Vol 42, No 11 (2016)

Chemical and electrochemical syntheses of the zinc(II) and cadmium(II) complexes with the tetradentate Schiff base (H₂L), the condensation product of 2-N-tosylaminobenzaldehyde with diaminodipropylamine, are carried out. The structures, compositions, and properties of the synthesized metal complexes are studied by elemental analyses, IR spectroscopy, ¹H NMR, UV spectroscopy, X-ray absorption spectroscopy, and quantum-chemical calculations. The structure of the cadmium(II) complex is determined by X-ray diffraction analysis (CIF file CCDC no. 1446393). The cadmium(II) and zinc(II) complexes exhibit luminescence in a CH₂Cl₂ solution in the blue spectral range (λ_PL = 425–428 nm) with the photoluminescence quantum yields ϕ = 0.20 and 0.75, respectively.

New heteronuclear gold(III)–mercury(II) compounds are synthesized by the chemisorption reaction of freshly precipitated mercury dimethyl (MeDtc) and diethyl dithiocarbamates (EtDtc) with [AuCl₄]⁻ anions in a medium of 2 M HCl. The crystals of complexes [Au{S₂CN(CH₃)₂}₂]₂[HgCl₄] (I) and ([Au{S₂CN(C₂H₅)₂}₂]₂[Hg₂Cl₆] • OC(CH₃)₂)_n (II) are obtained from solutions in methanol and acetone, respectively. The crystal and supramolecular structures of the preparatively isolated compounds are determined by X-ray diffraction analysis (CIF files CCDC nos. 1452118 (I) and 1452119 (II)). The structure of ionic complex I is built of alternating binuclear [Au₂{S₂CN(CH₃)₂}₄]²⁺ cations and [HgCl₄]²⁻ anions. A more complicated structure of compound II contains centrosymmetric isomeric [Au{S₂CN(C₂H₅)₂}₂]⁺ cations (A and B) and centrosymmetric binuclear [Hg₂Cl₆]²⁻ anions. The supramolecular structure of compound II is formed due to pairs of Au•••S secondary bonds between the adjacent gold(III) complex cations resulting in the formation of linear polymeric chains [•••A•••B•••]_n (directed along the x crystallographic axis). Isomeric cations A and B are alternated along the chains. The character of thermolysis of the complexes is studied and the regeneration conditions of bound gold are revealed by the simultaneous thermal analysis data. The thermal destruction of compounds I and II occurs simultaneously at the cationic and anionic moieties of the compounds to reduce gold(III) accompanied by the release and subsequent sublimation of mercury(II) chloride. The final product of the thermal transformations of the complexes is reduced elemental gold.

The solvates of tris(4-fluorophenyl)antimony diaryloxides with benzene, (4-FC₆H₄)₃Sb(OAr)₂ • 1/2PhH (Ar = C₆H₄Cl-4 (I), C₆H₄Br-4 (II), and C₆H₃Br₂-2,4 (III)), were prepared by the reaction of tris(4-fluorophenyl)antimony with 4-chlorophenol, 4-bromophenol, and 2,4-dibromophenol in diethyl ether in the presence of tert-butyl hydroperoxide followed by recrystallization from a benzene–heptane mixture (2: 1). The antimony atoms in I, II, and III form a distorted trigonal-bipyramidal coordination with oxygen atoms in axial positions (CIF files CCDC nos. 1047500 (I), 1048172 (II), 1048212 (III)). The OSbO angles are 177.23(8)° (I), 177.34(12)° (II), and 179.47(16)° (III). The Sb–O and Sb–C bond lengths are 2.0519(16), 2.0508(18), and 2.105(2)–2.121(2) Å (I); 2.045(3), 2.055(3), and 2.105(4)–2.126(4) Å (II); and 2.066(3), 2.058(3), and 2.100(6)–2.107(5) Å (III). The structural organization in crystals I–III is formed by weak intermolecular C−H•••F hydrogen bonds (H•••F 2.52 Å (I), 2.52 Å (II), and 2.61 and 2.51Å (III)).

The novel dinuclear complex [Pd₂(L)₂(Phen)₂] (Phen = 1,10-phenanthroline, H₂L = 2,2'-iminodibenzoic acid) was synthesized and characterized by IR spectra, element analysis, and X-ray single-crystal diffraction (СIF file CCDC no. 1469344). The competitive binding study with ethidium bromide (EtBr) was tested by fluorescence measurement. The result indicated that the complex has an ability to displace the EtBr bound to DNA. Gel electrophoresis assay demonstrated the ability of the complex to cleave the HL-60 DNA. Apoptotic research indicated that [Pd₂(L)₂(Phen)₂] exhibited significant cancer cell inhibitory rate.