102 research outputs found

    In situ monitoring and mechanism of the mechanochemical formation of a microporous MOF-74 framework

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    Mechanochemistry provides a rapid, efficient route to metal-organic framework Zn-MOF-74 directly from a metal oxide and without bulk solvent. In situ synchrotron X-ray diffraction monitoring of the reaction course reveals two new phases and an unusual step-wise process in which a close-packed intermediate reacts to form the open framework. The reaction can be performed on a gram scale to yield a highly porous material after activation

    Intra-Arterial Prostaglandin E1 Infusion in Patients with Rest Pain: Short-Term Results

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    Purpose. To present our results after short-term (1 month) intra-arterial infusion therapy of PGE1-alprostadil via a port system implanted in the ipsilateral external iliac artery (EIA) in patients with severe rest pain. Methods. Ten patients with severe rest pain were included. All patients showed extensive peripheral vascular disease below the knee. The tip of the catheter was introduced via a retrograde puncture in the ipsilateral external iliac artery (EIA). The patients received intraarterial infusion of PGE1, 20 mgr alprostadil daily, via the port catheter for 1 month. Results. Clinical success was evaluated according to subjective grading of pain (group A significant decrease, group B moderate decrease and group C no response). A significant decrease of rest pain was observed in 8 (group A, 80%) patients, a moderate decrease in 2 (Group B, 20%), whereas no patients demonstrated any significant response. Both patients of group B had Buergers' disease and continue to smoke during therapy. No peripheral thrombosis or clinical deterioration was noticed. Conclusion. Intraarterial infusion of PGE1 alprostadil on a daily basis, using a port catheter into the ipsilateral EIA, in selected patients with severe rest pain, seems to be very effective, without any serious complications

    Computational evaluation of metal pentazolate frameworks::Inorganic analogues of azolate metal-organic frameworks

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    We report a periodic density-functional theory evaluation of putative frameworks, including a topologically novel arhangelskite (arh) structure, based on the pentazolate ion, the ultimate all-nitrogen, inorganic member of the azolate series of aromatic 5-membered ring anions.</p

    Two-dimensional frameworks built from Single-Molecule Magnets

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    Fine tuning the Mn/salicylaldoxime/trimesic acid reaction conditions leads to the formation of a regular 2D net held together by dative bonds and to a non-regular 2D net stabilised by both dative and hydrogen bonds. Both networks are built from [Mn-6] Single-Molecule Magnets.</p

    In situ X-ray diffraction monitoring of a mechanochemical reaction reveals a unique topology metal-organic framework

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    Chemical and physical transformations by milling are attracting enormous interest for their ability to access new materials and clean reactivity, and are central to a number of core industries, from mineral processing to pharmaceutical manufacturing. While continuous mechanical stress during milling is thought to create an environment supporting non- conventional reactivity and exotic intermediates, such speculations have remained without proof. Here we use in situ, real-time powder X-ray diffraction monitoring to discover and capture a metastable, novel-topology intermediate of a mechanochemical transformation. Monitoring the mechanochemical synthesis of an archetypal metal-organic framework ZIF-8 by in situ powder X-ray diffraction reveals unexpected amorphization, and on further milling recrystallization into a non-porous material via a metastable intermediate based on a previously unreported topology, herein named katsenite (kat). The discovery of this phase and topology provides direct evidence that milling transformations can involve short-lived, structurally unusual phases not yet accessed by conventional chemistry
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