Opportunities and challenges of applying advanced X-ray spectroscopy to actinide and lanthanide N-donor ligand systems

N-donor ligands such as n-Pr-BTP [2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine] preferentially bind trivalent actinides (An3+) over trivalent lanthanides (Ln3+) in liquid–liquid separation. However, the chemical and physical processes responsible for this selectivity are not yet well understood. Here, an explorative comparative X-ray spectroscopy and computational (L 3-edge) study for the An/Ln L 3-edge and the N K-edge of [An/Ln(n-Pr-BTP)3](NO3)3, [Ln(n-Pr-BTP)3](CF3SO3)3 and [Ln(n-Pr-BTP)3](ClO4)3 complexes is presented. High-resolution X-ray absorption near-edge structure (HR-XANES) L 3-edge data reveal additional features in the pre- and post-edge range of the spectra that are investigated using the quantum chemical codes FEFF and FDMNES. X-ray Raman spectroscopy studies demonstrate the applicability of this novel technique for investigations of liquid samples of partitioning systems at the N K-edge.

Synthesis, Characterization and Biological Activity of ONO Donor Schiff Base and its Metal Complexes

A new Schiff base ligand (E)-2-((7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)-N-(5- methyl-3-phenyl-1H-indol-2-yl)hydrazine carboxamide (L) (3) was synthesized by the reaction of N-(5-methyl-3-phenyl-1H-indol-2-yl)hydrazinecarboxamide (1) and 7-hydroxy-4-methyl-2-oxo-2Hchromene- 8-carbaldehyde (2). The Cu(II), Co(II), Ni(II) and Zn(II) metal complexes (4a-d) were synthesized and its structural elucidation was done by different spectral techniques. The Schiff base (3) behaves as ONO donor ligand and forms the complexes of the sort [M(L)(Cl)(H2O)2] for Cu(II) (4a) and Zn(II) (4d) and [M(L)2] for Co(II) (4b) and Ni(II) (4c). Compounds (3) and (4a-d) were tested in vitro for antimicrobial action, cytotoxicity property against Artemia salina and anti-tuberculosis assay against Mycobacterium tuberculosis (ATCC 25177). The metal complexes showed very good biological activity.

Structural Diversities of a Series of Cd(II) Coordination Complexes Based on a Flexible Tripodal N-donor Ligand

Three Cd(II) coordination complexes with unique structures and topologies, namely, {[Cd(tttmb)(Hbtc)]·5H2O}n (1), {[Cd(tttmb)(m-phda)(H2O)]·2H2O}n (2), and {[Cd(tttmb)(o-cpla)]·(CH3CN)·(H2O)1.5}n (3), have been successfully synthesized under hydro(solvo)thermally condition based on a flexible tripodal N-contained ligand 1,3,5-tris(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (tttmb) and aromatic polycarboxylate acids (H3btc = 1,2,4-benzenetricarboxylic acid, m-H2phda = 1,3-phenylenediacetic acid and o-H2cpla = Homophthalic acid). Complexes 1–3 were characterized by elemental analysis, IR spectroscopy, X-ray single-crystal diffraction and thermogravimetric analyses. 1 crystallize in the orthorhombic chiral space group P212121 and feature 3D coordination networks. 2 reveals a 2D ladder-like structure with (4,4) topology containing alternating Cd(II)/m-phda2− left- and right-handed helical motifs. 3 exhibits a 3D net with (63)(66)(7·82) topology. The structural and dimensional diversity of these complexes not only indicates that the flexible ligand tttmb exhibits strong coordination ability and diverse coordination modes, but also shows that aromatic polycarboxylates play important roles in constructing the frameworks of complexes. Moreover, the different photoluminescence behaviors of 1–3 have been studied in the solid state.