Instructor: Instructor:

Dr. Marinella SandrosDr. Marinella Sandros

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NanochemistrNanochemistryy

NAN 601NAN 601

Lecture 8: Supramolecular Chemistry

“Supramolecular chemistry is the chemistry of theintermolecular bond, covering the structures andfunctions of the entities formed by the associationof two or more chemical species”J.-M- Lehn

"Supramolecular chemistry is defined as chemistry‘beyond the Molecule’, as chemistry of tailorshaped inter-molecular interaction.”F. Vögtle

http://www.waltry.f2s.com/lectures/supra-lec1.pdf

“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

Molecules Supermolecules

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Non-Covalent Interactions

Covalent Interactions

5http://www.tfp.uni-karlsruhe.de/Summerschool/Lectures/voegtle1.pdf

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

6http://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-lec2.pdf

Lock and Key Principle

Molecular Self-Assembly:Process by which 2 or more molecules interact from a larger structure or organization.

Super-Molecule:A complex formed by molecular self-assembly which contains a discrete number of subunits.

11http://www.waltry.f2s.com/lectures/supra-lec2.pdf

12http://www.waltry.f2s.com/lectures/supra-lec2.pdf

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http://www.waltry.f2s.com/lectures/supra-lec2.pdf

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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

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malina.ichf.edu.pl/educ/.../WYKLAD_SUPRA_NANO1_2005.ppt

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

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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

bettercomplementarity

faculty.swosu.edu/tim.hubin/InorganicLects/InorgCh12.2.ppt

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Thermodynamic Reasons for the Chelate Effect = Entropy

Why is favorable??

Ni(trien)2+ + H+ Ni2+ + H4trien4+ t½ = 2 seconds

Ni(cyclam)2+ + H+ 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 deformationThe increase in Ea required greatly slows down k-2

faculty.swosu.edu/tim.hubin/InorganicLects/InorgCh12.2.ppt

Macrocyclic chelate complexes are up 107 times more stable than non-cyclic chelates with the same number of donors

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• The result is a very stable complex as kd becomes miniscule

http://www.waltry.f2s.com/lectures/supra-lec1.pdf

http://www.waltry.f2s.com/lectures/supra-lec1.pdf

38http://www.ciam.unibo.it/photochem/Ri.mo_03.pdf

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

40http://www.ciam.unibo.it/photochem/Ri.mo_03.pdf

41http://www.ciam.unibo.it/photochem/Ri.mo_03.pdf

42http://www.ciam.unibo.it/photochem/Ri.mo_03.pdf

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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