Mechanically interlocked molecules in the gas phase isolated

Mechanically interlocked molecules in the gas phase: isolated molecule spectroscopy and dynamics Wybren Jan Buma Molecular Photonics van ‘t Hoff Institute for Molecular Sciences University of Amsterdam E Mol Phot S

Mechanically interlocked molecules Two separate components Non-covalently bound * macrocycle * thread → binding site E Mol Phot S

Mechanically interlocked molecules Weak bond provides unique rotational and translational degrees of freedom that can be accessed in a controllable and reversible manner E Mol Phot S

Objectives To control and manipulate molecular motors requires * exploration of conformational landscape * knowledge of interactions between the interlocked parts * characterization relative movement E Mol Phot S

Gas phase experiments * isolate molecules from external effects (solvent) * heating induces changes or decomposition * laser desorption technique to vaporize them * cool molecules by entraining them into supersonic expansion E Mol Phot S

High-resolution spectroscopy Laser desorption Mass spectrum + supersonic beam Excitation spectrum IR absorption spectrum E Mol Phot S

Spectroscopy desorption laser ions detector 1064 nm nozzle sample supersonic beam Excitation & ionization laser E Mol Phot S

Multiphoton ionization spectroscopy + ion IE S 1 S 0 Excitation energy Mass-selected vibrationally-resolved excitation spectra E Mol Phot S

IR ion dip spectroscopy + detection IE NH stretch frequencies diagnostic of details (changes in) hydrogen-bonding S 1 0 1 Ion signal S 0 v=1 S 0 v=0 IR UV ~ 200 ns E Mol Phot S

Does it work ? rotaxane 1148 amu macrocycle E Mol Phot S

Problems to be tackled today I. How does the macrocycle effect the II. conformational phase space of the thread ? II. Can we characterise the interactions between macrocycle and thread and find signatures for them ? E Mol Phot S

Building blocks in the gas phase E Mol Phot S

Excitation spectrum thread 6 b 01101 6 b 011201 origin 9 a 01 101 E Mol Phot S

Excitation spectrum thread E Mol Phot S

Low-frequency vibrations thread FFT 49 cm-1 12 cm-1 E Mol Phot S

Cooling conditions ~30 cm-1 argon ~12 cm-1 xenon E Mol Phot S

193 nm ionization Molecular motors in the gas phase E Mol Phot S

Molecular motors in the gas phase ~10 cm-1 ~30 cm-1 Direct view on conformational phase space restriction by macrocycle E Mol Phot S

Mechanically interlocked molecules E Mol Phot S

REMPI excitation spectroscopy: macrocycle E Mol Phot S

Ion-dip spectroscopy: macrocycle C-H N-H E Mol Phot S

Ion-dip spectroscopy: rotaxane E Mol Phot S

Ion-dip spectroscopy: rotaxane NH thread NH macrocycle NH. . . O=C E Mol Phot S

Present experiments IR-UV hole-burning spectroscopy at Free Electron Laser for Infrared e. Xperiments (FELIX) Far IR (30 - 2000 cm-1) (C=O, fingerprint region) brings within reach: - detailed view on conformational landscape - vibrations of macrocycle with respect to the thread (< 400 cm-1) E Mol Phot S

Conclusions We can bring supramolecular assemblies in the gas phase and perform high-resolution spectroscopy §Influence of macrocycle on conformational phase space thread §Conformational flexibility available to assembly E Mol Phot S

Uv. A Anouk Rijs Dick Bebelaar UC Santa Barbara Ali Abu-Riziq Bridgit Crews Mattanjah de Vries University of Edinburgh David Leigh Funding NWO EC-TMR (RTN) EC-FET EC-NMP EC-Marie Curie E Mol Phot S