Transcript Lecture 8_Supramolecular Chemistry

Nanochemistry
NAN 601
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Instructor:
 Dr.
Marinella Sandros
Lecture 8: Supramolecular Chemistry
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“Supramolecular chemistry is the chemistry of the
intermolecular bond, covering the structures and
functions of the entities formed by the association
of two or more chemical species”
J.-M- Lehn
"Supramolecular chemistry is defined as chemistry
‘beyond the Molecule’, as chemistry of tailor
shaped inter-molecular interaction.”
F. Vögtle
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
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“Chemistry beyond the molecule”
“Chemistry of molecular assemblies and of
the intermolecular bond.”
“The Chemistry of non-covalent bond.”
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Supramolecular chemistry involves investigating
molecular systems in which the most important
feature is that components are held together by
intermolecular forces, not by covalent bonds.
Atoms
Molecules
Covalent Interactions
Non-Covalent Interactions
Molecules
Supermolecules
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http://www.tfp.uni-karlsruhe.de/Summerschool/Lectures/voegtle1.pdf
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Where did it come from?
Inspired from biology and built on the
shoulders of traditional synthetic organic
chemistry.
Why does it deserve to be a field of study all
its own?
The next logical step in synthetic chemistry;
understanding and interface with the
biological world; nanotechnology
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http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
Lock and Key Principle
http://www.waltry.f2s.com/lectures/supra-lec2.pdf
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Molecular Self-Assembly:
Process by which 2 or more molecules
interact from a larger structure or
organization.
Super-Molecule:
A complex formed by molecular selfassembly which contains a discrete number
of subunits.
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http://www.waltry.f2s.com/lectures/supra-lec2.pdf
http://www.waltry.f2s.com/lectures/supra-lec2.pdf
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http://www.waltry.f2s.com/lectures/supra-lec2.pdf
http://www.waltry.f2s.com/lectures/supra-lec2.pdf
http://www.waltry.f2s.com/lectures/supra-lec2.pdf
http://www.waltry.f2s.com/lectures/supra-lec2.pdf
http://www.waltry.f2s.com/lectures/supra-lec2.pdf
 The
study of non-covalent interactions
is crucial to understanding many
biological processes from cell structure
to vision that rely on these forces for
structure and function. Biological
systems are often the inspiration for
supramolecular research.
http://en.wikipedia.org/wiki/Supramolecular_chemistry
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http://www.waltry.f2s.com/lectures/supra-lec1.pdf
people.bio.aau.dk/.../PowerPoint/Supramolecular%20chemistry.ppt
malina.ichf.edu.pl/educ/.../WYKLAD_SUPRA_NANO1_2005.ppt
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http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
 Two donor atoms linked together = a chelate (claw)
 Chelate ligands form much more stable metal complexes than
monodentate related ligands (up to 105 times as stable)
Ni2+ + L Formation Constants:
L = NH3
en
trien
2,3,2
8.12
13.54 13.8
16.4
better
complementarity
faculty.swosu.edu/tim.hubin/InorganicLects/InorgCh12.2.ppt
Why is favorable??
Thermodynamic Reasons for the Chelate Effect = Entropy
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Macrocyclic chelate complexes are up 107 times more stable
than non-cyclic chelates with the same number of donors
Ni(trien)2+
+
Ni(cyclam)2+
H+
+
Ni2+ + H4trien4+
H+
t½ = 2 seconds
Ni2+ + H4cyclam4+
t½ = 2 years
 Connecting all of the donors (having no end group) makes k-2 important
 Breaking the first M—L bond requires major ligand deformation
 The increase in Ea required greatly slows down k-2
faculty.swosu.edu/tim.hubin/InorganicLects/InorgCh12.2.ppt
• The result is a very stable complex as kd becomes miniscule
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http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.waltry.f2s.com/lectures/supra-lec1.pdf
http://www.ciam.unibo.it/photochem/Ri.mo_03.pdf
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They allow access to nanoscale objects using a
bottom-up approach in far fewer steps than a
single molecule of similar dimensions.
The process by which a supramolecular assembly
forms is called molecular self-assembly. Some
try to distinguish self-assembly as the process
by which individual molecules form the defined
aggregate. Self-organization, then, is the
process by which those aggregates create
higher-order structures.
http://en.wikipedia.org/wiki/Supramolecular_assembly
http://www.ciam.unibo.it/photochem/Ri.mo_03.pdf
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http://www.ciam.unibo.it/photochem/Ri.mo_03.pdf
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http://www.ciam.unibo.it/photochem/Ri.mo_03.pdf
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http://www.esonn.fr/0oldweb/ESONN04/Lectures/esonn_2004_Mascini3.pdf
http://www.google.com/search?client=safari&rls=en&q=molecular+imprinting+ppt&ie=UTF-8&oe=UTF-8
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