In the fields of fluid dynamics, aeronautical engineering, environment engineering, and energy technology, it is critical to accurately measure the physical parameters of a material surface. [1] Optoelectronic devices have generally been employed as temperature and pressure sensors. [2] However, their sensing area is limited to a single point on a surface. There is a need to measure entire surfaces and obtain multidimensional data for mapping surfaces. There are high expectations that materials for surface measurements, such as temperature and pressure-sensitive dyes, will overcome this intrinsic limitation of optoelectronic devices.We seek to design temperature-sensitive dyes using luminescent lanthanide complexes. Lanthanide complexes exhibit characteristic luminescence with narrow emission bands (full width at half maximum, fwhm < 10 nm) and long emission lifetimes (> 1 ms), [3] which make them suitable for use in sensing devices. In 2003, Amao and co-workers reported the first temperature-sensitive dye that employed an Eu III complex in a polymer film. [4] Khalil et al. demonstrated the high performance of an Eu III complex for a temperature-sensitive paint (temperature sensitivity: 4.42 % 8C À1 ). [5] We have reported a Tb III complex, Tb(hfa) 3 -(H 2 O) 2 (hfa: hexafluoro acetylacetonato), that is suitable as a temperature-sensing probe since it exhibits effective energy back transfer (BEnT) from the emitting level of the Tb III ion to the excited triplet state of the hfa ligand. [6] Since BEnT depends on the energy barrier of the process, the emission intensity varies with temperature.To improve the thermosensing performance, it is necessary to develop a thermostable structure for high-temperature sensing and to implement a dual sensing unit for a high sensing ability. First, we focused on a lanthanide coordination polymer to produce a thermostable structure. Thermally stable coordination polymers and metal-organic frameworks have been widely studied. [7] Carlos and co-workers recently reported novel three-dimensional lanthanide-organic frameworks with 2,5-pyridinedicarboxylic acid. [8] Marchetti et al. developed thermostable Eu III coordination polymers with 4acyl-pyrazolone ligands. [9] Here, we consider that introducing Tb III ion and hfa ligands to coordination polymer frameworks will produce a Tb III coordination polymer that can be used as a temperature-sensing probe. The triplet state of hfa (22 000 cm À1 ) is very close to the emitting level of the Tb III ion (20 500 cm À1 ), resulting in effective EnT1 and BEnT and thus high-performance thermosensing dyes (Figure 1 a). We also selected low-vibrational frequency phosphane oxide [10] as the linking part in the Tb III coordination polymer because lanthanide complexes with high emission quantum yields composed of hfa and bidentate phosphane oxide ligands have been reported. [11] Second, we attempted to impart ratiometric temperature sensing by using luminescent Eu III and Tb III ions in the frameworks of the coordination polymer to realize a high th...

Highly luminescent tris[β-diketonate (HFA, 1,1,1,5,5,5-hexafluoropentane-2,4-dione)] europium(III) complexes containing a chiral bis(oxazolinyl) pyridine (pybox) ligand--[(Eu(III)(R)-Ph-pybox)(HFA)(3)], [(Eu(III)(R)-i-Pr-pybox)(HFA)(3)], and [(Eu(III)(R)-Me-Ph-pybox)(HFA)(3)])--exhibit strong circularly polarized luminescence (CPL) at the magnetic-dipole ((5)D(0) → (7)F(1)) transition, where the [(Eu(III)(R)-Ph-pybox)(HFA)(3)] complexes show virtually opposite CPL spectra as compared to those with the same chirality of [(Eu(III)(R)-i-Pr-pybox)(HFA)(3)] and [(Eu(III)(R)-Me-Ph-pybox)(HFA)(3)]. Similarly, the [(Tb(III)(R)-Ph-pybox)(HFA)(3)] complexes were found to exhibit CPL signals almost opposite to those of [(Tb(III)(R)-i-Pr-pybox)(HFA)(3)] and [(Tb(III)(R)-Me-Ph-pybox)(HFA)(3)] complexes with the same pybox chirality. Single-crystal X-ray structural analysis revealed ligand-ligand interactions between the pybox ligand and the HFA ligand in each lanthanide(III) complex: π-π stacking interactions in the Eu(III) and Tb(III) complexes with the Ph-pybox ligand, CH/F interactions in those with the i-Pr-pybox ligand, and CH/π interactions in those with the Me-Ph-pybox ligand. The ligand-ligand interactions between the achiral HFA ligands and the chiral pybox results in an asymmetric arrangement of three HFA ligands around the metal center. The metal center geometry varies depending on the types of ligand-ligand interaction.

The distorted coordination structures and luminescence properties of novel lanthanide complexes with oxo-linked bidentate phosphane oxide ligands--4,5-bis(diphenylphosphoryl)-9,9-dimethylxanthene (xantpo), 4,5-bis(di-tert-butylphosphoryl)-9,9-dimethylxanthene (tBu-xantpo), and bis[(2-diphenylphosphoryl)phenyl] ether (dpepo)--and low-vibrational frequency hexafluoroacetylacetonato (hfa) ligands are reported. The lanthanide complexes exhibit characteristic square antiprism and trigonal dodecahedron structures with eight-coordinated oxygen atoms. The luminescence properties of these complexes are characterized by their emission quantum yields, emission lifetimes, and their radiative and nonradiative rate constants. Lanthanide complexes with dodecahedron structures offer markedly high emission quantum yields (Eu: 55-72 %, Sm: 2.4-5.0 % in [D(6)]acetone) due to enhancement of the electric dipole transition and suppression of vibrational relaxation. These remarkable luminescence properties are elucidated in terms of their distorted coordination structures.

Novel thermostable organo‐phosphor compounds composed of coordination polymers are reported. Tight‐binding structures with intermolecular interactions of the coordination polymer induce both thermostability (decomposition point >300 °C) and high emission quantum yield (ΦLn=83 %). Their structures (see picture), thermogravimetric analyses, and remarkable photophysical properties are presented for the first time.

Characteristic triboluminescence from a lanthanide coordination polymer with a non-centrosymmetric structure is reported. The lanthanide coordination polymer is composed of luminescent Eu III ions and bidentate phosphane oxides, poly[3,3Ј-bis(diphenylphosphoryl)-2,2Ј-bipyridine][tris(hexafluoroacetylacetonate)]europium (poly-Eu-BIPYPO) crystals. The coordination geometry of poly-Eu-BIPYPO is categorized as an asymmetric eight-coordinate square antiprism (8-SAP). The space group of the crystal is also classified as the [a] Division