Lecture 8 supramolecular chemistry

“Supramolecular chemistry is the chemistry of the intermolecular bond, covering the structures and functions of the entities formed by the associationof two or more chemical species” J.-

“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

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http://www.waltry.f2s.com/lectures/supra- “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.

http://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

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

http://www.waltry.f2s.com/lectures/supra-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- Two donor atoms linked together = a chelate (claw)

Chelate ligands form much more stable metal complexes

than monodentate related ligands (up to 10 5 times as stable)

Ni 2+ + L Formation Constants:

L = NH 3 en trien 2,3,2

8.12 13.54 13.8 16.4

better complementarity

faculty.swosu.edu/tim.hubin/InorganicLects/InorgCh1

2.2.ppt

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 deformation

 The increase in Ea required greatly slows down k-2

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

stable than non-cyclic chelates with the same number

of donors

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