Search results for "Organo"
showing 10 items of 1460 documents
Characterization of the laccase-mediated oligomerization of 4-hydroxybenzoic acid
2016
Modifying inert poly(ethersulfone) membranes using laccase has proven to be an environmentally benign and easily applicable process to alter the membrane's surface properties. By this method phenolic acid monomers such as 4-hydroxybenzoic acid are grafted from the membrane surface to make it anti-fouling. In order to enhance the anti-fouling capabilities even further it is important to study the molecular details of this reaction. However, the nature of the products of laccase modification, either on a surface or in solution, has been studied only poorly. In this paper we report the formation of C3–C3′, C3–O and C1–C3′ linked dimers as the first products of the solution-phase laccase-mediat…
Enantioselective Henry addition of methyl 4-nitrobutyrate to aldehydes. Chiral building blocks for 2-pyrrolidinones and other derivatives.
2010
A catalytic highly enantioselective Henry addition of methyl 4-nitrobutyrate to aldehydes using a Cu(II)-amino pyridine complex as catalyst is described. The products resulting from this reaction constitute a new, highly versatile family of chiral building blocks as a result of the presence of three different functional groups on the molecule. These products have been transformed into nonracemic chiral gamma-lactams, 5-hydroxy-5-substituted levulinic acid derivatives, and delta-lactones.
Metal–Organic Frameworks as Playgrounds for Reticulate Single-Molecule Magnets
2019
Achieving an accurate control on the final structure of Metal-Organic Frameworks (MOFs) is mandatory to obtain target physical properties. Here we describe how the combination of a metalloligand design strategy and a post-synthetic method is a versatile and powerful approach to success on this extremely difficult task. In a first stage, a novel oxamato-based tetranuclear cobalt(III) complex with a tetrahedron-shape geometry is used, for the first time, as metalloligand toward cal-cium(II) cations to lead a diamagnetic Ca(II)-Co(III) three-dimensional (3D) MOF (1). In a second stage, in a single-crystal to single-crystal manner the calcium(II) ions are replaced by terbium (III), dysprosium(I…
The construction of open GdIII metal–organic frameworks based on methanetriacetic acid: New objects with an old ligand
2010
11 páginas, 11 figuras, 2 esquemas.-- et al.
In-depth structural analysis of lanthanoid coordination networks based on a flexible tripodal zwitterionic isonicotinate ligand
2019
Crystallizing metal–organic frameworks (MOFs) has been studied using a tripodal pyridinecarboxylic acid derivative ligand and selected lanthanoid salts. The zwitterionic ligand, 1,1′,1′′-((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(pyridin-1-ium-4-carboxylate) (TTTPC) introduced as a bromide salt, forms coordination networks in aqueous environments and under ambient conditions with neodymium bromide, trifluoromethanesulfonate (OTf) or acetate (OAc). Seven structures are elucidated in detail using single crystal X-ray crystallography. TTTPC NdBr3, TTTPC NdBr2OTf, TTTPC NdBr(OTf)2 and TTTPC Nd(OTf)3 are porous 3D networks with similar ligand–metal and ligand–anion interactions, b…
Combining organocatalysis and lanthanide catalysis: a sequential one-pot quadruple reaction sequence/hetero-Diels-Alder asymmetric synthesis of funct…
2016
A stereoselective one-pot synthesis of functionalized complex tricyclic polyethers has been achieved using the combination of secondary amine and lanthanide catalysis. This one-pot quadruple reaction/Hetero-Diels–Alder sequence gave good yields (per step) as well as excellent diastereo- and enantioselectivities. Furthermore, the particular combination of lanthanide complexes with organocatalysis is one of the first examples described for sequential catalysis.
A Dysprosium Metallocene Single-Molecule Magnet Functioning at the Axial Limit
2017
Abstraction of a chloride ligand from the dysprosium metallocene [(Cpttt)2DyCl] (1Dy Cpttt=1,2,4‐tri(tert‐butyl)cyclopentadienide) by the triethylsilylium cation produces the first base‐free rare‐earth metallocenium cation [(Cpttt)2Dy]+ (2Dy) as a salt of the non‐coordinating [B(C6F5)4]− anion. Magnetic measurements reveal that [2Dy][B(C6F5)4] is an SMM with a record anisotropy barrier up to 1277 cm−1 (1837 K) in zero field and a record magnetic blocking temperature of 60 K, including hysteresis with coercivity. The exceptional magnetic axiality of 2Dy is further highlighted by computational studies, which reveal this system to be the first lanthanide SMM in which all low‐lying Kramers doub…
Structural investigations on diorganotin and triorganotin(IV) phosphomycin derivatives.
2008
Abstract Four new diorganotin(IV), (R = Me, Bu), and triorganotin(IV), (R = Me, Ph), derivatives of the phosphomycin disodium salt antibiotic[(1R,2S)-1,2-epoxypropylphosphonate]Na2 have been synthesized and their solid state configuration studied by X-ray crystallography, FT-IR, Mossbauer, UV–Vis spectroscopies. The X-ray diffraction investigation, performed on the bis[trimethyltin(IV)]phosphomycin, showed that the coordination geometry at all the Sn atoms is trigonal bipyramidal. The structure of the complex forms an unusual polymeric zig-zag planar network. The FT-IR and the 119Sn Mossbauer studies supported the formation of trigonal bipyramidal (Tbp) molecular structures, both in the dio…
Visible-light photoredox catalyzed synthesis of pyrroloisoquinolines via organocatalytic oxidation/[3 + 2] cycloaddition/oxidative aromatization reac…
2014
Beilstein journal of organic chemistry 10, 1233-1238 (2014). doi:10.3762/bjoc.10.122
Nonheme Fe(IV) Oxo Complexes of Two New Pentadentate Ligands and Their Hydrogen-Atom and Oxygen-Atom Transfer Reactions.
2015
Two new pentadentate {N5} donor ligands based on the N4Py (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) framework have been synthesized, viz. [N-(1-methyl-2-benzimidazolyl)methyl-N-(2-pyridyl)methyl-N-(bis-2-pyridyl methyl)amine] (L1) and [N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L2), where one or two pyridyl arms of N4Py have been replaced by corresponding (N-methyl)benzimidazolyl-containing arms. The complexes [FeII(CH3CN)(L)]2+ (L = L1 (1); L2 (2)) were synthesized, and reaction of these ferrous complexes with iodosylbenzene led to the formation of the ferryl complexes [FeIV(O)(L)]2+ (L = L1 (3); L2 (4)), which were characterized by UV–vis spe…