51 research outputs found

    Preparation and Solid-state Structural, Electronic, and Magnetic Properties of the 5-Cyano-1,3-benzene-Bridged Bis(1,2,3,5-dithiadiazolyl) and Bis(1,2,3,5-diselenadiazolyl) [5-CN-1,3-C6H3(CN2E2)2] (E = S, Se)

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    The preparation and solid-state characterization of the bifunctional radicals [4,4’-(5-cyanobenzene)-1,3-bis(1,2,3,5-dithiadiazolyl)] and [4,4’-(5-cyanobenzene)-1,3-bis( 1,2,3,5-diselenadiazolyl)] [5-CN-1,3-C6H3(CN2E2)2] (E = S, Se) are described. The crystals of the two title compounds are isomorphous and belong to the monoclinic space group P21/c, with (for E = S) a = 7.00(2), b = 30.050(6), c = 10.713(8) Å, β = 104.80(10)°, V = 2179(6) Å3, Z = 8 and (for E = Se) a = 7.124(4), b = 30.50(2), c = 10.874(2) Å, β = 105.46(3)°, V = 2277(2) Å3, Z = 8. The crystal structures consist of stacks of diradicals running parallel to x; radical dimerization up and down the stack generates a zigzag arrangement, as seen in the related 1,3-phenylene structures. Along the stacking axis the mean intradimer E-E contacts are 3.12 (E = S) and 3.23 Å (E = Se), while the mean interdimer E- - -E distances are 3.89 (E = S) and 3.91 Å (E = Se). Magnetic and conductivity data are presented and discussed in light of extended Hückel band structure calculations

    Molecular Conductors from Neutral-Radical Charge-Transfer Salts:Preparation and Characterization of an Iodine-Doped Hexagonal Phase of 1,2,3,5-Dithiadiazolyl ([HCN2S2]∙)

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    Sublimation of 1,2,3,5-dithiadiazolyl in vacuo affords a triclinic phase of the dimer [HCN2S2]2. The crystals belong to the space group P¯1, a = 6.816(3), b = 13.940(2), c = 14.403(3) Å, α = 116.830(14), β = 98.64(3), γ = 99.18(3)°, FW = 212.4 (for [HCN2S2]2·[N2]0.08) Z = 6. The crystal structure consists of stacked dimers, with three dimers per asymmetric unit. Pairs of asymmetric units, related by an inversion center, generate a pinwheel motif consisting of six dimers. The columnar structure associated with these pinwheels forms close-packed sets of “molecular tubes”. Cosublimation of the radical in the presence of iodine in the mole ratio (HCN2S2:I = 5:1) yields an iodine-doped hexagonal phase of composition [HCN2S2]6[I]1.1. Crystals of this material belong to the space group P61, a = b = 14.132(16), c = 3.352(5) Å, FW = 128.20, Z = 6. The crystal structure consists of sixfold pinwheels in which the now evenly spaced HCN2S2 rings form a spiral about the 61 axis. The iodine atoms lie within the columnar cavity of the pinwheels in a disordered array wrapped tightly about the sixfold screw axis. The single-crystal conductivity of the doped material is 15 S cm-1 at room temperature. Raman spectroscopic and magnetic susceptibility measurements on the doped material are reported

    Whole-genome sequencing reveals host factors underlying critical COVID-19

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    Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

    Silicon-29 NMR data of C24H33P3Si3

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    Preparation and Solid-state Structures of (Cyanophenyl)dithia- and (Cyanophenyl)diselenadiazolyl Radicals

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    The preparation and solid-state characterization of the dimers of the cyanophenyl-substituted 1,2,3,5-dithia- and 1,2,3,5-diselenadiazolyl radicals [NCC6H4CN2E2]· (E = S, Se) are described. Crystals of the 4-cyanophenyl derivatives 4 are triclinic, space group P¯1. The radicals dimerize in a cofacial fashion, with mean intradimer E- - -E spacings of 3.104/3.233 Å (E = S/Se). The dimer units form ribbonlike arrays connected by head-to-tail CN- - -E contacts. The ribbons are packed in an antiparallel fashion with no close interdimer E- - -E contacts. The 3-cyanophenyl sulfur derivative 5 crystallizes in two phases. The α-phase, along with the isomorphous selenium compound, belongs to the monoclinic space group P21/n. As in the 4-cyano derivatives, the radicals dimerize cofacially, generating ribbons connected by head-to-tail CN- - -E contacts. The ribbons, however, are layered with CN2E2 rings oriented into stacks parallel to the a axis. In addition to short intradimer E- - -E contacts (mean values = 3.13 (2)/3.27 (4) Å for E = S/Se), there are relatively short interdimer E- - -E contacts (mean values = 4.26 (5)/4.15 (5) Å (E = S/Se) along the stacking axis. The β-phase of the 3-cyanophenyl sulfur compound 5, monoclinic space group P21/n, forms discrete dimers associated in a trans antarafacial fashion, with intradimer S- - -S contacts of 3.121 (1) Å; there are no close interdimer S- - -S contacts. The 2-cyanophenyl selenium derivative 6 crystallizes in the polar space group P21. In this structure also the dimer units are laced together by short CN- - -Se contacts. The dimers form stacks parallel to the b axis, with mean intradimer and interdimer Se- - -Se contacts of 3.312/4.083 Å, respectively. Lattice constants for the six structures are: 4 (E = S), C8H4N3S2, a = 10.466 (3) Å, b = 10.342 (2) Å, c = 9.169 (2) Å, α = 104.97 (2)°, β = 112.97 (2)°, γ = 69.84 (2)°, V = 849.0 (3) Å3, Z = 4; 4 (E = Se), C8H4N3Se2, a = 10.478 (4) Å, b = 10.780 (4) Å, c = 9.432 (4) Å, α = 107.16 (3)°, β = 115.23 (2)°, γ = 68.39 (3)°, V = 883.8 (6) Å3, Z = 4; 5 (E = S, α-phase), C8H4N3S2, a = 7.295 (3) Å, b = 20.488 (2) Å, c = 11.276 (2) Å, β = 95.54 (2)°, V = 1676.0 (7) Å3, Z = 8; 5 (E = Se), C8H4N3Se2, a = 7.364 (8) Å, b = 21.085 (2) Å, c = 11.119 (4) Å, β = 94.91 (5)°, V = 1720 (7) Å3, Z = 8; 5 (E = S, β-phase), C8H4N3S2, a = 8.782 (1) Å, b = 5.638 (1) Å, c = 17.128 (4) Å, β = 102.94 (2)°, V = 826.5 (6) Å3, Z = 4; 6 (E = Se), C8H4N3Se2, a = 7.301 (1) Å, b = 11.883 (2) Å, c = 10.186 (1) Å, β = 101.50 (1)°, V = 866.1 (5) Å3, Z = 4.

    Tissue scar formation after transmyocardial laser revascularization

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    Journal of Cardiovascular Surgery413517-518JCVS

    Polymorphism of 1,3-Phenylene Bis(diselenadiazolyl). Solid-State Structural and Electronic Properties of β-1,3-[(Se2N2C)C6H4(CN2Se2)]

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    The solid-state characterization of a second or β-phase of the 1,3-phenylene-bridged diselenadiazolyl diradical 1,3-[(Se2N2C)C6H4(CN2Se2)] is reported. Crystals of this β-phase are monoclinic, space group P21/n, with a = 9.108 (6), b = 15.233 (13), c = 16.110 (5) Å, β = 103.37 (5)°, Z = 8. The crystal structure consists of chain-like arrays of discrete dimers (4 per unit cell), although one intradimer Se-Se linkage is notably longer (3.411 Å) than the other three (3.125, 3.196, 3.204 Å). The dimer units lie in chains that are linked by a complex three-dimensional array of Se-Se contacts. Variable-temperature single-crystal conductivity measurements on this phase indicate a band gap of 0.77 eV. Consistent with the conductivity measurements, extended Hückel band structure calculations suggest a relatively isotropic electronic structure.
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