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[Display omitted] Lanthanide complexes [CpXLnCl 2 (Me 3 tach)] n (Ln = Tb, Gd; CpX = Cp, Cp Ph 2 , Cp Ph 4 ; Me 3 tach = 1,3,5-trimethyl-1,3,5- triazacyclohexane; n = 1, 2), containing cyclopentadienyl (Cp), 1,3-diphenylcyclopentadienyl (Cp Ph 2) and tetraphenyl- cyclopentadienyl (Cp Ph 4) anions as ν-bonded antenna ligands, have been synthesized. A combined analysis of quantum chemical, optical and X-ray diffraction data has shown that the introduction of phenyl groups into the Cp ring leads to the inevitable appearance of intraligand charge transfer states due to the nonequivalence of the phenyl rings. [ABSTRACT FROM AUTHOR]

A series of europium and gadolinium complexes comprising a β-diketone moiety modified with a fluorinated side-group and thiophene ring have been designed and synthesized and a comparative study of their luminescence properties has been carried out. In this study, when the methyl side group was modified by sequential addition of fluorine substituents and then the perfluorinated carbon chain was extended up to n-C8F17 by adding CF2 fragments, it transpired that the non-radiative energy processes are significantly suppressed in structurally more rigid polyfluorinated β-diketonate compounds of the series as C–H oscillators are replaced with low-energy C–F oscillators. The impact of other electron-withdrawing and electron-donating substituents on the spectroscopic and photophysical properties of the complexes in the present study has also been observed. Despite the presence of low-lying ligand-to-metal charge transfer states, the fluorinated Eu3+ complexes proved to be bright luminophores capable of delivering ca. 50% quantum yield under UV radiation. The role of fluorination and carbon chain length was examined by using experimental spectroscopic methods and the results obtained were largely in good agreement with theoretical calculations (Judd–Ofelt theory analysis, and semiempirical quantum chemistry calculations) supporting our key experimental findings. [ABSTRACT FROM AUTHOR]

The mononuclear title complex, [Eu(C24H34O4P)3(CH4O)5]·CH4O, (1), has been obtained as a minor product in the reaction between EuCl3(H2O)6 and lithium bis­(2,6-diiso­propyl­phen­yl) phosphate in a 1:3 molar ratio in a methanol medium. Its structure exhibits monoclinic (P21/c) symmetry at 120 K and is isostructural with the La, Ce and Nd analogs reported previously [Minyaev et al. (2018a). Acta Cryst. C74, 590–598]. In (1), all three bis­(2,6-diiso­propyl­phen­yl) phosphate ligands display the terminal κ¹O-coordination mode. All of the hy­droxy H atoms are involved in O—H· · ·O hydrogen bonding, exhibiting four intra­molecular and two inter­molecular hydrogen bonds. Photophysical studies have demonstrated luminescence of (1) with a low quantum yield. [ABSTRACT FROM AUTHOR]

A series of lanthanide adducts with different amounts of 1,10-phenanthroline, chloride ions, and water molecules in the inner and outer coordination spheres are investigated with the aim of relating the chemical bonding pattern in the crystals to the luminescence properties of the Eu ion: [LnCl1Phen2(H2O)3]Cl2(H2O) (Ln = Eu, 1Eu; Gd, 1Gd; Tb, 1Tb), [EuCl2Phen2(H2O)2]Cl1(H2O) (2), and [EuCl2Phen1(H2O)4]Cl1(H2O) (3). The influence of inner- versus outer- sphere ligands on the Ln-X bond lengths and angles in the structure is examined. A detailed topological analysis of the electron density function derived from the X-ray diffraction data for lGd is performed within the frame of the "atoms in molecule" theory for the first time for a lanthanide complex. The chemical bonding pattern is interpreted in terms of net atomic charges, bond energies, and electron transfers from the ligands to the metal ion. A noteworthy finding is that the energy of extended noncovalent interactions occurring in the second coordination spheri (H- bonding and π-stacking interactions) is comparable to that of Ln-ligand bonds. The luminescence properties of the three Eu adducts are interpreted with the results of electron density distribution function topology. An intraligand charge transfer state is identified, and its contribution in the ligand-to-europium energy transfer process is analyzed. The outcome of this study is that specific interionic interactions which are usually not considered in theoretical calculations or in the interpretation of luminescence properties play an important role in the sensitization of the Eu luminescence. [ABSTRACT FROM AUTHOR]

Highlights: [•] Acentric complex of Cr(CO)3 with [2.2]paracyclophane was synthesized and characterized. [•] Theoretical and experimental investigation of 2nd order NLO properties was performed. [•] Importance of intraligand CT state on first hyperpolarizability is revealed. [Copyright &y& Elsevier]

A series of europium and gadolinium complexes comprising a β-diketone moiety modified with a fluorinated side-group and thiophene ring have been designed and synthesized and a comparative study of their luminescence properties has been carried out. In this study, when the methyl side group was modified by sequential addition of fluorine substituents and then the perfluorinated carbon chain was extended up to n -C 8 F 17 by adding CF 2 fragments, it transpired that the non-radiative energy processes are significantly suppressed in structurally more rigid polyfluorinated β-diketonate compounds of the series as C-H oscillators are replaced with low-energy C-F oscillators. The impact of other electron-withdrawing and electron-donating substituents on the spectroscopic and photophysical properties of the complexes in the present study has also been observed. Despite the presence of low-lying ligand-to-metal charge transfer states, the fluorinated Eu 3+ complexes proved to be bright luminophores capable of delivering ca. 50% quantum yield under UV radiation. The role of fluorination and carbon chain length was examined by using experimental spectroscopic methods and the results obtained were largely in good agreement with theoretical calculations (Judd-Ofelt theory analysis, and semiempirical quantum chemistry calculations) supporting our key experimental findings.

The mononuclear title complex, [Eu(C 24 H 34 O 4 P) 3 (CH 4 O) 5 ]·CH 4 O, ( 1 ), has been obtained as a minor product in the reaction between EuCl 3 (H 2 O) 6 and lithium bis-(2,6-diiso-propyl-phen-yl) phosphate in a 1:3 molar ratio in a methanol medium. Its structure exhibits monoclinic ( P 2 1 / c ) symmetry at 120 K and is isostructural with the La, Ce and Nd analogs reported previously [Minyaev et al. (2018 a ▸). Acta Cryst. C 74 , 590-598]. In ( 1 ), all three bis-(2,6-diiso-propyl-phen-yl) phosphate ligands display the terminal κ 1 O -coordination mode. All of the hy-droxy H atoms are involved in O-H⋯O hydrogen bonding, exhibiting four intra-molecular and two inter-molecular hydrogen bonds. Photophysical studies have demonstrated luminescence of ( 1 ) with a low quantum yield., (© Kalugin et al. 2019.)

A combined investigation of the structural, electronic, and optical properties of three crystalline nonaaqualanthanoid(III) triflates, [Ln(H2 O)9 (CF3 SO3 )3 ], has provided unambiguous experimental evidence for charge redistribution in the first coordination sphere of a lanthanide ion as a result of hydrogen bonds with outer-sphere anions. As well as resulting in charge transfer from the noncoordinated anions to the coordinated water molecules, these hydrogen bonds give rise to a new excited state, an hydrogen-bond-induced charge-transfer state, which is observed experimentally for the first time. This state was shown to be responsible for the previously unknown negative aspect of hydrogen bonds with a lanthanide-bound water molecule: rather than increasing the luminescence efficiency of the complex, they can lead to additional quenching that is unfavorable for the task-specific design of optical materials., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)