The neutron time-of-flight spectrometer NEAT has a long history of successful applications and is best suited to probe dynamic phenomena directly in the large time domain 10−14 – 10−10 s and on the ...length scale ranging from 0.05 to up to about 5 nm. To address user community needs for more powerful instrumental capabilities, a concept of the full upgrade of NEAT has been proposed. The upgrade started in 2010 after a rigorous internal and external selection process and resulted in 300-fold neutron count rate increase compared to NEAT′1995. Combined with new instrumental and sample environmental capabilities the upgrade allows NEAT to maintain itself at the best world class level and provide an outstanding experimental tool for a broad range of scientific applications. The advanced features of the new instrument include an integrated guide-chopper system that delivers neutrons with flexible beam properties: either highly homogeneous beam with low divergence suitable for single crystals studies or “hot-spot” neutron distribution serving best small samples. Substantial increase of the detector angle coverage is achieved by using 416 3He position sensitive detectors. Placed at 3 m from the sample, the detectors cover 20 m2 area and are equipped with modern electronics and DAQ using event recording techniques. The installation of hardware has been completed in June 2016 and on January 23, 2017 NEAT has welcomed its first regular users who took advantage of the high counting rate, broad available range of incoming neutron wavelengths and high flexibility of NEAT. Here we present details of NEAT upgrade, measured instrument characteristics and show first experimental results.
The neutron time-of-flight spectrometer NEAT has a long history of successful applications and is best suited to probe dynamic phenomena directly in the large time domain 10-14 – 10-10 s and on the ...length scale ranging from 0.05 to up to about 5 nm. To address user community needs for more powerful instrumental capabilities, a concept of the full upgrade of NEAT has been proposed. The upgrade started in 2010 after a rigorous internal and external selection process and resulted in 300-fold neutron count rate increase compared to NEAT'1995. Combined with new instrumental and sample environmental capabilities the upgrade allows NEAT to maintain itself at the best world class level and provide an outstanding experimental tool for a broad range of scientific applications. The advanced features of the new instrument include an integrated guide-chopper system that delivers neutrons with flexible beam properties: either highly homogeneous beam with low divergence suitable for single crystals studies or "hot-spot" neutron distribution serving best small samples. Substantial increase of the detector angle coverage is achieved by using 416 3He position sensitive detectors. Placed at 3 m from the sample, the detectors cover 20 m2 area and are equipped with modern electronics and DAQ using event recording techniques. The installation of hardware has been completed in June 2016 and on January 23, 2017 NEAT has welcomed its first regular users who took advantage of the high counting rate, broad available range of incoming neutron wavelengths and high flexibility of NEAT. Here we present details of NEAT upgrade, measured instrument characteristics and show first experimental results.
The novel supramolecular assembly of composition {(bz3tren)H4}4+ · (ReO4)— · 3(Cl)— resulted from the self‐organization of a mixture of tris2‐(benzylamino)ethylamine (bz3tren), HCl and NH4ReO4 at a ...molar ratio of 1:4.7:1 in methanol. The crystal architecture is characterized by stacks of repeating sandwich‐type building blocks that contain charge‐assisted N—H···O(Re) hydrogen bonds N···O 2.81‐2.86Å and weaker C—H···O(Re) interactions C···O 3.11Å. The stacks are further linked by N—H···Cl N···Cl 3.03Å and weaker C—H···Cl C···Cl 3.47‐3.74Å interactions into two‐dimensional layers bordered by the benzyl groups of the (bz3tren)H44+ cations. Edge‐to‐face C—H···π interactions involving the aromatic rings occur within and between the layers. The protonation constants of bz3tren in methanol were determined by potentiometric titration. The corresponding structures of the ligand in its different protonation states were calculated at the DFT‐level.
Anionen‐gesteuerte supramolekulare Selbstorganisation von vierfach protoniertem Tris2‐(benzylamino)ethylamin
Eine neue supramolekulare Verbindung der Zusammensetzung {(bz3tren)H4}4+ · (ReO4)— · 3(Cl)— wurde durch Selbstorganisation einer Mischung von Tris2‐(benzylamino)ethylamin (bz3tren), HCl und NH4ReO4 im Molverhältnis 1:4.7:1 in Methanol erhalten. Ihre Kristallstruktur ist durch Stapel sandwichartiger Baueinheiten charakterisiert, die auf ladungsunterstützten N—H···O(Re)‐Wasserstoffbrückenbindungen N···O 2.81—2.86Å und schwächeren C—H···O(Re)‐Wechselwirkungen C···O 3.11Å beruhen. Diese Stapel sind über ein ausgeprägtes zweidimensionales Wasserstoffbrückennetzwerk unter Nutzung von N—H···Cl‐N···Cl 3.03Å und schwächeren C—H···Cl‐Bindungen C···Cl 3.47—3.74Å verknüpft. Zusätzliche C—H···π‐Wechselwirkungen zwischen den endständigen Benzylgruppen des Kations (bz3tren)H44+ führen schließlich zu einer dreidimensionalen Struktur. Die Protonierungskonstanten von bz3tren wurden in Methanol durch potentiometrische Titration bestimmt; Strukturänderungen des Liganden wurden in Abhängigkeit von der Protonierung durch DFT‐Rechnungen ermittelt.
