Multiproperty materials: luminescent and/or magnetic coordination compounds containing f-block elements. Chirality

Abstract

[eng] The main goal of this Thesis work is the obtention of new lanthanide(III) coordination compounds presenting luminescence and magnetic properties, hence presenting multiproperty behavior. Moreover, by inducing chirality to the final compound, a third property is added to two families of the lanthanide complexes presented herein. In Chapter 2, ternary 4,4,4-trifluoro-1-phenyl-1,3-butanedionate (Btfa) mononuclear lanthanide compounds are obtained. Chapter 2.2 presents a Ce3+ family with general formula [Ln(Btfa3)(L)], where L is the 1,10-phenanthroline, 2,2’-bipyridil, 2,2';6',2"- terpyridine or 4,7-Diphenyl-1,10-phenanthroline. The magnetic properties of the Ce3+ family are studied to expand the limited knowledge on the slow relaxation of the magnetization of this cation. Moreover, the discussion of their magnetic properties is supported by Ab-initio calculations. For the second Btfa family, presented in Chapter 2.3 with the current [Ln(Btfa3)(4,4-dinonyl-2,2’-bipyridil)] general formula, luminescence in the solid state as well as in 1 mM chloroform solutions were studied. From the spectroscopic analyses, great stability of the compounds in DCM is observed. Due to the outstanding luminescence properties as well as great thermal stability presented for the Eu and Yb derivatives, these two compounds could be successfully used in the emissive layer of two different Organic Light Emitting Diode (OLED) devices. Moreover, the Dysprosium analogue of this family showed Single Ion Magnet (SIM) behavior and sensitized luminescence, hence multiproperty characteristics. In Chapter 3, four families of lanthanide fluorobenzoates derived from the 2- fluorobenzoic acid (2-HFBz) and 2,6-difluorobenzoic acid (2,6-HF2Bz) are obtained. For these compounds, the main goal is to increase the emission quantum yield of the Eu and Tb derivatives by designing new synthetic routes in order to completely remove the coordinating H2O molecules from the Ln3+ chemical environment. Four different families of dinuclear compounds were obtained. Water molecules could not be totally removed from the Ln3+ coordination sphere in structures containing the 2- FBz ligand with the general formula [Ln2(μ-2FBz)4(2FBz)2(H-2FBz)2(H2O)2] and (PPh4)2[Ln2(μ-2-FBz)2(2-FBz)6(H2O)2]. Whereas in compounds derived from 2,6- F2Bz ligand, two different dinuclear anhydrous structures with the general formula

(HPy)2[Ln2(μ-2,6-2FBz)4(NO3)4] and (HPy)2[Ln2(μ-2,6-2FBz)4(2,6-2FBz)4] were obtained. The Eu and Tb compounds of these flurorobenzoate families presented good luminescence properties. Moreover, synthesis with Ce, Nd, Dy, Er and Yb where also synthetized to study both properties, luminescence and slow relaxation of the magnetization. The dinuclear Dysprosium compounds derived from 2,6-F2Bz ligand, showed Single Molecular Magnet (SMM) behavior. Finally, in Chapter 4, the chirality property is added to the luminescent and magnetic characteristics of the final compounds. This is accomplished by using the enantiomerically pure R- and S--methoxyphenylacetic acid (R- and S-HMPA) and R and S-2-phenylbutanoic acids (R and S-2-HPhBut). In compounds derived from the enantiomerically pure R/S-HMPA acids and 1,10- phenathroline chromophore ligand, 1D chiral polymeric chains were obtained with the general formula [Ln(-R/S-MPA)(R/S-MPA)2(phen)]n. Circular Polarized Luminescence (CPL) and Circular Dichroism (CD) spectra are measured for the Eu and Tb analogues in the solid state. Moreover, the Ce, Nd, Dy and Er, 1D chiral chains presented slow relaxation of the magnetization added to the sensitized luminescence of the Nd, Dy and Er compounds. With the enantiomerically pure R/S-HPhBut acid and the 4,7-Diphenyl-1,10- phenanthroline chromophore ligand, dinuclear lanthanide coordination compounds with the general formula [Ln2(-R-2-PhBut)4(R-2PhBut)2(Bphen)2] were obtained. The compounds undergo a structural change (from structure a to structure b) on increasing the atomic number along the lanthanide series (Nd to Yb). For the Eu and Tb enantiomeric pairs, CD and CPL spectra were measured in solid state as well as in 1mM DCM solutions with improved chiroptical properties for the solution samples. The significant difference seen in the CD and CPL spectra from solid to solution samples, account to a structural change when dissolving the compounds into the DCM solutions. Moreover, the Nd, Dy, Yb, Sm derivatives were synthetized and all present luminescence as well as slow relaxation of the magnetization (for Nd and Yb) and SMM behaviour, for the Dy compound.

[cat] L’objectiu principal d’aquesta Tesi és l’obtenció de compostos de coordinació lantànid(III) amb propietats luminescents, magnètiques i/o quirals, per tant comportament multipropietat. Aquest objectiu, per una banda, s’ha desenvolupat mitjançant l’obtenció de compostos mononuclears derivats de la 4,4,4-trifluoro-1-phenyl-1,3-butanediona (HBtfa). Inicialment es presenta una família de compostos mononuclears de Ce3+ amb la fórmula general [Ln(Btfa3)(L)], on L és la 1,10-fenantrolina, 2,2’-bipyridina, 2,2';6',2"-terpiridina o 4,7-Difenil-1,10-fenantrolina. D’aquesta família s’han estudiat les propietats magnètiques ja que l’estudi de la relaxació lenta de la magnetització en aquests cations és escassa a la literatura. La segona família de compostos derivats del lligand HBtfa, presenten la fórmula [Ln(Btfa3)(4,4-dinonyl-2,2’-bipyridil)]. Per aquest compostos s’ha estudiat les propietats magnètiques i luminescents. Degut a les bones propietats òptiques presentades pels compostos derivats del Eu3+ i Yb3+, aquests s’han utilitzat en dos dispositius OLED. Seguidament, s’han sintetitzat quatre famílies de compostos lantànid amb lligands fluorobenzoat derivats del àcid 2-fluorobenzoic (2-HFBz) i del àcid 2,6-difluorobenzoic (2,6-HF2Bz). L’ objectiu principal, per aquests compostos, és reduir al màxim les molècules d’aigua de la esfera de coordinació del catió Ln3+ per tal d’augmentar el seu rendiment quàntic. Les molècules d’aigua coordinades al metall central no s’han pogut eliminar completament per als compostos derivats del 2-FBz, però si que ha estat possible fer-ho per als compostos derivats del 2,6-HF2Bz. Els compostos que contenen Tb3+ i Eu3+ d’aquestes quatre famílies de fluorobenzoats, presenten bones propietats luminescents. Finalment, per tal d’afegir propietats quirals al compost final, a més a més de les luminescents i magnètiques, s’ha sintetitzat compostos lantànid derivats dels àcids enantiomèricament purs R- o S-alfa−metoxifenilacètic (R o S-HMPA) i de l’àcid R- o S-fenilbutanoic (R- o S-PhBut). Amb el R o S-HMPA i la 1,10-pheantrolina, s’han obtingut estructures en forma de cadena polimèrica. D’altra banda, amb el R- o S-PhBut i la 4,7-Difenil-1,10-fenantrolina, s’han obtingut compostos lantànid dinuclears. Per ambdues famílies de compostos lantànid s’ha dut a terme l’estudi luminescent, de dicroisme circular i de Luminescència Circular Polaritzada a més a més de l’estudi de les propietats magnètiques.