Low-dimensional compounds containing bioactive ligands. Part XVII: Synthesis, structural, spectral and biological properties of hybrid organic-inorganic complexes based on [PdCl4]2- with derivatives of 8-hydroxyquinolinium

In this study, four hybrid organic-inorganic compounds (8-H₂Q)₂[PdCl₄] (1), (H₂ClQ)₂[PdCl₄] (2), (H₂NQ)₂[PdCl₄] (3) and (H₂MeQ)₂[PdCl₄]·2H₂O (4) (where 8-H₂Q = 8-hydroxyquinolinium, H₂ClQ = 5-chloro-8-hydroxyquinolinium, H₂NQ = 5-nitro-8-hydroxyquinolinium and H₂MeQ = 2-methyl-8-hydroxyquinolinium) were synthesized through organic cation modulation. Single-crystal X-ray structure analysis of compounds 1 and 3 indicates that their structures are planar and consist of [PdCl₄]^2- anions and 8-H₂Q or H₂NQ cations, respectively. Both ionic components are held together through ionic interactions and hydrogen bonds forming infinite chains linked through π-π interactions to form 2D structures. Furthermore, NMR spectroscopy, UV-Vis spectroscopy, elemental analysis, and FT-IR spectroscopy were used to explore the synthesized compounds. The DNA interaction, antimicrobial activity, antiproliferative activity, and radical scavenging effect of the compounds were evaluated. The hybrid compounds and their free ligands can interact with the calf thymus DNA via an intercalation mode involving the insertion of the aromatic chromophore between the base pairs of DNA; compound 1 has the highest binding affinity. Moreover, they have high antimicrobial efficacy against the tested 14 strains of microorganisms with minimum inhibitory concentration values ranging from <1.95 to 250 μg/mL. The antiproliferative activity of the compounds was investigated against three different cancer cell lines, and their selectivity was verified on mesenchymal stem cells. Compounds 1 and 2 displayed selective and high cytotoxicity against human lung and breast cancer cells and showed moderate cytotoxicity against colon cancer cells. Accordingly, they might be auspicious candidates for future pharmacological investigations in lung and breast cancer research.

Two novel organic–inorganic hybrid materials from tetrachloridometallate(II) salts and 4-[(E)-2-(pyridin-1-ium-2-yl)ethenyl]pyridinium

Two organic–inorganic hybrid compounds have been prepared by the combination of the 4-[(E)-2-(pyridin-1-ium-2-yl)ethenyl]pyridinium cation with perhalometallate anions to give 4-[(E)-2-(pyridin-1-ium-2-yl)ethenyl]pyridinium tetrachloridocobaltate(II), (C12H12N2)[CoCl4], (I), and 4-[(E)-2-(pyridin-1-ium-2-yl)ethenyl]pyridinium tetrachloridozincate(II), (C12H12N2)[ZnCl4], (II). The compounds have been structurally characterized by single-crystal X-ray diffraction analysis, showing the formation of a three-dimensional network throughX—H...ClnM−(X= C, N+;n= 1, 2;M= CoII, ZnII) hydrogen-bonding interactions and π–π stacking interactions. The title compounds were also characterized by FT–IR spectroscopy and thermogravimetric analysis (TGA).

Self-assembly of ferromagnetic organic-inorganic perovskite-like films

Perovskite-based organic-inorganic hybrids hold great potential as active layers in electronics or optoelectronics or as components of biosensors. However, many of these applications require thin films grown with good control over structure and thickness--a major challenge that needs to be addressed. The work presented here is an effort towards this goal and concerns the layer-by-layer deposition at ambient conditions of ferromagnetic organic-inorganic hybrids consisting of alternating CuCl4-octahedra and organic layers. The Langmuir-Blodgett technique used to assemble these structures provides intrinsic control over the molecular organization and film thickness down to the molecular level. Magnetic characterization reveals that the coercive field for these thin films is larger than that for solution-grown layered bulk crystals. The strategy presented here suggests a promising cost effective route to facilitate the excellently controlled growth of sophisticated materials on a wide variety of substrates that have properties relevant for the high density storage media and spintronic devices.

N-{1,2-Bis(pyridin-3-yl)-2-[(E)-(pyridin-3-yl)methylideneamino]ethyl}nicotinamide

In the title compound, C₂₄H₂₀N₆O, the pyridin-3-yl groups on the ethyl­ene fragment are found in a trans conformation with a C(py)—C(e)—C(e)—C(py) (py = pyridine, e = ethylene) torsion angle of 179.2 (3)°. The dihedral angle between the pyridine rings is 3.5 (1)°. In the crystal, N—H⋯N and C—H⋯O=C inter­actions form a layer arrangement parallel to the bc plane. The compound displays disorder of the ethyl­ene fragment over two positions with an occupancy ratio of 0.676 (7) to 0.324 (7) that extends into the amide section of the nicotinamide moiety.