A new series of neutral protomesogenic Eu III tris(diketonate) adducts with different Lewis bases have been synthesized. Only one of the complexes is liquid-crystalline and displays smectic A and nematic mesomorphism over a broad temperature range. Quantum-chemistry and small-angle X-ray scattering methods have permitted the evaluation of the influence of the structure of the Lewis base on the anisometry of [a] Physical and Colloid Eu(CPDk 3-Ph ) 3 Phen (1): Yield: 56 % (0.085 g). C 84 H

Europium(III) complexes that are the anisometric analogues of a well-known Eu(DBM)Phen (DBM = dibenzoylmethane; Phen = 1,10-phenanthroline) complex were synthesized. Quantum-chemical calculations of the excited states of new Eu(III) complexes and some conjugated polymers showed that poly(N-vinylcarbazole) provides the most efficient energy transfer in polymer films doped with synthesized Eu(III) complexes. These new composite films were prepared, and their luminescence properties were studied. The results of experimental data confirmed theoretical prediction about significant influence introduced in molecular structure long terminal alkyl chains and cyclohexane on the luminescence efficiency of "Ln(III)-polymer" composite. As the result a substantial contribution of complex anisometry to the luminescence efficiency of composite was revealed due to the increase of the complex limit concentration before self-quenching more than twofold.

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Uniform luminescent films with high optical quality are promising materials for modern molecular photonics. Such film materials based on β-diketonate complexes of lanthanides have the following application problem: rapid luminescence degradation under UV radiation, low thermostability, poor mechanical properties, and aggregation propensity. An alternative approach to solving these problems is the use of anisometric analogues of β-diketonate compounds of lanthanides (III). The main advantage of such compounds is that they do not crystallize because of long hydrocarbon substituents in the structure of complexes, so they can be used to fabricate thin nano-, micro-, and macroscale uniform film materials by a melt-processing technique at relatively low temperatures, as well as by spin-coating. The method of fabrication of microscale luminescent film materials with controlled optical properties from anisometric analogues of Ln(DBM) 3 Phen and Ln(bzac) 3 Phen complexes (Ln = Eu, Tb) is proposed in this paper. Within the framework of this research, we developed original films which are highly uniform and transparent. An important advantage of these films is their high photostability and potential for applications as reusable luminescent sensors and light converters.Photonics 2019, 6, 110 2 of 10 application problem: rapid luminescence degradation under UV radiation, low thermostability, poor mechanical properties and propensity to aggregation [9,10]. A possible solution is incorporating these compounds into host matrices (e.g., organic polymers, ionic liquids, zeolites, and etc.) [11][12][13]. There are also other methods of fabricating film materials based on these compounds, such as electro deposition and sol-gel technology [1][2][3].Another problem of many film materials based on β-diketonate complexes of lanthanides is that their adsorption band is limited by the UV range. Therefore, UV sources are required to excite luminescence in such films, such sources are unsuitable in many applications for certain reasons (such as low brightness and high cost of such devices as compared to visible light sources). Thus, an urgent problem of molecular photonics is to broaden this adsorption band so it can include the visible light range.The solutions for this problem offered today are known to be based on the following approaches: synthetic modification of β-diketonate ligands and coordination of complex chromophores to tris(β-diketonates) of lanthanides(III) with capabilities of efficient visible light adsorption. For example, it is challenging to select a proper solvent for both a matrix and a complex, where, in addition, this complex must not dissociate.An alternative approach to solution of these problems is the use of anisometric analogues of β-diketonate compounds of lanthanides (III) [14,15]. The main advantage of such compounds is that they do not crystallize because of long hydrocarbon substituents in the structure of complexes and possess thermostable properties [16], so they can be used to fabricate thin nano-, micro-...

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