16 research outputs found

    Sterically Rigid Bi-dentate N-(Aryl)imino-Acenapthenone (Ar-BIAO) Ligands in Zinc Coordination Sphere- Syntheses and Structures

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    My thesis work describes the synthesis of six different 1-alkyl-N-(arylimino)acenaphthylen-1-ol compounds 1a, 1b, 2a, 2b, 3a and 3c as the racemic products by varying steric demand on the imino nitrogen atom of N-(aryl)imino-acenapthenone (Ar-BIAO) ligand. The synthesized imino-alcohols are characterized by FT-IR, 1H, 13C{1H} NMR spectroscopy. The soild state structures of compounds 1a, 1b, 2a and 3a are established by single crystal X-ray diffraction analysis. In the molecular structure compounds 1a and 3a crystallize only R-isomers in their respective asymmetric unit, whereas compound 1b has S-isomer only in its asymmetric unit. However compound 2a crystallizes in both R- and S- isomers in its asymmetric unit. In addition with this work one new chiral ligand, N-(1-phenylethylamine)imino-acenaphthenone (4) was synthesized by the reaction of acenaphthenequinone and (R)-1-phenylethylamine in 1:1 ratio. Compound 4 was characterized by FT-IR and 1H NMR spectroscop

    Group 1 and group 2 metal complexes supported by a bidentate bulky iminopyrrolyl ligand: synthesis, structural diversity, and ε-caprolactone polymerization study

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    We report here a series of alkali and alkaline earth metal complexes, each with a bulky iminopyrrolyl ligand [2-(Ph3CN[double bond, length as m-dash]CH)C4H3NH] (1-H) moiety in their coordination sphere, synthesized using either alkane elimination or silylamine elimination methods or the salt metathesis route. The lithium salt of molecular composition [Li(2-(Ph3CN[double bond, length as m-dash]CH)C4H3N)(THF)2] (2) was prepared using the alkane elimination method, and the silylamine elimination method was used to synthesize the dimeric sodium and tetra-nuclear potassium salts of composition [(2-(Ph3CN[double bond, length as m-dash]CH)C4H3N)Na(THF)]2 (3) and [(2-(Ph3CN[double bond, length as m-dash]CH)C4H3N)K(THF)0.5]4 (4) respectively. The magnesium complex of composition [(THF)2Mg(CH2Ph){2-(Ph3CN[double bond, length as m-dash]CH)C4H3N}] (5) was synthesized through the alkane elimination method, in which [Mg(CH2Ph)2(OEt2)2] was treated with the bulky iminopyrrole ligand 1-H in 1 : 1 molar ratio, whereas the bis(iminopyrrolyl)magnesium complex [(THF)2Mg{2-(Ph3CN[double bond, length as m-dash]CH)C4H3N}2] (6) was isolated using the salt metathesis route. The heavier alkaline earth metal complexes of the general formula {(THF)nM(2-(Ph3CN[double bond, length as m-dash]CH)C4H3N)2} [M = Ca (7), Sr (8), and n = 2; M = Ba (9), n = 3] were prepared in pure form using two synthetic methods: in the first method, the bulky iminopyrrole ligand 1-H was directly treated with the alkaline earth metal precursor [M{N(SiMe3)2}2(THF)n] (where M = Ca, Sr and Ba) in 2 : 1 molar ratio in THF solvent at ambient temperature. The complexes 7–9 were also obtained using the salt metathesis reaction, which involves the treatment of the potassium salt (4) with the corresponding metal diiodides MI2 (M = Ca, Sr and Ba) in 2 : 1 molar ratio in THF solvent. The molecular structures of all the metal complexes (1-H, 2–9) in the solid state were established through single-crystal X-ray diffraction analysis. The complexes 5–9 were tested as catalysts for the ring-opening polymerization of ε-caprolactone. High activity was observed in the heavier alkaline earth metal complexes 7–9, with a very narrow polydispersity index in comparison to that of magnesium complexes 5 and 6

    Search for long-lived, massive particles in events with displaced vertices and multiple jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    A search for long-lived particles decaying into hadrons is presented. The analysis uses 139 fb−1 of pp collision data collected at √s = 13 TeV by the ATLAS detector at the LHC using events that contain multiple energetic jets and a displaced vertex. The search employs dedicated reconstruction techniques that significantly increase the sensitivity to long-lived particles decaying in the ATLAS inner detector. Background estimates for Standard Model processes and instrumental effects are extracted from data. The observed event yields are compatible with those expected from background processes. The results are used to set limits at 95% confidence level on model-independent cross sections for processes beyond the Standard Model, and on scenarios with pair-production of supersymmetric particles with long-lived electroweakinos that decay via a small R-parity-violating coupling. The pair-production of electroweakinos with masses below 1.5 TeV is excluded for mean proper lifetimes in the range from 0.03 ns to 1 ns. When produced in the decay of m(g∼) = 2.4 TeV gluinos, electroweakinos with m(χ∼01) = 1.5 TeV are excluded with lifetimes in the range of 0.02 ns to 4 ns

    Overview of Regioselective and Stereoselective Catalytic Hydroboration of Alkynes

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    Hydroboration of alkynes is of special interest to researchers since it is the most straightforward process for the synthesis of highly important vinylborane synthetic intermediate compounds. It is significant in terms of both regioselectivity and stereoselectivity, since several positional isomers are formed during the process of hydroboration. Given the importance of this class of compounds, an extensive study has been carried out regarding catalytic condition development and detailed mechanistic studies for selectively obtaining a single isomer. This review comprehensively summarizes both the regioselective and stereoselective catalytic hydroboration of alkynes. It is aimed at giving readers accurate knowledge of the catalytic systems available for the hydroboration of certain alkynes. We anticipate that this inclusive review will encourage researchers to explore more new types of catalytic systems to achieve the remarkable process of hydroboration of alkynes

    Rh(I)-catalyzed Addition of the ortho

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    Organosilicon Reducing Reagents for Stereoselective Formations of Silyl Enol Ethers from α‑Halo Carbonyl Compounds

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    Salt-free stereoselective synthesis of silyl enol ethers was achieved by treating α-halo carbonyl compounds with 2,3,5,6-tetramethyl-1,4-bis­(trimethylsilyl)-1,4-dihydropyrazine. In this reaction, easily removable trimethylsilyl halides and 2,3,5,6-tetramethylpyrazine were generated as the reaction byproducts. Due to the inertness of the reaction byproducts, we found a one-pot transformation of the <i>in situ</i> generated silyl enol ethers into various α-functionalized carbonyls by reaction with Togni-II reagent or aldehydes
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