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In the crystal, mol­ecules are linked by pairs of N—H⋯O hydrogen bonds into ribbons along the c-axis direction. The layered crystal packing is further consolidated by van der Waals and C—H⋯π inter­actions., In the crystal, the whole mol­ecule of the title compound, C14H12N4O7·0.224H2O, is nearly planar with a maximum deviation from the least-squares plane of 0.352 (1) Å. The mol­ecular conformation is stabilized by an intra­molecular N—H⋯O hydrogen bond, generating an S(6) ring motif. In the crystal, mol­ecules are linked by centrosymmetric pairs of N—H⋯O hydrogen bonds, forming ribbons along the c-axis direction. These ribbons connected by van der Waals contacts, forming sheets parallel to the ac plane. There are also inter­molecular van der Waals contacts and and C—H⋯π inter­actions between the sheets. A Hirshfeld surface analysis indicates that the most prevalent inter­actions are O⋯H/H⋯O (41.2%), H⋯H (19.2%), C⋯H/H⋯C (12.2%) and C⋯O/ O⋯C (8.4%).

The article has studied the removal of U(VI) chelatoforming sorbent based on anhydride with styrene chemically modified by dithizone. It was established that uranium is sorbed to its maximum at pH 5 (ammonia-acetate buffer) and concentration 1428 mg/dm3. Statistical sorption capacity—1249 mg/g. It was cleared out that ionic force up to 0.6 did not affect sorption and its consecutive increase at first gradually and then sharply decrease sorption. It is established that when using different mineral acids (HCIO4, H2SO4, HNO3, HCI) maximum desorption is observed in perchloric acid. The technique for concentration of U(VI) in sea water has been developed including sorption, elution and definition in the desorption solution.

Two known lanthanide complexes, [KLa(HL 1 ) 2 {(CH 3 ) 2 NCHO} 2 (H 2 O) 3 ] ( 1 ) and [Sm(H 2 O) 9 ]( E -H 2 L 2 ) 3 ·2H 2 O ( 2 ) were prepared by reaction of lanthanum(III) and samarium(III) nitrates with potassium 3-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonate (KH 2 L 1 ) and potassium ( E,Z )-5-chloro-3-(2-(1,3-dioxo-1-phenylbutan-2-ylidene)hydrazinyl)-2-hydroxybenzenesulfonate (KH 2 L 2 ), respectively. Catalytic activities of 1 and 2 were evaluated in the cyanosilylation of aldehydes with trimethylsilyl cyanide in different solvents such as tetrahydrofuran, dichloromethane or methanol. Complex 1 was found to be efficient catalyst for the cyanosilylation reaction in methanol medium at room temperature, producing cyanohydrin trimethylsilyl ethers with good yields (76–99%).

The ability of a chelating sorbent based on maleic anhydride–styrene copolymer to take up uranium was studied. The sorbent was prepared by modification of the copolymer with Norsulfazolum in the presence of formaldehyde. The dependence of the sorption capacity on the solution acidity was studied. At pH 5, the degree of sorption passes through a maximum. As the uranium concentration in the solution is increased, the amount of the sorbed metal increases, reaching a maximum at a concentration of 8 × 10–3 M (SC = 1253 mg g–1). The influence of the solution ionic strength on the uranium sorption was examined. The ionic strength of up to 0.4 M does not affect the sorption, but as the ionic strength is increased further, the sorption decreases, first gradually and then sharply. The desorption of the sorbed uranium ions was studied. The effect of mineral and organic acids on the uranium desorption was examined. The desorption is maximal with HClO4.