Synthesis, structural studies, theoretical calculations, and linear and nonlinear optical properties of terpyridyl lanthanide complexes: New evidence for the contribution of f electrons to the NLO activity
ABSTRACT The synthesis and structural, photophysical, and second-order nonlinear optical (NLO) properties of a novel lanthanide terpyridyl-like complex family LLn(NO(3))(3) (Ln = La, Gd, Dy, Yb, and Y) are reported. The isostructural character of this series in solution and in the solid state has been established on the basis of X-ray diffraction analysis in the cases of yttrium and gadolinium complexes, theoretical optimization of geometry (DFT), and NMR spectroscopy. The absorption, emission, and solvatochromic properties of the free terpyridyl-like ligand L were thoroughly investigated, and the twist intramolecular charge transfer (TICT) character of the lowest energy transition was confirmed by theoretical calculation (TDDFT and CIS). The similar ionochromic effect of the different lanthanide ions was evidenced by the similar UV-visible spectra of the complete family of complexes. On the other hand, the quadratic hyperpolarizability coefficient beta, measured by the harmonic light scattering (HLS) technique, is clearly dependent on the nature of the metal, and a careful examination of the particular case of yttrium unambiguously confirms the contribution of metal f electrons to the NLO activity.
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ABSTRACT: This paper reviews the syntheses, particle-size measurements and various aspects of the optical spectra of lanthanide ion doped insulating nanomaterials, with the focus upon the sesquioxides, and it contrasts their behaviour with bulk materials.Journal of Nanoscience and Nanotechnology 10/2005; 5(9):1455-64. DOI:10.1166/jnn.2005.311 · 1.34 Impact Factor
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ABSTRACT: We report the design of donor functionalized pi-conjugated pyridine dicarboxamide based chromophores presenting TPE fluorescence properties. Their use for the complexation of lanthanides and the sensitization of europium(III) luminescence by two photon antenna effect is also described.Proceedings of SPIE - The International Society for Optical Engineering 10/2006; DOI:10.1117/12.691090 · 0.20 Impact Factor
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ABSTRACT: The connection of twelve peripheral and divergent dodecyloxy chains to a central tridentate aromatic binding unit provides the dodecacatenar ligand L11, for which room-temperature mesomorphism is detected. An enthalpically unbalanced large melting entropy (DeltaSmL11=226 J mol(-1) K(-1)) results from the programmed microsegregation induced in the crystalline phase, a phenomenon which is maintained in the associated lanthanide complexes [Ln(L11)(NO3)3] and [Ln(L11)(CF3CO2)3]2. Low-temperature melting processes (-43<or=Tm<or=-25 degrees C) producing room-temperature hexagonal columnar liquid-crystalline phases thus result for these novel lanthanidomesogens. A combined photophysical (high-resolution emission spectroscopy), thermodynamic (differential scanning calorimetry, DSC) and structural (small-angle X-ray diffraction, SA-XRD) investigation of the melting process shows minor structural changes occurring between the crystal (Cr) and the hexagonal columnar mesophase (Colh) in the complexes, which allows the assignment of the existence of these unusual first-order phase transitions to the negligible mixing entropy produced by the two viscous phases at low temperature. Extension of the concept of chemical tuning of melting entropies for the global design of room-temperature metallomesogens and liquid crystals is discussed.Chemistry 01/2007; 13(31):8696-713. DOI:10.1002/chem.200700560 · 5.70 Impact Factor