The interaction of rhodium(III) aqua ions with nitrate ions in 3–16 m nitric acid solutions has been studied by 103Rh and 15N NMR and Raman spectroscopy. The mononuclear complexes [Rh(H2O)6–n(NO3)n]3–n (n = 1–4) were found to be the only form of rhodium(III) existing in the solutions with the metal concentration in the range 0.2–1.3 m. The dynamics of the H2O → NO3– substitution process was studied at 80 °C. An increase in the average number of nitrate groups bonded to rhodium with increasing concentration of nitric acid was also determined. The fine crystalline salt Rb4trans‐[Rh(H2O)2(NO3)4][Rh(NO3)6] was obtained by solvothermal concentration of the rhodium nitric acid solution on addition of rubidium nitrate. The structure of the salt was solved by the powder X‐ray diffraction method, with monodentate coordination of nitrato ligands found for both the [Rh(NO3)6]3– and trans‐[Rh(H2O)2(NO3)4]– anions.

ESIPT-capable pyrimidine-based compounds featuring short O–H···N intramolecular hydrogen bonds, 2-(2-hydroxyphenyl)-4-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyrimidine (HL1) and 2-(2-hydroxyphenyl)-4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-methylpyrimidine (HL2), were synthesized by the condensation of 4-hydrazinyl-2-(2-hydroxyphenyl)-6-methylpyrimidine with acetylacetone and dibenzoylmethane. In solution, HL1 and HL2...

The rhodium complexes [RhCl3(NH3)3], (I), and [Rh(NO3)3(NH3)3], (II), are built from octahedral RhX3(NH3)3 units; in (I) they are isolated units, while in (II) the units are stacked in columns with partially filled sites for the Rh atoms. The octahedra of monoclinic crystals of (I) are linked by N-H···Cl hydrogen bonds and the Rh(3+) ions are located on the mirror planes. In the trigonal crystals of (II), the discontinuous `columns' along the threefold axis are linked by N-H···O hydrogen bonds. The structure of (I) has been solved using laboratory powder diffraction data, the structure of (II) has been solved by single-crystal methods using data from a merohedrally twinned sample. Both compounds possess low solubility in water.

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