Light, Molecules, Action - PowerPoint Presentation

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Light, Molecules, Action - PPT Presentation

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

excited b12 light state b12 excited state light xanes kozlowski chem miller phys hocbl lowest vitamin energy surface time

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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.

Cobalamin (Vitamin B

) 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

based photoreceptor proteins use light to control

gene activation and carotenoid synthesis.

The upper group

“R”

can be replaced by a drug (

. 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

HOCblexc = 253 nm

Photochemistry is controlled by the

lowest singlet state (S

) surface

or by branching of states at higher

energy, bypassing S

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

~300 nm

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

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

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

X-ray absorption near edge structure

Sensitive to electronic and structural changes.

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.

3d pre-edge

np K-edgeSlide24

Excited State XANESSlide25

Excited State XANESComparison with Simulation

Lodowski

, P.;

Jaworska

, M.;

Kornobis, K.;

Andruniow

, T.; Kozlowski, P. M.:

. 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-CN1.857

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

ySlide33

ConclusionsStructural changes around the Co atom.With pulse: modest ring changes.

(1*1)



1 =

0.11 ps

: Axial bond elongation.

(

(

