The Derived Crystal The Derived Crystal Packing Model: a Way to Packing Model: a Way to Predict Crystal Predict Crystal Structures and Structures and Structural Phenomena Structural Phenomena Claire GERVAIS Claire GERVAIS Present Address: Department of Chemistry and Present Address: Department of Chemistry and Biochemistry, University of Berne, Biochemistry, University of Berne, Switzerland Switzerland
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The Derived Crystal Packing Model: a Way to Predict Crystal Structures and Structural Phenomena Claire GERVAIS Present Address: Department of Chemistry.
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The Derived Crystal Packing Model: The Derived Crystal Packing Model: a Way to Predict Crystal Structures a Way to Predict Crystal Structures
and Structural Phenomenaand Structural Phenomena
Claire GERVAISClaire GERVAIS
Present Address: Department of Chemistry and Biochemistry, Present Address: Department of Chemistry and Biochemistry, University of Berne, SwitzerlandUniversity of Berne, Switzerland
IntroductionIntroduction
N O2
NO 2
O 2N
Molecule Crystal structure
Expected physical properties
Real crystals
Real physical properties
IntroductionIntroduction
Twinning
Concomitant crystallization
Polymorphism
?Lamellar epitaxy
IntroductionIntroduction
Analogy between crystal packings
Concomitant crystallization
Polymorphism
Lamellar epitaxy
Twinning
IntroductionIntroduction
Analysis and prediction of structural phenomena
Crystal structure prediction
Derived Crystal Packing model
Derived Crystal Packing ModelDerived Crystal Packing Model
Mother phase Ribbon (PF1)
Ribbon (PF2)
Slice (PF3)
Step I : AStep I : Analysis of the mother phase and nalysis of the mother phase and extraction of extraction of periodic fragments (PF)periodic fragments (PF)
Derived Crystal Packing ModelDerived Crystal Packing Model
PF3PF2
PF1
Daughter phase 1
Daughter phase 2Daughter phase 3
Daughter phase 4
Daughter phase 5
Step II: Generation of daughter phase(s) by adding new Step II: Generation of daughter phase(s) by adding new symmetry operators to PFsymmetry operators to PF
Consequences of Structural Consequences of Structural Similarities between Mother and Similarities between Mother and
Daughter Phases ?Daughter Phases ?
Expression of the Daughter PhasesExpression of the Daughter Phases
Two-step procedure to generate new phases:• Extraction of periodic fragments• Addition of symmetry operators
Mother phase Daughter phase
Expression of the Daughter PhasesExpression of the Daughter Phases
Lattice energy difference determined by interactions
between PFs
Similar lattice energies
Provided a PF with strong intermolecular interactions,
Expression of the Daughter PhasesExpression of the Daughter Phases
Similar growth unit
Concomitant crystallization
Expression of the Daughter PhasesExpression of the Daughter Phases
• Aminoff and Broomé (Z. Krist., 80, 1931):[…] The transition structure is that of a possible polymorphic modification of the structure or else that of a modification which could be plausible for that substance.”
• Dauphiné twin of quartz
IndividualQuartz Trigonal
IndividualQuartz Trigonal
Twin zone
hexagonal
Quartz
Expression of the Daughter PhasesExpression of the Daughter Phases
Twinning of MP
During crystal growth: Continuation of the lattice…
…Or formation of twins or epitaxies.
Growth
Underlying expression of DP at
the twin zone
Expression of the Daughter PhasesExpression of the Daughter Phases
During crystal growth: Continuation of the lattice…
…Or formation of twins or epitaxies.
Epitaxy of DP on MP
Growth
Expression of the Daughter PhasesExpression of the Daughter Phases
Structural relationships between mother and daughter phases :
(Concomitant)
Polymorphism
• Similar lattice energies: similar stability• Same growth unit: similar conditions of growth
Twinning, Epitaxy
Applications of the DCP ModelApplications of the DCP Model
Resolution of racemic mixturesResolution of racemic mixturesDesign of polar structuresDesign of polar structures
Verification of structural purityVerification of structural purityHelp in crystal structure predictionHelp in crystal structure prediction
Chiral PF
Chiral mother phase
+ Symmetry of second kind
Racemic daughter phase
Resolution of Racemic MixturesResolution of Racemic Mixtures
The DCP model can generate racemic compounds from enantiomer structures and vice versa
If structural relationships + close lattice energies between chiral and racemic structures …
Resolution of Racemic MixturesResolution of Racemic Mixtures
R R R R R R R R RR
SS
SSSS
RRRR
RRRRRR RR
RRRR
RR
SSSSSS
SS
SS
SS
2D nucleation of S2D nucleation of S
SS
R R R R R R R R RRR R R R R R R R RRS S S S S S S S SS
SSRRRRRR
RRRR
SS
SS SS
Diffusion rate is too low
Growth rate is too high
Growth of R
RRSS
R R R R R R R R RRR R R R R R R R RR
SS
RRRR
RRRR
SSSS
SSSS SSSS
SSThe local supersaturation of S enantiomer is too high
Stable conglomerate
Resolution of Racemic MixturesResolution of Racemic Mixtures
• Several examples:– 5-ethyl-5-methyl-hydantoin (see poster),– Hexahelicene,– -amino-acids,– Triazolylketone,– Ammonium salts…
Stable conglomerate
Torbeev et al., J. Phys. Chem. B, 2003, 107, 13523-13531 and references (7)
Existence or generation of competitive racemic compounds
Resolution of Racemic MixturesResolution of Racemic Mixtures
S
SS
RR
RRR R
RR
R
SSS
S
S
SRRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
R R R R R R R R RR
Stable racemic compound
S S S S S S S S SS
Growth of R,S
Resolution of Racemic MixturesResolution of Racemic Mixtures
R R R R R R RR R R R R R R RR
RRRR
S
S S
RR
RR R
RR
R
R
SSS
SS
SRRR
R
S S S S S S S S SSS S S S S S S S SS
RRSS
RRSS
SS
RRSS
RRSS
RR RR RR RR RR
RR
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
RRSS
S S S S S S S S SSS S S S S S S S SSS S S S S S S S SS
S S S S S S S S SSS S S S S S S S SSS S S S S S S S SSS S S S S S S S SS
Tailor-made additive R to inhibit nucleation of R,S and R nuclei but…
…2D nucleation of R,S
Resolution of Racemic MixturesResolution of Racemic Mixtures
• Already observed experimentally for alanine:– I. Weissbuch et al. Chem. Mater. 1994, 6, 1258-1268– See Poster
Existence of structural relationships between chiral and
racemic phases (2D layer)
Resolution of Resolution of RRacemic Mixturesacemic Mixtures
• Generation of daughter phases with similar lattice energies and structures:
– Lamellar epitaxy between two enantiomers hinders preferential crystallization