Rafał Petrus

Probing the Role of π Interactions in the Reactivity of Oxygen Species: A Case of Ethylzinc Aryloxides with Different Dispositions of Aromatic Rings toward the Metal Center

Ethylzinc derivatives of ortho-hydroxybiphenyl and 2,6-diphenylphenol that bear different nuclearity and dispositions of aromatic rings toward the metal center were synthesized and structurally characterized in the solid state and solution. This family of well-defined compounds was examined as a model system for the activation of dioxygen mediated by using complexes that feature lack of a redox-active metal center. Experimental and theoretical studies indicate an essential role in the oxygenation process of intramolecular interactions that involve aromatic subunits. Additionally, novel results for the oxygenation chemistry of alkylzinc compounds, including the isolation and structural characterization of the unique octanuclear aryloxide (hydroxide) compound Zn8 (OAr)8 (OH)6 (O2 ) with an encapsulated peroxide species, are presented.

Transformation of barium-titanium chloro-alkoxide compound to BaTiO3 nanoparticles by BaCl2 elimination.

In this Article, we present how the molecular precursor of binary oxide material having an excess of alkali earth metal can be transformed to the highly phase pure BaTiO3 perovskite. Here, we synthesized and compared two barium-titanium complexes with and without chloride ligands to determine the influences of different ligands on the phase purity of binary oxide nanoparticles. We prepared two barium-titanium complexes, i.e., [Ba4Ti2(μ6-O)(OCH2CH2OCH3)10(HOCH2CH2OCH3)2(HOOCCPh3)4] (1) and [Ba4Ti2(μ6-O)(μ3,η2-OCH2CH2OCH3)8(μ-OCH2CH2OCH3)2(μ-HOCH2CH2OCH3)4Cl4] (2). The barium-titanium precursors were characterized using elemental analysis, infrared and nuclear magnetic resonance spectroscopies, and single-crystal X-ray structural analysis, and their thermal decomposition products were compared. The complex 1 decomposed at 800 °C to give a mixture of BaTiO3 and Ba2TiO4, whereas 2 gave a BaCl2/BaTiO3 mixture. Particles of submicrometer size (30-50 nm) were obtained after leaching of BaCl2 from the raw powder using deionized water. Preliminary studies of barium titanate doped with Eu(3+) sintered at 900 °C showed that the dominant luminescence band arose from the strong electric dipole transition, (5)D0-(7)F2.

Interaction of Piperidin Derivative of Mannich Base with DPPC Liposomes

The long chain Mannich bases, especially with the piperidine and morpholine groups, display very promising antimicrobial activity. In order to extend our knowledge on their impact on biological systems, we examined the interactions of the 5-pentadecyl-2-((piperidin-1-yl)methyl)phenol (PPDP) with model lipid membrane by means of differential scanning calorimetry (DSC) and fluorescence measurements. The small unilamellar vesicles of dipalmitoylophosphatidylcholine (DPPC) with different piperidine Mannich base concentration were investigated as a function of the increase of temperature. The phase separation accompanied by the rise of the transition enthalpy of both subcomponents, the increase of the function of the GP values of Laurdan versus the wavelength of excitation in the gel phase of PPDP/DPPC systems, and no remarkable differences in the fluorescence anisotropy of PPDP molecules in lipid environment for different mixtures of PPDP/DPPC was observed. Additionally, it was shown that PPDP itself interdigitated in solid state.

Unexpected Reactions between Ziegler–Natta Catalyst Components and Structural Characterization of Resulting Intermediates

In this work, we investigated precursors and procatalysts with well-defined crystal structures and morphologies in Ziegler-Natta systems to improve our understanding of the nature of the active metal sites. Molecular cluster precursors such as [Mg4Ti3(μ6-O)(μ3-OH)3(μ-OEt)9(OEt)3(EtOH)3Cl3], [Mg4Ti3(μ6-O)(μ3-OH)(μ3-OEt)2(μ-OEt)9(OEt)3(EtOH)3Cl3], and [Mg6Ti4(μ6-O)2(μ3-OH)4(μ-OEt)14(OEt)4(EtOH)2Cl2] were prepared via simple elimination of the cyclopentadienyl ring from Cp2TiCl2 as CpH in the presence of magnesium metal and ethanol. Titanocene dichloride acts as both a source of titanium and a magnesium-chlorinating agent. The resulting novel complexes were characterized using single-crystal X-ray diffraction. In these compounds, Ti(OEt)4 molecules are grafted onto Mg4 and Mg6 ethoxide cubane-like surfaces; this strongly affects the procatalyst morphology, which is transferred to the polymer. Mg4(OR)8 units act as carriers for the AlR3 co-catalyst, resulting in return of alkyl functions to the Ti center.

Two tetranuclear zinc clusters, [Zn4(μ3-OEt)2(μ2-MalO)4Et2] and [Zn4(μ3-GueO)2(μ2-GueO)2(μ2-MalO)2(MalO)2]·2C7H8, containing defective dicubane core geometries (MalOH is maltol and GueOH is guethol).

The zinc alkoxide molecules in di-μ(3)-ethanolato-diethyltetrakis(μ(2)-2-methyl-4-oxo-4H-pyran-3-olato-κ(3)O(3),O(4):O(3))tetrazinc(II), [Zn(4)(C(2)H(5))(2)(C(2)H(5)O)(2)(C(6)H(5)O(3))(4)], (I), and bis(μ(3)-2-ethoxyphenolato-κ(4)O(1),O(2):O(1):O(1))bis(μ(2)-2-ethoxyphenolato-κ(3)O(1),O(2):O(1))bis(μ(2)-2-methyl-4-oxo-4H-pyran-3-olato-κ(3)O(3),O(4):O(3))bis(2-methyl-4-oxo-4H-pyran-3-olato-κ(2)O(3),O(4))tetrazinc(II) toluene disolvate, [Zn(4)(C(6)H(5)O(3))(4)(C(8)H(9)O(2))(4)]·2C(7)H(8), (II), lie on crystallographic centres of inversion. The asymmetric units of (I) and (II) contain half of the tetrameric unit and additionally one molecule of toluene for (II). The Zn(II) atoms are four- and six-coordinated in distorted tetrahedral and octahedral geometries for (I), and six-coordinated in a distorted octahedral environment for (II). The Zn(II) atoms in both compounds are arranged in a defect dicubane Zn(4)O(6) core structure composed of two EtZnO(3) tetrahedra and ZnO(6) octahedra for (I), and of four ZnO(6) octahedra for (II), sharing common corners. The maltolate ligands exist mostly in a μ(2)-bridging mode, while the guetholate ligands prefer a higher coordination mode and act as μ(3)- and μ(2)-bridges.

Alkaline Earth Metal Zirconate Perovskites MZrO3 (M=Ba2+, Sr2+, Ca2+) Derived from Molecular Precursors and Doped with Eu3+ Ions

The effect of alkaline earth metal alkoxides on the protonation of zirconocene dichloride was investigated. This approach enabled the design of compounds with preset molecular structures for generating high-purity binary metal oxide perovskites MZrO3 (M=Ba(2+), Sr(2+), Ca(2+)). Single-source molecular precursors [Ba4 Zr2 (μ6 -O)(μ3 ,η(2)-OR)8 (OR)2(η(2) -HOR)2 (HOR)2 Cl4], [Sr4 Zr2 (μ6 -O)(μ3 ,η(2)-OR)8 (OR)2 (HOR)4 Cl4], [Ca4 Zr2 (μ6-O)(μ3 ,η(2)-OR)8 (OR)2 Cl4], and [Ca6 Zr2 (μ2 ,η(2)-OR)12 (μ-Cl)2 (η(2) -HOR)4 Cl6 ]⋅8 CH2 Cl2 were prepared via elimination of the cyclopentadienyl ring from Cp2 ZrCl2 as CpH in the presence of M(OR)2 and alcohol ROH (ROH=CH3OCH2 CH2OH) as a source of protons. The resulting complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction. The compounds were then thermally decomposed to MCl2 /MZrO3 mixtures. Leaching of MCl2 from the raw powder with deionized water produced highly pure perovskite-like oxide particles of 40-80 nm in size. Luminescence studies on Eu(3+)-doped MZrO3 revealed that the perovskites are attractive host lattices for potential applications in display technology.

Fluphenazine dihydro­chloride dimethanol solvate

In the title compound {systematic name: 1-(2-hydroxyethyl)-4-[3-(2-trifluoromethyl-10H-phenothiazin-10-yl)propyl]piperazine-1,4-diium dichloride dimethanol disolvate}, C22H28F3N3OS2+·2Cl−·2CH3OH, the dihedral angle between the planes of the two outer benzene rings of the tricyclic phenothiazine system is 46.91 (13)°. The piperazine ring adopts a chair conformation. The crystal structure is stabilized by O—H⋯Cl, N—H⋯Cl, C—H⋯O, C—H⋯Cl and C—H⋯F hydrogen bonds and contacts.

Fluphenazine: from an isolated molecule to its interaction with lipid bilayers

Fluphenazine (FPh) belongs to the phenothiazine family of compounds and exhibits a wide variety of biological effects, including antimutagenic, proapoptotic, antiproliferative and anti-multidrug resistance (MDR) activities. The ability of FPh to interact with lipid membranes can have a significant impact on its biological activities. However, the mechanisms involved in the interaction of FPh with lipid membranes are poorly understood. FTIR-ATR spectroscopy has been used in this study to visualize the interactions between FPh and a model lipid bilayer composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Subsequent interpretation of the temperature-dependent FTIR spectra obtained for FPh:DPPC systems containing different concentrations of FPh was efficiently supported by principal component analysis.

Impact of Group 13 Metals on Cp2TiCl2 Reduction and Structural Characterization of Resulting Compounds

The aim of the current study was to examine the effects of group 13 metals on Cp2TiCl2 reduction in the presence of 2-methoxyethanol (MeOEtOH) or ethanol (EtOH) and the compositions of the resulting products. Direct reaction of Cp2TiCl2 and M [Al, Al (Fe contaminated), Ga, In] in toluene/alcohol for 2 h gave a new family of uncommon homo- and heterometallic compounds: [Cp2Ti2Al(μ,η2-OEtOMe)4Cl2][Ti2(μ,η2-OEtOMe)3(η2-OEtOMe)2Cl4] (1), [Cp2Ti2Al(μ,η2-OEtOMe)4Cl2]Cl (2), [Cp2Ti2Al(μ,η2-OEtOMe)4Cl2][Cp2Ti(η2-HOEtOMe)][FeCl4] (3), [Cp2Ti(η2-HOEtOMe)][Ga2Cl6]0.25[Cl]0.5 (4), [Cp3Ti2(μ-OEt)2(OEt)][GaCl4] (5), [CpTi(μ,η2-OEtOMe)Cl]2 (6), and [Cp3Ti2(μ,η2-OEtOMe)(μ-OEtOMe)Cl] (7). The reaction with indium for 48 h resulted in isolation of [TiIn2(μ,η2-OEtOMe)4(OEtOMe)2Cl4] (8), [In2(μ-OEtOMe)2(HOEtOMe)4Cl4]2 (9), and [Ti(OEtOMe)4] (10). The complexes were characterized using elemental analysis, IR and NMR spectroscopies, and, for 1-9, single-crystal X-ray diffraction. The use of metallic gallium and indium to reduce Cp2TiCl2 opens up a previously unexplored path that may provide access to novel and unique compounds.

Dieth­yl(μ3-2-methyl-4-oxo-4H-pyran-3-olato-κ4O3,O4:O3:O3)tris­(μ2-2-methyl-4-oxo-4H-pyran-3-olato-κ3O3,O4:O3)trizinc toluene disolvate

The title compound, [Zn3(C2H5)2(C6H5O3)4]·2C7H8, crystallizes with one complex molecule solvated by two molecules of toluene in the asymmetric unit. The ZnII ions are coordinated by two terminal ethyl (Et) groups and four maltolate ligands, which act as μ3- and μ2-bridges. The metal atoms are arranged in an incomplete cubane Zn3O4 core structure, derived from one EtZnO3 tetrahedron, one EtZnO4 bipyramid and one ZnO6 octahedron, sharing common corners. The structure is stabilized by weak C—H⋯O and C—H⋯π interactions.