An ytterbium complex with unique luminescence properties: detecting the temperature based on a luminescence spectrum without the interference of oxygen.

We report a novel ytterbium complex [Yb(tta)3DFQZ] which exhibited obviously enhanced two-photon sensitized near-infrared luminescence properties of Yb(3+) compared to the usually reported Yb(3+) complexes, with a two-photon excitation action cross-section of 22 GM under excitation at 860 nm at 298 K. Unlike other lanthanide complexes, [Yb(tta)3DFQZ] under nitrogen exhibited quantum yields for the sensitized Yb(3+) luminescence that increased with increasing temperature. [Yb(tta)3DFQZ] was dispersed in a polymer film to prepare a near-infrared-emission sensor that made it possible to conveniently detect the temperature in a range from 178 to 378 K without the influence of O2, via a luminescence spectrum of Yb(3+) in the film. This provided a promising solution to the long-standing problem that complex calculations and complicated structures are usually needed for eliminating the influence of O2 on temperature sensing with a luminescent sensor.

A europium complex with enhanced long-wavelength sensitized luminescent properties.

We report a new complex Eu(tta)(3).bpt (tta = thenoyltrifluoroacetonate; bpt = 2-(N,N-di-ethylanilin-4-yl)-4,6-bis(pyrazol-1-yl)-1,3,5-triazine) with excellent long-wavelength sensitized luminescent properties, in which four hydrogen atoms replace the methyl groups at the 3,3'- and 5,5'-positions of the pyrazolyl rings in a previously reported complex Eu(tta)(3).dpbt. Upon visible-light excitation (lambda(ex) = 410 nm) at 295 K, the quantum yield (Phi(Ln)(L)) of Eu(3+) luminescence of Eu(tta)(3).bpt is higher by 23% than that of Eu(tta)(3).dpbt. Different from the case of Eu(tta)(3).dpbt, Phi(Ln)(L) of Eu(tta)(3).bpt increases linearly with the decrease in temperature. Because of the different coordination environments around Eu(3+) ion, the fine structure of the hypersensitive (5)D(0)-->(7)F(2) emission band of Eu(tta)(3).bpt is quite different from that of Eu(tta)(3).dpbt, with the strongest emission line locating at 620 nm rather than 613 nm where the strongest emission line of Eu(tta)(3).dpbt appears. The excitation window of Eu(tta)(3).bpt is much broader than that of Eu(tta)(3).dpbt with a red edge extending up to 450 nm in a dilute toluene solution (1.0 x 10(-5) M) and 500 nm in a toluene solution (1.0 x 10(-2) M). Eu(tta)(3).bpt also exhibits excellent two-photon-excitation luminescent properties.