183383-68-8Relevant articles and documents
Effect of ligand polarization on asymmetric structural formation for strongly luminescent lanthanide complexes
Hasegawa, Yasuchika,Ohkubo, Tomoki,Nakanishi, Takayuki,Kobayashi, Atsushi,Kato, Masako,Seki, Tomohiro,Ito, Hajime,Fushimi, Koji
, p. 5911 - 5918 (2013)
The effect of ligand polarization on the formation of strongly luminescent lanthanide complexes with asymmetric structures is described for the first time. The lanthanide complexes are composed of EuIII ions, three hexafluoroacetylacetonate (hfa) ligands, and two monodentate phosphine oxide ligands, namely, triphenylphosphine oxide (TPPO), p-tolyldiphenylphosphine oxide (TPPO-Me), tri-p-tolylphosphine oxide (TPPO-3Me) or o- phenoxyphenyldiphenylphosphine oxide (TPPO-OPh). The luminescence properties of the EuIII complexes are characterized by their emission quantum yields, emission lifetimes, and their radiative (kr) and nonradiative (knr) rate constants. The EuIII complex with TPPO-OPh ligands offers a markedly high emission quantum yield (72 % in [D 6]acetone, 85 % in the solid state) owing to enhancement of the electric dipole transition and suppression of vibrational relaxation, which are directly related to kr and knr. The coordination geometries of the EuIII complexes are categorized by shape-measure calculations. The EuIII complexes exhibit characteristic square-antiprismatic or trigonal-dodecahedral structures, depending on the ligand polarization. Strongly luminescent Eu(hfa)3(TPPO-OPh) 2 has an asymmetric dodecahedron structure. The formation of distorted dodecahedral structures with low vibrational frequencies for the enhancement of luminescence is elucidated in terms of the ligand polarization of the monodentate phosphine oxide ligands in the EuIII complexes. EuIII complexes with three hexafluoroacetylacetonate and two monodentate phosphine oxide ligands exhibit characteristic square-antiprismatic or trigonal-dodecahedral structures depending on the ligand polarization. Ligands with large dipole moments result in characteristic dodecahedron structures and markedly high emission quantum yields (72 % in [D 6]acetone, 85 % in the solid state).
Organolithium displacement of aryl anions from tertiary phosphine derivatives of diphenyl ether
Levy, Jack B.,Walton, Richard C.,Olsen, Ron E.,Symmes Jr., Courtland
, p. 545 - 548 (2007/10/03)
Methyllithium displaces a phenyl anion from 10-phenyl-10H-phenoxaphosphine to produce a 70:30 mixture of 10-methyl-10H-phenoxaphosphine and starting phosphine. Butyllithium gives 50% conversion to 10-butyl-10H-phenoxaphosphine. These reactions could take place either by a one-step nucleophilic displacement or by ring cleavage followed by recyclization. To show the feasibility of the two-step process, non-heterocyclic lithiated tertiary phosphines were generated and shown to cyclize to phenoxaphosphines. For example, reaction of 2-phenoxyphenyldiphenylphospnine with phenyllithium produced 10-phenyl-10H-phenoxaphosphine (by lithiation ortho to oxygen followed by cyclization) along with triphenylphosphine (by direct displacement of 2-lithiodiphenyl ether). Other compounds prepared in this work: 2,2′-bis(diphenylphosphino)-diphenyl ether, bis(2-phenoxyphenyl)phenylphospnine, tris(2-phenoxyphenyl)phosphine, 4-carboxy-10-phenyl-10H-phenoxaphosphine, and the oxides and sulfides of the phosphines.
