Towards Practical Molecular Devices

Noel O’BoyleHan Vos Research Group X246

Introduction Molecular device

“capable of performing a useful function at the molecular level”

Supermolecule “has the intrinsic properties of each of its

components” “has properties above and beyond those of

the individual components”

Supramolecular chemistry

Ground state

Excited state

Supramolecular chemistry

Ground state

Excited state

Supramolecular chemistry

Ground state

Excited state (1)

Supramolecular chemistry

Ground state

Excited state (1)

Supramolecular chemistry

Ground state

Excited state (1)

Excited state (2)

Supramolecular chemistry

Ground state

Metal-Metal dyads

RuN

N

NN

OHO

OHO

O

OH

O

OH

N

NN

NN

RuN

N

N N

RuN

N

NN

OHO

OHO

O

OH

O

OH

N

NN

NN

OsN

N

N N

Ru-Ru Ru-Os

3+ 3+

Molecular device

Ru

e-

TiO2- +

Molecular device

e-

e-

-

+

Charge injection

Can be studied using: UV-Vis of ruthenium complex UV-Vis of TiO2

Lifetime of excited state of ruthenium complex

But occurs in <100 fs! (ultrafast)

Outline of future work

Slow down the charge injection

Change surface roughnesses

Use different surfaces

Use different complexes

Semiempirical calculations Using ZINDO (in Hyperchem) to find:

Orbital energies Location of HOMO levels Contribution of ligands and metal

centres to orbitals Assign the peaks in the UV-Vis

spectrum to specific transitions between energy levels

H H-1 H-2

-8.94 eV -9.55 eV -9.64 eV 22% Ru, 74% LL, 3% bpy 38% Ru, 54% LL, 8% bpy 74% Ru, 4% LL, 22% bpy

[Ru(bpy)2(pytrzph(OMe)2)]+

Acknowledgements Prof. Han Vos Han Vos Research Group

Enterprise Ireland

For more information see:http://www.dcu.ie/~chemist/Staffpages/han_vos.htm