Download presentation
Presentation is loading. Please wait.
Published byBarrie Alexander Modified over 6 years ago
1
S. Bocklitz, * D. M. Hewett, † T. S. Zwier, † M. A. Suhm*
Probing the conformational landscape of polyether building blocks by Raman jet spectroscopy S. Bocklitz, * D. M. Hewett, † T. S. Zwier, † M. A. Suhm* *Göttingen University, Germany †Purdue University, IN, USA International Symposium on Molecular Spectroscopy
2
Motivation Water soluble polymers Surfactants Adaptive aggregation
Folding effects 06/20/2016 Sebastian Bocklitz -1-
3
Retrospect simplest representative: 1,2-dimethoxyethane (monoglyme)
Three most stable conformations of monoglyme: ttt tgt tgg' Our best estimates: 2.0 kJ·mol-1 1.2 kJ·mol-1 S. Bocklitz, M. A. Suhm, Z. Phys. Chem. 2015, 229, 06/20/2016 Sebastian Bocklitz -2-
4
Diglyme Lots and lots of different conformers: 36 = 729 (193 relevant)
E / kJ·mol-1 tgg‘tg‘g g‘gttgg‘ 2 tgttg‘t tgg‘tgg‘ tttg‘gt tgttgg‘ tgtgg‘t ttttgg‘ 1 tgg‘g‘gt tgg‘tgt tttttt tgttgt ttttgt tgttg‘g Calculated energy differences based on B3LYP-D3BJ/aug-cc-pVTZ 06/20/2016 Sebastian Bocklitz -3-
5
Family origins tgttg‘g tgtttt tgttgt tttttt 0.2 kJ·mol-1 0.0 kJ·mol-1
Calculated energy differences based on B3LYP-D3BJ/aug-cc-pVTZ 06/20/2016 Sebastian Bocklitz -4-
6
Spectra Physics Millennia eV 25
Setup saturator magnetic valve beam stop camera lens bypass nozzle pumps lens cw laser Spectra Physics Millennia eV 25 l = 532 nm, Pmax = 25 W slit width w = 0.15 mm slit length l = 4 mm 06/20/2016 Sebastian Bocklitz -5-
7
Raman spectrum 06/20/2016 Sebastian Bocklitz -6-
8
Longer Glymes 06/20/2016 Sebastian Bocklitz -7-
9
Zwier lab spectroscopy
UV Fluorescence Laser Induced Fluorescence (LIF) UV IR Fluorescence Fluorescence Dip Infrared Spectroscopy (FDIRS) Dt ~200 ns 06/20/2016 Sebastian Bocklitz -8-
10
Setup 06/20/2016 Sebastian Bocklitz -9-
11
1-Methoxy-2-phenoxyethane
ttt tgt tgg‘ B2PLYP-D3BJ/aug-cc-pVTZ 0.0 0.7 3.6 B3LYP-D3BJ/aug-cc-pVTZ 0.6 4.5 B3LYP-D3BJ/def2TZVP 0.4 1.4 18 W, 1mm, m34 °C (10 mbar), 1.9bar He, 5x10mins All values in kJ·mol-1 06/20/2016 Sebastian Bocklitz -10-
12
LIF 06/20/2016 Sebastian Bocklitz -11-
5 W, 1mm, m35°C (10 mbar), 1.9 bar Gas, 5 x 10 min 06/20/2016 Sebastian Bocklitz -11-
13
Local mode approach to model anharmonic effects
CH-spectra Local mode approach to model anharmonic effects Daniel Tabor & Edwin Sibert (UW-Madison) 06/20/2016 Sebastian Bocklitz -12-
14
CH-spectra 06/20/2016 Sebastian Bocklitz -13-
15
Summary Folded structures compete for the global minimum in diglyme
All four family origins (relaxation model) are almost equal in energy Most spectral signs (in jet expansions) can be assigned to one of the four low-energy conformers All-trans conformer becomes energetically unfavoured in longer glymes Phenoxy-substituted monoglyme shows a similar conformeric landscape as monoglyme Local mode approach to model anharmonic effects in the CH-stretching region possible 06/20/2016 Sebastian Bocklitz -14-
16
Acknowledgements Prof. Suhm and the whole Suhm group
Prof. Zwier, Dan Hewett and the whole Zwier group Prof. Sibert & Daniel Tabor
17
Thank you for your attention !
Funding Thanks for generous financial support SU 121/6-1 Thank you for your attention !
18
Raman spectrum 06/20/2016 Sebastian Bocklitz
25 W, 1mm, He, 1.9bar, m35°C(10mbar), 0.5bar Reservoir 06/20/2016 Sebastian Bocklitz
19
Raman spectrum 06/20/2016 Sebastian Bocklitz
25 W, 1mm, He, 1.9bar, m35°C(10mbar), 0.5bar Reservoir 06/20/2016 Sebastian Bocklitz
20
Carrier gas 06/20/2016 Sebastian Bocklitz
25 W, 1mm, He, 1.9bar, m35°C(10mbar), 0.5bar Reservoir 06/20/2016 Sebastian Bocklitz
21
Nozzle distance 06/20/2016 Sebastian Bocklitz
25 W, 1mm, He, 1.9bar, m35°C(10mbar), 0.5bar Reservoir 06/20/2016 Sebastian Bocklitz
22
CH spectra 06/20/2016 Sebastian Bocklitz
25 W, 1mm, He, 1.9bar, m35°C(10mbar), 0.5bar Reservoir 06/20/2016 Sebastian Bocklitz
23
UV-UV-HB 06/20/2016 Sebastian Bocklitz
25 W, 1mm, He, 1.9bar, m35°C(10mbar), 0.5bar Reservoir 06/20/2016 Sebastian Bocklitz
24
Figure references Motivation (slide no. 1)
content/uploads/2012/05/pourintowaterR.jpg Stretching and folding of 2-nanometer hydrocarbon rods Soft Matter 2014, 10, Setup (slide no. 5) N.O. B. Lüttschwager, Raman Spectroscopy of Conformational Rearrangements at Low Temperatures, Springer Verlag, 2014. 25 W, 1mm, He, 1.9bar, m35°C(10mbar), 0.5bar Reservoir 06/20/2016 Sebastian Bocklitz
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.