Publications by authors named "Sebastian B Vittardi"

3 Publications

  • Page 1 of 1

A Future Perspective on Phototriggered Isomerizations of Transition Metal Sulfoxides and Related Complexes.

J Am Chem Soc 2021 Jan 5;143(2):526-537. Epub 2021 Jan 5.

Department of Chemistry and Chemical Biology, 300 Terrace Street NE, University of New Mexico, Albuquerque, New Mexico 87131-001 United States.

Photochromic molecules are examples of light-activated bistable molecules. We highlight the design criteria for a class of ruthenium and osmium sulfoxide complexes that undergo phototriggered isomerization of the bound sulfoxide. The mode of action in these complexes is an excited-state isomerization of the sulfoxide from S-bonded to O-bonded. We discuss the basic mechanism for this transformation and highlight specific examples that demonstrate the effectiveness and efficiency of the isomerization. We subsequently discuss future research directions within the field of phototriggered sulfoxide isomerizations on transition metal polypyridine complexes. These efforts involve new synthetic directions, including the choice of metal as well as new ambidentate ligands for isomerization.
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http://dx.doi.org/10.1021/jacs.0c08820DOI Listing
January 2021

Luminescent lanthanide complexes with a pyridine-bis(carboxamide)-bithiophene sensitizer showing wavelength-dependent singlet oxygen generation.

Dalton Trans 2020 May 6;49(20):6661-6667. Epub 2020 May 6.

Department of Chemistry, University of Nevada, Reno, Nevada 89557, USA.

A new pyridine-bis(carboxamide)-based ligand with a bithiophene pendant, 2Tcbx, was synthesized. Its lanthanide ion (Ln) complexes, [Ln(2Tcbx)], were isolated and their photophysical properties were explored. Upon excitation at 360 nm, these complexes display emission in the near-infrared (NIR) with efficiencies of 0.69% for Ln = Yb, 0.20% for Ln = Nd, and 0.01% for Ln = Er, respectively. Concurrent O formation was seen for all complexes, with efficiencies of 19% for the Yb complex, 25% for the Nd complex, and 9% for the Er complex. When exciting at a longer wavelength, 435 nm, only Ln emission was observed and larger efficiencies of Ln-centered emission were obtained. The lack of O generation indicates that energy pathways involving different ligand conformations, which were investigated by transient absorption spectroscopy, are involved in the sensitization process, and enable the wavelength-dependent generation of O.
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http://dx.doi.org/10.1039/d0dt01034kDOI Listing
May 2020

Wavelength-Dependent Singlet Oxygen Generation in Luminescent Lanthanide Complexes with a Pyridine-Bis(Carboxamide)-Terthiophene Sensitizer.

Chemistry 2020 Jun 19;26(32):7274-7280. Epub 2020 May 19.

Department of Chemistry, University of Nevada, Reno, Reno, NV, 89557, USA.

Lanthanide ion (Ln ) complexes, [Ln(3Tcbx) ] (Ln =Yb , Nd , Er ) are isolated with a new pyridine-bis(carboxamide)-based ligand with a 2,2':5',2''-terthiophene pendant (3TCbx), and their resulting photophysical properties are explored. Upon excitation of the complexes at 490 nm, only Ln emission is observed with efficiencies of 0.29 % at 976 nm for Ln =Yb and 0.16 % at 1053 nm for Ln =Nd . Er emission is observed but weak. Upon excitation at 400 nm, concurrent O formation is seen, with efficiencies of 11 % for the Yb and Nd complexes and 13 % for the Er complex. Owing to the concurrent generation of O , as expected, the efficiency of metal-centered emission decreases to 0.02 % for Yb and 0.05 % for Nd . The ability to control O generation through the excitation wavelength indicates that the incorporation of 2,2':5',2''-terthiophene results in access to multiple sensitization pathways. These energy pathways are unraveled through transient absorption spectroscopy.
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http://dx.doi.org/10.1002/chem.202000587DOI Listing
June 2020