3
4
-(Dioctylamino)-1-(pyridin-2-yl)butan-1-one (5j). Keton e 5j was prepared from 2-brom o-
pyridin e (3.685 g, 23.32 m m ol) an d n itrile 6j (5.625 g, 18.23 m m ol). Gradien t elution with
dich lorom eth an e–m eth an ol from 100:1 to 1:1. Pure product was obtain ed as a reddish vis-
1
2
cous liquid (3.905 g, 55%). H NMR (CDCl ): 0.84 t, 6 H, J(8′′,7′′) = 6.6 (CH ); 1.22 m , 20 H
3
3
(CH ) ); 1.35 m , 4 H (N(CH CH ) ); 1.85 qi, 2 H, J(2,1) = 2J(2,3) = 7.4 (COCH CH ); 2.35 t,
2
(
4
2 5 2 2 2 2 2
2
2
2
H, J(1′′,2′′) = 7.4 (N(CH ) ); 2.47 t, 2 H, J(1,2) = 7.4 (CH N(C H17)2); 3.19 t, 2 H, J(3,2) =
2 2 2 8
.1 (CH CO); 7.41 td, 1 H, J(5′,4′) = 7.7, J(5′,6′) = 4.4, J(5′,3′) = 1.1 (H-5′); 7.78 td, 1 H,
2
J(4′,3′) = J(4′,5′) = 7.7, J(4′,6′) = 1.7 (H-4′); 8.00 d, 1 H, J(3′,4′) = 7.7 (H-3′); 8.64 d, 1 H,
J(6′,5′) = 4.4 (H-6′). C NMR (CDCl ): 14.0 (C-8′′); 21.5 (C-7′′); 22.6 (C-6′′); 26.9 (C-5′′);
2
2
3
7
2
2
3
2
2
13
3
2
(
7.6 (C-2); 29.3 (C-4′′); 29.5 (C-3′′); 31.8 (C-2′′); 35.5 (C-3); 53.4 (C-1); 54.0 (C-1′′); 121.6
C-5′); 126.8 (C-4′); 136.7 (C-3′); 148.8 (C-6′); 153.6 (C-2′); 201.7 (C=O).
-(Didecylamino)-1-(pyridin-2-yl)butan-1-one (5k). Keton e 5k was prepared from 2-brom o-
4
pyridin e (3.205 g, 20.28 m m ol) an d n itrile 6k (5.615 g, 15.40 m m ol). Gradien t elution with
dich lorom eth an e–m eth an ol from 100:3 to 10:1. Pure product was obtain ed as a reddish vis-
1
2
cous liquid (1.560 g, 23%). H NMR (CDCl ): 0.86 t, 6 H, J(10′′,9′′) = 6.9 (CH ); 1.23 m , 28 H
3
3
(
2
(CH ) ); 1.50 m , 4 H (N(CH CH ) ); 1.97 qi, 2 H, 2J(2,1) = 2J(2,3) = 7.4 (COCH CH );
2 7 2 2 2 2 2
2
.56 m , 4 H (N(CH ) ); 2.66 m , 2 H (CH N(C10H21)2); 3.25 t, 2 H, J(3,2) = 6.9 (CH CO);
2 2 2 2
.45 ddd, 1 H, J(5′,4′) = 7.7, J(5′,6′) = 4.4, J(5′,3′) = 1.1 (H-5′); 7.81 td, 1 H, J(4′,3′) =
2
2
3
2
7
2
3
2
2
J(4′,5′) = 7.7, J(4′,6′) = 1.7 (H-4′); 8.01 d, 1 H, J(3′,4′) = 7.7 (H-3′); 8.65 d, 1 H, J(6′,5′) =
5
.5 (H-6′). 13C NMR (CDCl ): 13.9 (C-10′′); 20.0 (C-9′′); 22.5 (C-8′′); 25.6 (C-7′′); 27.2 (C-6′′);
3
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
461
2
(
9.1 (C-5′′); 29.3 (C-2); 29.3 (C-4′′); 29.4 (C-3′′); 31.7 (C-2′′); 35.1 (C-3); 52.6 (C-1); 53.3
C-1′′); 121.5 (C-5′); 126.9 (C-4′); 136.6 (C-3′); 148.7 (C-6′); 153.2 (C-2′); 201.0 (C=O).
-(Didodecylamino)-1-(pyridin-2-yl)butan-1-one (5l). Keton e 5l was prepared from
-brom opyridin e (2.310 g, 14.60 m m ol) an d n itrile 6l (3.550 g, 8.40 m m ol). Gradien t elu-
4
2
tion with dich lorom eth an e–m eth an ol from 100:3 to 1:1. Pure product was obtain ed as a red-
1
2
dish viscous liquid (2.530 g, 60%). H NMR (CDCl ): 0.88 t, 6 H, J(12′′,11′′) = 6.7 (CH );
3
3
1
.25 m , 36 H ((CH ) ); 1.68 m , 4 H (N(CH CH ) ); 2.12 m , 2 H (COCH CH ); 2.80 m , 6 H
2 9 2 2 2 2 2
2
2
2
(
3
N(CH ) ); 3.31 t, 2 H, J(3,2) = 6.6 (CH CO); 7.47 ddd, 1 H, J(5′,4′) = 7.4, J(5′,6′) = 4.9,
2 3 2
J(5′,3′) = 1.3 (H-5′); 7.82 td, 1 H, J(4′,3′) = J(4′,5′) = 7.7, J(4′,6′) = 1.7 (H-4′); 8.00 dd, 1 H,
2
2
3
2
J(3′,4′) = 7.7, J(3′,5′) = 1.1 (H-3′); 8.65 dd, 1 H, 2J(6′,5′) = 5.5, 3J(6′,4′) = 1.7 (H-6′). C NMR
3
13
(
CDCl ): 14.0 (C-12′′); 22.6 (C-11′′); 27.0 (C-10′′); 29.1 (C-9′′); 29.2 (C-8′′); 29.4 (C-7′′, C-6′′);
3
2
9.4 (C-5′′, C-4′′, C-3′′); 29.5 (C-2); 31.8 (C-2′′); 34.8 (C-3); 52.0 (C-1); 52.9 (C-1′′); 121.6
(
C-5′); 127.2 (C-4′); 136.8 (C-3′); 149.0 (C-6′); 153.0 (C-2′); 200.6 (C=O).
4
-(Dialkylam in o)butan en itriles (6). Gen eral Procedure
A solution of 4-brom obutan en itrile (20.0 m m ol), dialkylam in e (20.3 m m ol), an d N-eth yl-
diisopropylam in e (20.1 m m ol) in eth an ol (125 m l) was refluxed for 100 h . After coolin g th e
reaction m ixture an d evaporation of th e solven ts, th e residue was dissolved in dich loro-
m eth an e (150 m l), wash ed with 2 M h ydroch loric acid (8 × 100 m l) an d th en vigorously
stirred with a saturated solution of potassium carbon ate (120 m l) for 2 h . Organ ic layer was
dried with an h ydrous m agn esium sulfate. Evaporation of th e solven t afforded crude product
wh ich was purified by colum n ch rom atograph y.
4
-(Dihexylamino)butanenitrile (6i). Nitrile 6i was prepared from 4-brom obutan en itrile
(
(
2
0
3.050 g, 20.61 m m ol), dih exylam in e (3.880 g, 20.93 m m ol), an d N-eth yldiisopropylam in e
2.675 g, 20.69 m m ol). Gradien t elution with petroleum eth er–eth yl acetate from 100:30 to
1
:1. Pure product was obtain ed as a yellow viscous liquid (4.070 g, 78%). H NMR (CDCl ):
3
2
2
.86 t, 6 H, J(6′,5′) = 6.6 (CH ); 1.25 m , 12 H ((CH ) ); 1.36 t, 4 H, J(2′,1′) = 6.6
3
2 3
2
2
2
(
N(CH CH ) ); 1.72 qi, 2 H, J(3,2) = J(3,4) = 6.6 (NCCH CH ); 2.33 t, 4 H, J(1′,2′) = 7.1
2 2 2 2 2
N(CH ) ); 2.38 t, 2 H, J(4,3) = 7.1 (CH N(C H13)2); 2.45 t, 2 H, J(2,3) = 6.6 (NCCH ).
2 2 2 6 2
C NMR (CDCl ): 14.0 (C-6′); 14.7 (C-2); 22.6 (C-5′); 23.8 (C-4′); 27.1 (C-3′); 27.2 (C-3);
2
2
(
1
3
3
3
1
1.8 (C-2′); 52.3 (C-4); 54.1 (C-1′); 120.0 (C-1). For C16H32N2 (252.4) calculated: 76.13% C,
2.78% H, 11.10% N; foun d: 74.58% C, 12.86% H, 11.24% N.
4
-(Dioctylamino)butanenitrile (6j). Nitrile 6j was prepared from 4-brom obutan en itrile
(
(
4.435 g, 36.72 m m ol), dioctylam in e (8.980 g, 37.19 m m ol), an d N-eth yldiisopropylam in e
4.750 g, 36.75 m m ol). Gradien t elution with petroleum eth er–eth yl acetate from 100:30 to
1
1
0
6
7
:1. Pure product was obtain ed as a yellow viscous liquid (6.525 g, 58%). H NMR (CDCl ):
3
.87 t, 6 H, 2J(8′,7′) = 6.6 (CH ); 1.26 m , 20 H ((CH ) ); 1.39 qi, 4 H, 2J(2′,1′) = 7.1, 2J(2′,3′) =
.6 (N(CH CH ) ); 1.74 qi, 2 H, J(3,2) = 6.6, J(3,4) = 7.1 (NCCH CH ); 2.35 t, 4 H, J(1′,2′) =
.7 (N(CH ) ); 2.40 t, 2 H, J(4,3) = 7.1 (CH N(C H13)2); 2.47 t, 2 H, J(2,3) = 6.6 (NCCH ).
C NMR (CDCl ): 13.4 (C-8′); 13.9 (C-2); 22.1 (C-7′); 23.3 (C-6′); 26.7 (C-5′); 26.9 (C-3);
3
2 5
2
2
2
2
2 2
2
2
2
2
2
2
2
6
2
1
3
3
2
8.8 (C-4′); 29.0 (C-3′); 31.3 (C-2′); 51.7 (C-4); 53.5 (C-1′); 118.9 (C-1). For C20H40N2 (308.6)
calculated: 77.85% C, 13.07% H, 9.08% N; foun d: 77.19% C, 13.06% H, 9.44% N.
-(Didecylamino)butanenitrile (6k ). Nitrile 6k was prepared from 4-brom obutan en itrile
4
(
(
3.560 g, 24.05 m m ol), didecylam in e (7.160 g, 24.06 m m ol), an d N-eth yldiisopropylam in e
3.120 g, 24.14 m m ol). Gradien t elution with petroleum eth er–eth yl acetate from 4:1 to 1:1.
1
Pure product was obtain ed as a yellow viscous liquid (6.693 g, 76%). H NMR (CDCl ): 0.86 t,
3
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

4
62
Svobodová, Cibulka, Hampl, Šmidrkal, Liška:
6
H, 2J(10′,9′) = 6.6 (CH ); 1.25 m , 28 H ((CH ) ); 1.38 m , 4 H (N(CH CH ) ); 1.73 qi, 2 H,
3
2
7
2
2 2
2
2
2
J(3,2) = 6.6, J(3,4) = 7.1 (NCCH CH ); 2.34 t, 4 H, J(1′,2′) = 7.7 (N(CH ) ); 2.39 t, 2 H,
2
2
2 2
2
2
13
J(4,3) = 7.1 (CH N(C10H21)2); 2.47 t, 2 H, J(2,3) = 6.6 (NCCH ). C NMR (CDCl ): 14.1
2
2
3
(
C-10′); 14.7 (C-2); 22.8 (C-9′); 24.0 (C-8′); 27.3 (C-7′); 27.6 (C-6′); 29.4 (C-5′); 29.7 (C-4′,
C-3′); 29.8 (C-3); 32.0 (C-2′); 54.2 (C-1′); 54.4 (C-4); 119.9 (C-1). For C24H48N2 (364.7) calcu-
lated: 79.05% C, 13.27% H, 7.68% N; foun d: 78.79% C, 13.58% H, 7.67% N.
4
-(Didodecylamino)butanenitrile (6l). Nitrile 6l was prepared from 4-brom obutan en itrile
(
(
2.895 g, 19.56 m m ol), didodecylam in e (6.900 g, 19.51 m m ol), an d N-eth yldiisopropylam in e
2.540 g, 19.65 m m ol). Elution with petroleum eth er–eth yl acetate 5:1. Pure product was ob-
1
2
tain ed as a yellow viscous liquid (4.985 g, 61%). H NMR (CDCl ): 0.88 t, 6 H, J(12′,11′) =
3
2
2
6
1
2
1
.6 (CH ); 1.27 m , 36 H ((CH ) ); 1.39 qi, 4 H, J(2′,1′) = J(2′,3′) = 6.9 (N(CH CH ) );
3 2 9 2 2 2
2
2
2
.76 qi, 2 H, J(3,2) = J(3,4) = 6.6 (NCCH CH ); 2.36 t, 4 H, J(1′,2′) = 7.4 (N(CH ) ); 2.42 t,
2
2
2 2
2
2
13
H, J(4,3) = 7.1 (CH N(C12H25)2); 2.49 t, 2 H, J(2,3) = 6.5 (NCCH ). C NMR (CDCl ):
2
2
3
4.1 (C-12′); 14.8 (C-2); 22.7 (C-11′); 23.8 (C-10′); 27.1 (C-9′); 27.5 (C-8′); 29.3 (C-7′); 29.6
(
C-6′, C-5′); 29.6 (C-4′, C-3′); 29.7 (C-3); 31.9 (C-2′); 52.4 (C-4); 54.1 (C-1′); 120.0 (C-1). For
C28H56N2 (420.8) calculated: 79.93% C, 13.41% H, 6.66% N; foun d: 79.98% C, 13.71% H,
6
.60% N.
N,N-Dialkyl-N-m eth yl-4-oxo-4-(pyridin -2-yl)butan -1-am in ium Iodides (7).
Gen eral Procedure
Method A: A solution of keton e 5 (2.0 m m ol) an d m eth yl iodide (15.3 m m ol) in toluen e
(
50 m l) was h eated un der stirrin g at 90 °C in a m icrowave reactor (Syn th ewave 402, Prolabo)
for 10 m in . Evaporation of th e solven t afforded th e crude product.
Method B: A solution of keton e 5 (2.0 m m ol) an d m eth yl iodide (15.3 m m ol) in dich loro-
m eth an e (50 m l) was stirred at am bien t tem perature for 78 h . Evaporation of th e solven t
afforded th e crude product. Th e obtain ed salts 7 were used for th e preparation of target lig-
an ds 3 with out an y purification .
N,N-Dihexyl-N-methyl-4-oxo-4-(pyridin-2-yl)butan-1-aminium iodide (7i). Salt 7i was prepared
from keton e 5i (0.700 g, 2.11 m m ol) an d m eth yl iodide (1.0 m l, 16 m m ol) usin g m eth od A.
1
2
Yield 0.620 g (62%). H NMR (CDCl ): 0.87 t, 6 H, J(6′′,5′′) = 6.6 (CH ); 1.33 m , 12 H
3
3
(CH ) ); 1.77 m , 4 H (N (CH CH ) ); 2.14 qi, 2 H, 2J(2,1) = 8.2, 2J(2,3) = 6.6 (COCH CH );
+
(
3
2 3 2 2 2 2 2
+
+
+
.34 s, 3 H (N CH ); 3.45 m , 6 H (N (CH ) , CH CO); 3.59 m , 2 H (CH N (C H13)2); 7.48
3 2 2 2 2 6
ddd, 1 H, J(5′,4′) = 2.8, J(5′,6′) = 4.9, J(5′,3′) = 1.1 (H-5′); 7.83 td, 1 H, J(4′,3′) = 7.7,
J(4′,5′) = 1.7 (H-4′); 7.98 d, 1 H, 2J(3′,4′) = 8.2 (H-3′); 8.65 d, 1 H, 2J(6′,5′) = 4.9 (H-6′).
2
2
3
2
2
N-Methyl-N,N-dioctyl-4-oxo-4-(pyridin-2-yl)butan-1-aminium iodide (7j). Salt 7j was prepared
from keton e 5j (3.480 g, 8.95 m m ol) an d m eth yl iodide (1.2 m l, 19 m m ol) usin g m eth od A.
1
2
Yield 3.08 g (65%). H NMR (CDCl ): 0.86 t, 6 H, J(8′′,7′′) = 6.3 (CH ); 1.37 m , 20 H
3
3
(CH ) ); 1.75 m , 4 H (N (CH CH ) ); 2.15 qi, 2 H, 2J(2,1) = 7.3, 2J(2,3) = 6.6 (COCH CH );
+
(
3
2 5 2 2 2 2 2
+
+
+
.35 s, 3 H (N CH ); 3.46 m , 6 H (N (CH ) , CH CO); 3.60 m , 2 H (CH N (C H17)2);
3 2 2 2 2 8
.49 ddd, 1 H, 2J(5′,4′) = 1.7, J(5′,6′) = 5.5, J(5′,3′) = 1.1 (H-5′); 7.84 td, 1 H, J(4′,3′) = 7.7,
J(4′,5′) = 1.7 (H-4′); 7.99 d, 1 H, 2J(3′,4′) = 7.7 (H-3′); 8.66 d, 1 H, 2J(6′,5′) = 4.4 (H-6′).
N,N-Didecyl-N-methyl-4-oxo-4-(pyridin-2-yl)butan-1-aminium iodide (7k ). Salt 7k was pre-
pared from keton e 5k (1.550 g, 3.49 m m ol) an d m eth yl iodide (3.0 m l, 48 m m ol) usin g
2
3
2
7
2
1
2
m eth od B. Yield 2.044 g (99%). H NMR (CDCl ): 0.85 t, 6 H, J(10′′,9′′) = 6.6 (CH ); 1.24 m ,
3
3
+
2
3
8 H ((CH ) ); 1.77 m , 4 H (N (CH CH ) ); 2.15 m , 2 H (COCH CH ); 3.08 m , 2 H (CH CO);
2 7 2 2 2 2 2 2
.34 s, 3 H (N CH ); 3.45 m , 6 H (N (CH ) ); 3.58 m , 2 H (CH N (C10H21)2); 7.49 td, 1 H,
+
+
+
3
2
2
2
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Metal Ion Transport Through Bulk Liquid Membrane
463
2
J(5′,4′) = 1.1, 2J(5′,6′) = 4.4 (H-5′); 7.84 td, 1 H, 2J(4′,3′) = 7.7, 2J(4′,5′) = 1.7 (H-4′); 7.98 d, 1 H,
J(3′,4′) = 7.7 (H-3′); 8.65 d, 1 H, 2J(6′,5′) = 3.9 (H-6′).
2
N,N-Didodecyl-N-methyl-4-oxo-4-(pyridin-2-yl)butan-1-aminium iodide (7l). Salt 7l was pre-
pared from keton e 5l (2.445 g, 4.88 m m ol) an d m eth yl iodide (4.5 m l, 72 m m ol) usin g
1
2
m eth od B. Yield 2.775 g (88%). H NMR (CDCl ): 0.88 t, 6 H, J(12′′,11′′) = 6.7 (CH ); 1.26 m ,
3
3
+
2
3
7
6 H ((CH ) ); 1.78 m , 4 H (N (CH CH ) ); 2.17 m , 2 H (COCH CH ); 3.03 t, 2 H, J(3,2) =
2 9 2 2 2 2 2
.0 (CH CO); 3.36 s, 3 H (N CH ); 3.48 m , 4 H (N (CH ) ); 3.63 m , 2 H (CH N (C12H25) );
.50 td, 1 H, J(5′,4′) = 7.4, J(5′,6′) = 4.2, J(5′,3′) = 1.4 (H-5′); 7.84 ddd, 1 H, J(4′,3′) = 7.7,
J(4′,5′) = 7.7, J(4′,6′) = 1.7 (H-4′); 7.99 dd, 1 H, J(3′,4′) = 7.1, J(3′,5′) = 1.1 (H-3′); 8.66 d,
+
+
+
2
3
2
2
2
2
2
2
3
2
7
2
3
2
3
1
H, 2J(6′,5′) = 4.7 (H-6′).
Tran sport Experim en ts
A glass tube (48 m m an d 44.5 m m were th e extern al an d in tern al diam eters, respectively)
was im m ersed coaxially in to a cylin drical glass vessel (in tern al diam eter 57 m m ) ben eath
th e surface of th e ch loroform layer (70 m l), th us separatin g two aqueous ph ases: th e source
ph ase (50 m l) an d th e receivin g ph ase (25 m l). Th e ch loroform layer (liquid m em bran e) was
stirred slowly (60 rpm ) by a m ech an ical stirrer keepin g th e ph ase in terfaces m otion less
–
3
(
Fig. 3). Th e cell was th erm ostatted at 25 ± 0.5 °C. Th e source ph ases were 5.0 × 10
M
–
3
aqueous solution s of Cu(NO ) , Ni(NO ) an d Co(NO ) , an d 5.0 × 10 M PdCl2 in 2.0 ×
M aqueous NaCl. Acetate buffer (5.0 × 10 m ol l , pH 4.7) was used to adjust pH of
th e source ph ases. Th e receivin g ph ase was 0.1 M HCl (Cu2+, Co , an d Ni ), 5.0 M HCl
3
2
3
2
3 2
–
2
–1
–1
1
0
2+
2+
2
+
2+
(
Pd ), or 4.9 M NaCl in 0.1 M HCl (Pd ). In all cases, th e con cen tration of th e carrier in
ch loroform m em bran e was 1.0 × 10 m ol l–1
–
3
.
Con cen tration of Cu , Co2+, an d Ni2+ ion s in source an d receivin g ph ases an d in ch loro-
2+
form m em bran e was determ in ed spectroph otom etrically usin g sodium dieth yldith iocarba-
8
m ate trih ydrate . Th e absorban ce was m easured with a Hewlett–Packard HP8452 spectro-
2
+
ph otom eter. Con cen tration of Pd
in all ph ases was determ in ed spectroph otom etrically
2
4
usin g pyridin e-2-carbaldoxim e
.
The authors thank the Prague Institute of Chemical Technology and Ministry of Education, Youth
and Sports of the Czech Republic (grant No. 223100001) for financial support of this project.
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