Search results for "Bifunctional"

Speciation Studies of Bifunctional 3-Hydroxy-4-Pyridinone Ligands in the Presence of Zn2+ at Different Ionic Strengths and Temperatures

2019

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Efficient synthesis of new C-functionalized macrocyclic polyamines

2010

A powerful synthetic route for the preparation of new poly-azamacrocycles, valuable precursors of bifunctional chelating agents with applications in nuclear medicine, is reported. The desired functional group was introduced onto the macro-cycle backbone during the cyclization step, thus avoiding the tedious preparation of a C-functionalized synthon. The regioselective reaction of macrocycles bearing an aminomethyl pendant arm with aldehydes is also described.

Reversible self-assembly of metal chalcogenide/metal oxide nanostructures based on Pearson hardness.

2010

Nanotechnology has reached a stage of development where not individual nanoparticles but rather systems of greater complexity are the focus of concern. These complex structures incorporate two or more types of materials, an example of which is the formation of metal–semiconductor hybrids, which effectively combine the properties of both materials. The assembly of multicomponent nanoparticles from constituents with different optical, electrical, magnetic, and chemical properties can lead to novel functionalities that are independent of the individual components and may be tailored to fit a specific application. These applications include such far-reaching challenges as solar energy conversio…

Bifunctional coordination polymers as efficient catalysts for carbon dioxide conversion

2019

Extraction of dansylated amino acids using the supported liquid membrane technique

1997

Extraction using the supported liquid membrane (SLM) technique demands conditions where the extracted compounds can be made uncharged allowing them to pass through the membrane. For amino acids, being bifunctional, such conditions can not be obtained directly. One way to overcome this problem is to block one of the functionalities by derivatization, utilising the other group for the transport. The SLM extraction of dansylated amino acids was investigated and optimized. It was possible to obtain high extraction efficiencies (>90%) for most amino acids. For amino acids with polar side chains, such high extraction efficiencies were only obtained at low analyte concentrations ( 10 nmol 1-l). Fo…

Reductive transformations - 11. stereoselective cycloannelation and bridging of the cyclooctatetraene dianionMakromol. Chem., Rapid. Commun. 1988, 9,…

1988

Abstract Bifunctional electrophiles with C4-, C6-, and C8-chains are reacted with the cyclooctatetraene dianion to selectively give novel cycloannelation and bridging products which possess a surprising stereochemistry and are useful starting compounds for further syntheses.

3'-Arylazido-beta-alanyl-2-azido ATP, a cross-linking photoaffinity label for F1ATPases.

1989

Abstract The synthesis of the 3′-arylazido-2-azido ATP derivative 3′-O-{3-[N-(4-azido-2-nitrophenyl)-amino]propionyl}2-azido-adenosine 5′-triphosphate (2,3′-DiN3ATP) is described. The bifunc­ tional photoreactive ATP analog is characterized spectroscopically. Photoaffinity labeling of F, ATPase from Micrococcus luteus by this analog results in the inactivation of the enzyme and in the formation of higher molecular weight cross-links,

Catalytic Diastereo- and Enantioselective Synthesis of 2-Imidazolinones.

2019

Chiral cyclic ureas (2-imidazolinones) were prepared by the reaction of nitrones and isocyanoacetate esters using a multicatalytic system that combines a bifunctional Brønsted base-squaramide organocatalyst and Ag+ as a Lewis acid. The reaction could be achieved with a range of nitrones derived from aryl- and cycloalkylaldehydes with moderate diastereo- and good enantioselectivity. A plausible mechanism involving an initial formal [3 + 3] cycloaddition of the nitrone and isocyanoacetate ester, followed by rearrangement to an aminoisocyanate and cyclization to the imidazolinone, is proposed.

Relationship between conformation and physicochemical properties of polypeptides. I. Synthesis of homo- and co-oligopeptides by the liquid-phase meth…

1980

The synthesis of the following oligo- and co-oligopeptides by the liquid-phase method is described: (L-Met)15 (I), [L-Glu(OBzl)]20 (II), (L-Val)8-Gly (IV), (L-Ile)8-Gly (V), (L-Ile)4-Gly-(L-Ile)4 (VI), (L-Ile)4-Pro-(L-Ile)4 (VII), (L-Met)5-L-Pro-(L-Met)5 (VIII), [L-Glu(OBzl)]7-L-Pro-[L-Glu(OBzl)]7 (IX). The oligomers are covalently bound to bifunctional polyethylene glycol (PEG) and monofunctional PEG-M of Mr 5 × 103−2 × 104. Analytical controls were carried out after each step of synthesis in order to ensure quantitative coupling yields. All products could be obtained in high purity as indicated by amino acid analysis, thin-layer chromatography and chiroptical methods. The solubility of th…

2,2′:6′,2″-Terpyridine Trimethylplatinum(IV) Iodide Complexes as Bifunctional Halogen Bond Acceptors

2016

Three new organometallic trimethylplatinum(IV) iodide complexes of 2,2′:6′,2″-terpyridines have been synthesized and characterized by 1H NMR spectroscopy, mass spectrometry, elemental analysis, and single crystal X-ray diffraction analysis. The X-ray crystal structures of PtMe3I(L) complexes 1–3 {L for 1 = 4′-chloro-2,2′:6′,2″-terpyridine, 2 = 4′-(4-cyanophenyl)-2,2′:6′,2″-terpyridine, and 3 = 4′-(4-tolyl)-2,2′:6′,2″-terpyridine} reveal distorted octahedral coordination geometry of the platinum(IV) metal centers with bidentate coordination of the terpyridine ligands. Complexation of 1–3 with iodopentafluorobenzene (IPFB) afforded single-crystal structures of halogen bond (XB) complexes 1a–3…