3274-28-0Relevant academic research and scientific papers
Controlling spontaneous mirror symmetry breaking in cubic liquid crystalline phases by the cycloaliphatic ring size
Reppe, Tino,Dressel, Christian,Poppe, Silvio,Tschierske, Carsten
, p. 711 - 714 (2020)
Rod-like molecules combining a fork-like triple chain end and a cycloaliphatic apex are introduced as a new design concept for materials with broad ranges of bicontinuous cubic (Cubbi) phases. By ring expansion from n = 4 to 12 a sequence of three Cubbi phases is observed; the achiral double gyroid la3d phase, a chiral Im3m phase and an achiral re-entrant la3d phase. The chiral Im3m phase is formed if the helical twist between the molecules along the networks is in the range of 8.6°-9.5°, either for the individual compounds or their mixtures.
Ruthenium-catalysed hydroxycarbonylation of olefins
Dühren, Ricarda,Kucmierczyk, Peter,Jackstell, Ralf,Franke, Robert,Beller, Matthias
, p. 2026 - 2030 (2021/04/09)
State-of-the-art catalyst systems for hydroxy- and alkoxycarbonylations of olefins make use of palladium complexes. In this work, we report a complementary ruthenium-catalysed hydroxycarbonylation of olefins applying an inexpensive Ru-precursor (Ru3(CO)12) and PCy3as a ligand. Crucial for the success of this transformation is the use of hexafluoroisopropanol (HFIP) as the solvent in the presence of an acid co-catalyst (PTSA). Overall, moderate to good yields are obtained using aliphatic olefins including the industrially relevant substrate di-isobutene. This atom-efficient catalytic transformation provides straightforward access to various carboxylic acids from unfunctionalized olefins.
Three-component 1D and 2D metal phosphonates: structural variability, topological analysis and catalytic hydrocarboxylation of alkanes
Demadis, Konstantinos D.,Anagnostou, Zafeiria,Panera, Aggeliki,Mezei, Gellert,Kirillova, Marina V.,Kirillov, Alexander M.
, p. 17788 - 17799 (2017/03/30)
Herein, we report the use of diphosphonate building blocks and chelating auxiliary N,N-ligands to generate novel polymeric architectures. Specifically, we report new 1D and 2D coordination polymers incorporating three components: transition metal ions (Co2+, Cu2+, Mn2+ or Zn2+), diphosphonate ligands (methane-diphosphonate, MDPA, or 1,2-ethanediphosphonate, EDPA) and N,N-heterocyclic chelators (1,10-phenanthroline, phen, or 2,2′-bipyridine, bpy). Six compounds were isolated under mild synthesis (ambient temperature) conditions: [Cu2(phen)2(EDPA)2(H2O)4]∞ (1), [Co(phen)(EDPA)(H2O)2]∞ (1a), {[Cu(phen)(MDPA)]·H2O]}∞ (2), [Mn(bpy)(EDPA)(H2O)2]∞ (3), [Zn(bpy)(EDPA)]∞ (4), and, lastly, a discrete Ni2+ molecular derivative [Ni(phen)(H2O)4](EDPA) (5). Synthetic details, crystal structures, and intermolecular interactions (π-π stacking and hydrogen bonding) in 1-5 are discussed. Topological analyses and classification of the underlying metal-organic networks in 1-4 were performed, revealing the uninodal 1D chains with the 2C1 topology in 1-3 and the binodal 2D layers with the 3,4L13 topology in 4. In 1-3 and 5, multiple hydrogen bonds lead to the extension of the structures to give 3D H-bonded nets with the seh-4,6-C2/c topology in 1 and 3, 2D H-bonded layers with the 3,5L52 topology in 2, and a 3D H-bonded net with the 6,6T1 topology in 5. The catalytic activity of compounds 1 and 1a was evaluated in a single-step hydrocarboxylation of cyclic and linear C5-C8 alkanes to furnish the carboxylic acids with one more carbon atom. These reactions proceed in the presence of CO, K2S2O8, and H2O at 60 °C in MeCN/H2O medium. Compound 1 showed higher activity than 1a and was studied in detail. Substrate scope was investigated, revealing that cyclohexane and n-pentane are the most reactive among the cyclic and linear C5-C8 alkanes, and resulting in the total yields of carboxylic acids (based on substrate) of up to 43 and 36%, respectively. In the case of cycloalkane substrates, only one cycloalkanecarboxylic acid is produced, whereas a series of isomeric monocarboxylic acids is generated when using linear alkanes; an increased regioselectivity at the C(2) position of the hydrocarbon chain was also observed.
Improved synthesis and low-temperature performance of a series of saturated α-branched fatty acids
Jiang, Yang,Hu, Wenjing,Xu, Jian,Li, Jiusheng
, p. 2359 - 2363 (2017/10/06)
Five saturated α-branched fatty acids, also known as Guerbet acids, including α-propylhexyl acid (G 1 ), α-butylhexyl acid (G 2 ), α-propyloctyl acid (G 3 ), α-butyloctyl acid (G 4 ), and α-hexyloctyl acid (G 5 ), were synthesized in high yields by four-step reaction. Colorless, almost odorless, and oily products were obtained with high purity, whose structures were confirmed by GC, 1H/13C NMR, and ESI-MS characterization. G 1, G 3, and G 4 had pour points lower than -60 °C, while G 2 and G 5 showed higher pour points (-42 °C and 6 °C, respectively) because of their molecular symmetry. Considering the low-temperature properties, G 1, G 3, G 4, and even G 2 held great potential applications in the lubricant and oilfield.
Site-Selective Catalytic Carboxylation of Unsaturated Hydrocarbons with CO2 and Water
Gaydou, Morgane,Moragas, Toni,Juliá-Hernández, Francisco,Martin, Ruben
, p. 12161 - 12164 (2017/09/12)
A catalytic protocol that reliably predicts and controls the site-selective incorporation of CO2 to a wide range of unsaturated hydrocarbons utilizing water as formal hydride source is described. This platform unlocks an opportunity to catalytically repurpose three abundant, orthogonal feedstocks under mild conditions.
How to force a classical chelating ligand to a metal non-chelating bridge: The observation of a rare coordination mode of diethanolamine in the 1D complex {[Cu2(Piv)4(H3tBuDea)](Piv)}n
Nesterova, Oksana V.,Kirillova, Marina V.,Guedes Da Silva, M. Fatima C.,Boca, Roman,Pombeiro, Armando J. L.
, p. 775 - 783 (2014/01/17)
The novel chain coordination polymer {[Cu2(Piv) 4(H3tBuDea)](Piv)}n (1) has been prepared through the self-assembly reaction of copper(ii) nitrate with pivalic acid (HPiv) and N-tert-butyldiethanolamine (H2tBuDea) in acetonitrile solution. Crystallographic analysis revealed the extremely rare non-chelating bridging coordination mode of diethanolamine ligand in 1, observed for the first time in transition metal complexes, as well as in complexes of diethanolamine having a non-coordinating aliphatic group at the N atom. Possible reasons for such a coordination and analysis of the main coordination modes of diethanolamine-based ligands are discussed. Variableerature (1.8-300 K) magnetic susceptibility measurements showed that 1 represents a rare example of dicopper(ii) tetracarboxylate that is a diamagnetic solid at room temperature. This behaviour is compared with literature examples and discussed on the basis of DFT calculations. Furthermore, 1 acts as an efficient catalyst for the mild hydrocarboxylation of linear and cyclic C5-C8 alkanes into the corresponding carboxylic acids.
Tautomeric effect of hydrazone Schiff bases in tetranuclear Cu(ii) complexes: Magnetism and catalytic activity towards mild hydrocarboxylation of alkanes
Sutradhar, Manas,Kirillova, Marina V.,Guedes Da Silva, M. Fatima C.,Liu, Cai-Ming,Pombeiro, Armando J. L.
, p. 16578 - 16587 (2013/12/04)
Three new tetranuclear copper(ii) complexes [Cu(HL1)] 4·4EtOH (1·4EtOH), [Cu(HL2)]4 (2) and [Cu(H2L3)]4(NO3) 4·2H2O (3·2H2O) have been synthesized using three different hydrazone Schiff base ligands derived from the condensation of the aromatic acid hydrazides 2-hydroxybenzo-, 2-aminobenzo- or benzo-hydrazide, with 2,3-dihydroxybenzaldehyde. Complexes 1 and 3 have been characterized by single crystal X-ray diffraction analysis. The coordinating behaviour of the ligand depends on the nature of the ortho substituent present in the hydrazide moiety. The ligands bearing a strong electron donating group (by resonance) in the ortho position undergo complexation via enolization and deprotonation, whereas the absence of such an effect leads to complexation via the keto form, and two different types of tetranuclear Cu(ii) clusters, viz. open-cubane and cubane, are obtained. Variable temperature magnetic susceptibility measurements of complexes 1 and 3 have been carried out to examine the nature of magnetic interaction between the Cu(ii) centres. All the three complexes (1-3) act as good catalyst precursors towards mild hydrocarboxylation of linear and cyclic alkanes into carboxylic acids in water-acetonitrile medium.
Mild oxidative functionalization of alkanes and alcohols catalyzed by new mono- and dicopper(II) aminopolyalcoholates
Kirillov, Alexander M.,Kirillova, Marina V.,Shul'Pina, Lidia S.,Figiel, Pawe? J.,Gruenwald, Katrin R.,Guedes Da Silva, M. Fátima C.,Haukka, Matti,Pombeiro, Armando J.L.,Shul'Pin, Georgiy B.
experimental part, p. 26 - 34 (2012/01/14)
The new mono- and dicopper(II) complexes [Cu(H3L 1)(NCS)] (1) and [Cu2(μ-HL2) 2(NCS)2] (2) were easily self-assembled from Cu(CH 3COO)2·H2O, NaNCS, NaOH and N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine (H 4L1) or N-ethyldiethanolamine (H2L 2), respectively. They were fully characterized by IR spectroscopy, ESI-MS(±), elemental and single-crystal X-ray diffraction analyses, and applied as homogeneous catalysts for (i) the oxidation of alkanes by t-BuOOH in air to alkyl peroxides, alcohols and ketones, and in turn the oxidation of alcohols to ketones, and (ii) the single-pot aqueous medium hydrocarboxylation, by CO, H2O and K2S2O8, of various linear and cyclic Cn (n = 5-8) alkanes into the corresponding C n+1 carboxylic acids. Compound 1 was significantly more active in the oxygenation of alkanes and oxidation of alcohols, allowing to achieve 18% yield (TON = 800) of oxygenates in the oxidation of cyclohexane, and 78% yield (TON = 780) of cyclohexanone in the oxidation of cyclohexanol. In alkane hydrocarboxylations, 1 and 2 exhibited comparable activities with the total yields (based on alkane) of carboxylic acids attaining 39%. The selectivity parameters for oxidative transformations were measured and discussed, supporting free-radical mechanisms.
Mild, single-pot hydrocarboxylation of linear C5-C9 alkanes into branched monocarboxylic C6-C10 acids in copper-catalyzed aqueous systems
Kirillova, Marina V.,Kirillov, Alexander M.,Pombeiro, Armando J.L.
experimental part, p. 106 - 113 (2012/04/04)
A single-pot method has been developed for the hydrocarboxylation of the liquid C5-C9 alkanes (n-pentane, n-hexane, n-heptane, n-octane, n-nonane and 3-methylhexane) into the branched monocarboxylic C 6-C10 acids bearing one more carbon atom. This method is characterized by a direct, selective and low-temperature (60 °C) hydrocarboxylation reaction of the alkane with carbon monoxide, water (which acts as a reagent besides being a solvent component) and potassium peroxodisulfate, in H2O/MeCN medium. The hydrocarboxylations are markedly enhanced in the presence of a tetracopper(II) triethanolaminate complex as a homogeneous catalyst precursor. Total yields (based on alkane) of carboxylic acids up to 46% (with 97-99% overall selectivity) have been achieved, which are remarkable in the field of alkane functionalization under mild conditions, especially for a C-C bond formation reaction in aqueous acid-solvent-free medium. The regio- and bond selectivity parameters have been determined and a free radical mechanism has been proposed.
Pentanoic acid derivatives
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, (2008/06/13)
Formula (I) compounds: wherein R1 is alkyl substituted by fluorine(s); R2 is hydroxy, alkoxy, alkoxy substituted by phenyl, NR3R4, in which R3, R4 is (i) hydrogen, (ii) alkyl, (iii) phenyl, (iv) phenyl substituted by alkoxy or carboxyl, (v) heterocyclic ring containing nitrogen atom, (vi) alkyl substituted by phenyl, phenyl subsituted by alkoxy or carboxyl, heterocyclic ring containing nitrogen atom, (vii) the nitrogen bonded to R3 and R4, taken together is a saturated heterocyclic ring or amino acid residue; and non-toxic salts and acid addition salts thereof. Also, Formula (X) compounds: wherein n is 0 or 1, R11 is hydrogen and chlorine, R5 is R7—CH2— or R8, or R5 and R11, taken together is alkylidene; R6 is hydroxy, alkoxy, alkoxy substituted by phenyl, NR9R10, in which R9, R10 is (i) hydrogen, (ii) alkyl, (iii) phenyl, (iv) phenyl substituted by alkoxy or carboxyl, (v) heterocyclic ring containing nitrogen atom, (vi) alkyl substituted by phenyl, phenyl-substituted by alkoxy or carboxyl, heterocyclic ring containing nitrogen atom, (vii) the nitrogen bonded to R9 and R10, taken together is a saturated heterocyclic ring or amino acid residue, R7 is (i) F—(CH2)m— or F3C—CH2—, (ii) alkyl subsstituted by chlorine, (iii) alkyl substituted by alkoxy, cycloalkyl, phenyl, phenoxy; R8 is alkyl, alkenyl, alkoxy, alkylthio, cycloalkyl, phenyl, phenoxy. Non-toxic and acid addition salts thereof are useful to prevent and/or treat neurodegenerative disease (e.g., Alzheimer's) and neuronal dysfunction by stroke or traumatic injury (e.g., Multiple sclerosis).
