PACCON2014
High Pressure Coordination
Chemistry: The Search for New
Phenomena
Alexander J. Blake
School of Chemistry
The University of Nottingham
Outline of Talk
 Introduction
 Experimental
 Initial results for [PdCl2([9]aneS3)]
 High pressure facilities
 HP studies
 [MX2([9]aneS3)] complexes
 [Pd([9]aneS3)(PPh3)2][PF6]2
 [Pt([9]aneS3)(PPh3)2][PF6]2
 Multi-phase [PdCl2([9]aneS2O)]
 Current and future work
 Acknowledgements
Pressure in the solar system
Location
Interplanetary space
Surface of Mars
Surface of the Earth
Surface of Venus
Marianas Trench
Centre of Jupiter
Centre of the sun
Pressure/bar
10-9
10-2
1
90
1,100
40,000,000
150,000,000,000
3
Under our feet:
pressure increases with depth
Depth /km
3 (crust)
400 (upper mantle ends)
2900 (mantle/core boundary)
6371 (centre of the earth)
Pressure/bar
1,000
133,000
1,300,000
3,500,000
4
Pressure around us
System
Car tyre
Bicycle tyre
Pressure washer
Stiletto heel
Rifle chamber
Synthesis of diamonds
Pressure/bar
2
8
100
50-110
4,000
55,000
5
Pressure in chemistry
Application
Pressure/bar
A hydrogenation reaction
Ethene polymerisation
Critical pressure for CO2
Haber process
KBr press for IR disks
3
10-40
73
200
10,000
6
Very high pressures
Pressure Possible processes
/kbar
up to 100
30-200
100
300-600
400
1,000
“very high”
van der Waals space compressed
coordination, packing changes
melting point of ice = 400ºC
deformation of covalent bonds
organic solid-state reactions
nearly all elements become metallic
electrons move off atoms
7
High pressure crystallography
from 1950’s onward
• initial interest from geophysics and astrophysics
• rocks, minerals, seismology, phase transitions
• planetary interiors
from early 1990’s
• work on molecular compounds
• compressed liquids: acetone, phenol, alcohols
• solvates, pharmaceuticals, energetic materials
8
High pressure crystallography
Very few metal-organic compounds reported, e.g.
• bis(dimethylglyoximato)platinum(II) O…O proton transfer
• spin-crossover in Fe(II) complexes
• resistivity in BEDT-TTF salts as a function of pressure
• pressure-dependence of structure in LiCp and KCp
• pressure-induced metal-to-insulator transitions in Pt(dmg)2
• metal-organic networks: (4-chloropyridinium)2[CoX4])
• some recent studies of copper complexes, MOFs, etc
• typically a few structures a year, but growing steadily
J. P. Tidey, H. L. S. Wong, M. Schröder and A. J. Blake, Coord. Chem. Rev. 2014, submitted
9
Experimental – the Technology
• pressure = force/area
• 1 Nm-2 = 1 Pa = 10-5 bar
• diamond anvil cell (~100 kbar)
• small sample compartment
• pressure-transmitting medium
• measure pressure by ruby fluorescence
10
Diamond Anvil Cell
fully assembled
metal cell body
5 cm
Allen screws
aperture (200 μm)
support
(goniometer head)
Fits easily into the palm of a hand
Fits a ‘standard’ X-ray diffractometer
11
Experimental issues
limited extent of data
limited quality of data
diamond
reflection
gasket
sample
reflection
12
Results for [PdCl2([9]aneS3)]
C9
C2
S1
C3
C6
C8
Square planar +
C5
S4
S7
Cl2
Pd1
Cl1
D.R. Allan, A.J. Blake, D. Huang, T.J. Prior, M. Schröder,
Chem. Commun. 2006, 4081-4083
13
Response of [PdCl2([9]aneS3)]
Between ambient pressure and 76.8 kbar
•
•
•
•
•
•
axial Pd…S 3.159(10)  2.771(13) Å
intermolecular Pd…S 3.525(8)  3.006(10) Å
intense colour change at 44 kbar
ligand conformation [234] → [1233]
unit cell volume contracts by 23%
density increases from 2.105 to 2.732 g cm-3
14
[PdCl2([9]aneS3)]
- axial Pd…S1 distance contracts
3.009(5) Å
42.5 kbar
2.846(7) Å
46 kbar
15
[PdCl2([9]aneS3)]
- intermolecular Pd…S contracts
- distorted octahedral coordination
- chain polymer formed
3.204(5) Å
3.117(8) Å
42.5 kbar
46 kbar
16
[PdCl2([9]aneS3)]
- ligand changes conformation
[234]
42.5 kbar
[1233]
46 kbar
17
[PdCl2([9]aneS3)]
- dramatic, reversible colour change
42.5 kbar
46 kbar
18
A short movie
19
Increasing pressure now …
20
Diamond I19 Sample Environment
Workshop 21-5-2013
21
Diamond I19 Sample Environment
Workshop 21-5-2013
22
Diamond I19 Sample Environment
Workshop 21-5-2013
23
Diamond I19 Sample Environment
Workshop 21-5-2013
24
Diamond I19 Sample Environment
Workshop 21-5-2013
25
Diamond I19 Sample Environment
Workshop 21-5-2013
26
Diamond I19 Sample Environment
Workshop 21-5-2013
27
Diamond I19 Sample Environment
Workshop 21-5-2013
28
Diamond I19 Sample Environment
Workshop 21-5-2013
29
Now decreasing pressure …
30
Diamond I19 Sample Environment
Workshop 21-5-2013
31
Diamond I19 Sample Environment
Workshop 21-5-2013
32
Diamond I19 Sample Environment
Workshop 21-5-2013
33
Diamond I19 Sample Environment
Workshop 21-5-2013
34
Diamond I19 Sample Environment
Workshop 21-5-2013
35
Diamond I19 Sample Environment
Workshop 21-5-2013
36
Diamond I19 Sample Environment
Workshop 21-5-2013
37
Diamond I19 Sample Environment
Workshop 21-5-2013
38
Diamond I19 Sample Environment
Workshop 21-5-2013
39
Disclaimers
“Based on a true story …”
The film you have just seen is based on real results, but
does not represent an actual sequence of experiments.
“No animals …”
Unfortunately, several crystals were quite definitely
harmed during the making of this film.
40
High Pressure Crystallography
Laboratory in Nottingham
Oxford Diffraction (Agilent) SuperMovaII CCD diffractometer
[Ancillary equipment for pressure measurement, etc.]
41
HP work at SRS and Diamond
Synchrotron Radiation Source
Daresbury Laboratory, Warrington, UK
Diamond Light Source
Oxfordshire, UK
High intensity synchrotron X-ray
source on Stations 9.8 and 16.2SMX
Very high intensity synchrotron X-ray
source on Beamline I19 (EH1 and EH2)
2005–2008
2008–date
[MX2([9]aneS3)] complexes studied
at high pressure
Compound
Short
axial
contact
Chain
polymer
formed
Ligand
Marked
conformation colour
changes
change
Catenation
induced
[PdCl2([9]aneS3)]





[PtCl2([9]aneS3)]





[PdBr2([9]aneS3)]




At 58 kbar
PtBr2([9]aneS3)]




At 58 kbar
[PdI2([9]aneS3)]




At 19 kbar
[PtI2([9]aneS3)]




At 19 kbar
Daniel Bailey
D. R. Allan, D. Bailey, N. Bird, A. J. Blake, N. R. Champness, D Huang, C. P. Keane, J. McMaster,
T. J. Prior, J. P. Tidey & M. Schröder, Acta Crystallogr., Sect. B 2014, 70, 469−486.
Pressure-induced  stacking and molecular
deformation in [Pd([9]aneS3)(PPh3)2][PF6]2
Cation at 0.001 kbar
Henry Wong
Pyramidalisation at
C11 at 65.5 kbar
α = 149.3(8)⁰
… stacking
H. L. S. Wong, D. R. Allan, N. R. Champness, J. McMaster,
M. Schröder & A. J. Blake, Angew. Chem. 2013, 52, 5093–5095.
Current work: [Pt([9]aneS3)(PPh3)2][PF6]2
• does not behave anything like the Pd analogue
• pressure does not induce … stacking
• no pyramidalisation at C11 under compression
• edge-to-face interactions are more important
• have preliminary results but need higher precision
Jeremiah Tidey
Current work: [PdCl2([9]aneS2O)]
 α-[PdCl2([9]aneS2O)] - known phase:
2.985(16) Å
 facially bound, endo macrocycle
 forms alternating sheets of Pd2 dimers
3.768(4) Å
 HP study complete
3.405(4) Å
3.4937(8) Å
 β-[PdCl2([9]aneS2O)] - new phase:
 equatorially bound, exo macrocycle
 similar Pd2 dimers as in the α form
 but different packing of these
 cutting transforms crystals to α form
 γ-[PdCl2([9]aneS2O)] - new phase:
 equatorially bound, exo macrocycle
 proto-chains via intermolecular Pd···O
 HP study complete
3.213(15) Å
3.39(2) Å
Jeremiah Tidey
Current work: [PdCl2([9]aneS2O)]
 β-[PdCl2([9]aneS2O)] is a possible “disappearing polymorph”
 see J. D. Dunitz & J. Bernstein, Acc. Chem. Res. 1995, 28, 193–200
 formation of the β form may be kinetically favoured
 the γ polymorph may be more thermodynamically stable
 it may now be impossible to obtain the β form
 Multiple attempts over a year to regrow β-[PdCl2([9]aneS2O)]
 different solvents and solvent mixtures
 different methods, techniques and variations
 all such efforts were uniformly unsuccessful
 Obtained stable crystals of β-[PtCl2([9]aneS2O)]
 isomorphous with β-[PdCl2([9]aneS2O)]
 used as a seed for epitaxial growth of β-[PdCl2([9]aneS2O)]
 the disappearing polymorph has been recovered
 high pressure studies are underway on both complexes
Jeremiah Tidey
Future work
• In-house high pressure laboratory
all preliminary studies will be done here
also most of the complete studies
• Central facilities
Beamline I19 at Diamond Light Source
– for any difficult cases
– for structures near pressure limits
• Main areas of investigation
[M([9]aneS3)1-2]x+
[MX2([9]aneS2O)]
[M([9]aneS3)PP]x+
MOFs
48
Future work at Diamond
• High pressure studies on our new flexible MOFs
• Focus on MOFs with interesting properties
• Require the capabilities of EH2
• Intensity, focussed beam, sample centring
• Working at the limits of sample quality
• Need to optimise experimental conditions
• Develop the best experimental approaches
49
Acknowledgements
Dr Dave Allan
Professor Martin Schröder
Professor Neil Champness
Dr Jon McMaster
Daniel Bailey
Henry Wong
Alice O’Connor
Jeremiah Tidey
Dr Deguang Huang
Dr Tim Prior (Daresbury)
Tom McDonnell
Conal Keane
Nigel Bird
Joe Cavan
Dr John Warren (Daresbury)
The Diamond I19 Team
Professor Geoff Lawrance
(Newcastle, AU)
50