Development of new methods in modern selective organic synthesis: preparation of functionalized molecules with atomic precision

Abstract

Stable negative ions containing up to sixteen silicon atoms have been measured by mass spectromettry in RF power-modulated silane plasmas for amorphous silicon deposition. These hydrogenated silicon cluster ions reach much higher masses than the positive ions, which have no more than six silicon atoms. This supports the view that negative ions are the precursors to particulate formation in silane plasmas. The time-dependent fluxes d positive and negative ions from the plasma are shown with a 5 p s time resolution. Possible cluster reaction sequences are discussed and the effect of visible light on the negative ion signal i s commented upon.

An effective one-pot access to polynuclear dispiroheterocyclic structures comprising pyrrolidinyloxindole and imidazothiazolotriazine moieties via a 1,3-dipolar cycloaddition strategy

“…A global trend in modern organic chemistry is the design of molecular systems with various degrees of complexity to maximize the incorporation of useful properties while optimizing cost and efficiency [1]. A very extended and powerful approach for constructing complex N-heterocyclic systems in a regio and stereocontrolled fashion is the 1,3-dipolar cycloaddition of azomethine ylides to electron-deficient alkenes as dipolarophiles [2–8].…”

Production of Pure Aqueous 13C‐Hyperpolarized Acetate by Heterogeneous Parahydrogen‐Induced Polarization

“…The average particles ize of the 23.2 wt %R h/TiO 2 catalystw as estimated from TEM data as circa 3nm, which is favorable for the observation of PHIP effects. [39] Therefore, this catalyst was used for heterogeneous hydrogenationo fv inyl acetate in an aqueous medium with subsequent polarization transfer from para-hydrogen-derived protons to 13 Cn uclei and detection by 13 CNMR spectroscopy (Figure 2,3).…”

Parawasserstoff‐basierte Hyperpolarisierung für die Biomedizin

“…Eine Reduktion der Oberflächenmobilität von Wasserstoff wird auch für Metalloxide erwartet. Tatsächlich wurde PHIP bei vielen solcher Materialien (beispielsweise CeO 2 , Cr 2 O 3 , CaO, ZrO 2 ) beobachtet …”