1. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat1 Chimica Fisica dei Materiali Avanzati Part 9 – Dendrimers Laurea specialistica in Scienza e Ingegneria dei Materiali Curriculum Scienza dei Materiali

2. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat2 Nomenclature of dendrimers

3. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat3 Pros: highly iterative chemistry – good control on different generations – possibility to go to high generations (i.e. obtain very large dendrimers). Cons: number of reaction steps increases rapidly with generation – poor control on structural defects, particularly on high generations Dendrimer synthesis: divergent approach

4. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat4 Dendrimer synthesis: convergent approach Pros: number of reaction steps does not increase rapidly with generations – good control on structural defects – possibility to obtain anisotropic dendrimers Cons: synthesis of large dendrimers is often hindered

5. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat5 Functional dendrimers Functional units at the periphery Functional units in the branching points Functional units in the core

6. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat6 From synthesis to applications antenna systems sensors with signal amplification NLO systems nano-reactors drug delivery systems catalysts contrast agents in medical diagnosis molecular batteries Unimolecular micelles templates for nanoparticle synthesis ….

7. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat7 Molecular light-harvesting antennae An antenna for light harvesting is an organized multicomponent system in which several chromophoric molecular species absorb the incident light and channel the excitation energy to a common acceptor component. Organization must be achieved in the dimensions of time, energy, and space

8. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat8 Natural antenna systems Structure of the LH2 light-harvesting antenna system of Rhodopseudomonas acidophila which contains rings of 18 (left) and 9 (right) bacteriochlorophyll molecules. The ring of B850 Bchl a molecules The positions of the B800 Bchl a molecules between the helices of the b-apoproteins forming the outer cylindrical wall of the complex. The a-apoproteins are coloured yellow and the b- apoproteins green.

9. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat9 Natural antenna systems - 2 Schematic representation of the overall light harvesting process by LH2 and LH1 antenna complexes in bacterial photosynthesis. RC is the reaction center Kuhlbrandt, Nature, 1995

10. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat10 Light harvesting sytems

11. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat11 … an example

12. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat12 Dansyl: a commonly used fluorescent dye highly fluorescent molecule useful to probe interactions with: Protons metal ions dyes Absorption and emission spectra in CH3CN:CH2Cl2 5:1 v/v

13. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat13 Chemical sensors Conventional fluorescent sensor Fluorescent sensor with high signal amplification

14. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat14 Sensor of metal ions with signal amplification One Co 2+ guest is sufficient to quench each one of the 64 dansyl units, when they are excited J. Am. Chem. Soc. 2000, 122, 10398

15. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat15 Light controlled drug delivery systems

16. U NIVERSITA DEGLI S TUDI DI P ADOVA Corso CFMA. LS-SIMat16 Medical applications: photodynamic therapy Light absorption O2O2 1O21O2 Singlet oxygen production