Search results for "Moiety"
showing 10 items of 621 documents
Expanding the chemical scope of RNA:methyltransferases to site-specific alkynylation of RNA for click labeling.
2010
This work identifies the combination of enzymatic transfer and click labeling as an efficient method for the site-specific tagging of RNA molecules for biophysical studies. A double-activated analog of the ubiquitous co-substrate S-adenosyl-l-methionine was employed to enzymatically transfer a five carbon chain containing a terminal alkynyl moiety onto RNA. The tRNA:methyltransferase Trm1 transferred the extended alkynyl moiety to its natural target, the N2 of guanosine 26 in tRNA(Phe). LC/MS and LC/MS/MS techniques were used to detect and characterize the modified nucleoside as well as its cycloaddition product with a fluorescent azide. The latter resulted from a labeling reaction via Cu(I…
A Chromogenic Probe for the Selective Recognition of Sarin and Soman Mimic DFP
2014
The synthesis, characterization and sensing features of a novel probe 1 for the selective chromogenic recognition of diisopropylfluorophosphate (DFP), a sarin and soman mimic, in 99:1 (v/ v) water/acetonitrile and in the gas phase is reported. Colour modulation is based on the combined reaction of phosphorylation of 1 and fluoride-induced hydrolysis of a silyl ether moiety. As fluoride is a specific reaction product of the reaction between DFP and the OH group, the probe shows a selective colour modulation in the presence of this chemical. Other nerve agent simulants, certain anions, oxidant species and other organophosphorous compounds were unable to induce colour changes in 1. This is one…
A ferromagnetic tetranuclear nickel(II) Schiff-base complex with an asymmetric Ni4O4 cubane core
2014
Abstract The ferromagnetic tetranuclear nickel(II) complex [Ni4(L)4(CH3OH)2]·2MeOH·8H2O (1) has been synthesized by reacting nickel nitrate hexahydrate with the Schiff base ligand H2L (H2L = N-(2-hydroxyphenyl)-3-methoxy-salicylideneamine). Complex 1 was characterized by analytical, thermogravimetric, optical and magnetic techniques. The solid state structure of 1 was established by single crystal X-ray diffraction analysis. Crystal structure determination shows the formation of a distorted Ni4O4 cubane moiety encapsulated by four Schiff base ligands. Compound 1 crystallizes in the triclinic space group P 1 ¯ with a = 12.7624(9) A, b = 15.0477(9) A, c = 16.8589(10) A, α = 94.732(2)°, β = 94…
Synthesis, X-ray crystal structure and magnetic study of a novel μ2-1,1-azido bridged dimeric copper(II) complex
2007
Abstract A new azido derivative of tridentate Schiff base copper(II) complex has been synthesized and characterized. X-ray single crystal structure analysis reveals that the complex [Cu2L2(N3)2(NO3)2] (1), containing 1-(N-pyridylimino)-3-aminopropane (L) as co-ligand, is a dimer in which copper(II) ions are bridged by two azido groups in end-on fashion. The coordination environment around copper(II) is distorted octahedral which is rarely observed among these types of azido bridged copper(II) dimers. Three among the four coordination sites of the basal plane of the octahedron are occupied by the nitrogen atoms of the Schiff base and the fourth site is occupied by a nitrogen atom of a μ2-1,1…
Investigations on organoantimony compounds XI. Triorganoantimony(V) compounds containing potentially tridentate ligands
1974
Triorganoantimony(V) compounds of the types RSbVL, in which R = Me or Ph, and L represents a potentially tridentate dianionic Schiff base ligand of the ONO or SNO type, have been synthesized and investigated by spectroscopic (UV, IR, PMR) methods. Molecular weight determinations in benzene reveal the monomeric nature of these compounds. The free ligands, HL, used in this study are:,′-(methylidynenitrilo)diphenol (HSab), -(o-hydroxyphenyl)benzothiazoline (H-Sat), -(o_hydroxyanilino)crotonophenone (HBah), 4-(o-hydroxyphenylimino)--pentanone (HAah) and -acetonyl--methylbenzothiazoline (HAat). Both the UV and the IR data suggest hexacoordinate molecular structures for the complexes RSbL in whic…
Isolation and Characterization of an Fe(III)-Chelating Compound Produced by Pseudomonas syringae
1986
The phytopathogenic bacterium Pseudomonas syringae produces a fluorescent pigment when it is grown in iron-deficient media. This pigment forms a very stable Fe(III) complex that was purified in this form by using a novel procedure based on ultrafiltration and column chromatography. The Fe(III) complex has a molecular weight of 1,100 and contains 1 mol of Fe(III). The pigment is composed of an amino acid moiety with three threonines, three serines, one lysine, δ- N -hydroxyornithine, and a quinoline-type fluorescent chromophore. These features and its stability constant (in the range of 10 32 ) suggest that the fluorescent pigment of P. syringae is related to the siderophores produced by an…
Alkoxysilylation of π-systems with extended conjugation—reactive chromophores for organic–inorganic hybrid materials
2004
Luminescent stilbenoid chromophores with diethoxysilane end groups are prepared via Heck reactions. Diethoxysilane-substituted styrenes are used as vinylic components, thus allowing the combined connection of the chromophore to the silane moiety with an extension of the π-system. 1,4-Distyrylbenzenes with a terminal bromine are used as coupling partners. The electrical and optical properties the four-ring OPVs are tuned via substitution with donating alkoxy side chains and electron withdrawing cyanide and a naphthyl-1,2,3-oxadiazole moiety. Hydrolysis yields film forming and luminescent cyclosiloxanes.
Cooperative Catechol-Functionalized Polypept(o)ide Brushes and Ag Nanoparticles for Combination of Protein Resistance and Antimicrobial Activity on M…
2018
Prevention of biofouling and microbial contamination of implanted biomedical devices is essential to maintain their functionality and biocompatibility. For this purpose, polypept(o)ide block copolymers have been developed, in which a protein-resistant polysarcosine (pSar) block is combined with a dopamine-modified poly(glutamic acid) block for surface coating and silver nanoparticles (Ag NPs) formation. In the development of a novel, versatile, and biocompatible antibacterial surface coating, block lengths pSar were varied to derive structure-property relationships. Notably, the catechol moiety performs two important tasks in parallel; primarily it acts as an efficient anchoring group to me…
Selective Synthesis of Partially Protected Nonsymmetric Biphenols by Reagent‐ and Metal‐Free Anodic Cross‐Coupling Reaction
2016
The oxidative cross-coupling of aromatic substrates without the necessity of leaving groups or catalysts is described. The selective formation of partially protected nonsymmetric 2,2'-biphenols via electroorganic synthesis was accomplished with a high yield of isolated product. Since electric current is employed as the terminal oxidant, the reaction is reagent-free; no reagent waste is generated as only electrons are involved. The reaction is conducted in an undivided cell, and is suitable for scale-up and inherently safe. The implementation of O-silyl-protected phenols in this transformation results in both significantly enhanced yields and higher selectivity for the desired nonsymmetric 2…
ChemInform Abstract: Selective Synthesis of Partially Protected Nonsymmetric Biphenols by Reagent- and Metal-Free Anodic Cross-Coupling Reaction.
2016
The oxidative cross-coupling of aromatic substrates without the necessity of leaving groups or catalysts is described. The selective formation of partially protected nonsymmetric 2,2'-biphenols via electroorganic synthesis was accomplished with a high yield of isolated product. Since electric current is employed as the terminal oxidant, the reaction is reagent-free; no reagent waste is generated as only electrons are involved. The reaction is conducted in an undivided cell, and is suitable for scale-up and inherently safe. The implementation of O-silyl-protected phenols in this transformation results in both significantly enhanced yields and higher selectivity for the desired nonsymmetric 2…