Calixarene Complexes with Transition Metal, Lanthanide and Actinide Ions

23 Pages·2003·0.63 MB·English

CROATICA CHEMICA ACTA CCACAA 75 (1) 131¿153 (2002)
ISSN-0011-1643
CCA-2788 Review
Calixarene Complexes with Transition Metal,
Lanthanide and Actinide Ions
Wanda BSliwa
Institute of Chemistry and Environmental Protection, Pedagogical University,
al. Armii Krajowej 13/15, 42-201 Czeustochowa, Poland
(E-mail: [email protected])
Received December 13, 2000; revised April 9, 2001; accepted May 2, 2001
Selectedcalixarenecomplexeswithtransitionmetalaswellaslan-
thanide and actinide ions are described, showing their syntheses
and possible applications.
Key words: actinides, calixarenes, complexes, lanthanides, nickel,
platinum, rhodium, tantalum, transition metals, tungsten.
INTRODUCTION
Due to their structure and properties, calixarenes are a topic of many
works.1-8 Numerous metal ion complexes of calixarenes are known,9-14 among
them those with transition metal ions.15-18 Title complexes are interesting
from both theoretical and practical viewpoints, for example they are used in
the extraction of lanthanides and actinides from nuclear waste.19,20
The following complexes are described in the present review:
– calixarene complexes with nickel, copper, zinc and silver ions,
– calixarene complexes with chromium, tantalum, tungsten and niobium
ions,
– calixarene complexes with lanthanide and actinide ions,
– calixarene complexes with ruthenium, rhodium, palladium and plati-
num ions.
Referencesofworksthatappearedduringtheyears1998-2000arecited.
132 b
W.SLIWA
CALIXARENE COMPLEXES WITH NICKEL, COPPER,
ZINC AND SILVER IONS
Nickel-thiolato-calixarenecomplexeshavebeeninvestigated.21Thereac-
tion of dichloroethylcalix(cid:1)4(cid:2)arene (1) with nickel(II)thiolate (2) in the pres-
ence of NaI affords nickel(II) and bis-nickel(II)-calixarene complexes (3 and
4), Scheme 1.
N S
O HO OH O + N Ni S NaI/MeCN
Cl 1 Cl 2
O HO OH O + O HO OH O
2I- 2I-
S S S S S S
Ni Ni Ni
N N N N N N
3 4
Scheme 1.
Nickel ion can be removed from complex 3 by treatment with KCN. The
formed free ligand 5 of a crown ether structure contains two nitrogen, two
oxygen and two sulfur electron-donors convenient for further complexation
(Scheme 2).
O HO OH O O HO OH O
KCN/MeCN
S S S S
Ni
N N 2I- N N
3 5
Scheme 2.
133
CALIXARENECOMPLEXES
In the study of fluorescent chemosensors for optical detection of transi-
tion metal ions, bispyrenylcalixarene 6 has been synthesized.22 This com-
pound exists in CDCl solution at room temperature as a mixture of cone
3
and partial cone conformers 6a and 6b (Scheme 3).
Me
O
O O O O O O O
Me R R Me R R Me
6a 6b
OH
N
*
O
R=
Scheme 3.
Fluorescenceintensityinmethanol-watersolutionissensitivetopHand
thepresenceoftransitionmetalions.AdditionofCu2+andNi2+ionsinduces
a strong, pH dependent quenching of fluorescence of 6. Calixarene 6, acting
as an excimer-forming photoresponsive ligand is therefore a selective chemo-
sensor for the detection of Cu2+ and Ni+ ions. The proton induced decom-
plexation makes it possible to distinguish CuII and NiII ions in solution via
fluorescence emission enhancement.22
DinuclearCuIIandZnIIcomplexes7and8(Scheme4)havebeeninvesti-
gated as enzyme models of phosphodiesterase.18,23,24
Me MeMe
Cu2+ Cu2+ N N Me N N
N N N N Zn2+ Zn2+
Me N N N N Me Me N N Me
HO OH
Me Me
O OO O O OO O
O O O O O O O O
7 8
Scheme 4.
134 b
W.SLIWA
Softmetalions,suchasAg+,havehighaffinityto(cid:3)-coordinatinggroups,
e.g. to allyl or phenyl. t-Butyl(cid:1)4(cid:2)arenes have been chosen as examples of such
neutral carriers containing (cid:3)-coordinating substituents for Ag+ sensors. It
was observed that tetraallylether 9a has good ionophoric properties; it shows
very high silver ion selectivity against sodium ion. The calixarene tetraal-
lylester 9b, however, has only low silver ion selectivity with a considerable
sodium ion interference (Scheme 5).25,26
OR 4
R
9a
9b O
O
Scheme 5.
Selenium containing calixarenes 10 and 11 have been synthesized and
their complexing abilities have been investigated.27For comparative purposes,
sulphur and oxygen analogues of 10, i.e. calixarenes 12 and 13, have been
prepared (Scheme 6).27
The highest Ag+ extraction selectivity was found for selenium calixarenes
10 and 11, and for sulphur compound 12, while oxygen calixarene 13 shows
only very low affinity to Ag+ ion. These complexing properties of selenium
calixarenes are of interest in their application for the detection of Ag+ ions
O HO OH O O HO OH O
Se Se
Y Y
Y Me Me
10 Se
12 S 11
13 O
Scheme 6.
135
CALIXARENECOMPLEXES
and for the recovery of Ag+ from industrial waste water.27 A rather unex-
pectedobservationwasthattherewasalmostnoaffinityofcalixarenes10–13
towards Pb2+ ion, whose size is similar to that of Ag+.27,28
In order to obtain calixarene based ion-selective electrodes sensitive to soft
heavy metal ions such as Ag+, Pb2+ and Hg2+, calixarene should be functiona-
lized with groups containing nitrogen and sulphur atoms; in this case, the
binding of soft heavy metal ions is higher than that of alkali metal ions. For
thispurpose,compounds14a,bbearingbenzothiazolylthioalkoxymoietieshave
been synthesized by treating calixarenes 15a,b with 2-mercaptobenzothiazole
(Scheme 7).29 Calixarenes 14a,b adopt cone conformations; it was found that
they are convenient ionophores for silver ion-selective electrodes.29
SH
N S
O HO OH O
O HO OH O NaHCO3
n
n S S
nX Y n
N S S N
X Y n
15a Cl Br 1
15b Br Br 2
n
14a 1
14b 2
Scheme 7.
CALIXARENE COMPLEXES WITH CHROMIUM, TANTALUM,
TUNGSTEN AND NIOBIUM IONS
In the study of the calixarene chromium complexes, the reaction of 16
with (cid:1)CrCl (thf) (cid:2)leading to (cid:1)Cr(cid:4)p-t-Bucalix(cid:1)4(cid:2)(O) (OMe) (cid:5)(Cl)(thf)(cid:2) was car-
3 3 2 2
ried out (Scheme 8).30
[CrCl3(thf)3] O O
NaO MeO OMe
MeO ONa OMe
Cr
16 THF Cl
17
Scheme 8.
136 b
W.SLIWA
Complex17reactswithLiMesandNaCptogivemesitylandcyclopenta-
dienyl derivatives 18 and 19, respectively (Scheme 9).30Complex 18 crystal-
lizes with toluene in 1:2 ratio, one toluene molecule being hosted in the cali-
xarene cavity.
O
O O
MeO OMe MeO O OMe
Cr
Cr
Me Me
19
Me
18
Scheme 9.
The reactivity of CrIII in 18 and 19 is very low, even under photochemi-
cal or thermal conditions. Compound 17, however, undergoes one electron
reduction leading to 20 by treatment with sodium in the presence of naph-
thalene in THF. Complex 20 crystallizes with THF in 1:2 molar ratio, one of
the two THF molecules being encapsulated in the calixarene cavity. This spe-
cies is air sensitive, it readily undergoes oxidation to give 21 via a bridged
peroxodichromium derivative 22, undergoing a cleavage of the O–O bond
(Scheme 10).30
O O O O
MeO OMe MeO OMe
1.O2inn-hexane Cr Cr
17 Na/C8H10 2.toluenereflux
O O O O O O
MeO OMe
Cr Cr
Cr
MeO OMe MeO OMe
THF O O O O
20
22 21
Scheme 10.
The reaction of calixarene 23 with TaCl affords the bis-tantalum com-
5
plex 24, and the reaction of 25 with TaCl results in its demethylation lead-
5
ing to complex 26 (Scheme 11).31
137
CALIXARENECOMPLEXES
O
O
O O
Cl
TaCl5 Cl Ta Ta
OH HO OH OH O O O
O
23
24
TaCl5
HO O
MeO OH OMe O O
MeO
25
Ta
Cl Cl
26
Scheme 11.
The alkylation of 24 gives 27a-c, which are in equilibrium with their
monomeric forms 28a-c. Similar alkylation of 26 leads to 29a-c, which in
thepresenceofpyridineundergodemethylationtogive28a-c(Scheme12).31
26
24
RMgX
RMgX orRLi
orRLi
O
O O
MeO
Ta
O O O O R 29a R
R 29b
R Ta Ta 29c
O O O pyridine
O
O
O O
R O
27a Me Ta
27b CH2Ph
27c p-MeC6H4 R R
28a Me
28bCH2Ph
28c p-MeC6H4
Scheme 12.
138 b
W.SLIWA
Complex 26 may be used for the synthesis of derivatives containing un-
saturated carbon groups bonded with metal, as shown in Scheme 13.31
L L
Li
26 LiC CPh O O O LiC CPh/Et2O O O O
MeO MeO
Ta Ta
C C C C C
C C C C
Ph Ph Ph Ph C
Ph
L=Et2O
Scheme 13.
The reaction of 26 with Mg(C H ) leads to the tantalum-butadiene com-
4 6
plex 30, converted by treatment with acetone into dioxo metallacycle 31
(Scheme 14).31
26 Mg(C4H6) O O O Me2CO O O O
MeO MeO
Ta Ta
Me O O Me
C C
Me Me
30
31
Scheme 14.
In the study of tungsten complexes of calixarenes, the following reac-
tions of 32 were performed (Scheme 15).32,33
It was observed that complex 33 reacts with Ph SnCl to give 34, useful
3
in transmetalation reactions with transition metal derivatives.34,35 The re-
actionof33withphosgeneaffordstheketenylderivative35,whichbytreat-
ment with another molecule of 33 gives an equimolar mixture of 36 and 37;
this reaction proceeds via intermediate 38 (Scheme 16).34
139
CALIXARENECOMPLEXES
+
B(C6F5)3
O
O O
O
W [MeB(C6H5)3]-
Me
O O O O ZnMe2 O O O O
W W
Cl Cl Me Me
32
O
SnCl4 O O O
W
Me Cl
Scheme 15.
Ph3SnCl
O
- O O O
W
C
Ph SnPh3
34
O
O O O
W
C
3P3h Mg+0.5.6THF COCl2 O O O O
W
Cl
C C O
Ph
35
-
O
Ph
C W O
O
Ph
35 33 Cl WC C O O -Cl- O O O O + O O O O
O O O O W W
C O
Mg+0.5.6THF Ph CC 37
Ph
36
38
Scheme 16.
140 b
W.SLIWA
Complex 33 may be used for the synthesis of phosphanylalkylidenes and
theirtransformationintodimetalliccomplexes;itsreactionwithClPPh gives
2
39, which by treatment with (cid:1)(thf)Cr(CO) (cid:2) and (cid:1)CuCOCl(cid:2) affords dimetallic
5
complexes 40 and 41, respectively (Scheme 17).34
O
O O O
[(thf)Cr(CO)]
5 W
C
Ph P Cr(CO)5
Ph2
40
ClPPh
33 2
O
O O O
W
C
[CuCOCl]
Ph PPh2
39
O O O O O O O O
W W
C Cl C
Ph P Cu P Ph
Ph2 Cl Ph2
41
Scheme 17.
Oxidation of 33 by I leads to complex 42, in which the iodine atom may
2
be replaced by various organometallic nucleophiles. For example, the reac-
tion of 42 with NaNMe affords aminoalkylidene 43 (Scheme 18).34
2
-
I2 NMe2
33
O O O O O O O O
W W
C C
Ph I Ph NMe2
42 43
Scheme 18.