48 research outputs found
Bis(2-methyl-4-nitroanilinium) tetrachloridomercurate(II)
The title compound, (C7H9N2O2)2[HgCl4], self-assembles into cationic organic bilayers containing the 2-methyl-4-nitroanilinium cations, sandwiched between anionic inorganic layers built up by the distorted tetrahedral [HgCl4]2− groups. The organic sheets are interlinked through weak C—H⋯O hydrogen bonds, while they interact with the anionic part via strong charge-assisted N+—H⋯Cl—Hg hydrogen bonds. The [HgCl4]2− anions are bisected by a mirror plane passing through the metal and two of the chloride ions
Robust motifs in 2-phenylethylammonium and related tetrahalometallates
The novel crystal structures of seven compounds which combine 2-phenylethylammonium cations and
perhalometallate anions, all with the general formula (C8H9NH3
+)2 MX4
2 , were determined to
establish the effect of metal atom and halogen ligand substitution on the structures and hydrogen
bonding interactions. Five of the structures, bis(2-phenylethylammonium) tetrachlorozincate,
(C8H9NH3
+)2 ZnCl4
2 , bis(2-phenylethylammonium) tetraiodozincate, (C8H9NH3
+)2 ZnI4
2 , bis(2-
phenylethylammonium) tetrabromodichloroiodozincate, (C8H9NH3
+)2 ZnCl2BrI2 , bis(2-
phenylethylammonium) tetrabromocadmate, (C8H9NH3
+)2 CdBr4
2 , and bis(2-
phenylethylammonium) tetrabromomercurate, (C8H9NH3
+)2 HgBr4
2 , were found to be isostructural,
while two of the compounds containing iodo ligands, bis(2-phenylethylammonium) tetraiodocadmate,
(C8H9NH3
+)2 CdI4
2 , and bis(2-phenylethylammonium) tetraiodomercurate, (C8H9NH3
+)2 HgI4
2 ,
crystallize in a different, but related disordered structure. Strong N+–H/X –M hydrogen bonding
interactions, as well as weaker C–H/p aromatic interactions occur in all seven structures, and two
robust tetrameric hydrogen bonded zero-dimensional motifs are present in all seven structures. C–H/
Cl–M hydrogen bonding interactions are present in the structure of bis(2-phenylethylammonium)
tetrachlorozincate, and result in the distortion of the geometry of the 2-phenylethylammonium cation.
Comparison of the identified zero-dimensional hydrogen bonding motifs with those occurring in
related structures reported in the literature shows that the motifs are robust and can tolerate changes in
cation, metal and ligand to a large extent.www.rsc.org/crystengcom
4-Nitroanilinium triiodide monohydrate
In the title compound, C6H7N2O2
+·I3
−·H2O, the triiodide anions form two-dimensional sheets along the a and c axes. These sheets are separated by the 4-nitroanilinium cations and water molecules, which form part of an extended hydrogen-bonded chain with the triiodide along the c axis, represented by the graph set C
3
3(14). The second important hydrogen-bonding interaction is between the nitro group, the water molecule and the anilinium group, which forms an R
2
2(6) ring and may be the reason for the deviation of the torsion angle between the benzene ring and the nitro group from 180 to 163.2 (4)°. These two strong hydrogen-bonding interactions also cause the benzene rings to pack off-centre from one another, with an edge-on-edge π–π stacking distance of 3.634 (6) Å and a centroid–centroid separation of 4.843 (2) Å
N,N′-Bis[(2-hydroxyphenyl)(phenyl)methylidene]propane-1,2-diamine
In the the title compound, C29H26N2O2, two strong intramolecular O—H⋯N hydrogen bonds involving the hydroxy and imine groups generate S(6) ring motifs. The dihedral angles between the pairs of terminal benzene rings are 89.8 (2) and 87.8 (2)°
2,2′-[(Propane-1,3-diyldinitrilo)bis(phenylmethylidyne)]diphenol
In the title molecule, C29H26N2O2, there are two strong intramolecular O—H⋯N hydrogen bonds involving the hydroxy and imine groups, forming S(6) ring motifs. The dihedral angles between adjacent phenyl rings and phenol-containing planes are 85.27 (19) and 91.38 (18)°. In the crystal structure, weak intermolecular C—H⋯O hydrogen bonds connect molecules into a two-dimensional network
A sinter resistant Co Fischer-Tropsch catalyst promoted with Ru and supported on titania encapsulated by mesoporous silica
One of the pathways responsible for the deactivation of Fischer-Tropsch catalysts is the loss of active metal surface area due to nanoparticle agglomeration. To combat this effect efforts have been made to increase the interaction between the metal nanoparticles and the support using materials like silica. In this study, the supported metal particles were covered with a highly porous layer of silica to stabilize the Co nanoparticles on a titania support both during reduction and under reaction conditions. Co3O4 nanoparticles (size range: 8–12 nm) supported on titania were stabilized by coating them with a thin layer of mesoporous silica (
∼
4 nm) to make Fischer-Tropsch catalysts that are less prone to sintering (Co/TiO2@mSiO2). To mitigate the strong metal support interactions brought about by the titania and silica a Ru promoter was loaded together with the cobalt nanoparticles onto the titania (CoRu/TiO2@mSiO2). Temperature programmed XRD studies on the evolution of the Co metal nanoparticles showed that there was no significant particle size growth under reduction conditions in the temperature range from 30 to 600 °C. Chemisorption studies following reduction under hydrogen at 350 °C and 450 °C gave results consistent with the in situ XRD data when compared to the Co/TiO2. Fischer-Tropsch synthesis on the Co/TiO2@mSiO2 and CoRu/TiO2@mSiO2 catalysts encapsulated inside the mesoporous silica shell exhibited good catalytic performance without any display of significant mass transport limitations that might arise due to a silica shell coating of the active sites. For these two catalysts the Fischer-Tropsch activity increased with reduction temperature without any significant negative changes in their selectivity due to sintering, while the activity on Co/TiO2 decreased due to Co nanoparticle sintering
Universality of Thermodynamic Constants Governing Biological Growth Rates
Background: Mathematical models exist that quantify the effect of temperature on poikilotherm growth rate. One family of such models assumes a single rate-limiting ‘master reaction ’ using terms describing the temperature-dependent denaturation of the reaction’s enzyme. We consider whether such a model can describe growth in each domain of life. Methodology/Principal Findings: A new model based on this assumption and using a hierarchical Bayesian approach fits simultaneously 95 data sets for temperature-related growth rates of diverse microorganisms from all three domains of life, Bacteria, Archaea and Eukarya. Remarkably, the model produces credible estimates of fundamental thermodynamic parameters describing protein thermal stability predicted over 20 years ago. Conclusions/Significance: The analysis lends support to the concept of universal thermodynamic limits to microbial growth rate dictated by protein thermal stability that in turn govern biological rates. This suggests that the thermal stability of proteins is a unifying property in the evolution and adaptation of life on earth. The fundamental nature of this conclusion has importance for many fields of study including microbiology, protein chemistry, thermal biology, and ecological theory including, for example, the influence of the vast microbial biomass and activity in the biosphere that is poorly described in current climate models
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Characterization, Leaching, and Filtration Testing for Tributyl Phosphate (TBP, Group 7) Actual Waste Sample Composites
.A testing program evaluating actual tank waste was developed in response to Task 4 from the M-12 External Flowsheet Review Team (EFRT) issue response plan. The bulk water-insoluble solid wastes that are anticipated to be delivered to the Waste Treatment and Immobilization Plant (WTP) were identified according to type such that the actual waste testing could be targeted to the relevant categories. Eight broad waste groupings were defined. Samples available from the 222S archive were identified and obtained for testing. The actual waste-testing program included homogenizing the samples by group, characterizing the solids and aqueous phases, and performing parametric leaching tests. The tributyl phosphate sludge (TBP, Group 7) is the subject of this report. The Group 7 waste was anticipated to be high in phosphorus as well as aluminum in the form of gibbsite. Both are believed to exist in sufficient quantities in the Group 7 waste to address leaching behavior. Thus, the focus of the Group 7 testing was on the removal of both P and Al. The waste-type definition, archived sample conditions, homogenization activities, characterization (physical, chemical, radioisotope, and crystal habit), and caustic leaching behavior as functions of time, temperature, and hydroxide concentration are discussed in this report. Testing was conducted according to TP-RPP-WTP-467
The DREAM Dataset: Supporting a data-driven study of autism spectrum disorder and robot enhanced therapy
We present a dataset of behavioral data recorded from 61 children diagnosed with Autism Spectrum Disorder (ASD). The data was collected during a large-scale evaluation of Robot Enhanced Therapy (RET). The dataset covers over 3000 therapy sessions and more than 300 hours of therapy. Half of the children interacted with the social robot NAO supervised by a therapist. The other half, constituting a control group, interacted directly with a therapist. Both groups followed the Applied Behavior Analysis (ABA) protocol. Each session was recorded with three RGB cameras and two RGBD (Kinect) cameras, providing detailed information of children’s behavior during therapy. This public release of the dataset comprises body motion, head position and orientation, and eye gaze variables, all specified as 3D data in a joint frame of reference. In addition, metadata including participant age, gender, and autism diagnosis (ADOS) variables are included. We release this data with the hope of supporting further data-driven studies towards improved therapy methods as well as a better understanding of ASD in general.CC BY 4.0DREAM - Development of robot-enhanced therapy for children with autism spectrum disorders