11 research outputs found

    Otrzymywanie acetali w katalizowanych kompleksami rutenu reakcjach eterów allilowych i winylowych z alkoholami i fenolami

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    Celem pracy jest synteza nowych acetali symetrycznych i niesymetrycznych w reakcjach addycji alkoholi i fenoli do eterów allilowych (alkilowych i arylowych) oraz eterów winylowych. Przedmiotem badań była również katalizowana przez kompleksy metali, kwasy Lewisa oraz kwasy protonowe cyklizacja eterów allilowych i winylowych glikoli prowadząca do acetali cyklicznych. Generalnie, przedmiotem dysertacji była więc między i wewnątrzcząsteczkowa addycja grupy OH do wiązania podwójnego allilowego lub sprzężonego z atomem tlenu. Praca ma na celu również poznanie ograniczeń wynikających ze stosowania tej metody syntezy acetali - zarówno po stronie substratów jak i możliwości doboru układu katalitycznego. Ważnym aspektem badań są też mechanizmy reakcji zachodzących w układach eter allilowy lub winylowy - alkohol lub fenol, katalizowanych przez kompleksy rutenu, kompleksy innych metali oraz kwasy protonowe. Wobec powyższego, zakres dysertacji obejmuje: ■ Syntezę substratów allilowych, 1-propenylowych i winylowych; ■ Zbadanie możliwości otrzymywania acetali mieszanych (przede wszystkim) oraz acetali symetrycznych i acetali cyklicznych z eterów allilowych, 1-propenylowych i winylowych o różnych strukturach; ■ Opracowanie procedur wydzielania czystych produktów, to jest acetali; ■ Opracowanie warunków reakcji addycji między- i wewnątrzcząsteczkowych grupy OH, alkoholowej i fenolowej do wiązania podwójnego w eterach allilowych lub winylowych. Katalizatorami tych reakcji były kompleksy i związki metali przejściowych, głównie rutenu; ■ Badania nad mechanizmem reakcji głównej, to jest acetalizacji, oraz reakcji towarzyszących, szczególnie transacetalizacji, migracji wiązania podwójnego; ■ Możliwie kompleksowe przedyskutowanie mechanizmów reakcji w badanych układach pod kątem typów procesów katalitycznych w nich występujących

    Effect of N-donor ancillary ligands on structural and magnetic properties of oxalate copper(II) complexes

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    Through varying the auxiliary N-donor ligands under similar synthetic conditions nine new compounds: [Cu(C2O4)(pz)]n (1), [Cu(C2O4)(apz)2]n·(3H2O)n (2), [Cu2(μ-C2O4)2(H2O)2(ampz)4] (3), [Cu(C2O4)(mpz)2]n (4), [Cu(C2O4)(aind)2]n (5), [Cu2(C2O4)2(bpzm)2]n·(3.5H2O)n (6), [Cu(C2O4)(ampy)(H2O)]n (7) {[Cu2(μ-C2O4)(aepy)2][Cu(C2O4)2(H2O)2]}n·(2H2O)n (8) and [Cu4(μ-C2O4)3(aepy)4(H2O)2]Cl2 (9) (pz = pyrazole, apz = 3(5)-aminopyrazole, mpz = 3(5)-methylpyrazole, ampz = 3(5)-amino-5(3)-methylpyrazole, aind = 7-azaindole, bpzm = bis(pyrazol-1-yl)methane, ampy = 2-aminomethylpyridine and aepy = 2-(2-pyridyl)ethylamine) have been synthesized and characterised structurally (by single crystal X-ray analysis) and spectroscopically. On the basis of structural data, the influence of neutral N-donor ligands on the control of the final complex structures and the role of weak intermolecular interactions in the creation of molecular architectures have been discussed in detail. The two independent oxalate anions in 1, adopting μ3-oxalato-1κ2O1,O2:2κO1:3κO2a and a relatively rare μ4-oxalato-1κ2O1,O2:2κO1:3κO1a,O2a:4κO2a coordination mode, connect the Cu centers into a two-dimensional net extending along the crystallographic plane (100). Simultaneous existence of both amino and methyl groups in the ampz ligand results in the formation of a 0D dimeric structure of 3. Compounds 2 and 4–8 display one-dimensional coordination structures, and the most significant differences between these structures concern the geometry around the copper(II) center and the coordination mode of the oxalate bridge. The structures of 2–9 are stabilized by the extensive hydrogen-bonding interactions that give rise to the supramolecular architectures. Additionally, the magnetic properties of the complexes 1–9 have been investigated and discussed in the context of their structures

    Organic-to-aqueous phase transfer of alloyed AgInS2-ZnS nanocrystals using simple hydrophilic ligands : comparison of 11-mercaptoundecanoic acid, dihydrolipoic acid and cysteine

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    The exchange of primary hydrophobic ligands for hydrophilic ones was studied for two types of alloyed AgInS2-ZnS nanocrystals differing in composition and by consequence exhibiting two different emission colors: red (R) and green (G). Three simple hydrophilic ligands were tested, namely, 11-mercaptoundecanoic acid, dihydrolipoic acid and cysteine. In all cases, stable aqueous colloidal dispersions were obtained. Detailed characterization of the nanocrystal surface before and after the ligand exchange by NMR spectroscopy unequivocally showed that the exchange process was the most efficient in the case of dihydrolipoic acid, leading to the complete removal of the primary ligands with a relatively small photoluminescence quantum yield drop from 68% to 40% for nanocrystals of the R type and from 48% to 28% for the G ones

    Synthesis of unsymmetrical alkyl acetals via addition of primary alcohols to allyl ethers mediated by ruthenium complexes

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    Ru-catalyzed synthesis of mixed alkyl–alkyl acetals via addition of primary alcohols to allyl ethers has been extended to include long-chain and/or functionalized substrates. The catalytic systems for these reactions were generated from RuCl2(PPh3)3 and [RuCl2(1,5-COD)]x and phosphines [PPh3 or P(p-chlorophenyl)3] or SbPh3 . Of particular importance is the almost quantitative elimination of transacetalization. The addition proceeds through allyl complexes, not via isomerization of allyl ethers––subsequent addition of ROH to vinyl ethers

    From red to green luminescence via surface functionalization. Effect of 2-(5-mercaptothien-2-yl)-8-(thien-2-yl)-5-hexylthieno[3,4-c]pyrrole-4,6-dione ligands on the photoluminescence of alloyed Ag-In-Zn-S nanocrystals

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    A semiconducting molecule containing a thiol anchor group, namely 2-(5-mercaptothien-2-yl)-8-(thien-2-yl)-5-hexylthieno- [3,4-c]pyrrole-4,6-dione (abbreviated as D-A-D-SH), was designed, synthesized, and used as a ligand in nonstoichiometric quaternary nanocrystals of composition Ag1.0In3.1Zn1.0S4.0(S6.1) to give an inorganic/organic hybrid. Detailed NMR studies indicate that D-AD- SH ligands are present in two coordination spheres in the organic part of the hybrid: (i) inner in which the ligand molecules form direct bonds with the nanocrystal surface and (ii) outer in which the ligand molecules do not form direct bonds with the inorganic core. Exchange of the initial ligands (stearic acid and 1-aminooctadecane) for D-A-DSH induces a distinct change of the photoluminescence. Efficient red luminescence of nanocrystals capped with initial ligands (λmax = 720 nm, quantum yield = 67%) is totally quenched and green luminescence characteristic of the ligand appears (λmax = 508 nm, quantum yield = 10%). This change of the photoluminescence mechanism can be clarified by a combination of electrochemical and spectroscopic investigations. It can be demonstrated by cyclic voltammetry that new states appear in the hybrid as a consequence of D-A-D-SH binding to the nanocrystals surface. These states are located below the nanocrystal LUMO and above its HOMO, respectively. They are concurrent to deeper donor and acceptor states governing the red luminescence. As a result, energy transfer from the nanocrystal HOMO and LUMO levels to the ligand states takes place, leading to effective quenching of the red luminescence and appearance of the green one

    Indium(II) chloride as a precursor in the synthesis of ternary (Ag–In–S) and quaternary (Ag–In–Zn–S) nanocrystals

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    A new indium precursor, namely, indium(II) chloride, was tested as a precursor in the synthesis of ternary Ag−In−S and quaternary Ag−In−Zn−S nanocrystals. This new precursor, being in fact a dimer of Cl2In−InCl2 chemical structure, is significantly more reactive than InCl3, typically used in the preparation of these types of nanocrystals. This was evidenced by carrying out comparative syntheses under the same reaction conditions using these two indium precursors in combination with the same silver (AgNO3) and zinc (zinc stearate) precursors. In particular, the use of indium(II) chloride in combination with low concentrations of the zinc precursor yielded spherical-shaped (D = 3.7−6.2 nm) Ag−In−Zn−S nanocrystals, whereas for higher concentrations of this precursor, rodlike nanoparticles (L = 9−10 nm) were obtained. In all cases, the resulting nanocrystals were enriched in indium (In/Ag = 1.5−10.3). Enhanced indium precursor conversion and formation of anisotropic, longitudinal nanoparticles were closely related to the presence of thiocarboxylic acid type of ligands in the reaction mixture. These ligands were generated in situ and subsequently bound to surfacial In(III) cations in the growing nanocrystals. The use of the new precursor of enhanced reactivity facilitated precise tuning of the photoluminescence color of the resulting nanocrystals in the spectral range from ca. 730 to 530 nm with photoluminescence quantum yield (PLQY) varying from 20 to 40%. The fabricated Ag−In−S and Ag−In−Zn−S nanocrystals exhibited the longest, reported to date, photoluminescence lifetimes of ∼9.4 and ∼1.4 μs, respectively. It was also demonstrated for the first time that ternary (Ag−In− S) and quaternary (Ag−In−Zn−S) nanocrystals could be applied as efficient photocatalysts, active under visible light (green) illumination, in the reaction of aldehydes reduction to alcohols

    Photoinduced Processes in Rhenium(I) Terpyridine Complexes Bearing Remote Amine Groups: New Insights from Transient Absorption Spectroscopy

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    Photophysical properties of two Re(I) complexes [ReCl(CO)3(R-C6H4-terpy-κ2N)] with remote amine groups, N-methyl-piperazinyl (1) and (2-cyanoethyl)methylamine (2), were investigated. The complexes show strong absorption in the visible region corresponding to metal-to-ligand charge transfer (1MLCT) and intraligand-charge-transfer (1ILCT) transitions. The energy levels of 3MLCT and 3ILCT excited-states, and thus photoluminescence properties of 1 and 2, were found to be strongly affected by the solvent polarity. Compared to the parent chromophore [ReCl(CO)3(C6H5-terpy-κ2N)] (3), both designed complexes show significantly prolonged (by 1–2 orders of magnitude) phosphorescence lifetimes in acetonitrile and dimethylformamide, contrary to their lifetimes in less polar chloroform and tetrahydrofuran, which are comparable to those for 3. The femtosecond transient absorption (fsTA) measurements confirmed the interconversion between the 3MLCT and 3ILCT excited-states in polar solvents. In contrast, the emissive state of 1 and 2 in less polar environments is of predominant 3MLCT nature

    In Vitro and In Vivo Biological Activities of Dipicolinate Oxovanadium(IV) Complexes

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    funds granted under the Research Excellence Initiative of the University of Silesia in Katowice. The authors thank Dr inż. Mariola Siwy for measurements of elemental analysis. Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.The work is focused on anticancer properties of dipicolinate (dipic)-based vanadium(IV) complexes [VO(dipic)(N∩N)] bearing different diimines (2-(1H-imidazol-2-yl)pyridine, 2-(2-pyridyl)benzimidazole, 1,10-phenanthroline-5,6-dione, 1,10-phenanthroline, and 2,2′-bipyridine), as well as differently 4,7-substituted 1,10-phenanthrolines. The antiproliferative effect of V(IV) systems was analyzed in different tumors (A2780, HCT116, and HCT116-DoxR) and normal (primary human dermal fibroblasts) cell lines, revealing a high cytotoxic effect of [VO(dipic)(N∩N)] with 4,7-dimethoxy-phen (5), 4,7-diphenyl-phen (6), and 1,10-phenanthroline (8) against HCT116-DoxR cells. The cytotoxicity differences between these complexes can be correlated with their different internalization by HCT116-DoxR cells. Worthy of note, these three complexes were found to (i) induce cell death through apoptosis and autophagy pathways, namely, through ROS production; (ii) not to be cytostatic; (iii) to interact with the BSA protein; (iv) do not promote tumor cell migration or a pro-angiogenic capability; (v) show a slight in vivo anti-angiogenic capability, and (vi) do not show in vivo toxicity in a chicken embryo.publishersversionpublishe

    Multifaceted Strategy for the Synthesis of Diverse 2,2'-Bithiophene Derivatives

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    New catalytically or high pressure activated reactions and routes, including coupling, double bond migration in allylic systems, and various types of cycloaddition and dihydroamination have been used for the synthesis of novel bithiophene derivatives. Thanks to the abovementioned reactions and routes combined with non-catalytic ones, new acetylene, butadiyne, isoxazole, 1,2,3-triazole, pyrrole, benzene, and fluoranthene derivatives with one, two or six bithiophenyl moieties have been obtained. Basic sources of crucial substrates which include bithiophene motif for catalytic reactions were 2,2'-bithiophene, gaseous acetylene and 1,3-butadiyne
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