CHE5480 Summer 2005CHE5480 Summer 2005

Dendrimers

June 14, 2005

Starburst DendrimersStarburst Dendrimers

What is a dendrimer? What is a dendrimer? Branched polymersBranched polymers

((dendron dendron = tree in Greek)= tree in Greek)

Functionality = 3 (Nitrogen)= 3 (Nitrogen)

Silicon, Si,

functionalty f=4

Rose bengal inside PPI dendrimer.Rose bengal inside PPI dendrimer.

Dendrimers:Dendrimers:

1. Manufacture2. Structure3. Characterization4. Applications

Manufacture:Manufacture:

(i) Divergent Method(ii) Convergent Method

Methods of Synthesis:Methods of Synthesis:

(i) Divergent Growth(i) Divergent Growth

Methods of Synthesis:Methods of Synthesis:

(ii) Convergent Growth(ii) Convergent Growth

Comparison: Comparison: Divergent vs. ConvergentDivergent vs. Convergent

Structure:Structure:

Generations of DendrimersGenerations of Dendrimers

2nd gen.

4th gen.

5th gen.

PAMAM Dendrimer PAMAM Dendrimer (polyamidoamine)(polyamidoamine)

Alternating

(B)-AB-AB-AB-...Ethylenediamine (B)H2N-C-C-NH2

Methylacrylate (A)C=C-CO-OCH3

PAMAM Moieties:PAMAM Moieties:

Acryla

te

Diami

ne

NH3 or

Diamin

e

Characterization:Characterization:

f=3 fc=3

Spacer b

123

generations

Construction of Generations:Construction of Generations:

Core: Ethylenediamine (Moiety B = D)

“Michael Addition” of 4 Methylacrylates (A= O)

Amidization: add 4 ethyldiamines (D)

Result: Generation “0”

Continue Branching:Continue Branching:Generation “1”:

Generation “2”:Generation “2”:

Calculations:Calculations:Note that Core functionality (2

nitrogens): fc = 4 Branch functionality

(nitrogen): f=3

No. of Spacers (A+B): b=2

Generation = G

Number of Branches: Number of Branches: NNbrbr

Number of Mers (A+B): Number of Mers (A+B): NNmermer

Applications of DendrimersApplications of Dendrimers

Gas and chemical sensorsCatalystsDrug delivery and gene therapySurface modifiers (tribology, and

information storage)Bio compatible materialsElectronic devices and antennae

Size of PAMAM DendrimersSize of PAMAM Dendrimers

Generation M.W. Angstrom (dia.) End GpsGeneration M.W. Angstrom (dia.) End Gps

(1 nm = 10 Angstroms)

Equivalent Sizes with Cells:Equivalent Sizes with Cells:

Dendrimer: PAMAMDendrimer: PAMAM

2. Nanostructured materials: 2. Nanostructured materials: Gas adsorption in dendrimersGas adsorption in dendrimers