Multiparameter High-Throughput and in Situ X-ray Diffraction Study of Six New Bismuth Sulfonatocarboxylates: Discovery, Phase Transformation, and Reaction Trends

With the employment of high-throughput methods, the system Bi³⁺/4,8-disulfonyl-2,6-naphthalenedicarboxylic acid (H₄DSNDC)/H₂O/additive (HNO₃ or NaOH) was systematically investigated under hydrothermal reaction conditions. The influence of the molar ratio of the starting materials, pH, and reaction temperature and time was investigated in more than 500 reactions. The product formation is highly sensitive toward small changes of the synthesis parameters, but six new bismuth sulfonatocarboxylates were reproducibly obtained starting from clear solutions of the reactants. All compounds were structurally characterized from single-crystal X-ray diffraction data. Fully deprotonated linker ions are found in [Bi₆O₆(OH)₂(H₂O)₄(DSNDC)] (1), [Bi₂(OH)₂(DSNDC)] (2), [Bi₈O₇(OH)₂(H₂O)₂(DSNDC)₂] (3), and [Bi₇O₅(OH)₃(H₂O)₄(DSNDC)₂]·4H₂O (4), while the presence of larger amounts of acid or short reaction times leads to compounds with noncoordinating -COOH groups, [Bi₂(OH)₂(H₂O)₂(DSNDC)(H₂DSNDC)] (5) and [Bi₆O₄(OH)₄(H₂O)₁₂(H₂DSNDC)₃]· xH₂O (6), respectively. The inorganic building units (IBUs) in all six structures differ substantially from each other; the IBUs found in 2 ({Bi₂(OH)₂}), 5 (BiO₈ polyhedron), and 6 ({Bi₆O₄(OH)₄} cluster) have been reported in the literature, while new IBUs are observed for 1 (chains of composition {Bi₃O₃(OH)}_∞), 3 ({Bi₁₆O₁₄(OH)₄} cluster), and 4 ({Bi₇O₅(OH)₃} cluster). Systematic variation of the reaction temperature and time indicated their distinct influence on product formation. Hence, in situ powder X-ray diffraction measurements at Deutsches Elektronen-Synchrotron, Hamburg, Germany, employing synchrotron radiation were carried out. In all studied in situ reactions, compound 6 is first observed and subsequently transformed to 1, 2, 4, and 5, depending on the reaction time and temperature as well as concentration of the starting materials.

High-Performance Hybrid Bismuth-Carbon Nanotube Based Contrast Agent for X-ray CT Imaging

Carbon nanotubes (CNTs) have been used for a plethora of biomedical applications, including their use as delivery vehicles for drugs, imaging agents, proteins, DNA, and other materials. Here, we describe the synthesis and characterization of a new CNT-based contrast agent (CA) for X-ray computed tomography (CT) imaging. The CA is a hybrid material derived from ultrashort single-walled carbon nanotubes (20-80 nm long, US-tubes) and Bi(III) oxo-salicylate clusters with four Bi(III) ions per cluster (Bi₄C). The element bismuth was chosen over iodine, which is the conventional element used for CT CAs in the clinic today due to its high X-ray attenuation capability and its low toxicity, which makes bismuth a more-promising element for new CT CA design. The new CA contains 20% by weight bismuth with no detectable release of bismuth after a 48 h challenge by various biological media at 37 °C, demonstrating the presence of a strong interaction between the two components of the hybrid material. The performance of the new Bi₄C@US-tubes solid material as a CT CA has been assessed using a clinical scanner and found to possess an X-ray attenuation ability of >2000 Hounsfield units (HU).

Synthesis, structure, and photoluminescent behaviour of molecular lanthanide–2-thiophenecarboxylate–2,2′:6′,2′′-terpyridine materials

A lanthanide series incorporating 2-thiophenecarboxylate and terpyridine is presented. Four structure types are observed with differences in the coordination number and nuclearity of the complexes attributed to the effects of the lanthanide contraction.

Simple soluble Bi(iii) salts as efficient catalysts for the oxidation of alkanes with H2O2

Simple soluble Bi(iii) salts exhibit pronounced catalytic activity in the oxidation of inert alkanes with H₂O₂via a radical mechanism with participation of the HO˙ radicals.

Stability and toxicity of heteroleptic organometallic Bi(v) complexes towards Leishmania major

A series of organometallic bismuth(v) dicarboxylates, [BiPh₃(O₂CR′)₂], were synthesised and evaluated for their anti-leishmanial activity. The complexes are effective against parasite promastigotes (0.6–2.5 μM), but prone to slow reductive decomposition.

Effect of robust π–π stacking synthon on the formation of mercury coordination compounds; an unusual pseudo-square planar geometry

In this study, three Hg(ii) complexes, [HgCl₂(L2-naph)]_n, 1, [HgBr₂(L2-naph)]_n, 2 and [HgI₂(L2-naph)₂], 3 where L2-naph is N-(naphthalene-2-yl)pyrazine-2-carboxamide ligand have been synthesized and characterized.