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Steed, J. W.; Atwood, J. L. Supramolecular Chemistry,Wiley 2000 $ 40,-
Balzani, V.; Venturi, M.; Credi, A.Molecular Devices and MachinesWiley VCH 2003
Schneider, H.-J.; Yatsimirski, A. Principles and Methods in Supramolecular ChemistryWiley 2000 £ 39,95
Comprehensive Supramolecular Chemistry, Vol. 1-10; Lehn, J.-M., Series editor, Pergamon/Elsevier Oxford etc, 1996 $ 425 per volume
Encyclopedia of Supramolecular Chemistryedited by Jerry L. Atwood and Jonathan W. SteedDekker, 2004 • 1,500 pages • $489.00
What is Supramolecular Chemistry?
MULTIDISCIPLINARY FIELD
NATURE (biological systems) - inspiration
ORGANIC and INORGANIC CHEMISTRY – building blocks(supramolecular synthons)
PHYSICAL CHEMISTRY – methods to study and understand their properties
What is Supramolecular Chemistry?
The ultimate supramolecular material?
Held together by many specific hydrogen bonds, π-π stacking, etc.
Encodes gigabytes of data Can Self-Replicate
Built-in Error Correction
Information Storage Is the basis of life
What is Supramolecular Chemistry?
Tobacco Mosaic Virus (TMV)
What is Supramolecular Chemistry?
Actin-Myosin Complex
What is Supramolecular Chemistry?
Kinesin Crawling Along a Microtubule
What is Supramolecular Chemistry?
MOLECULAR CHEMISTRY – covalent bonds formation
SUPRAMOLECULAR CHEMISTRY – “non-covalent bond” format ion
What is Supramolecular Chemistry?
J. M. Lehn:„Supramolecular chemistry is the chemistry of the i ntermolecular bond, covering the structures and functions of the e ntities formed by the association of two or more chemical species“
F. Vögtle:„In contrast to molecular chemistry, which is predo minantly basedupon the covalent bonding of atoms, supramolecular c hemistry is based upon intermolecular interactions, i.e. on the association of two or more building blocks, which are held together by intermolecular bond”
Top-Down (current technology). Continued reduction in size of bulk semiconductor d evices optical, ultra-violet, ion-beam, electron-beam lith ography
Bottom-Up (molecular scale electronics). Design of molecules with specific electronic functi on Design of molecules for self-assembly into supramol ecular structures Connecting molecules to the macroscopic world Man-made synthesis (e.g. carbon nanotubes)
What is Supramolecular Chemistry?
1-50 nm 1-500 nm
SupramolecularAggregates
Nanoelectronicsnanobiology
Development - History
Development - History
Classification of Host-Guest Compounds
Classification of Host-Guest Compounds
Spherand
Classification of Host-Guest Compounds
Corpora non agunt nisi fixata
Receptors and the Lock and Key Analogy
The Chelate and Macrocyclic Effects
The Chelate and Macrocyclic Effects
The Chelate and Macrocyclic Effects
Less entropically favorable
Stabilization offered by the chelate effect
Preorganization and Complementarity
Preorganization and Complementarity
Nature of Supramolecular Interactions
Covalent bond energies:
C-O bond 340kJ / mol 1.43ÅC-C bond 360kJ / mol 1.53Å
C-H bond 430kJ / mol 1.11Å
C=C bond 600kJ / mol 1.33ÅC=O bond 690kJ / mol 1.21Å
Compared to most non-covalent interactions these are:
• Very high energies
• Very short distances • Highly dependant on orientation
Nature of Supramolecular Interactions
Driving Forces for the Formation of Supramolecular Structures
Example: Acetone pointing directly at Na ion (θ = zero) at a distance of 1nm (in chloroform)
IonIon--Dipole InteractionDipole Interaction
u = q * l (dipole moment)l = length of the dipoleq = partial charge on dipoler = distance from charge to center of dipoleQ = charge on ion
Nature of Supramolecular Interactions
IonIon--Dipole InteractionDipole Interaction
Directional forces
Can be attractive or repulsive
Medium range (1/r2)
Significantly weaker then ion-ion interactions
Nature of Supramolecular Interactions
Nature of Supramolecular Interactions :Hydrogen Bonding
Nature of Supramolecular Interactions :Hydrogen Bonding
Nature of Supramolecular Interactions :Hydrogen Bonding
Nature of Supramolecular Interactions :Hydrogen Bonding
Van der Waals radius of H: 1.1Å, O 1.5Å. Therefore closest approach should be 2.6Å.
Actual separation is about 1Å less!Distance of 1.76Å.
Intermediate between vdw distance and typical O-H covalent bond of 0.96Å.
O H OR
RH
O H OR
RH
Nature of Supramolecular Interactions :Hydrogen Bonding
Nature of Supramolecular Interactions :Hydrogen Bonding
Nature of Supramolecular Interactions :Hydrogen Bonding
Nature of Supramolecular Interactions :Halogen Bonding
Halogen atoms iodine, bromine, chlorine and even fl uorine can function as Lewis acids and engage in electron dono r-acceptor interactions with atoms with lone pairs such as nit rogen, oxygen, phosphorus and sulfur.
BI…X- Halogen bonding may involve dihalogenes X2 and X-Y as well as
organic halides
The strength of the donor-acceptor interaction depe nds on the polarizability of the halogen atom, decreases in the order:
I > Br > Cl (> F)
Nature of Supramolecular Interactions :Halogen Bonding
DMSO to haloarene halogen bonding geometry:
“head on“ to C-X, Γ~ 158(13)° (Cl), 162(12)°(Br), and ~165(8)°(I);
“side on“ to S=O, Ω: 125-135°.
Increase of polarity of the both C-X and S=O bond increases the strength of interaction:
Nature of Supramolecular Interactions :The Cation – ππππ Interaction
Nature of Supramolecular Interactions :Charge-Transfer Complex
Nature of Supramolecular Interactions :Van der Waals Forces
Strength of interaction is essentially a function of the surface area of contact. The larger the surface area the stronger the interaction will be.
Regardless of other interactions found within a complex there will almost always be a contribution from vdw.
This is what drives molecules to eliminate spaces or vacuums and makes it difficult to engineer porous or hollow structures and gives rise to the phrase “Nature abhors a vacuum”.
Nature of Supramolecular Interactions :Van der Waals Forces
Nature of Supramolecular Interactions :CLOSE PACKING IN THE SOLID STATE
Conformers allowing maximum intermolecular interactions, even very weak (which do not play a r ole in solution)
„Empty“ space: crystal pores and channels -> inclusi on crystals
TETRIS analogy
Nature of Supramolecular Interactions :Hydrophobic Effects
Nature of Supramolecular Interactions :Hydrophobic Effects