Publications by authors named "Manuel A Gracia-Nava"

2 Publications

  • Page 1 of 1

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