Sensitised lanthanide luminescence using a RuII polypyridyl functionalised dipicolinic acid chelate

A visible light absorbing [RuII(tpy)2]2+-type chromophore appended with a dipicolinic acid LnIII chelator has been prepared and complexed with several differing lanthanide cations to form the corresponding heterobimetallic d-f assemblies. The subseqent solution speciation analysed by 1H NMR spectroscopy revealed an unexpected decrease in the LnIII chelate complex stability, in particular for the 1 : 3 complex, when compared to the parent dipicolinic acid. As a result, the desired Ln(ML)3 complexes could not be isolated, and the 1 : 1 LnIII-ML complexes were instead characterised and investigated using steady state absorption and emission spectroscopy. Sensitised NIR emission from the YbIII, NdIII and ErIII complexes was observed upon 1MLCT excitation of the RuII based metalloligand in the visible region at ca. 485 nm. Investigations using transient absorption spectroscopy revealed essentially quantitative intersystem crossing to form the 3MLCT excited state, as expected, which then acts as the energy donor for the metalloligand based antennae effect, facilitating sensitisation efficiencies of 4.8, 17.0 and 37.4% respectively for the YbIII, ErIII and NdIII cations.

The effect of weighted averages when determining the speciation and structure–property relationships of europium(iii) dipicolinate complexes

Europium(iii) dipicolinate complexes have been a model system in lanthanide solution chemistry for decades, here it is investigated in unprecedented detail.

Syntheses, crystal structures and magnetic properties of a series of luminescent lanthanide complexes containing neutral tetradentate phenanthroline-amide ligands

Six lanthanide compounds have been prepared from a neutral tetra-dentate ligand. Their luminescent and magnetic properties were investigated in detail.

Synthesis, molecular and supramolecular structure of a new dinuclear aluminium(III) complex derived from 3-aminopyrazine- 2-carboxylic acid

Solvothermal reaction of aluminum(III) nitrate nonahydrate with 3-aminopyrazine-2-carboxylic acid (HL) gave rise to a bis(μ2-hydroxo)-tetrakis(3-aminopyrazine-2-carboxylato)-dialuminium(III) complex [Al(L)2(OH)]2 (1) (L = 3-aminopyrazine-2-carboxylate). Crystal structure analysis reveals that each hexacoordinated Al(III) centre adopts a distorted octahedral geometry occupied by two Ocarboxylate, two Npyrazine and two Ohydroxo atoms. The L– ligand binds the metal cation by means of one pyrazine N-atom and carboxylate O-atoms via chelating fashion. Two hydroxo groups bridge between two aluminum(III) centres, assisting to construct a dinuclear structure. In the crystal lattice of 1 two symmetry non-equivalent dinuclear complexes are present. A 3D supramolecular associate in the crystal lattice of 1 has been stabilized by a number of non-covalent H-bonding interactions. Topology of the hydrogen bonded network has been also analyzed.