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16/08/2010
1
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Ionic liquids for Inorganic
and Materials Chemistry
K.U.Leuven, Summer School Ionic Liquids
August 24, 2010
Peter Nockemann
Queen‘s University of Belfast
QUILL Research Centre
E-mail: [email protected]
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Ionic Liquids for Inorganic and Materials Chemistry
Outline
1. Introduction
2. Solvation & Solubility of Metal Salts in Ionic Liquids
3. Speciation of Metals in Ionic Liquids
4. Ionic Liquids for Nanomaterials Synthesis
5. Summary and Outlook
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Applications of ILs in inorganic & materials
chemistry
Catalysis
Zeolithe synthesis
Shaped nanoparticles
Metal-organicframeworks
Coordination chemistry
Introduction
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
1. Introduction
What are the features of ionic liquids that make them interesting for
inorganic and materials synthesis?
• ILs possess a high polarity and high dipole moment
• Tunable functionalities
• Reactions in the liquid phase are possible at high temperatures -compared
to convential solvents, or low temperatures compared to solid state
chemistry
• Negligible vapour pressure – e.g. water can be reversibly removed
• Large electrochemical window & chemical stability
• Preorganised solvent structures
Ionic Liquids for Inorganic and Materials Chemistry
16/08/2010
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Solvothermal
Solvent chemistryCoordination chemistry
Solid-state chemistry
Temperature
„Ionothermal Synthesis“
A „temperature gap“
Novel inorganic synthetic pathways in coordination & materials chemistry
Towards low temperature solid state chemistry in ILs
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2. Solvation and Solubility of Metal Salts in Ionic Liquids
2.1. Considerations on Metal Salt Solubility
2.2. Coordination Chemistry in ILs
2.3. Metal-Containing Ionic Liquids
2.4. Conlusions
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2. Solvation and Solubility of Metal Salts in Ionic Liquids
Selected reviews:
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2. Solvation and Solubility of Metal Salts in Ionic Liquids
• Solubility of metal salts in ionic liquids depends strongly on the nature of
the ionic liquid
• The solubility can be very poor in certain ionic liquids
• Especially weakly coordinating anions of the ionic liquids result in low
solubilities
• Functionalised ionic liquids can increase the solubility due to the
coordinating ability of the functional group
• Solubility of metal salts is strongly dependent on the water content –
traces of water can have a huge effect on solubility – especially
hydrophilic Ils often contain significant amounts of water
• The high viscosity of ionic liquids means often slow mass transfer
Ionic Liquids for Inorganic and Materials Chemistry
16/08/2010
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2. Solvation and Solubility of Metal Salts in Ionic Liquids
Ways to improve the solubility of metal salts:
• Strongly coordinating anions can form anionic complexes – ionic nature
of the metal complex increases compatibility with the ionic liquid
• Mimic the cation of an ionic liquid – e.g. imidazolium instead of sodium
• Addition of poly (ethylene glycol) (PEG) increases usually the solubility of
inorganic metal salts
• Rule of thumb: solubility increases with temperature (and chance of
crystallisation upon cooling)
• Trick: use co-solvent (e.g. methanol) to dissolve the metal salt first – then
evaporate the volatile solvent
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010 Peter Nockemann
P. Nockemann et al. Chem. Commun. 2005 (34): 4354-4356.
Lanthanide spectroscopy in ionic liquids
Ionic Liquids for Inorganic and Materials Chemistry
• Strongly coordinating anions can form
anionic complexes – ionic nature of the
metal complex increases compatibility with
the ionic liquid
• Mimic the cation of an ionic liquid – e.g.
imidazolium instead of sodium
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2.2 Coordination Chemistry in Ionic Liquids, Example 1:
• Coordination in an ionic liquid with a strongly coordinating anion
• Dissolved metal complexes form anionic species
• Conceptually suitable for extraction of metals
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
CoO / Co2O3
+ HTf2N + IL
H2O
IL + CoCo(Tf2N)x
Co(Tf2N)x
Ionic Liquid + [Co(hfac)3]-
in H2O
in H2OIonic liquid
Concept for metal extraction using ionic liquids
Example: extraction of a cobalt(II) solution using an ionic liquid
NNF3C CF3
O OAqueous solution of Co(Tf2N)2
[BMIM][hfac]
No contamination of the aqueous phase with residues of the ionic liquidH. Mehdi et al., Chem. Commun., 2010, 113, 234-236.
Ionic Liquids for Inorganic and Materials Chemistry
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Interactions in the structure of [C18MIM][hfac]
Crystal structure of [C18
MIM][hfac]
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
+
(a) Nd(Tf2N)3 in H2O(b) Ionic liquid
Neodymium extraction using an ionic liquid
NNF3C CF3
O O
(a)
(b)
Aqueous solution of Nd(Tf2N)3
[BMIM][hfac]
Peter Nockemann
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Structure of a neodymium(II) complex obtained after extraction
[C4mim][Nd(hfac)4]
Nd(Tf2N)3,aq + 4[C4mim][hfac]org
-> [C4mim][Nd(hfac)4]org + 3[C4mim][Tf2N]org
Crystallised from a
concentrated solution
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Na
O
O
F3C
F3C
3
N
N
2
Surprising result: structure of [BMIM] 2[Na(hfac) 3]
→ extraction of alkaline metals?
H. Mehdi et al., Chem. Commun., 2010, 113, 234-236.
Ionic Liquids for Inorganic and Materials Chemistry
16/08/2010
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2.2 Coordination Chemistry in Ionic Liquids, Example 2:
• Coordination of a cobalt(II) salt in a nitrile functionalised ionic liquid
• Example for tunable coordinating abilities and solvent interaction
• Cationic ‘solvent coordination’
Ionic Liquids for Inorganic and Materials Chemistry
Chemistry – A European Journal 2010, 16, 1849-1858.
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
S
O
NS
OO
CF3
O
F3C
N
CN
HH
Structure of a nitrile functionalised ionic liquid
P. Nockemann et al. Chemistry – A European Journal 2010, 16, 1849-1858.
2.2 Coordination Chemistry in Ionic Liquids, Example 2
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
1 2 3 4 5
-0,30
-0,27
-0,24
-0,21
-0,18
part
ial c
harg
e
chain length
Alkyl analogue Pyrrolidinium IL
O r i g i n D e m o O r i g i n D e m o O r i g i n D e m o
O r i g i n D e m o O r i g i n D e m o O r i g i n D e m o
O r i g i n D e m o O r i g i n D e m o O r i g i n D e m o
O r i g i n D e m o O r i g i n D e m o O r i g i n D e m o
O r i g i n D e m o O r i g i n D e m o O r i g i n D e m o
O r i g i n D e m o O r i g i n D e m o O r i g i n D e m o
Calculation of the charge distribution of nitrile functionalized ionic liquids
A natural bond orbital analysis was performed. The partialcharge of the nitrile function (N1 and C1) was determined by thenatural charge (NPA) of the natural atomic orbitals.(S. Zahn/ B. Kirchner, Leipzig)
2.2 Coordination Chemistry in Ionic Liquids, Example 2
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Co
SO
N
SO
O
O
CF3
CF3
S O
N
S O
O
O
F3C
F3C
S
O
N
S
O
O
O
CF3
CF3
S
O
N
S
O
O
O
F3C
F3C
N2+
2
2.2 Coordination Chemistry in Ionic Liquids, Example 2
16/08/2010
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Co
Tf2N
Tf2NNTf2
N
Tf2N
C
N
N C
N
2.2 Coordination Chemistry in Ionic Liquids, Example 2
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Co
N
N
N
N
C
N
N CN
NC
N
C
N
C
N
C
N
+8
2.2 Coordination Chemistry in Ionic Liquids, Example 2
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Co
Tf2N
Tf2NNTf2
N
H2O
NS
S
O
O
O
O
F3CF3C
C
N
N C
N
Crystal structure of
[Co(Tf2N)
3(H
2O)(C
2NMPyr)
2](Tf
2N)
Hydration of a solvate – but reversible!
2.2 Coordination Chemistry in Ionic Liquids, Example 2
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2.2 Coordination Chemistry in Ionic Liquids, Example 3:
• A protic betaine based functionalised ionic liquid
• Dissolution of metal oxides
• Dissolution of oxides & subsequent crystallisation as a synthetic
pathway to unusual coordination compounds
Ionic Liquids for Inorganic and Materials Chemistry
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
J. Phys. Chem. B, 2006, 110, 20978 – 20992.
N+
COOH
CF3S
N-
SCF3
O
O
OO
Betainium ionic liquid [Hbet][Tf2N]
Stripping of metal ions from the ionic liquid
[Hbet][Tf2N] can solubilize large
quantities of metal oxides
Inorg. Chem., 2008, 47, 9987 - 9999.
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Solubility of metal oxides in the task-specific ionic liquid [Hbet][Tf2N]
formation of pentameric Ni-clusters
potential magnetic material
high solubility of the complexesin ionic liquidsP. Nockemann et al., Crystal Growth & Design, 2008, 8, 1353 – 1363.
[Ni5(bet)12(H2O)6][Tf2N]10
[Cu3(bet)8(H2O)4][Tf2N]6
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Solubility of metal oxides in the task-specific ion ic liquid [Hbet][Tf 2N]
soluble
not soluble
not tested
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Structure of [Ni5(bet)
12(H
2O)
6][Tf
2N]
10obtained from an ionic liquid
Cation [Ni5(bet)
12(H
2O)
6]+10
P. Nockemann et al., Crystal Growth & Design, 2008, 8, 1353 – 1363.
Ionic Liquids for Inorganic and Materials Chemistry
16/08/2010
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
P. Nockemann et al., Crystal Growth & Design, 2008, 8, 1353 – 1363.
Packing in the structure of [Ni5(bet)
12(H
2O)
6][Tf
2N]
10
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
O
Pb
Pb
PbPb
O
Pb
H N
S
SO
O
OO
CF3
CF3
N
S
S O
O
O
O
F3C
F3C
NS S
O
O
O
O
CF3 CF3
O
ON
OO
N
OO
NOO
N
OO
N
OO
N
OO
NO
O
N
H2O
Structure of [(Pb4O)Pb(OH)(bet)
8(Tf
2N)
3][Tf
2N]
4obtained from an ionic liquid
Cationic [(Pb4O)Pb(OH)(bet)8(Tf2N)3]4+ cluster
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Pathway provides access to new classes of compounds and materials
Indication of the high potential of synthesis from ionic liquids
P. Nockemann et al., Crystal Growth & Design, 2008, 8, 1353 – 1363.
Metal oxidesdissolved in a task-
specific ionic liquid
PbNiMn
ZnCo
P. Nockemann et al., Inorg. Chem., 2008, 47, 9987 - 9999.
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2.3 Metal-Containing Ionic Liquids:
• Metals can be part of the ionic liquids
• Properties of ionic liquids with additional intrinsic properties of the metal
• Versatile applications in catalysis, catalyst precursors, reagents for
chemical reactions or for nanomaterials synthesis
• Functional materials with luminescent of magnetic properties
Ionic Liquids for Inorganic and Materials Chemistry
Review paper:
16/08/2010
9
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2.3 Metal-Containing Ionic Liquids, Example 2
Depending on the type of boron cluster anions, these compounds
exhibit a high thermal stability up to 480°C (type [Cnmim]
2[B
12Cl
12], n =
2, 4, 8, 10, 12, 14, 16, 18) and low glass transition temperatures (type
[Cnmim][Co(C
2B9H11
)2], n = 2, 4, 6, 8, 10, 12, 14).
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
2.3 Metal-Containing Ionic Liquids, Example 3
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
N N
5
Ln(NCS)8
Structure of [BMIM]5[Ln(NCS)8] (BMIM = 1-butyl-3-methylimidazolium; Ln = La –Yb)
Lanthanide-containing ionic liquids
Miscibility with other ionic liquids like [BMIM][Tf2N] or [BMIM][PF6]
P. Nockemann et al. J. Am. Chem. Soc. 2006, 128, 13658.
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
3. Speciation of metals in ionic liquids:
• Basic question: What is surrounding of a metal in IL-solution? How is it
coordinated? What about IL-metal interactions?
• Methods to probe the surrounding of a metal ion in an ionic liquid
• Methods should work in the liquid state
• Equilibria or mixtures of different species of metal complexes are possible
• Solid state structure can be different from liquid state species
• Speciation is extremely important for the further progress of inorganic and
materials chemistry in ionic liquids
Ionic Liquids for Inorganic and Materials Chemistry
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Some techniques & methods for metal speciation
UV-Vis absorption spectroscopy
Luminescence and excitation spectroscopy (steady state and dynamic
measurements, visible & near-infrared spectroscopy)
Extended X-ray Absorption Fine Structure (EXAFS)
NMR spectroscopy (1H, 13C, diamagnetic metal cores)
Infrared & Raman spectroscopy of metal complexes
XPS; neutron diffraction
3. Metal speciation in ionic liquids
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
3. Metal speciation in ionic liquids, Example 1
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Speciation of lanthanide-containing ionic liquids
Optical absorption& emission spectroscopy(Lanthanide as symmetry probes)
EXAFS
Extended X-Ray
Absorption
Fine Structure
89Y- and 139La-NMR
Speciation in the liquid state
Bond lengths & coord. numb.
Number of species (sites) present
FT-IR and FT-RamanSpectroscopybond lengths / angles,coordination mode
Initial models for speciationfrom crystallography
Models for speciation from theoryDFT, molecular dynamics simulations
3. Metal speciation in ionic liquids, Example 1
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Speciation of Rare-Earth Betaine Bistriflimide Complexes
Dissolved in Ionic Liquids
[Eu2(bet)8(H2O)4][Tf2N]6
18000 17000 16000 15000 14000
600 650 700
Inte
nsi
ty (
a.u
.)
Wavenumber (cm-1)
Wavelength (nm)
0 1 2 3 4 5 60,0
0,5
1,0
1,5
2,0
2,5
(b)
FT
R + ∆ / Å
89Y- and 139La-NMRFT-IR and FT-Raman
Spectroscopybond lengths / angles,
coordination mode
Optical absorption
& emission spectroscopy
(Lanthanide as
symmetry probes)
EXAFSExtended X-Ray
Absorption
Fine Structure
Luminescence
decay curve:Bi-exponential
components:
657 ± 40 ms (61%)
1225 ± 142 ms (39%)
3. Metal speciation in ionic liquids, Example 2
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
∆T
- 2 H2O
[Eu2(bet)8(H2O)2][Tf2N]6
[Eu2(bet)8(H2O)4][Tf2N]6
17300 17280 17260 17240 17220 17200
578,5 579 579,5 580 580,5 581
Inte
nsity
(a.u
.)
Wavenumber (cm-1)
17 240 cm-1
17 245 cm-1
Wavelength (nm)
Indication for two species fromoptical spectroscopy
→ At least two different speciespresent in the ionic liquid solution
P. Nockemann et al., Chemistry – A European Journal, 2009, 15, 1449 – 1461.
3. Metal speciation in ionic liquids, Example 2
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Beam line 11-ID-B at APS
MAR 345 Image Plate
X-ray scatteringThe scattering experiment
at APS
Monochromator: Si (511)E = 90.48 keV,λ = 0.13702 Å.
D = 277 mm
3. Metal speciation in ionic liquids
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
CeO2 powder 0.5 M U(VI) 1 M HClO4
Image plate screenings of MAR 345 detector
Bragg Scattering Diffuse Scattering
3. Metal speciation in ionic liquids
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
1 2 3 4 5 6
0.0
0.5
1.0
1.5
2.0
2.5
3.0 1.42 Å
2.63 Å
2.50 Å
4.01 Å
g(r)
r [Å]
500 mM Eu [Hbet] [Tf2N]
pure [Hbet] [Tf2N]
crystalline dimer
HEXS of the solid and liquid samplesPair distribution function
3. Metal speciation in ionic liquids
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Solid state Solution
P. Nockemann et al., Chemistry – A European Journal, 2009, 15, 1449 – 1461.
3. Metal speciation in ionic liquids
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
P. Nockemann et al. Inorg. Chem. 2007, 46, 11335-11344.
Speciation of uranyl complexes in ionic liquids
D4h
D3h
[UO2(NO3)3]-
[bmim]2[UO2Br4]
3. Metal speciation in ionic liquids, Example 3
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
3. Metal speciation in ionic liquids
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
4. Ionic liquids for nanomaterials synthesis:
4.1 Nanoparticles & shaped nanomaterials
4.2 Porous framework materials
Ionic Liquids for Inorganic and Materials Chemistry
Review papers:
16/08/2010
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
4.1 Nanoparticles & shaped nanomaterials
What is the role of ionic liquids in nanomaterials synthesis?
• Nanoparticle can be synthesised in-situ in ionic liquids
• Ionic liquids can stabilise nanoparticles
• NPs with small diameters and a narrow size distribution
• Stable colloidal systems can be generated which can be used for high
turnover rates e.g. in catalytic hydrogenations
• Preorganised solvent structure
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
4.1 Nanoparticles & shaped nanomaterials
What is the role of ionic liquids in nanomaterials synthesis?
• Tunable surface tensions:
• Low suface tensions result in high nucleation rates – generation of very small particles
• ILs with low interface energies for larger objects – good stabilisation / solvatisation of
molecular species
• Inorganic Synthesis under ambient conditions – also anhydrous or water-
poor conditions are possible
• Hydroxide / oxihydrate formation can be suppressed – low generation of
amorphous species, so condensed systems are likely to crystallise
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
4.1 Nanoparticles & shaped nanomaterials
What is the role of ionic liquids in nanomaterials synthesis?
• Extended hydrogen-bond systems and therefore highly structured –
induces structural directionality (IL effect)
Ionic Liquids for Inorganic and Materials Chemistry
[EMIM][PF6] [OMIM][PF6]
Segregation of polar and
non-polar domains in
imidazolium ILs
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
4.1 Nanoparticles & shaped nanomaterials
What is the role of ionic liquids in nanomaterials synthesis?
• Extended hydrogen-bond systems and therefore highly structured –
induces structural directionality (IL effect)
• High self-organisation in the liquid state as “entropic driver” for
spontaneous, well defined and extended ordering of nanoscale structures
Ionic Liquids for Inorganic and Materials Chemistry
Different gold nanoparticle morphologies from different IL conditions.
Y. Qin, Y. Song, N. J. Sun, N. Zhao, M. X. Li, L. M. Qi, Chem. Mater. 2008, 20, 3965.
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Ionic precursor
Polar
region
Apolar metal-
organic precursor
Non-polar Tail of ionic liquid
4.1 Nanoparticles & shaped nanomaterials
Ionic Liquids for Inorganic and Materials Chemistry
• Preferential solubility of the nanomaterials precursor determines in which domain of
the IL it will be preferentially distributed
• So one approach to control size & shape is to modulate the volumes of the polar /
non-polar domains in the ionic liquid
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Synthesis of iron oxide nanorods and nanocubes in an imidazolium ionic liquid Yong Wang, Hong YangChemical Engineering Journal, 2009, 147, 71–78.
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Ionic Liquids for Inorganic and Materials Chemistry
A. Taubert, Angew. Chem. Int. Ed. 2004, 43, 5380.
Copper(I) chloride nanoplatelets from a copper-containing ionic liquid precursor
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
4.1 Nanoparticles & shaped nanomaterials
Interaction of metal nanoparticles with the ionic liquids
There are indications that the interaction of metal NPs with anions or cations is size-dependent.
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Photoinduced Oxidation of Water to Oxygen in the Ionic Liquid BMIM BF4 as the Counter Reaction in the Fabrication of Exceptionally Long Semiconducting Silver
Tetracyanoquinodimethane Nanowires Chuan Zhao and Alan M. Bond, J. Am. Chem. Soc. 2009.
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
4.2 Ionic Liquids for Porous Materials
Ionothermal synthesis for framework materials
• Ionic liquids act as solvents and template provider
• Usually temperatures between 150°C -220°C
• In theory, the ionic liquids act as space fillers during the zeolithe synthesis
• Long range correlations (structuring) within the ionic liquids is believed to
increase the likelihood of transferring chemical information from the
template cation to the framework
• Reactions in an ionic environment
• Small quantities of water can have huge influence on resulting structure
Ionic Liquids for Inorganic and Materials Chemistry
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
SIZ-1 (St Andrews Ionothermal Zeolite-1) and
SIZ-6 (Figure 2) are new zeotype structures
and were produced without the addition of
fluoride. Both structures have hanging P–O
bonds and aluminium coordinated to more
than four oxygens.19,24 SIZ-3 (AEL) and SIZ-4
(CHA) were produced with the addition of HF
and consist of fully condensed frameworks.
SIZ-5 (AFO) was produced with the addition of
water and can be classified as hydrothermal
synthesis due to the quantity of water used
being greater in molar terms than the
quantity of ionic liquid.
Parnham, E. R.; Morris, R. E. 1-Alkyl-3-methylimidazolium bromide ionic liquids in the ionothermal synthesis of aluminium
phosphate molecular sieves. Chem. Mater. 2006, 18, 4882–4887.
Ionothermal synthesis of porous alumophosphate molecular sieves
-> reaction conditions lead to
different structure types
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
5. Summary and Outlook (1):
• Ionic liquids open new frontiers in inorganic and materials chemistry
• Ionic liquids themselves can be considered as ‘advanced’ or hybrid
materials (see applications in dye sensitised solar cells, lithium ion
batteries, sensors, new composite materials, etc.)
• ILs allow interesting possibilities in coordination- and possibly metal-
organic chemistry -> e.g. stabilisation of unusual oxidation states
• Great potential for controlled growth of nanoporous, nanoparticular or
nanoshaped materials
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
„Ionothermal Synthesis“Access to new
classes of compounds
and materials
New possiblities for
speciation-, process and
reaction control
Chemistry at the interface
of coordination- and
solid state chemistry
Basic research:
Fundamental issues in a
new solution chemistry
= Synthesis in ionic liquids
at elevated temperature
5. Summary and Outlook (1):
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
5. Summary and Outlook (2):
• IL-containing composite materials are an emerging field!
A flexible dye-sensitized solar cell with a
solvent-free ionic liquid
electrolyte.(courtesy G24i Ltd.)
Flexible nanocomposites for energy
storage in supercapacitors. PNAS 2007,
34, 13574.
Ionic Liquids for Inorganic and Materials Chemistry
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Peter Nockemann, Leuven Summer School Ionic Liquids 2010
5. Summary and Outlook: still some work to do…!
• Solubility has only been studied for some selected examples
• More fundamental data on coordination of metals in ionic liquids required
• More detailed speciation studies in the liquid state on a variety of metals
in ionic liquids would be desirable
• The fundamentals of nanoparticle / nanoshapes with controlled and
predictable growth is still in its infancy – a lot of trial and error
• Lack of understanding the ‘nanostructured liquids’
• Great potential for controlled growth of nanoporous, nanoparticular or
nanoshaped materials
Ionic Liquids for Inorganic and Materials Chemistry
Peter Nockemann, Leuven Summer School Ionic Liquids 2010
• Queen’s University Belfast• The QUILL Research Centre• Prof. Ken Seddon• Dr. Małgorzata Swadźba-Kwaśny, Léa Chancelier, David Bailie• Dr. Paul Nancarrow, Moira Lewis• EPSRC
• K.U.Leuven (Belgium)• Prof. Koen Binnemans• Dr. Ben Thijs, Dr. Kyra Lunstroot, Michael Pellens• Dr. Kristof Van Hecke, Prof. Luc Van Meervelt
Acknowledgement