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The effect of counteranions on the molecular structures of phosphanegold() cluster cations formed by polyoxometalate (POM)-mediated clusterization
The effect of counteranions on the molecular structures of phosphanegold( i ) cluster cations formed by polyoxometalate (POM)-mediated clusterization was investigated. A novel intercluster compound, [{(AuL Cl ) 2 (-OH)} 2 ] 3 [-PMo 12 O 40 ] 2 3EtOH ( 1-PMo 12 ), was obtained as orange-yellow plate...
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| Published in: | Dalton transactions : an international journal of inorganic chemistry 2016-09, Vol.45 (34), p.13565-13575 |
|---|---|
| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Subjects: | |
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| Online Access: | Get full text |
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| Summary: | The effect of counteranions on the molecular structures of phosphanegold(
i
) cluster cations formed by polyoxometalate (POM)-mediated clusterization was investigated. A novel intercluster compound, [{(AuL
Cl
)
2
(-OH)}
2
]
3
[-PMo
12
O
40
]
2
3EtOH (
1-PMo
12
), was obtained as orange-yellow plate crystals in 12.0% yield from a 6:1 molar ratio reaction of the monomeric phosphanegold(
i
) carboxylato complex [Au(
RS
-pyrrld)(L
Cl
)] (
RS
-Hpyrrld =
RS
-2-pyrrolidone-5-carboxylic acid; L
Cl
= tris(4-chlorophenyl)phosphane) in CH
2
Cl
2
with the free acid-form of Keggin polyoxometalate (POM), H
3
[-PMo
12
O
40
]14H
2
O. An EtOH/H
2
O (5:1, v/v) solvent mixture was used. The dimeric cation [{(AuL
Cl
)
2
(-OH)}
2
]
2+
in
1-PMo
12
was in a parallel-edge arrangement that was formed by self-assembly through the inter-cationic aurophilic interactions of the -OH-bridged dinuclear phosphanegold(
i
) cation. The POM anion in
1-PMo
12
was successfully exchanged with a smaller PF
6
anion by the use of an anion-exchange resin. POM-free, colorless block crystals of [{(AuL
Cl
)
3
(
3
-O)}
2
](PF
6
)
2
4CH
2
Cl
2
(
2-PF
6
) were obtained by vapor diffusion in 14.1% yield. During the synthesis of
2-PF
6
, a compound with mixed counteranions (one POM and one PF
6
anion),
i.e.
[{(AuL
Cl
)
4
(
4
-O)}]
2
[-PMo
12
O
40
]PF
6
(
3-PMo
12
PF
6
), was obtained in 66.4% yield. Both products were characterized by elemental analysis, TG/DTA, FT-IR,
31
P{
1
H} NMR,
1
H NMR, and X-ray crystallography. X-ray crystallography revealed that the countercation in
2-PF
6
was the dimeric cation of the
3
-O-bridged tris{phosphanegold(
i
)} species, whereas that in
3-PMo
12
PF
6
consisted of an unusual
4
-O-bridged tetragonal-pyramidal tetrakis{phosphanegold(
i
)} cation. Therefore, we concluded that the POM anion significantly contributed to the stabilization of these countercations (parallel-edged arrangement in
1-PMo
12
and
4
-O-bridged tetragonal-pyramid in
3-PMo
12
PF
6
). Moreover, the previously reported yellow crystals of [{(AuL
F
)
2
(-OH)}
2
]
3
[PMo
12
O
40
]
2
3EtOH (
4-PMo
12
: L
F
= tris(4-fluoro phenyl)phosphane) were successfully converted to the POM-free crystalline OTf
salt [{(AuL
F
)
2
(-OH)}
2
](OTf)
2
0.5Et
2
O (
4-OTf
) by the use of an anion-exchange resin. X-ray crystallography also revealed that the parallel-edge arrangement of the dimeric cation in
4-PMo
12
was converted to the crossed-edge arrangement of that in
4-OTf
. These results illustrate that the AuO
POM
and hydro |
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| ISSN: | 1477-9226 1477-9234 |
| DOI: | 10.1039/c6dt02670b |