130 research outputs found
A New Pseudopolymorph of Hexakis-(4-cynaophenyl)benzene
The title compound (systematic name: benzene-4,4′,4′′,4′′′,-4′′′′,4′′′′′-hexaylhexabenzonitrile dichloromethane disolvate), C48H24N6•2CH2Cl2, crystallizes as an inclusion compound during the slow diffusion of methanol into a solution of hexakis(4-cyanophenyl)benzene in CH2Cl2. The hexakis(4- cyanophenyl)benzene molecule lies on an axis of twofold rotation in the space group Pbcn. Weak C—H•••N interactions between hexakis(4-cyanophenyl)benzene molecules define an open network with space for including guests. The resulting structure is a new pseudopolymorph of hexakis-(4-cyanophenyl)benzene. The eight known pseudopolymorphs have few shared architectural features, in part because none of the intermolecular interactions that are present plays a dominant role or forces neighboring molecules to assume particular relative orientations
Coordination to a di-tert-butylphosphidoboratabenzene ligand with electronically unsaturated group 10 transition metals
A new boratabenzene-phosphine ligand, di-tert-butylphosphidoboratabenzene, [DTBB]−, has successfully been synthesized by reduction of the corresponding di-tert-butylchlorophosphidoborabenzene compound (2). The species was structurally characterized with both K+ (3) and 18-crown-6·K+ (4) as counterions. Reactions of two equivalents of di-tert-butylphosphidoboratabenzene with NiBr2(PPh3)2, PtCl2, and PtCl2(COD) were undertaken and were successful in yielding three new organometallic boratabenzene species, (μ-κ-η6-C5H5BP(tBu)2)2Ni2 (5), (η3-(C,B,P)-C5H5BP(tBu)2)2Pt (6), and (η3-(C,B,P)-C5H5BP(tBu)2)(κ-C8H12(P(tBu)2BC5H5)Pt (7), respectively. The di-tert-butylphosphidoboratabenzene species displays a remarkable tendency to coordinate to transition metal species in two distinct modes closely associated with other reported boratabenzene and allyl-like interactions. Also of interest is the ability for di-tert-butylphosphidoboratabenzene to be able to coordinate within monomeric as well as dimeric transition metal compounds. The synthesis and characterization will be discussed in detail along with DFT calculations in order to validate these research findings
trans-Dichloridobis[(pyridin-4-yl)boronic acid-κN]palladium(II) dimethyl sulfoxide disolvate
In the title compound, [PdCl2(C5H6BNO2)2]·2C2H6OS, the PdII ion is located on an inversion centre and is four-coordinated in a trans square-planar geometry by two chloride ions and two (pyridin-4-yl)boronic acid ligands. The Pd—N and Pd—Cl distances are 2.023 (2) and 2.2977 (7) Å, respectively, and the average N—Pd—Cl angle is 90°. The dimethyl sulfoxide solvent molecules play a key role in the crystal structure by bridging the complex molecules via O—H⋯O hydrogen bonds, forming tapes running along the b axis. C—H⋯O interactions also contribute to the cohesion of the crystal
fac-Triaqua(1,10-phenanthroline-κ2 N,N′)(sulfato-κO)cobalt(II): crystal structure, Hirshfeld surface analysis and computational study
Dicyclohexylammonium hydrogen phenylphosphonate
In the title salt, [(C6H11)2NH2]+·[C6H5PO2(OH)]−, the anion is monodeprotonated and acts as both a hydrogen-bond donor and acceptor. The anions are linked by pairs of O—H⋯O interactions, forming inversion dimers with R
2
2(8) ring motifs. These dimers are bridged by two dicyclohexylaminium cations via pairs of N—H⋯O hydrogen bonds, giving R
4
4(12) ring motifs, forming chains propagating along [010]. The chains are bridged by C—H⋯O interactions, forming a two-dimensional network lying parallel to (101)
Unconventional field induced phases in a quantum magnet formed by free radical tetramers
We report experimental and theoretical studies on the magnetic and
thermodynamic properties of NIT-2Py, a free radical-based organic magnet. From
magnetization and specific heat measurements we establish the temperature
versus magnetic field phase diagram which includes two Bose-Einstein
condensates (BEC) and an infrequent half magnetization plateau. Calculations
based on density functional theory demonstrates that magnetically this system
can be mapped to a quasi-two-dimensional structure of weakly coupled tetramers.
Density matrix renormalization group calculations show the unusual
characteristics of the BECs where the spins forming the low-field condensate
are different than those participating in the high-field one.Comment: 12 pages, 12 figure
On the interaction of acetone with electrophilic metallocavitands having extended cavities
We report the synthesis and characterization of tantalum–boronate trimetallic clusters of general formula {[Cp*Ta]3(μ2-RB(O)2)3(μ2-OH)(μ2-O)2(μ3-OH)} (R= 4-(C6H5)(C6H4) (Ta3-4Ph), 4-(C6H5O)(C6H4) (Ta3-4OPh), 4-(C7H7O)(C6H4) (Ta3-4OBn), 4-(C8H5)(C6H4) (Ta3-4PhEt), and 4-(C12H7)(C6H4) (Ta3-4Napht)). All complexes have been characterized by NMR spectroscopy and X-ray diffraction. The trimetallic species feature a large Lewis acid type cavity allowing for substrate binding in both the solid and the liquid state using a unique electrostatic interaction and a hydrogen bond. ΔH° and ΔS° values for association of acetone with the complexes vary between −2.0 and −4.1 kcal·mol–1 and −3 and 2 cal·mol–1·K–1, respectively, showing weaker binding than smaller cavitands of the same type. The barrier for acetone exchange at equilibrium is similar for all complexes, and ΔH‡ values vary between 8.2 and 11.4 kcal·mol–1
In-flight calibration and verification of the Planck-LFI instrument
In this paper we discuss the Planck-LFI in-flight calibration campaign. After
a brief overview of the ground test campaigns, we describe in detail the
calibration and performance verification (CPV) phase, carried out in space
during and just after the cool-down of LFI. We discuss in detail the
functionality verification, the tuning of the front-end and warm electronics,
the preliminary performance assessment and the thermal susceptibility tests.
The logic, sequence, goals and results of the in-flight tests are discussed.
All the calibration activities were successfully carried out and the instrument
response was comparable to the one observed on ground. For some channels the
in-flight tuning activity allowed us to improve significantly the noise
performance.Comment: Long technical paper on Planck LFI in flight calibration campaign:
109 pages in this (not final) version, 100 page in the final JINST versio
Electrophysiological dynamics of Chinese phonology during visual word recognition in Chinese-English bilinguals
Silent word reading leads to the activation of orthographic (spelling), meaning, as well as phonological (sound) information. For bilinguals, native language information can also be activated automatically when they read words in their second language. For example, when Chinese-English bilinguals read words in their second language (English), the phonology of the Chinese translations is automatically activated. Chinese phonology, however, consists of consonants and vowels (segmental) and tonal information. To what extent these two aspects of Chinese phonology are activated is yet unclear. Here, we used behavioural measures, event-related potentials and oscillatory EEG to investigate Chinese segmental and tonal activation during word recognition. Evidence of Chinese segmental activation was found when bilinguals read English words (faster responses, reduced N400, gamma-band power reduction) and when they read Chinese words (increased LPC, gamma-band power reduction). In contrast, evidence for Chinese tonal activation was only found when bilinguals read Chinese words (gamma-band power increase). Together, our converging behavioural and electrophysiological evidence indicates that Chinese segmental information is activated during English word reading, whereas both segmental and tonal information are activated during Chinese word reading. Importantly, gamma-band oscillations are modulated differently by tonal and segmental activation, suggesting independent processing of Chinese tones and segments
Forensic mental health in Europe: some key figures
Purpose. While the number of forensic beds and the duration of psychiatric forensic psychiatric treatment have increased in several European Union (EU) states, this is not observed in others. Patient demographics, average lengths of stay and legal frameworks also differ substantially. The lack of basic epidemiological information on forensic patients and of shared indicators on forensic care within Europe is an obstacle to comparative research. The reasons for such variation are not well understood. Methods. Experts from seventeen EU states submitted data on forensic bed prevalence rates, gender distributions and average length of stay in forensic in-patient facilities. Average length of stay and bed prevalence rates were examined for associations with country-level variables including Gross Domestic Product (GDP), expenditure on healthcare, prison population, general psychiatric bed prevalence rates and democracy index scores. Results. The data demonstrated substantial differences between states. Average length of stay was approximately ten times greater in the Netherlands than Slovenia. In England and Wales, 18% of patients were female compared to 5% in Slovenia. There was a 17-fold difference in forensic bed rates per 100,000 between the Netherlands and Spain. Exploratory analyses suggested average length of stay was associated with GDP, expenditure on healthcare and democracy index scores. Conclusion. The data presented in this study represent the most recent overview of key epidemiological data in forensic services across seventeen EU states. However, systematically collected epidemiological data of good quality remain elusive in forensic psychiatry. States need to develop common definitions and recording practices and contribute to a publicly available database of such epidemiological indicators
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