WP4 - BIOMACH

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Midterm-Review Meeting

Molecular Machines-

Design and Nano-Scale Handling of Biological Antetypes and Artificial Mimics

Work Package 4: Photochemical Devices

Objectives

Partners

PM

Integrate appropriate Light-Fueled Molecular Components into nanomotors as alternative fueling concept

CIAM , ETH , FZK-INT , ULP

(additional contribution of MPI-FKF )

CIAM : 15 PM

FZK-INT 3 PM

ETH

ULP

: 21 PM

: 3 PM

Specific Targeted Research Project (STREP) in FP6-NMP-2002

ENERGY

Midterm-Review Meeting

Work Package 4: Photochemical Devices triggering molecular motor molecular machine

WORK FUNCTION monitoring

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Light stimulation ...

... can cause the occurrence of endergonic and reversible reactions

... is very easy to achieve (by means of lamps or lasers, or from the sun)

... allows a precise control of the amount of energy conferred to the chemical systems by adjusting the radiation’s intensity and wavelength

... can be switched on and off easily and rapidly

... can be performed with high spatial (down to nm level with near-field techniques) and temporal control (down to fs time domain)

... does not need to “touch” or “wire” the molecules to the energy source

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Moreover ...

... photons can also be used to read the state of the system: by means of luminescence spectroscopy, for instance, detection can be made at the single molecule level

... the formation of waste products can be prevented by using “clean” photochemical reactions

... light stimulation allows the design of autonomous molecular motors

M4-1 (m06): Planning and synthesis of a LFMC

M4-2 (m12): Photophysical characterization of LFMC‘s in solution

D4-1 (m12): Final design of a LFMC

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Design strategies of light-driven molecular machines

1) Photoinduced electron transfer processes in multicomponent systems h n e

– state

A light-fueled component mechanical switching device state

B isomer B

2) Photoisomerization reactions h n isomer A geometrical changes

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

An artificial autonomous nanomotor driven by visible light

State-of-the-art

Photoinduced reversible shuttling in rotaxanes

Murakami et al., J. Am. Chem. Soc. 1997 , 119 , 7605

Ashton et al., Chem. Eur. J. 2000 , 6 , 3558

Brouwer et al., Science 2001 , 291 , 2124

Anderson et al., Angew. Chem. Int. Ed. 2002 , 41 , 1769

Light-driven rotary motors

Feringa et al., Nature 1999 , 401 , 152

Org. Biomol. Chem. 2003 , 1 , 33

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

An artificial autonomous nanomotor driven by visible light

Photosensitizer and stopper

P

N

N

N

Ru II

N

N

N

Rigid spacer

S

Electron acceptor A

2

+

N

A

2

N

+

Electron donor macrocycle

O

O

O

O

Electron acceptor A

1

O

O

+

N

A

1

N

+

O

O

O

O

O

Dumb stopper

R

T

Partners CIAM (design; photochemical and electrochemical characterization; validation of motor operation in solution)

Collaboration with Fraser Stoddart , Dept Chemistry & Biochemistry and California Nanosystems

Institute, University of California, Los Angeles (design; synthesis; structural characterization)

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

An artificial autonomous nanomotor driven by visible light

Conditions: Acetonitrile solution, room temperature

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

An artificial autonomous nanomotor driven by visible light

Conditions: Acetonitrile solution, room temperature

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

An artificial autonomous nanomotor driven by visible light

Conditions: Acetonitrile solution, room temperature

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

An artificial autonomous nanomotor driven by visible light

= 2% Conditions: Acetonitrile solution, room temperature

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

An artificial autonomous nanomotor driven by visible light

NANOMOTOR MOVIE

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

An artificial autonomous nanomotor driven by visible light

The present nanomotor constitutes a breakthrough compared to previous systems because it gathers together the following features:

• it is powered by visible light, i.e., sunlight

• it exhibits autonomous behaviour (like motor proteins)

• it does not generate waste products since only photons are consumed

• its operation relies only on intramolecular processes (no limitations of principle to single-molecule operation)

• it is fast (it can be driven at a frequency exceeding 1 kHz)

• it works in mild environmental conditions (ambient temperature, fluid solution) and is remarkably stable.

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

D4-2 (m18): Computational treatment of light-induced rotary movements in LFMCs

Computational study on the shuttling motion with

Metadynamics

• Metadynamics allows a fast escape from the energy basins and the identification of other stable and metastable configurations

• The Free Energy Surface (FES) can be reconstructed with controlled accuracy

Partners ETH (theoretical and computational work); CIAM (experimental work)

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Computational study on the shuttling motion with

Metadynamics

METADYNAMICS MOVIE

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Computational study on the shuttling motion with metadynamics

Collective variables

1.

Position of R along the thread

2.

Number of hydrogen bonds between R and A

1

3.

Number of hydrogen bonds between R and A

2

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Free energy surfaces

A

1

Position of R along the thread Position of R along the thread

A

2

Position of R along the thread Position of R along the thread

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

The shuttling mechanism

Saddle

A

2

<14 kcal/mol <9 kcal/mol

A

2

A

1

Estimated error : 1 kcal/mol

Experimental values determined by CIAM :

A

A

1

2

Saddle : ~12 kcal/mol

Saddle : ~14 kcal/mol

Specific Targeted Research Project (STREP) in FP6-NMP-2002

A

1

Midterm-Review Meeting

Work Package 4: Photochemical Devices

The shuttling mechanism

SHUTTLING MOVIE

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

M4-3 (m16): Self-assembly of LFMCs on surfaces

Molecular motions on surfaces with a photoisomerization reaction bulk: azobenzene

State-of-the-art bulk: azodibenzoic acid

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

State-of-the-art: bulk self-assembly and UV light-induced isomerization azodibenzoic acid

F. Rakotondradany et al., Chem. Eur. J. 2003 , 9 , 4771 from linear chains...

...to cyclic tetramers

(  2.3 nm)

M4-3 (m16): Self-assembly of LFMCs on surfaces

self-assembly on surfaces ?

effect of UV light on structures ?

Partners FZK-INT (synthesis) ; MPI-FKF (STM experiment)

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Self-assembly of azodibenzoic acid on Cu(100)…

...through hydrogen bonding trans domains formation

...through metal-ligand interactions cavities

Partners FZK-INT (synthesis) ; MPI-FKF (STM experiment)

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Ongoing Experiment: Light-induced Surface-Switching

OH

O

N

N

O

HO

STM

In collaboration with

WP1 “Nanohandling„ UV

Vis sublimation on Cu(100) surface trans domains formation

?

cis domains formation

Partners FZK-INT (synthesis) ; MPI-FKF (STM experiment)

Specific Targeted Research Project (STREP) in FP6-NMP-2002

Midterm-Review Meeting

Work Package 4: Photochemical Devices

Objectives

Milestones

Deliverables

Integrate appropriate Light-Fueled Molecular Components into nanomotors as alternative fueling concept

M4-1 (m06): Planning and synthesis of a LFMC

M4-2 (m12): Photophysical characterization of LFMC‘s in solution

M4-3 (m16): Self-assembly of LFMC‘s on surfaces

D4-1 (m12): Final design of a LFMC (report)

D4-2 (m18): Computational treatment of light-induced rotary movements (report)

1) A light-powered nanomotor based on a rotaxane was successfully designed ( CIAM , collaboration with

UCLA), synthesized (UCLA) and operated ( CIAM ). Computational simulations on this system ( ETH ) have started to unravel the mechanism of the shuttling process, and are expected to be crucial for the design of novel prototypes with improved performance.

2) The trans-cis photoisomerization of an azobenzene derivative is being studied on a metal surface. The experiments performed by FZK-INT in connection with MPI-FKF (WP1) have shown that the azobenzene species can indeed be deposited as a monolayer onto a Cu(100) surface by sublimation under UHV, and that domains of the trans -isomer are formed.

Specific Targeted Research Project (STREP) in FP6-NMP-2002

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