1. Light-Induced Sulfur to Oxygen Isomerization
of Ruthenium Sulfoxide Complexes
Jackson Majher

2. Rhodopsin
Photoswitchable molecules: molecules which change optically and electronically due to activation via electromagnetic radiation.
Examples:
Oxazine
Sodium nitroprusside
Kim, J. E.; McCamant, D. W.; Zhu, L.; Mathies, R. A.; J. Phys. Chem. B 2001, 105, 1240–1249.
(2) Rymo, F. M.; J. Phys. Chem. A 2012, 116 (48),
(3) Woike, T., Krasser, W., Bechthold, P. S., Haussuhl, S.; Phys. Rev. Lett. 1984, 53, 767–1770.

3. Background:
(4) Rack, J. J.; Coordination Chemistry Reviews. 2009, 253,
(5) Yeh, A.; Scott, N.; Taube, H.;Inorg. Chem. 1982, 21, 2542.
(6) Roeker, L.; Dobson, J. C.; Vining, W. J.; Meyer, T. J.; Inorg. Chem. 1987, 29, 779.
(7) Root, M. J.; Deutsch, E.; Inorg. Chem. 1985, 24,1464.
(8) Silve, D. O.; Saika, J. J.; Toma, H. E.; J. Photochem. Photobiol. A 1998, 112, 209.
(9) Smith, M. K.; Gibson, J. A.; Young, C. G.; Broomhead, J. A.; Junk, P. C.; Keene, F. R.; Eur. J. Inorg. Chem. 2000, 1365.
(10) Rachford, A. A.; Rack, J. J.; J. Am. Chem. Soc. 2006, 128,
(11) McClure, B. A.; Mockus, N. V.; Butcher, D. P.; Lutterman, D. A.; Turro, C.; Petersen, J. L.; Rack, J. J. Inorg. Chem. 2009, 48, 8084–8091.

4. [Ru(bpy)2(OSO)]+ -Relatively large quantum yield (0.45) achieved.
-Chelate effects changes mechanism
-Ruthenium (w/ sulfoxide character) to * bpy transition assigned.
-No evidence of O-bonded 3MLCT excited state.
-Vibrationally relaxed 3MLCT 2 structure proposed.
(11) McClure, B. A.; Mockus, N. V.; Butcher, D. P.; Lutterman, D. A.; Turro, C.; Petersen, J. L.; Rack, J. J.; Inorg. Chem. 2009, 48, 8084–8091.

5. -Transient absorption spectroscopy utilized for kinetic information.
Summary:
-Series of ruthenium sulfoxide complexes that undergo SO isomerization were synthesized.
-Characterization by electronic absorbance spectroscopy, IR, NMR and cyclic voltammetry.
-Transient absorption spectroscopy utilized for kinetic information.
-Results show picosecond timescale kinetics, suggestive of a mechanism including rapid nonradiative decay through conical intersection.
(12) McClure, B. A.; Abrams, E. R.; Rack, J. J.; J. Am. Chem. Soc. 2010, 132,
Goals of Paper:
-Study relationship between distortion energy and
isomerization reactivity.
-Effect of changing electronic and steric factors
contributing to exited state isomerization.

6. Absorption Spectra:
-Absorption shift to lower wavelengths for BnF5
-Absorption applies to the d* transition.
-fwhm highest for R=BnF5 complex which suggests larger nuclear displacement between ground and triplet excited state.
-fwhm analysis showed metal-ligand contribution as being the major source of distortion.

7. Analysis Continued..
-Zero-zero energy was calculated using known values and the absorption
spectra to predict room temperature wavelength emission at 1070,
1530, and 1780 nm for R = Nap, BnF5, and Bn respectively.
-Were unable measure emission at these wavelengths though they
did not see any emission from nm.
-Emission max observed at 580, 576, and 572 nm for R = Nap, Bn, BnF5
respectively (77K).
-Further testing required to see if NIR emission observed.
-Relevant information: Strong affect of metal-ligand vibrations on absorption
spectra and PES has temperature dependence.
E0 = Eop - * - ST

8. Picosecond Transient Absorption
O-Bonded Isomer
S-Bonded Isomer:
1.0, 2.0, 5.0, 10.3, 20.4, , 203.0, 508.0, 1008 ps
5.0, 10.2, 20.3, 50.7, 100.3, ps

9. R = Me

10. Conclusions: Criticisms:
-Distortion energy plays a large role in isomerization through conical intersections, primarily through metal-ligand
interactions.
-R = BnF5 complex shows good isomerization characteristics, electronic influence through sulfur bond achievable.
-More testing needs to be done to narrow down specific electronic and steric factors needed to maximize
isomerization conditions.
Criticisms:
-Not a significant expansion of knowledge past their previous work.
-Would be helpful to include more R group types to solidify trends observed.
-No computational calculations that provide reasoning to their results.
-Emission calculations not backed up by any experimental data.

11. Acknowledgements:
And Eric R. Abrams
Beth McClure
J. J. Rack

12. Questions?