Metastable Se6 as a ligand for Ag+: from isolated molecular to polymeric 1D and 2D structures

Attempts to prepare the hitherto unknown Se6 2+ cation by the reaction of elemental selenium and Ag[A] ([A]- = [Sb(OTeF5)6]-, [Al(OC(CF3)3)4]-) in SO2 led to the formation of [(OSO)Ag(Se6)Ag(OSO)][Sb(OTeF5)6]2 1 and [(OSO)2Ag(Se6)Ag(OSO)2][Al(OC(CF3)3)4]2 2a. 1 could only be prepared by using bromine as co-oxidant, however, bulk 2b (2a with loss of SO2) was accessible from Ag[Al(OC(CF3)3)4] and grey Se in SO2 (chem. analysis). The reactions of Ag[MF6] (M= As, Sb) and elemental selenium led to crystals of 1/∞{[Ag(Se6)]∞[Ag2(SbF6)3]∞} 3 and {1/∞[Ag(Se6)Ag]∞}[AsF6]2 4. Pure bulk 4 was best prepared by the reaction of Se4[AsF6]2, silver metal and elemental selenium. Attempts to prepare bulk 1 and 3 were unsuccessful. 1–4 were characterized by single-crystal X-ray structure determinations, 2b and 4 additionally by chemical analysis and 4 also by X-ray powder diffraction, FT-Raman and FT-IR pectroscopy. Application of the PRESTO III sequence allowed for the first time 109Ag MAS NMR investigations of 4 as well as AgF, AgF2, AgMF6 and {1/∞[Ag(I2)]∞}[MF6] (M= As, Sb). Compounds 1 and 2a/b, with the very large counter ions, contain isolated [Ag(Se6)Ag]2+ heterocubane units consisting of a Se6 molecule bicapped by two silver cations (local D3d sym). 3 and 4, with the smaller anions, contain close packed stacked arrays of Se6 rings with Ag+ residing in octahedral holes. Each Ag+ ion coordinates to three selenium atoms of each adjacent Se6 ring. 4 contains [Ag(Se6)+]∞ stacks additionally linked by Ag(2)+ into a two dimensional network. 3 features a remarkable 3-dimensional [Ag2(SbF6)3]- anion held together by strong Sb–F … Ag contacts between the component Ag+ and [SbF6]- ions. The hexagonal channels formed by the [Ag2(SbF6)3]- anions are filled by stacks of [Ag(Se6)+]∞ cations. Overall 1–4 are new members of the rare class of metal complexes of neutral main group elemental clusters, in which the main group element is positively polarized due to coordination to a metal ion. Notably, 1 to 4 include the commonly metastable Se6 molecule as a ligand. The structure, bonding and thermodynamics of 1 to 4 were investigated with the help of quantum chemical calculations (PBE0/TZVPP and (RI-)MP2/TZVPP, in part including COSMO solvation) and Born–Fajans–Haber-cycle calculations. From an analysis of all the available data it appears that the formation of the usually metastable Se6 molecule from grey selenium is thermodynamically driven by the coordination to the Ag+ ions

Population-based prevalence of cervical infection with human papillomavirus genotypes 16 and 18 and other high risk types in Tlaxcala, Mexico

This study was supported by the National Institute of Public Health of Mexico, the Coordinación de Investigación en Salud del Instituto Mexicano del Seguro Social, the Secretaría de Salud Tlaxcala, the Instituto Nacional de las Mujeres, and the Consejo Nacional de Ciencia y Tecnología [FOSISS 2013 202468]. Additional support has been provided by Roche Diagnostics, BD Diagnostics, DICIPA and Arbor Vita Corporation. The study sponsors did not played a role in designing the study, collecting, analyzing or interpreting the data, writing the report, or submitting this paper for publication. UC Berkeley Center for Global Public Health, Schoeneman Grant, Joint Medical Program Thesis Grant, and Cancer Research UK (C569/A10404)

Analysis of shared heritability in common disorders of the brain

ience, this issue p. eaap8757 Structured Abstract INTRODUCTION Brain disorders may exhibit shared symptoms and substantial epidemiological comorbidity, inciting debate about their etiologic overlap. However, detailed study of phenotypes with different ages of onset, severity, and presentation poses a considerable challenge. Recently developed heritability methods allow us to accurately measure correlation of genome-wide common variant risk between two phenotypes from pools of different individuals and assess how connected they, or at least their genetic risks, are on the genomic level. We used genome-wide association data for 265,218 patients and 784,643 control participants, as well as 17 phenotypes from a total of 1,191,588 individuals, to quantify the degree of overlap for genetic risk factors of 25 common brain disorders. RATIONALE Over the past century, the classification of brain disorders has evolved to reflect the medical and scientific communities' assessments of the presumed root causes of clinical phenomena such as behavioral change, loss of motor function, or alterations of consciousness. Directly observable phenomena (such as the presence of emboli, protein tangles, or unusual electrical activity patterns) generally define and separate neurological disorders from psychiatric disorders. Understanding the genetic underpinnings and categorical distinctions for brain disorders and related phenotypes may inform the search for their biological mechanisms. RESULTS Common variant risk for psychiatric disorders was shown to correlate significantly, especially among attention deficit hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder (MDD), and schizophrenia. By contrast, neurological disorders appear more distinct from one another and from the psychiatric disorders, except for migraine, which was significantly correlated to ADHD, MDD, and Tourette syndrome. We demonstrate that, in the general population, the personality trait neuroticism is significantly correlated with almost every psychiatric disorder and migraine. We also identify significant genetic sharing between disorders and early life cognitive measures (e.g., years of education and college attainment) in the general population, demonstrating positive correlation with several psychiatric disorders (e.g., anorexia nervosa and bipolar disorder) and negative correlation with several neurological phenotypes (e.g., Alzheimer's disease and ischemic stroke), even though the latter are considered to result from specific processes that occur later in life. Extensive simulations were also performed to inform how statistical power, diagnostic misclassification, and phenotypic heterogeneity influence genetic correlations. CONCLUSION The high degree of genetic correlation among many of the psychiatric disorders adds further evidence that their current clinical boundaries do not reflect distinct underlying pathogenic processes, at least on the genetic level. This suggests a deeply interconnected nature for psychiatric disorders, in contrast to neurological disorders, and underscores the need to refine psychiatric diagnostics. Genetically informed analyses may provide important "scaffolding" to support such restructuring of psychiatric nosology, which likely requires incorporating many levels of information. By contrast, we find limited evidence for widespread common genetic risk sharing among neurological disorders or across neurological and psychiatric disorders. We show that both psychiatric and neurological disorders have robust correlations with cognitive and personality measures. Further study is needed to evaluate whether overlapping genetic contributions to psychiatric pathology may influence treatment choices. Ultimately, such developments may pave the way toward reduced heterogeneity and improved diagnosis and treatment of psychiatric disorders

Preparation and properties of nitrogen oxide trifluoride

Nitrogen oxide trifluoride was prepared in trace quantities by the reaction of nitric oxide and fluorine. Low, but improved yields were obtained when nitrosyl fluoride and fluorine were heated together at 220°. It was found that (NO)₂2NiF₆ was formed by the reaction of the walls of the Monel reaction vessels, with nitrosyl fluoride, and fluorine, and that pyrolysis of this salt (in 70 p.s.i. fluorine at 350°) gave the new compound in good yield. The reactions of platinum and iridium hexafluoride with nitrosyl fluoride were investigated as routes to ONF₃. Nitrogen oxide trifluoride was colourless in the solid, liquid, and gaseous phases, melting at -161° and boiling at -87.5°. The vapour pressure was determined over the range -128° to -78°. The empirical formula was established by elemental analysis, and by determination of its molecular weight. The structural formula ONF₃ was established from the ¹⁹F n.m.r., and the infrared spectrum of the compound. Nitrogen oxide trifluoride was found to be only moderately reactive. There was no evidence that ONF₃ could be protonated by strong acids. A 1:1 adduct was formed with AsF₅. The chemical behaviour and infrared spectrum of ONF3,AsF₅ was consistent with the formulation ONF₂⁺AsF₆⁻. The empirical formula of (NO)₂^NiF₆ was established by elemental analysis. Its infrared spectrum, and magnetic susceptibility showed that it contained the (NO)⁺ and (NiF₆)²⁻ ions, and a low spin d⁶ arrangement for Ni(IV). The X-ray powder diffraction patterns of (NO)₂NiF₆ could be indexed on the basis of a hexagonal unit cell a = 5.524 Å, c = 5.097 Å, except for five diffuse lines that varied in intensity from sample to sample. Weissenberg (h k 0, h k 1,h k 2, h k 3) photographs showed two sets of reflections. One sharp strong set that could be indexed on the basis of the same hexagonal cell as the lines of the powder photograph, and a weak diffuse set of reflections that together with the strong reflections could be indexed on the hexagonal unit cell, a = 4x5.524, c = 5.097 Å. A structure determination was carried out using the strong sharp set of reflections. The diffraction data were consistent with various models, but the most likely model consisted of (NiF₆)²⁻ groups with the fluorine atoms in a regular octahedron around the nickel atom and the Ni-F bond distance equal to 1.76 Å. The N-O bond distance was very short, 0.88Å, and had associated with it regions of electron density normal to the axis defined by the nitrogen and oxygen atoms. A similar situation for the O2⁺ ion in O₂PtF₆ was reported by Ibers and Hamilton.(108) At 200° chlorine pentafluoride and iridium hexafluoride reacted to give small quantities of a yellow compound which was characterised as ClF₂⁺IrF₆⁻ from elemental analysis, magnetic susceptibility measurements, and its infrared spectrum. A structural determination was attempted from single crystal X-ray data. Preliminary results suggest that the iridium atoms form an ab face centred array, and the chlorine atoms are situated almost in the centre of the square pyramidal holes defined by the iridium atoms.Arts, Faculty ofPhilosophy, Department ofGraduat

Preference of npp-npp Bonding (n = 3, 4) over Purely s-Bonded Species in M42+ (M = S, Se): Geometries, Bonding, and Energetics of Several M42+ Isomers

The dimerization energies of 2M2+ to give M42+ (M = S, Se) were calcd. as input into thermodn. Born-Fajans-Haber cycle calcns. to det. the relative stabilities of salts of these mono- and dications in the solid state. Computed dimerization energies showed a strong dependence on the basis set and correlated method utilized. Coupled cluster calcns., compd. methods or hybrid HF/DFT methods employing large basis sets [CCSD(T)/cc-pV5Z, CBS-Q or B3PW91/6-311+G(3df)//B3PW91/6-311+G*] had to be used and showed an av. dimerization energy of 258 (199) kJ/mol for S (Se). Square planar M42+ (M = S, Se) was fully optimized (B3LYP, B3PW91), and the calcd. vibrational spectra of M42+ were then compared to averaged exptl. data to derive scaling factors. The structure, bonding, and energetics of 7 starting geometries of the M42+ (M = S, Se) dication were computed (B3PW91), as well as AIM and NBO analyses of these species. The global min. of the examd. S (Se) species is the planar, 6p-arom. D4h sym. square, which is 76 (106) and 155 (115) kJ/mol more stable than a D2h sym. p*-p*-bonded rectangular (S2+)2 [(Se2+)2] dimer and a classical, s-bonded, butterfly-shaped isomer, resp. This supports the thesis that the obsd. geometries of the homopolyat. cations of groups 16 and 17 and related species maximize pos. charge delocalization, resulting in thermodynamically stable npp-npp (n >= 3) and p*-p* bonds. The formation of chain-like (Te42+)n, polymeric Te84+, and square planar Te42+ is accounted for semiquant. The published, exptl. enthalpy of formation of gaseous S4+ (1131 kJ/mol) was computationally shown to be due to a fragmentation of S6 to give S4+ and S2, confirming earlier photoionization studies. An enthalpy of formation of 972 kJ/mol was then established for the gaseous S4+ cation, 159 kJ/mol lower than the erroneously assigned published exptl. value. [on SciFinder (R)

Evidence for the Blue 10p S62+ Dication in Solutions of S8(AsF6)2: A Computational Study Including Solvation Energies

The energetics of dissocn. reactions of S82+ into stoichiometric mixts. of Sn+, n = 2-7, and Sm2+, m = 3, 4, 6, 10, were investigated by the B3PW91 method [6-311+G(3df)//6-311+G*] in the gas phase and in soln., with solvation energies calcd. using the SCIPCM model and in some cases also the COSMO model [B3PW91/6-311+G*, dielec. consts. 2-30, 83, 110]. UV-vis spectra of all species were calcd. at the CIS/6-311G(2df) level and for S42+ and S62+ also at the TD-DFT level (BP86/SV(P)). Std. enthalpies of formation at 298 K were derived for S32+ (2538 kJ/mol), S62+ (2238 kJ/mol), and S102+ (2146 kJ/mol). A comparison of the obsd. and calcd. UV-vis spectra based on our calcd. thermochem. data in soln. suggests that, in the absence of traces of facilitating agent (such as dibromine Br2), S82+ dissocs. in dil. SO2 soln. giving an equil. mixt. of ca. 0.5S62+ and S5+ (K ~ 8.0) while in the more polar HSO3F some S82+ remains (K ~ 0.4). According to our calcns., the blue color of this soln. is likely due to the p*-p* transition of the previously unknown 10p S62+ dication, and the previously assigned S5+ is a less important contributor. Although not strictly planar, S62+ may be viewed as a 10p electron Huckel-arom. ring contg. a thermodynamically stable 3pp-3pp bond [d(S-S) = 2.028 .ANG.; t(S-S-S-S) = 47.6 Deg]. The computations imply that the new radical cation S4+ may be present in sulfur dioxide solns. given on reaction of sulfur oxidized by AsF5 in the presence of a facilitating agent. The std. enthalpy of formation of S6(AsF6)2(s) was estd. as -3103 kJ/mol, and the disproportionation enthalpy of 2S6(AsF6)2(s) to S8(AsF6)2(s) and S4(AsF6)2(s) as exothermic by 6-17 kJ/mol. The final preference of the obsd. disproportionation products is due to the inclusion of solvent mols., e.g., AsF3, that addnl. favors the disproportionation of 2S6(AsF6)2(s) into S8(AsF6)2(s) and S4(AsF6)2(AsF3)(s) by 144 kJ/mol. [on SciFinder (R)