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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Amine templating effect absent in uranyl sulfates synthesized with 1,4-n-butyldiamine

Two new uranyl sulfates, (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2}){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS2) and (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS3), were synthesized and their crystal structures determined. NDUS2 was obtained in highly acidic media heat-treated at 373 K and subsequently maintained at 278 K until crystals formed after two months. NDUS3 results from the degradation of NDUS2 over the course of a few days. NDUS2 and NDUS3 crystallize in the monoclinic space group P2{sub 1}/n, a=10.9075(4) A, b=10.4513(4) A, c=17.7881(7) A, {beta}=97.908(2) Degree-Sign , V=2008.52(13) A{sup 3}, Z=4, at 140 K and a=8.8570(4) A, b=7.3299(3) A, c=20.4260(9) A, {beta}=95.140(2) Degree-Sign , V=1320.74(10) A{sup 3}, Z=4, at 140 K, respectively. The compounds contain interlayer 1,4-n-butyldiammonium cations that charge-balance the anionic structural units. - Graphical abstract: Amine templating effect absent in uranyl sulfates synthesized with 1,4-diaminobutane, as shown by the synthesis of two new uranyl sulfates, (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2}){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS2) and (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS3). Highlights: Black-Right-Pointing-Pointer Two layered uranyl sulfates were synthesized. Black-Right-Pointing-Pointer Amine molecules are located in the interlayers of the compounds. Black-Right-Pointing-Pointer No templating effect of the amine was observed. Black-Right-Pointing-Pointer Amine molecules are only charge balancing cations in the structures.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Evaluation of Attractive Interactions in the Second Coordination Sphere of Iron Complexes Containing Pendant Amines

The interactions between pendant amines in the second coordination sphere and ligands in the first coordination sphere are important for understanding the structures and reactivity of complexes containing PR2NR'2 ligands, which have been shown to be highly active H2 oxidation/production catalysts. A series of [Fe(PPh2NBn2)2(X)(Y)]n+ complexes have been prepared and structurally characterized. These complexes have two different ligands with which the pendant amines of the diphosphine ligand can interact. The solid state structure of cis-Fe(PPh2NBn2)2Cl2 reveals that the six-membered rings adjacent to the P atoms are in a boat confirmation, resulting in close N•••P distances that suggests the P atoms have a greater affinity for the lone pair of electrons on the N atom than chloride ligands. Similarly, boat conformations are observed for both rings adjacent to the hydride ligands of trans-[HFe(PPh2NBn2)2(CH3CN)]+ and trans-HFe(PPh2NBn2)2Cl, resulting in short N•••H distances. Spectroscopic and computational studies of trans-[HFe(PPh2NBn2)2(CO)]+, trans-[HFe(PPh2NBn2)(PPh2NBn2H)(CO)]2+, and trans-[HFe(PPh2NBn2)2(H2)]+ indicate the complexes are more stable when the pendant amines in boat conformations are adjacent to the hydride ligand. These data suggest an attractor ordering of H- > CO > H2 > PR3 > Cl- ~ CH3CN. This work was supported by the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory (PNNL) is operated by Battelle for the U.S. DOE. Computations were performed using the Cascade supercomputer at the Environmental Molecular Sciences Laboratory, a National Scientific User Facility sponsored by the DOE’s Office of Biological and Environmental Research and located at PNNL.

Liao, Qian↗
DOE OSTI2019

Photo-generated reactive oxygen species assisted tandem amine homocoupling and amine-alcohol cross-coupling reaction on mesoporous spinel cobalt oxide

Mesoporous spinel cobalt oxide (Co 3 O 4 ) with fine-tuned pore size distributions (9.6–17.6 nm) and different surface areas (33–85 m 2 /g) were synthesized using a series of nonionic surfactants. A direct influence of the chemical composition of the surfactants and calcination temperature on crystallite size, morphology, pore size/volume, surface area, valance band edge, and Co 2+ /Co 3+ ratio was recognized. Correlation between the aforementioned factors, transition metal ion incorporation and benzylamine homocoupling reaction was discussed. Shape-specific binding of amine on the cobalt oxide active sites was proposed based on substrate scope study. Tandem synthesis strategy to selectively synthesize amine (aliphatic/aromatic) homo-coupled imines and amine-alcohol cross-coupled imines was introduced. Low-intensity light-induced singlet oxygen and hydroxyl radical-mediated reaction mechanism was proposed based on the EPR, XPS, photoreactor, and reactive oxygen species scavenger tests. Selective and switchable synthesis of homo-coupled (yield 85%) and cross-coupled (yield 87%) products was achieved with sodium azide and mannitol additives.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1983

Synthesis and characterization of bisimide amines and bisimide amine-cured epoxy resins

An attempt is made to develop tough, moisture resistant, high char yield epoxy resins by means of novel bisimide amine (BIA) hardener curing agents and a state-of-the-art epoxy resin system. The BIAs are isolated as mixtures containing monomer, oligomer, and polymeric species, and then characterized by elemental analysis and high pressure liquid chromatography. The bisimide amine-cured epoxies (IMEs) were characterized with respect to moisture absorption, thermal properties, and physical and mechanical properties, as well as in the role of matrices in Celion 6000/IME composites. The relative toughness characteristics of each IME formulation was measured by the 10 deg off-axis tensile test, measuring the uniaxial tensile strength, shear strength, and shear-strain-to-failure of the composite systems.

Scola, D. A.↗
DOE OSTI2018

Mesoporous cobalt/manganese oxide: a highly selective bifunctional catalyst for amine–imine transformations

Here, we discuss a heterogeneous catalytic protocol using cobalt doped mesoporous manganese oxide for amine–alcohol cross-coupling to selectively produce symmetric or asymmetric imines. Thorough investigations on the surface chemistry and physical properties of the material revealed its outstanding oxidation–reduction properties and reaction mechanism which was supported by quantum mechanical calculations done by using density functional theory (DFT).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Synthesis and reactivity of molybdenum and tungsten bis(dinitrogen) complexes supported by diphosphine chelates containing pendant amines

In this study, we report the synthesis and characterization of molybdenum bis(dinitrogen) complexes supported by two PNP diphosphine ligands, Mo(N{sub 2}){sub 2}(PNP){sub 2}; PNP = [(R{sub 2}PCH{sub 2}){sub 2}N(R'), R = Et (ethyl), Ph (phenyl); R'= Me (methyl), Bn (benzyl)], and a series of tungsten bis(dinitrogen) complexes containing one or two PNP ligands, W(N{sub 2}){sub 2}(dppe)(PNP) and W(N{sub 2}){sub 2}(PNP){sub 2}, respectively, and the analogues complexes without pendant amines for comparison. These Mo- and W-N{sub 2} complexes were characterized by NMR, IR, spectroscopy, cyclic voltammetry and structurally characterized by X-ray crystallography. In addition, reactivity of the complexes with CO is described.

36 MATERIALS SCIENCE↗
DOE OSTI2021

New reactions of diazene and related species for modelling combustion of amine fuels

Potential energy surfaces for reactions involving N 2 H 2 isomers of diazene (diimide) have been explored using density functional theory, with energies based on coupled-cluster theory. A focus is on processes that create or consume these species, and isomerisation between the E (trans) and Z (cis) forms of HNNH. Furthermore, these include isomerisation and dissociation pathways for HNNH, addition of H atoms to form N 2 H 3 , abstraction by H atoms yielding short-lived NNH, and abstraction reactions of H with N 2 H 3 . Transition state and capture theories are applied for high-pressure-limiting behaviour, while low-pressure and falloff regions are characterised via the methods of Troe and coworkers. Rate constants and thermochemistry are provided to improve models of diamine chemistry, relevant to the combustion of NH 3 especially at high concentrations, high pressures or under reducing conditions. Results indicate that amine radical recombination mainly yields the E HNNH isomer, while H-abstraction from N 2 H 3 results in E HNNH and H 2 NN. However, at elevated temperature E → Z isomerisation becomes competitive, and Z HNNH, being more reactive, acts to enhance the diazene consumption rate.

10 SYNTHETIC FUELS↗
NASA NTRS1982

Synthesis and characterization of bisimide amines and bisimide amine-cured epoxy resins

A study has been conducted with the objective of developing tough, moisture resistant, high char yield epoxy resins using novel bisimide amine (BIA) hardeners as curing agents with MY-720, a commercial state-of-the-art epoxy resin system. BIA cured epoxies are shown to have lower moisture absorption than MY-720 and other state-of-the-art epoxy resins; the tensile strengths and strain-to-failures of several of the bisimide epoxy resins (IME's) are higher than those of the state-of-the-art epoxies. Most IME's have compression properties equivalent to those of state-of-the-art epoxies. Two resin systems, IME-10 and IME-12-3, have better overall properties than other resin systems investigated.

Scola, D. A.↗
DOE OSTI2011

Directing Protons to the Dioxygen Ligand of a Ruthenium(II) Complex with Pendent Amines in the Second Coordination Sphere

The activation and reduction of dioxygen (O2) by transition metal centers are key to a variety of biochemical and industrial processes. Efficient reduction of dioxygen to water is also important in the operation of fuel cells. These processes are typically proton-coupled electron transfer (PCET) reactions, requiring the coordinated movement of multiple protons and electrons. In biological systems, it is known that initial dioxygen bonding is facilitated by hydrogen bonding and proton delivery. This material is based upon work supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

08 HYDROGEN↗