Synthesis of alpha-amino acid derived (1,2,3-triazol-4-yl)-picolinamide (tzpa) ligands and their corresponding luminescent Tb(iii) complexes

The synthesis of chiral a-amino acid derived (1,2,3-triazol-4-yl)-picolinamide (tzpa) ligands 4-6 designed by combining the coordination properties of two well-known ligand structures within a single unit is described. The self-assembly formation between these ligands and the lanthanide ion Tb(iii) was investigated in solution by probing the ground and the singlet excited state properties of the ligands as well as monitoring the evolution of the Tb(iii) emission at long wavelengths. The spectroscopic results showed that while under thermodynamic control the 1 : 3 (Tb : L) is produced, then analysis of the titration data using non-liner regression analysis demonstrated that the main species in solution is the 1 : 2 (Tb : L) after the addition of 0.5 equivalents of Tb(iii)

Unexpected linkage isomerism in chiral tetranuclear bis-tridentate (1,2,3-triazol-4-yl)-picolinamide (tzpa) grids

The synthesis of a chiral bis-tridentate (1,2,3-triazol-4-yl)-picolinamide (tzpa) ligand is described and its coordination chemistry with Cu(NO3)2 and [Cu(MeCN)4]PF6 is explored in the crystalline phase as well as in solution. Chiral [2 × 2] tetranuclear square grid complexes [Cu4(H21)4](NO3)8 and [Cu4(H1)4](PF6)4 were observed, and crystallographically analysed, these being linkage isomers with N4O2 and N5O coordination spheres, respectively. These come about by an unusual in situ amide deprotonation and coordination, which accompanies a CuI → CuII oxidation process

Balancing connectivity with function in silver(i) networks of pyridyltriazole (tzpa) ligands results in the formation of a metallogel

A new flexible and divergent 1,2,3-triazol-4-yl-picolinamide (tzpa) ligand 2 and the half-equivalent model ligand 1, both functionalised with pendant 3-pyridyl groups, are reported and their coordination behaviour with silver(i) ions is explored, both in the crystalline phase and through the formation of a supramolecular metallogel. The self-assembly of tzpa ligand 1 with AgCF3SO3 resulted in the formation of a 1D coordination polymer, binding in a bidentate fashion through the pyridyl and triazole nitrogen atoms of the tzpa binding site and a pendant pyridyl nitrogen atom of an adjacent ligand. Doubling the number of metal binding sites in ligand 2, while retaining the same metal binding domain, gives rise to the formation of a supramolecular metallogel on reaction with AgBF4 at 5 wt% in MeCN, possessing self-healing properties

Luminescent (metallo-supramolecular) cross-linked lanthanide hydrogels from a btp (2,3-bis(1,2,3-triazol-4-yl)picolinamide) monomer give rise to strong Tb(iii) and Eu(iii) centred emissions

Acknowledgements: We thank the School of Chemistry TCD, Science Foundation Ireland (SFI PI Awards 10/IN.1/B2999 and 13/IA/1865 to TG). TG would also like to thank the SFI funded AMBER Centre for financial support (SFI 12/RC/2278_P2). EPSRC EP/S009000/1 is acknowledged for support of Dr Niamh Willis-Fox.The synthesis and study of the lanthanide luminescent 2,3-bis(1,2,3- triazol-4-yl)picolinamide (btp) based hydrogels F1 and F2 is described where Tb(iii) or Eu(iii) are also used to crosslink the btp units within the polymers.</jats:p

The development of a language unit An evaluation of Rose Hill Language Unit, Oxford

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Integration in action Case studies in the integration of pupils with special needs

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Educating pupils with special needs in the ordinary school

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