Dinuclear lanthanide(III) complexes with large-bite Schiff bases derived from 2,6-diformyl-4-chlorophenol and hydrazides: Synthesis, structural characterization and spectroscopic studies

Novel lanthanide(III) 4-methylbenzoylhydrazide complexes as precursors for lanthanide oxide nanophotocatalysts

A series of metal complexes were prepared from separate reactions of lanthanide nitrate salts (La(iii), Ce(iii), Sm(iii), Gd(iii) and Ho(iii)) with 4-methylbenzoylhydrazide. The structures of the complexes were confirmed by analytical studies, spectral measurements and thermal studies. Complexes were formed with different stoichiometries of 1 : 2 and 1 : 3 (M : L). The ligand chelates by the nitrogen and oxygen atoms of the amino and carbonyl groups of the hydrazide moiety in the neutral keto form. The coordination compounds were converted to metal oxide nanoparticles (MONPs) through solid state thermal decomposition as monocular source precursors. The obtained MONPs were investigated via XRD, TEM and UV-Vis spectra. As a representative, CeO₂ was utilized as a nanophotocatalyst to examine the photocatalytic activity of the MONPs for methylene blue (MB) photodegradation. CeO₂ showed high removal of MB dye by 90.1% after UV illumination for 220 min. The reported method provides a generalized and systematic method for the preparation of many metal oxide nanoparticles with manageable and reproducible features.

A series of metal complexes were prepared from separate reactions of lanthanide nitrate salts (La(iii), Ce(iii), Sm(iii), Gd(iii) and Ho(iii)) with 4-methylbenzoylhydrazide.

Conformation-induced light emission switching of N-acylhydrazone systems

Bis-N-acylhydrazones bearing different substituents were found to display different colour emissions, through ESIPT or AIE, as a result of conformation switching, triggered by physical stimuli.

Synthesis, density functional theory calculations and luminescence of lanthanide complexes with 2,6-bis[(3-methoxybenzylidene)hydrazinocarbonyl] pyridine Schiff base ligand

A pyridine-diacylhydrazone Schiff base ligand, L = 2,6-bis[(3-methoxy benzylidene)hydrazinocarbonyl]pyridine was prepared and characterized by single crystal X-ray diffraction. Lanthanide complexes, Ln-L, {[LnL(NO₃ )₂ ]NO₃ .xH₂ O (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Er)} were prepared and characterized by elemental analysis, molar conductance, thermal analysis (TGA/DTGA), mass spectrometry (MS), Fourier transform infra-red (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. Ln-L complexes are isostructural with four binding sites provided by two nitro groups along with four coordination sites for L. Density functional theory (DFT) calculations on L and its cationic [LnL(NO₃ )₂ ]⁺ complexes were carried out at the B3LYP/6-31G(d) level of theory. The FT-IR vibrational wavenumbers were computed and compared with the experimentally values. The luminescence investigations of L and Ln-L indicated that Tb-L and Eu-L complexes showed the characteristic luminescence of Tb(III) and Eu(III) ions. Ln-L complexes show higher antioxidant activity than the parent L ligand.

Symmetrical N-acylsubstituted dihydrazones containing bithiophene core--Photophysical, electrochemical and thermal characterization

Four symmetrical N-acylsubstituted dihydrazones containing bithiophene core were synthesized from condensation of 2,2'-bithiophene-5,5'-dicarboxyaldehyde with benzoic, isonicotinoyl, 2-thiophenic and 2-furoic hydrazide. The obtained compounds were characterized through the data from (1)H nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), elemental analysis, UV-vis absorption spectroscopy, photoluminescence (PL), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements. Additionally, the electronic properties including orbital energies and resulting energy gaps were calculated by density functional theory (DFT). Their thermal behavior was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). They were thermal sable up to 320°C. The prepared N-acylsubstituted dihydrazones emitted light with λ(em) in the range of 499-530 nm in solution, whereas, in solid state as blend with PMMA blue emission was observed. They undergo quasi-reversible and irreversible electrochemical reduction and oxidation processes, respectively. Additionally, the selected compounds were tested preliminary as component of active layer in organic photovoltaic cells. The highest value of power conversion efficiency, equal to 1.68% under simulated 100 mW/cm(2) AM 1.5G irradiation was found for device with the architecture ITO/PEDOT:PSS/P3HT:PCBM:FBTH (1:2:2)/Al.

Structure, luminescence and magnetic properties of an erbium(iii) β-diketonate homodinuclear complex

The photoluminescence properties and field-induced single-molecule-magnetic behavior of a novel erbium(iii) β-diketonate homodinuclear complex, [Er₂(nd)₆(μ-bpm)] (nd = 2,4-nonanedione and bpm = 2,2′-bipyrimidine), are presented.

Triply phenoxo bridged Eu(iii) and Sm(iii) complexes with 2,6-diformyl-4-methylphenol-di(benzoylhydrazone): structure, spectra and biological study in human cell lines

Two dinuclear lanthanide(iii) complexes, [M₂(HL)₃] (M = Sm(iii) (1), Eu(iii) (2); H₃L, 2,6-diformyl-4-methylphenol-di(benzoylhydrazone)) were generated with good yield and characterised systematically.

The first example of erbium triple-stranded helicates displaying SMM behaviour

Subcomponent self-assembly gives a new family of the triple-stranded helicates of the {LnIII2O₃}³⁻ core (Ln = Tb, Dy, Ho, Er, Tm and Yb) yielding an erbium congener revealing field-induced SMM characteristics.