Wybren Jan BumaWybren Jan Buma

Molecular PhotonicsMolecular Photonics

van ‘t Hoff Institute for Molecular Sciences

University of Amsterdam

Mechanically interlocked molecules Mechanically interlocked molecules in the gas phase:in the gas phase:

isolated molecule spectroscopy and dynamicsisolated molecule spectroscopy and dynamics

MolMol PhotPhotEE

SS

MolMol PhotPhotEE

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Mechanically interlocked moleculesMechanically interlocked molecules

Two separate componentsNon-covalently bound

* macrocyclemacrocycle* threadthread → binding sitebinding site

Two separate componentsNon-covalently bound

* macrocyclemacrocycle* threadthread → binding sitebinding site

MolMol PhotPhotEE

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Mechanically interlocked moleculesMechanically interlocked molecules

Weak bond provides unique rotationalrotational and translationaltranslational degrees of freedom

that can be accessed in a controllablecontrollable and reversiblereversible manner

Weak bond provides unique rotationalrotational and translationaltranslational degrees of freedom

that can be accessed in a controllablecontrollable and reversiblereversible manner

MolMol PhotPhotEE

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ObjectivesObjectives

To control and manipulate molecular motors requires

* exploration of conformational landscapeconformational landscape

* knowledge of interactionsinteractions between the interlocked parts

* characterization relative movementrelative movement

To control and manipulate molecular motors requires

* exploration of conformational landscapeconformational landscape

* knowledge of interactionsinteractions between the interlocked parts

* characterization relative movementrelative movement

MolMol PhotPhotEE

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Gas phase experimentsGas phase experiments

* isolateisolate molecules from external effects (solvent)

* heating induces changes or decomposition

* laser desorptionlaser desorption technique to vaporize them

* cool molecules by entraining them into supersonic expansionsupersonic expansion

* isolateisolate molecules from external effects (solvent)

* heating induces changes or decomposition

* laser desorptionlaser desorption technique to vaporize them

* cool molecules by entraining them into supersonic expansionsupersonic expansion

MolMol PhotPhotEE

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High-resolution spectroscopyHigh-resolution spectroscopy

Laser desorption Mass spectrum

Excitation spectrum IR absorption spectrum

2800 3000 3200 3400 3600

0.0

0.2

0.4

0.6

0.8

1.0

Inte

nsity

IR wavenumbers (cm-1)

+ supersonic beam

NH

ONH

NH HN

HN

OO

OO

HN

O

NH

ONH

NH HN

HN

OO

OO

HN

O

MolMol PhotPhotEE

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SpectroscopySpectroscopy

supersonic beam

desorption laser

sample

nozzle

ions

Excitation & ionization laser

detector

1064 nm

MolMol PhotPhotEE

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Multiphoton ionization spectroscopyMultiphoton ionization spectroscopy

Mass-selected vibrationally-resolved excitation spectraMass-selected vibrationally-resolved excitation spectra

S0

S1

IE

Excitation energy

+ion

MolMol PhotPhotEE

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IR ion dip spectroscopyIR ion dip spectroscopy

~ 200 nsIR UV

S0 v=0

S1

IE

S0 v=1

+ion detection

NH NH stretch frequencies diagnostic of details (changes in)

hydrogen-bondinghydrogen-bonding

10

Ion signal

MolMol PhotPhotEE

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Does it work ?Does it work ?

macrocycle

rotaxane1148 amu

NH

ONH

NH HN

HN

OO

OO

HN

O

NH

ONH

NH HN

HN

OO

OO

HN

O

MolMol PhotPhotEE

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Problems to be tackled todayProblems to be tackled today

I. How does the macrocycle effect the conformational phase spaceconformational phase space of the thread ?

II. Can we characterise the interactionsinteractions between macrocycle and thread and find signatures for them ?

I. How does the macrocycle effect the conformational phase spaceconformational phase space of the thread ?

II. Can we characterise the interactionsinteractions between macrocycle and thread and find signatures for them ?

MolMol PhotPhotEE

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Building blocks in the gas phaseBuilding blocks in the gas phase

N

O

N

O

N

OO

NH

NH

O

O

N

OO

NH

NHPh

Ph

Ph

Ph

MolMol PhotPhotEE

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Excitation spectrum threadExcitation spectrum thread

origin

6b01

101

1201

9a01

6b0110

1

6b01120

1

N

O

N

O

MolMol PhotPhotEE

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Excitation spectrum threadExcitation spectrum thread

37800 37850 37900 37950 38000 38050 38100 38150 38200

Inte

nsit

y

one-photon energy (cm-1)37800 37850 37900 37950 38000 38050 38100 38150 38200

Inte

nsit

y

one-photon energy (cm-1)

MolMol PhotPhotEE

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Low-frequency vibrations threadLow-frequency vibrations thread

FFTFFT

49 cm-1 12 cm-1

MolMol PhotPhotEE

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Cooling conditionsCooling conditions

xenon

argon

~30 cm-1

~12 cm-1

MolMol PhotPhotEE

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Molecular motors in the gas phaseMolecular motors in the gas phase

N

OO

NH

NH

O

O

N

OO

NH

NHPh

Ph

Ph

Ph

193

nm io

niza

tion

MolMol PhotPhotEE

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Molecular motors in the gas phaseMolecular motors in the gas phase

~30 cm-1

~10 cm-1

Direct view on conformational phase space restrictionconformational phase space restriction by macrocycle

MolMol PhotPhotEE

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Mechanically interlocked moleculesMechanically interlocked molecules

NH

O

NH

HN

O

HN

O O

NH

ONH

NH HN

HN

OO

OO

HN

O

NH

ONH

NH HN

HN

OO

OO

HN

O

MolMol PhotPhotEE

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REMPI excitation spectroscopy: macrocycleREMPI excitation spectroscopy: macrocycle

NH

O

NH

HN

O

HN

O O

MolMol PhotPhotEE

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Ion-dip spectroscopy: macrocycleIon-dip spectroscopy: macrocycle

37200 37400 37600 37800 38000 38200 38400 38600

0.0

0.2

0.4

0.6

0.8

1.0

Nor

mal

ized

Int

ensi

ty

one-photon energy (cm-1)

NH

O

NH

HN

O

HN

O OC-H N-H

MolMol PhotPhotEE

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Ion-dip spectroscopy: rotaxaneIon-dip spectroscopy: rotaxane

NH

O

NH

HN

O

HN

O O

MolMol PhotPhotEE

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NH.....O=C

NH thread

Ion-dip spectroscopy: rotaxaneIon-dip spectroscopy: rotaxane

NH

ONH

NH HN

HN

OO

OO

HN

O

NH

ONH

NH HN

HN

OO

OO

HN

O

NH macrocycle

MolMol PhotPhotEE

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Present experimentsPresent experiments

IR-UV hole-burning spectroscopy at Free Electron Laser for Infrared eXperimentsFree Electron Laser for Infrared eXperiments

(FELIX)

Far IR (30 - 2000 cm-1) (C=O, fingerprint region)(C=O, fingerprint region)brings within reach:

- detailed view on conformational landscape

- vibrations of macrocycle with respect to the thread (< 400 cm-1)

IR-UV hole-burning spectroscopy at Free Electron Laser for Infrared eXperimentsFree Electron Laser for Infrared eXperiments

(FELIX)

Far IR (30 - 2000 cm-1) (C=O, fingerprint region)(C=O, fingerprint region)brings within reach:

- detailed view on conformational landscape

- vibrations of macrocycle with respect to the thread (< 400 cm-1)

MolMol PhotPhotEE

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ConclusionsConclusions

We can bring supramolecular assemblies We can bring supramolecular assemblies in the gas phase and perform in the gas phase and perform high-resolution spectroscopyhigh-resolution spectroscopy

Influence of macrocycle on conformational phase space thread

Conformational flexibility available to assembly

We can bring supramolecular assemblies We can bring supramolecular assemblies in the gas phase and perform in the gas phase and perform high-resolution spectroscopyhigh-resolution spectroscopy

Influence of macrocycle on conformational phase space thread

Conformational flexibility available to assembly

MolMol PhotPhotEE

SS

UvAUvAAnouk RijsAnouk Rijs

Dick Bebelaar

UC Santa BarbaraUC Santa BarbaraAli Abu-RiziqBridgit Crews

Mattanjah de VriesMattanjah de Vries

University of EdinburghUniversity of EdinburghDavid Leigh

UvAUvAAnouk RijsAnouk Rijs

Dick Bebelaar

UC Santa BarbaraUC Santa BarbaraAli Abu-RiziqBridgit Crews

Mattanjah de VriesMattanjah de Vries

University of EdinburghUniversity of EdinburghDavid Leigh

FundingFunding

NWONWOEC-TMR (RTN)EC-TMR (RTN)

EC-FETEC-FETEC-NMP EC-NMP

EC-Marie CurieEC-Marie Curie