نتایج جستجو برای: fluorine
تعداد نتایج: 7204 فیلتر نتایج به سال:
Since its first use in the steroid field in the late 1950s, the use of fluorine in medicinal chemistry has become commonplace, with the small electronegative fluorine atom being a key part of the medicinal chemist's repertoire of substitutions used to modulate all aspects of molecular properties including potency, physical chemistry and pharmacokinetics. This review will highlight the special n...
It is a great pleasure to be able to introduce this Themed series on organo-fluorine chemistry in the Beilstein Journal of Organic Chemistry. The introduction of fluorine into organic molecules is widely practiced particularly when tuning the properties of molecules for specialist functions. Of particular prominence is the role fluorine substitution finds in pharmaceutical development [1], and ...
The aims of this study were to evaluate the fluorine depth profiles of pure titanium (Ti), stainless steel (SUS), and polymethyl methacrylate (PMMA) modified by plasma-based fluorine ion implantation and the effects of fluorine ion implantation on contact angle, fluoride ion release, and S. mutans adhesion. Fluorine-based gases used were Ar+F2 and CF4. By means of SIMS, it was found that the pe...
We report density functional electronic structure calculations to monitor the change in the surface characteristics of the Si (100)-2x1 surface after fluorination followed by interaction with water. Embedded finite silicon clusters are used to model an extended Si (100)-2x1 surface. Two high symmetry pathways and subsequent adsorption sites were examined: (i) adsorption of an fluorine atom dire...
Matrix metalloproteases (MMPs) have been found to be highly expressed in a variety of malignant tumor tissues. Noninvasive visualization of MMP activity may play an important role in the diagnosis of MMP associated diseases. Here we report the design and synthesis of a set of fluorine-19 dendron-based magnetic resonance imaging (MRI) probes for real-time imaging of MMP-2 activity. The probes ha...
Neutral fluorine (F i) lines are identified in the optical spectra of several RCoronae Borealis stars (RCBs) at maximum light. These lines provide the first measurement of the fluorine abundance in these stars. Fluorine is enriched in some RCBs by factors of 800 to 8000 relative to its likely initial abundance. The overabundances of fluorine are evidence for the synthesis of fluorine. These res...
The results of the study of the impact of phosphogypsum on the accumulation and migration of fluorine in the southern chernozems of the North-West Black Sea coast area of Ukraine are presented herein. It has been found that the introduction of phosphogypsum as a chemical ameliorator of irrigated chernozems resulted in a fluorine increase both in the soils and in the soil (lysimetric) waters.1 D...
the effects of halogens; fluorine, chlorine and bromine, on the stability and multiplicity of phenylcarbenes / silylenes/ germylenes structures are compared and contrasted at b3lyp/6-311++g**//b3lyp/6-31+g* level. the singlet-triplet energy gaps, δes-t , values for all the above speciesincrease through fluorinated up, δes-ts and δehomo–lumos support the stability of the singlet statesinspite of...
A regio- and stereoselective method has been developed for the synthesis of novel fluorinated 2-aminocyclohexanecarboxylic acid derivatives with the fluorine attached to position 4 of the ring. The synthesis starts from either cis- or trans-β-aminocyclohex-4-enecarboxylic acids and involves regio- and stereoselective transformation of the ring C-C double bond through iodooxazine formation and h...
Fe- and Ln-DOTAm-F12 Are Effective Paramagnetic Fluorine Contrast Agents for MRI in Water and Blood.
A series of fluorinated macrocyclic complexes, M-DOTAm-F12, where M is LaIII, EuIII, GdIII, TbIII, DyIII, HoIII, ErIII, TmIII, YbIII, and FeII, was synthesized, and their potential as fluorine magnetic resonance imaging (MRI) contrast agents was evaluated. The high water solubility of these complexes and the presence of a single fluorine NMR signal, two necessary parameters for in vivo MRI, are...
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