Volume 50, Nº 5 (2024)

Five coordination compounds of the general formula [LnL₂(NO₃)₃]n (Ln³⁺ = Eu (I), Sm (II), Tb(III), Dy (IV), and Gd (V)) are synthesized from 2-[((4-chlorophenyl)amino)methylene]-5,5-dimethylcyclohexane-1,3-dione (L). The crystal structures of the ligand and complex III are determined by X-ray diffraction (XRD) of single crystals (CIF files CCDC nos. 2298715 (L) and 2298716 (III)). Complex III is polymeric due to the bidentate-bridging coordination of the ligand by the oxygen atoms of the cyclohexanedione fragment, and the coordination number of the central atom is ten. According to the phase XRD data, all synthesized polycrystalline compounds are isostructural to the single crystals of complex III. The photoluminescence properties of the ligand and coordination compounds in the polycrystalline state are studied. The energy transfer from the ligand to lanthanide(III) ion is shown to proceed via the “antenna” mechanism in the case of the europium(III), samarium(III), and terbium(III) compounds. Among the series of the complexes, the highest quantum yield is observed for compound I (21.9%), and the sensibilization efficiency of the europium(III) complex is 43.5%.

The oxidative addition of methyl iodide or molecular iodine to the bis(С,N-chelate) deprotonated diaminocarbene platinum(II) complexes [Pt{C(N(H)Ar)(NC(N(H)Ph)N(Ph)}₂] (Ar = C₆H₃-2,6-Me₂ (Xyl), C₆H₂-2,4,6-Me₃ (Mes), and C₆H₄-4-Me (pTol)) affords the corresponding platinum(IV) derivatives in a yield of 89–99%. The addition of CF3CO2H is accompanied by the protonation of the nitrogen atoms of the diaminocarbene fragment to form the cationic complexes [[PtI(X)-{C(N(H)Ar)(NC(N(H)Ph)N(Ph)}₂]CF₃CO₂H (X = Me, I). The structures of the compounds are determined by elemental analysis; high resolution mass spectrometry with electrospray ionization (ESI HRMS); IR spectroscopy; ¹H, ¹³C{1H}, ¹⁹F{1H}, and ¹⁹⁵Pt{¹H} NMR spectroscopy; 2D NMR spectroscopy (¹H,¹Н COSY, ¹H,¹Н NOESY, ¹H,¹³C HSQC, ¹H,¹³C HMBC, ¹H,¹⁵N HSQC, ¹H,¹⁵N HMBC), and X-ray diffraction

(XRD) and thermogravimetric analyses. The synthesized platinum(IV) complexes are thermally stable to 200–260°C and are electroneutral molecules with the octahedral coordination sphere formed by two deprotonated diaminocarbene C,N-chelate substituents and iodine and methyl or two iodine atoms localized in the apical positions.

The reactions of the dilithium derivatives of 9,12-dihalogen-ortho-carboranes 1,2-Li₂-C₂B₁₀H₈-9,12-X₂ (X = Cl, Br, I) with mercury chloride HgCl2 afford a number of complexes of the chloride ion with the halogen derivatives of [12] mercuracarborand-4: {[(9,12-X₂-C₂B₁₀H₈-1,2ʹ-Hg)₄]Cl}Na · _nH₂O. The molecular crystal structure of the complex of the
[12]mercuracarborand-4 octaiodine derivative with the chloride ion is determined by X-ray diffraction. The substituents at the periphery of the mercury-containing macrocycle are found to exert a substantial effect on the macrocycle geometry leading to the transition from the planar to butterfly conformation, whose geometry is predetermined by a set of intermolecular interactions in the crystal.