Using light to power molecular devices USING ULTRAFAST UVVISIBLE AND XRAY SPECTROSCOPY TO PROBE EXCITED STATE DYNAMICS IN PHOTOACTIVE MOLECULES R Cobalamin Vitamin B 12 Photochemistry ID: 633169
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Slide1
Light, Molecules, Action!Using light to power molecular devices
USING ULTRAFAST UV-VISIBLE AND X-RAY SPECTROSCOPY TO PROBE EXCITED STATE DYNAMICS IN PHOTOACTIVE MOLECULES.
R
Cobalamin (Vitamin B
12
) PhotochemistrySlide2
AcknowledgementsSynthesis of novel designed compoundsSpectroscopic and Physical measurements
Development of light sourcesTheoretical simulation and predictionBernhard Kräutler
Pawel
KozlowskiOur group,Jim
Penner-HahnKevin
KubarychLCLS Beamline scientists
Students:
Ted Wiley
Nick Miller
Laura
Kiefer
William
Miller
Jon Elrod
Anushka Gupta
Roberto Alonso-Mori
James M. Glownia Jake Koralek Marcin SikorskiDiling Zhu
Collaborators:
Pawel Kozlowski(Univ. Louisville)Bernhard Kräutler(Univ. of Innsbruck)Ken Spears Kevin KubarychKen SpearsJim Penner-HahnAniruddha Deb
Funding:Slide3
Light, Molecules, Action!Using light to power molecular machines
Light is a versatile energy source Light (esp. laser light) can be shaped, timed, tuned, focused, aimed and delivered at a target as required. Spatial and temporal control of molecular activation.Optically controlled molecular devices
motors, switches, activators, junctions, memory, logic circuits, actuators, sensors, and delivery platforms.
Function is controlled by photochemistry Photon energy produces action via movement of charge, change in shape or cleavage of a bond – light activates a change in the chemical nature of a molecular system. Slide4
B12 AnalogsAnti-Vitamins and Optical Control
The photochemistry of cobalamins is of interest:
Newly discovered B
12
based photoreceptor proteins use light to control
gene activation and carotenoid synthesis.
The upper group
“R”
can be replaced by a drug (
eg
. a cancer drug) to allow
photoactivated
drug delivery.
Reactive radicals can be produced with spatiotemporal control
.
Photoresponsive “anti-vitamins” allow control of biological availability.Molecular switches and sensors can be developed by designing appropriate ligands, “R”.
RSlide5
B12 Photolysis
HOCblexc = 253 nm
Photochemistry is controlled by the
lowest singlet state (S
1
) surface
or by branching of states at higher
energy, bypassing S
1
state barriers.Slide6
B12 SpectraTypical UV-Visible Spectra
RSlide7
HOCbl (B12b) Photolysis
pH 10.3, 99+%
HOCbl
exc:
269 nm404 nm535 nm560 nm
575 nm
Wiley, T. E.; Miller, W. R.; Miller, N. A.;
Sension
, R. J.;
Lodowski
, P.;
Jaworska
, M.; Kozlowski, P. M. J. Phys. Chem. Lett. 2016, 7, 143-147.Slide8
HOCbl (B12b) PhotolysisSlide9
HOCbl (B12b) Photolysis
pH 10.3, 99+%
HOCbl
269 nm only:Slide10
R
<
~300 nm
~
2
%
The surfaces for three different electronic configurations define the lowest excited state surface for cobalamins
. (Calculations: Kozlowski et al.)
Photochemistry is controlled by the lowest
surface or by branching of states at higher energy.
HOCbl
(B
12b
) PhotolysisSlide11
<~300 nm~2%
The surfaces for three different electronic configurations define the lowest excited state surface for cobalamins. (Calculations: Kozlowski et al.)Photochemistry is controlled by the lowest
surface or by branching of states at higher energy.
HOCbl (B12b) PhotolysisSlide12
Antivitamin B12 EtPhCbl
Photo conditional “anti-vitamin” B
12
.
Metabolically inert.
Optical control of biological availability.
Miller, N. A.; Wiley, T. E.; Spears, K. G.;
Ruetz
, M.;
Kieninger
, C.;
Kräutler
, B.;
Sension
, R. J. J. Am. Chem. Soc. 2016, 138, 14250-14256.Slide13
Antivitamin B12 EtPhCblSlide14
Antivitamin B12 EtPhCblSlide15
Coenzyme B12: AdoCbl
In Ethylene GlycolSlide16
Coenzyme B12: AdoCbl
In Water (~pH 7)Slide17
Vitamin B12: CNCbl
5Slide18
Vitamin B12: CNCblSlide19
Vitamin B12: CNCbl
Lodowski, P.;
Jaworska, M.; Andruniów, T.;
Garabato, B. D.; Kozlowski, P. M.: Phys. Chem. Chem. Phys. 2014, 16, 18675-18679.Slide20
Femtosecond XANES of Vitamin B12Slide21
Femtosecond XANES of Vitamin B12Slide22
Polarized XANES of Electronically Excited Vitamin B12
y
x
X-ray absorption near edge structure
Sensitive to electronic and structural changes.
O
ptical excitation is along “x”.
Perpendicular in-plane direction is “y”.
The “z” direction is out-of-plane.
Miller, N. A
. et
al. J. Am. Chem. Soc. 2017, 139, 1894-1899.Slide23
Polarized XANESProbe at the cobalt K-edge excited Co 1s electrons. Measuring the difference signal across the near edge region.
Perpendicular difference signal.
1s
3d pre-edge
1s
np K-edgeSlide24
Excited State XANESSlide25
Excited State XANESComparison with Simulation
Lodowski
, P.;
Jaworska
, M.;
Kornobis, K.;
Andruniow
, T.; Kozlowski, P. M.:
J
. Phys. Chem. B 2011, 115, 13304-13319
.
Lodowski
, P.;
Jaworska
, M.;
Andruniów, T.; Garabato, B. D.; Kozlowski, P. M.: Phys. Chem. Chem. Phys. 2014, 16, 18675-18679.S1S0
S1Co-CN1.857
2.216
Co-Nimd2.0542.275S0Slide26
Polarized XANESComparison with SimulationSlide27
XANES Time DependenceSlide28
XANES Time DependenceSlide29
XANES Time Dependence
Potential energy curves of the lowest vertical excited singlet (red dot) and the optimized first excited state (red solid line) of the
CNCbl
model along the structural parameter q computed at BP86/6-31G(d)
with
solvent using the COSMO/H2O model. Lodowski, P.; Jaworska
, M.;
Kornobis
, K.;
Andruniow
, T.; Kozlowski, P. M.: J. Phys. Chem. B 2011, 115, 13304-13319
.Slide30
XANES Time Dependence
(5)Slide31
XANES Time Dependence
Potential energy curves of the lowest vertical excited singlet (red dot) and the optimized first excited state (red solid line) of the CNCbl model along the structural parameter q computed at BP86/6-31G(d) with solvent using the COSMO/H2O model. Lodowski, P.; Jaworska, M.; Kornobis, K.; Andruniow, T.; Kozlowski, P. M.: J. Phys. Chem. B 2011, 115, 13304-13319
.Slide32
XANES Time Dependence
z
ySlide33
ConclusionsStructural changes around the Co atom.With pulse: modest ring changes.
(1*1)
1 =
0.11 ps
: Axial bond elongation.
(
(
/d)
1
(
*/dxy+n*/*dz2)1) 2 = 0.26
ps: Corrin ring/axial relaxation (1(*dz2)1)3 = 6.2 ps: Excited state population decay.
(2)Ultrafast XAS and UV-Vis combine to give picture of the structural and electronic dynamics on the excited state surface.Slide34
AcknowledgementsSynthesis of novel designed compoundsSpectroscopic and Physical measurements
Development of light sourcesTheoretical simulation and predictionBernhard Kräutler
Pawel
KozlowskiOur group,Jim
Penner-HahnKevin
KubarychLCLS Beamline scientists
Students:
Ted Wiley
Nick Miller
Laura
Kiefer
William
Miller
Jon
Elrod
Anushka Gupta
Roberto Alonso-Mori James M. Glownia Jake Koralek Marcin Sikorski
Diling Zhu
Collaborators:Pawel Kozlowski(Univ. Louisville)Bernhard Kräutler(Univ. of Innsbruck)Ken Spears Kevin KubarychKen Spears
Jim Penner-Hahn
Aniruddha Deb
Funding: