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
... 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
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
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 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
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
...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
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