A novel mesoporous SBA-15 type of hybrid material (phen-SBA-15) covalently bonded with 1,10-phenanthroline (phen) ligand was synthesized by co-condensation of tetraethoxysilane (TEOS) and the chelate ligand 5-[N,N-bis-3-(triethoxysilyl)propyl]ureyl-1,10-phenanthroline (phen-Si) in the presence of Pluronic P123 surfactant as a template. The preservation of the chelate ligand structure during the hydrothermal synthesis and the surfactant extraction process was confirmed by Fourier transform infrared (FTIR) and (29)Si MAS NMR spectroscopies. SBA-15 consisting of the highly luminescent ternary complex Eu(TTA)(3)phen (TTA = 2-thenoyltrifluoroacetone) covalently bonded to a silica-based network, which was designated as Eu(TTA)(3)phen-SBA-15, was obtained by introducing the Eu(TTA)(3).2H(2)O complex into the hybrid materials via a ligand exchange reaction. XRD, TEM, and N(2) adsorption measurements were employed to characterize the mesostructure of Eu(TTA)(3)phen-SBA-15. For comparison, SBA-15 doped with Eu(TTA)(3).2H(2)O and Eu(TTA)(3)phen complexes and SBA-15 covalently bonded with a binary europium complex with phen ligand were also synthesized, and were named SBA-15/Eu(TTA)(3), SBA-15/Eu(TTA)(3)phen, and Eu-phen-SBA-15, respectively. The detailed luminescence studies on all the materials showed that, compared with the doping sample SBA-15/Eu(TTA)(3)phen and binary europium complex functionalized sample Eu-phen-SBA-15, the Eu(TTA)(3)phen-SBA-15 mesoporous hybrid material exhibited higher luminescence intensity and emission quantum efficiency. Thermogravimetric analysis on Eu(TTA)(3)phen-SBA-15 demonstrated that the thermal stability of the lanthanide complex was evidently improved as it was covalently bonded to the mesoporous SBA-15 matrix.

The crystal structure of a ternary Er(DBM)3phen complex (DBM = dibenzoylmethane; phen = 1,10‐phenanthroline) and its in‐situ synthesis via a sol–gel process are reported. The infrared (IR), diffuse reflectance (DR), and fluorescence spectra of the pure complex and the Er3+/DBM/phen co‐doped luminescent hybrid gel, formed via an in‐situ method (ErDP gel), have been investigated. The results reveal that the erbium complex is successfully synthesized in situ in the ErDP gel. Excitation at the maximum absorption wavelength of the ligands resulted in the typical near‐IR luminescence (centered at around 1.54 μm) resulting from the 4I13/2 → 4I15/2 transition of the Er3+ ion, which contributes to the efficient energy transfer from the ligands to the Er3+ ion in both the Er(DBM)3phen complex and the ErDP gel (an antenna effect). The full width at half maximum (FWHM) centered at 1541 nm in the emission spectrum of the ErDP gel is 72 nm, which has potential for optical‐amplification applications. Further theoretical analysis on the Er3+ ion in the ErDP gel shows that it appears to be a promising candidate for tunable lasers and planar optical amplifiers.

A luminescent europium-organic framework with tubular channels based on the H4BTMIPA ligand (H4BTMIPA = 5,5'-methylenebis(2,4,6-trimethylisophthalic acid)) was assembled and characterized. The [H2N(CH3)2](+) ions as counterions are located in the channels. The cation exchange between [H2N(CH3)2](+) and metal ions resulted in complex that can selectively sense Fe(3+) and Al(3+) ions through fluorescence quenching and enhancement, respectively.

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The near-infrared (NIR) luminescent lanthanide ions, such as Er(III), Nd(III), and Yb(III), have been paid much attention for the potential use in the optical communications or laser systems. For the first time, the NIR-luminescent Ln(dbm)(3)phen complexes have been covalently bonded to the ordered mesoporous materials MCM-41 and SBA-15 via a functionalized phen group phen-Si (phen-Si = 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline; dbm = dibenzoylmethanate; Ln = Er, Nd, Yb). The synthesis parameters X = 12 and Y = 6 h (X denotes Ln(dbm)(3)(H(2)O)(2)/phen-MCM-41 molar ratio or Ln(dbm)(3)(H(2)O)(2)/phen-SBA-15 molar ratio and Y is the reaction time for the ligand exchange reaction; phen-MCM-41 and phen-SBA-15 are phen-functionalized MCM-41 and SBA-15 mesoporous materials, respectively) were selected through a systematic and comparative study. The derivative materials, denoted as Ln(dbm)(3)phen-MCM-41 and Ln(dbm)(3)phen-SBA-15 (Ln = Er, Nd, Yb), were characterized by powder X-ray diffraction, nitrogen adsorption/desorption, Fourier transform infrared (FT-IR), elemental analysis, and fluorescence spectra. Upon excitation of the ligands absorption bands, all these materials show the characteristic NIR luminescence of the corresponding lanthanide ions through the intramolecular energy transfer from the ligands to the lanthanide ions. The excellent NIR-luminescent properties enable these mesoporous materials to have potential uses in optical amplifiers (operating at 1.3 or 1.5 mum), laser systems, or medical diagnostics. In addition, the Ln(dbm)(3)phen-SBA-15 materials show an overall increase in relative luminescent intensity and lifetime compared to the Ln(dbm)(3)phen-MCM-41 materials, which was explained by the comparison of the lanthanide ion content and the pore structures of the two kinds of mesoporous materials in detail.

The crystal structures of ternary Ln(DBM)(3)phen complexes (DBM = dibenzoylmethane, phen = 1,10-phenanthroline, and Ln = Nd, Yb) and their in situ syntheses via the sol-gel process are reported. The properties of the Ln(DBM)(3)phen complexes and their corresponding Ln(3+)/DBM/phen-co-doped luminescent hybrid gels obtained via an in situ method (Ln-D-P gel) have been studied. The results reveal that the lanthanide complexes are successfully in situ synthesized in the corresponding Ln-D-P gels. Both Ln(DBM)(3)phen complexes and Ln-D-P gels display sensitized near-infrared (NIR) luminescence upon excitation at the maximum absorption of the ligands, which contributes to the efficient energy transfer from the ligands to the Ln(3+) ions (Ln = Nd, Yb), an antenna effect. The radiative properties of the Nd(3+) ion in a Nd-D-P gel are discussed using Judd-Ofelt analysis, which indicates that the (4)F(3/2) --> (4)I(11/2) transition of the Nd(3+) ion in the Nd-D-P gel can be considered as a possible laser transition.

This paper describes an investigation into the general trend in electronic properties of anatase TiO2 photocatalysts co-doped with transition metals and nitrogen employing first-principles density functional theory. Fourteen different transition metals (M), including Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Cd, have been considered. The characteristic band structures of the co-doping systems involving the transition metal series are presented. Our results indicate that the absorption edges of TiO2 are shifted to the visible-light region upon introduction of dopants, due to the reduced conduction band minimum (CBM) and the formation of impurity energy levels (IELs) in the band gap. These IELs are primarily formed from (a) the anti-bonding orbitals of the M-O (M indicates the doped transition metal) bonds, (b) the unsaturated nonbonding d orbitals of the doped transition metal (mainly d(xy), d(yz), and d(xz)), and (c) the Ti-O bonding/Ti-N anti-bonding orbitals of the bond next to the doped transition metal. When the valence d electrons of the doped metal are between 3 and 7, all three types of IELs appear in the band gap of the (M, N) co-doped systems. For systems doped with a metal of more than 7 valence electrons, only types (a) and (c) of IELs as well as the unoccupied pz state of N are observed. Based on our analysis, we propose that the co-doping systems such as (V, N), (Cr, N), and (Mn, N), which have the IELs with a significant bandwidth, are of great potential as candidates for photovoltaic applications in the visible light range.