title: LMCT facilitated room temperature phosphorescence and energy transfer in substituted thiophenolates of Gd and Yb.
abstract: To obtain luminescent lanthanide complexes with a low energy LMCT state the 2-(2'-mercaptophenyl)benzothiazolates, Ln(SSN)3, and 2-(2'-mercaptophenyl)benzoxazolates, Ln2(OSN)6(Ln = Gd, Yb), were synthesized by the reaction of amides Ln[N(SiMe3)2]3with respective thiophenols. Ytterbium complexes were structurally characterized by X-ray diffraction analysis. Cyclic voltammetry revealed that the deprotonated mercaptophenyl ligands have significantly lower oxidation potentials than their phenoxy analogues and some β-diketones. The photophysical properties of Gd and Yb compounds were studied both in solution and in the solid state. The fluorescence spectra of the compounds in solution display the bands of the keto and enol forms of the ligands. No energy transfer from the organic part to Yb3+has been detected in solutions of both Yb complexes, whereas in solids an intense metal-centered emission in the near infrared region was observed. The solid Gd compounds exhibited room temperature phosphorescence caused by unusually efficient intersystem crossing facilitated by the essentially reducing properties of OSN and SSN ligands. To explain the sensitization process occurring in solids Yb2(OSN)6and Yb(SSN)3a specific non-resonant energy transfer mechanism via a ligand to metal charge transfer state has been proposed. Based on the Yb derivatives, NIR-emitting OLEDs with 860 μW cm-2maximal irradiance were obtained. Their Gd counterparts showed bright electrophosphorescence (up to 1350 cd m-2) in the devices containing doped emission layers.
authors.affiliation: G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropininast. 49, 603950 Nizhny Novgorod, Russian Federation. ilichev@iomc.ras.ru.
authors.forename: Vasily A
authors.identifier: http://orcid.org/0000-0001-7724-3180
authors.initials: VA
authors.lastname: Ilichev
authors.affiliation: G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropininast. 49, 603950 Nizhny Novgorod, Russian Federation. ilichev@iomc.ras.ru.
authors.forename: Anton V
authors.initials: AV
authors.lastname: Rozhkov
authors.affiliation: G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropininast. 49, 603950 Nizhny Novgorod, Russian Federation. ilichev@iomc.ras.ru.
authors.forename: Roman V
authors.initials: RV
authors.lastname: Rumyantcev
authors.affiliation: G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropininast. 49, 603950 Nizhny Novgorod, Russian Federation. ilichev@iomc.ras.ru.
authors.forename: Georgy K
authors.initials: GK
authors.lastname: Fukin
authors.affiliation: Nizhny Novgorod State University, Gagarina avenue 23/2, 603950 Nizhny Novgorod, Russian Federation.
authors.forename: Ivan D
authors.initials: ID
authors.lastname: Grishin
authors.affiliation: A. N. Frumkin Institute of Physical Chemistry and Electrochemistry of Russian Academy of Sciences, Leninsky prospect 31, 199071 Moscow, Russian Federation.
authors.forename: Artem V
authors.initials: AV
authors.lastname: Dmitriev
authors.affiliation: A. N. Frumkin Institute of Physical Chemistry and Electrochemistry of Russian Academy of Sciences, Leninsky prospect 31, 199071 Moscow, Russian Federation.
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Lypenko
authors.affiliation: A. N. Frumkin Institute of Physical Chemistry and Electrochemistry of Russian Academy of Sciences, Leninsky prospect 31, 199071 Moscow, Russian Federation.
authors.forename: Eugeny I
authors.initials: EI
authors.lastname: Maltsev
authors.affiliation: Institute for Physics of Microstructures of Russian Academy of Sciences, 7 ul. Akademicheskaya, 603950 Nizhny Novgorod, Russian Federation.
authors.forename: Artem N
authors.initials: AN
authors.lastname: Yablonskiy
authors.affiliation: Nizhny Novgorod State University, Gagarina avenue 23/2, 603950 Nizhny Novgorod, Russian Federation and Institute for Physics of Microstructures of Russian Academy of Sciences, 7 ul. Akademicheskaya, 603950 Nizhny Novgorod, Russian Federation.
authors.forename: Boris A
authors.identifier: http://orcid.org/0000-0002-5692-0418
authors.initials: BA
authors.lastname: Andreev
authors.affiliation: G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropininast. 49, 603950 Nizhny Novgorod, Russian Federation. ilichev@iomc.ras.ru and Nizhny Novgorod State University, Gagarina avenue 23/2, 603950 Nizhny Novgorod, Russian Federation.
authors.forename: Mikhail N
authors.initials: MN
authors.lastname: Bochkarev