Effect of crystal packing

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Effect of crystal packing

• Packing refers to arrangement of individual
  molecules in the crystal.
• The packing forces to simply fill the space if
  no significant intermolecular interactions.
• Examples of possible intermolecular interactions
• Electrostatic interactions in ionic crystals
• Dipole-dipole interactions in salts and polar
  molecules.
• H-bonding(may be considered a sub-type of
  dipole-dipole interactions)
• Closed-shell M-M interactions metallophilic
  bonding
• Good understanding of packing may allow us the
  understanding of what leads to certain
  interesting physical properties that may be
  important for a variety of applications.

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• Just packing forces even without specific
  intermolecular forces may lead to various
  interesting properties when certain
  crystallographic point or space groups are
  obtained
• We illustrated this last time (piezoelectricity,
  pyroelectricity, ferroelectricity, optical
  activity, enantiomorphism, )
• Certain types of intermolecular interactions
  may lead to other interesting properties.
• ? H-bonding and protein structure, electrostatic
  stacking and magnets or conductors, metallophilic
  stacking and luminescent materials, etc.
• We shall illustrate some specific cases studies
  from the literature.

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Literature case studies

• TRIBOLUMINESCENCE
• Non-centric space groups
• Conducting materials
• Segregated 1-D stacks
• Magnetic materials
• Integrated 1-D stacks
• Photoluminescent materials
• Packing by closed-shell metal-metal interactions

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Case study 1 TRIBOLUMINESCENCE

• DISCUSSED IT LAST TIME
• Related to piezoelectricity.
• Non-centric space groups (Zinks rule).
• Exceptions might occur if
• Compound is ionic
• Presence of iezoelectric impurities
• Papers discussed (responsible for)
• B. P. Chandra, J. I. Zink, Inorg. Chem., 1980,
  19, 3098.
• Cotton, F. A. Daniels, L. M. Huang, P.
• Inorg. Chem. Comm., 2001, 4, 319.

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Case study 2 Conducting materials

• Crystal packing infinite 1-D chains, but
  segregated stacks
• D-D-D-D-.//A-A-A-A-.
• D electron donor
• A electron acceptor
• Electrostatic interactions between the two
  segregated chains
• Conducting materials (Metals)

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Case study 3 Magnets

• Crystal packing infinite 1-D chains with
  alternating D/A molecules (integrated stacks)
• D-A-D-A-D-A-D-A-.
• D electron donor
• A electron acceptor
• Electrostatic interactions WITHIN the chain
• ? Molecular Magnets (strong ferromagnetic
  coupling)

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• Organic example
• TTF-based Organic Metals
• Donor (D)/Acceptor(A) adducts of TTF with
  organic acceptors like TCNQ.
• TTF tetrathiafulvalene
• TCNQ 7,7,8,8-tetracyanoquinodimethane
• Draw structures

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• Crystal structure shows segregated stacks (draw
  structure)
• ORGANIC METALS!!!
• Papers to read
• Shaik, S. S. J. Am. Chem. Soc. 1982, 104, 5328.
• Ferraris, J. Cowan, D. O. Walatka, V. J.
  Perlstein, J. H., J. Am. Chem. Soc. 1973, 95,
  948.
• Coleman, L. B. Cohen, M. J. Sandmand D. J.
  Yamagishi, F. G. Garito, A. F. Heeger, A. J.
  Solid State Commun 1973, 12, 1135.
• Noble Laureate, 2001

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• Inorganic example
• Dithiolene complexes of d8 metals
• M(SS)22M(SS)22-
• Stack in two ways
• (1) D-A-D-A-D-A-D-A-.
• Produce ion pair charge transfer (IPCT)
  absorptions and lead to electrical conductivity
  (conductors)
• (2) D-D-A-D-D-A-.
• Dont have IPCT but can be paramagnetic (usually
  TIP) and semiconducting

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• Papers to read
• Robertson, N. Cronin, L. Coord. Chem. Rev. 2002,
  227, 93.
• Kisch, H. Eisen, B. Dinnebier, R. Shankland,
  K. David, W. I. F. Knoch, F. Chem. Eur. J.
  2001, 7, 738.
• Kisch, H. Comments Inorg. Chem. 1994, 16, 113.
• Bigoli, F. Deplano, P. Mercuri, M. L.
  Pellinghelli, M. A. Pilia, L. Pintus, G.
  Serpe, A. Trogu, E. F. Inorg. Chem. 2002, 41,
  5241.
• Tanaka, H. Okano, Y. Kobayashi, H. Suzuki, W.
  Kobayashi, A. Science 2001, 291, 285.
• Coomber, A. T. Beljonne, D. Friend, R. H.
  Brédas, J. K. Charlton, A. Robertson, N.
  Underhill, A. E. Kurmoo, M. Day, P. Nature
  1996, 380, 144.

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(dbbpy)Pd(dmid)2 TCNQ ?
3.48
3.40
Smucker, B. W. Hudson, J. M. Omary, M. A.
Dunbar, K. R. Structural, Magnetic, and
Optoelectronic Properties of Diimine-dithiolato
Pt(II) and Pd(II) Complexes and their
Charge-Transfer Adducts with Nitrile Acceptors,
Inorg. Chem. 2003, 42, in press.
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Stacking in the supramolecular chains of
(dbbpy)Pt(dmid)2TCNQ?
--DDADDADDADDA infinite stacks
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Magnetic Measurements of (dbbpy)Pt(dmid)2TCNQ
Simple Paramagnet
cT (emu cgs K/mol)
T (K)
Predicted to be Pauli Paramagnetism exhibited by
conductors or semiconductors due to unusually
large TIP magnitude
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Clear SEM images were obtained for crystals that
were not coated with a conducting film,
suggesting a non-insulator behavior for these
solid crystals (conductors or semiconductors).
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Case study 4 Photoluminescent materials

• Crystal packingby virtue of closed-shell
  metal-metal interactions
• e.g., d10 complexes of Au(I), Ag(I), and Cu(I)
• D10-d10 bonding is counterintuitive but takes
  place due to correlation/relativistic/hybridizatio
  n effects
• Aurophilic argentophilic cuprophilic
  argentoaurophilic attractions often lead to
  photoluminescence

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Scheme 1. Versatility of the reported
supramolecular structures of Au(RNC)X compounds.
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White-Morris, R. L. Olmstead, M. M. Balch, A.
L. Elbjeirami, O. Omary, M. A. Orange
Luminescence and Structural Properties of Three
Isostructural Halocyclohexylisonitrilegold(I)
Complexes, Submitted to Inorg. Chem. on February
19, 2003.
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The structural organization of (CyNC)AuIBr
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Luminescence emission and excitation spectra for
single crystals of (CyNC)AuICl, (CyNC)AuIBr, and
(CyNC)AuII.
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GLOWING Chains
Burini Fackler Omary, et al. Inorg. Chem.2000,
39, 3158.
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LUMINESCENCE THERMOCHROMISM
Burini Fackler Omary Staples, et al. Inorg.
Chem.2000, 39, 3158.
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SUPRAMOLECULAR CHAIN ASSEMBLIES
Burini Fackler Omary Staples et al. J. Am.
Chem. Soc. 2000, 122, 11264-11265.
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Luminescence spectra of TR(carb) and
TR(carb)2TRHg in the solid state at 77 K. t
10ms
Raman spectrum of a solution of TR(carb) in
CH2Cl2 at RT
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Au3(carb)3.C6F6 , 11 stacks
Au3(bzim)3.TCNQ, 21 stacks
3.152 Å
3.152 Å
Omary Fackler Burini et al. J. Am. Chem. Soc.
2001, 123, 9689-9691.
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• Exposure to C6F6 VAPOR leads to the quenching of
  the luminescence of TR(carb).
• Luminescence re-generated when crystals immersed
  in non-dissolving solvent.

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Photoluminescence properties of
Au3(carb)3.octafluoronaphthalene

• The bright yellow luminescence is assigned to
  emission of the organic component.
• The emission is strong at ambient temperature in
  the adduct while the octafluoronaphthalene is
  luminescent only at cryogenic temperatures.
• The structured emission at 77K has a similar
  profile to that in the organic compound, with a
  modest red shift.
• The Au-based emission is quenched because it is
  related to a dimer of the Au3 unit while the
  structure of the adduct does not show this
  dimerization.

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Do acidic trinukes have similar exciting
luminescence properties?
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Omary Kassab Haneline Elbjeirami Gabbai
Inorg. Chem. 2003, 42, 2176-2178.
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Luminescence spectra of Hg3.pyrene at RT and 77 K

• 568 8 ms (RT)
• 423 8 ms (77K)

Omary Kassab Haneline Elbjeirami Gabbai
Inorg. Chem. 2003, 42, 2176-2178.
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Copper and silver trimersDo you always get
what you pay for???
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FIGURE 1
lexc290nm
lexc330nm
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FIGURE 2
IR spectrum
Raman spectrum
1138 cm-1
1147 cm-1
The indicated vibrational peaks are in good
agreement with the vibronic spacing in the
emission spectra of Ag1, Cu1, and Cu2.
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FIGURE 3
lexc330nm
lexc290nm
lexc325nm
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FIGURE 4
lexc290nm
lexc260nm
lexc265nm
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Tunable phosphorescence lifetimes!
Example of curve fitting

• Compound Lifetime (at lmax)
• Cu1 168 ms
• Ag1 118 ms
• Cu2 73 ms
• Cu3 52 ms
• Ag2 1.5 ms
• Ag3 1.0 ms

• Ligand based emissions Nice illustration of the
  heavy-atom effect!note the decrease in t on
  going from Cu1 to the heavier Ag1 and from Cu1 to
  Cu2.
• As the metal contribution increases, the
  lifetime decreases. note the decrease in t on
  going from Ag2?Ag3.