surface

Crystal structure, Hirshfeld surface analysis and inter­action energy and DFT studies of 2-(2,3-di­hydro-1H-perimidin-2-yl)-6-meth­oxy­phenol

The title compound, C18H16N2O2, consists of perimidine and meth­oxy­phenol units, where the tricyclic perimidine unit contains a naphthalene ring system and a non-planar C4N2 ring adopting an envelope conformation with the NCN group hinged by 47.44 (7)° with respect to the best plane of the other five atoms. In the crystal, O—HPhnl⋯NPrmdn and N—HPrmdn⋯OPhnl (Phnl = phenol and Prmdn = perimidine) hydrogen bonds link the mol­ecules into infinite chains along the b-axis direction. Weak C—H⋯π inter­actions may further stabilize the crystal structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (49.0%), H⋯C/C⋯H (35.8%) and H⋯O/O⋯H (12.0%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Computational chemistry indicates that in the crystal, the O—HPhnl⋯NPrmdn and N—HPrmdn⋯OPhnl hydrogen-bond energies are 58.4 and 38.0 kJ mol−1, respectively. Density functional theory (DFT) optimized structures at the B3LYP/ 6–311 G(d,p) level are compared with the experimentally determined mol­ecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.




surface

Crystal structure and Hirshfeld surface analysis of hexyl 1-hexyl-2-oxo-1,2-di­hydro­quinoline-4-carboxyl­ate

The asymmetric unit of the title compound, C22H31NO3, comprises of one mol­ecule. The mol­ecule is not planar, with the carboxyl­ate ester group inclined by 33.47 (4)° to the heterocyclic ring. Individual mol­ecules are linked by aromaticC—H⋯Ocarbon­yl hydrogen bonds into chains running parallel to [001]. Slipped π–π stacking inter­actions between quinoline moieties link these chains into layers extending parallel to (100). Hirshfeld surface analysis, two-dimensional fingerprint plots and mol­ecular electrostatic potential surfaces were used to qu­antify the inter­molecular inter­actions present in the crystal, indicating that the most important contributions for the crystal packing are from H⋯H (72%), O⋯H/H⋯O (14.5%) and C⋯H/H⋯C (5.6%) inter­actions.




surface

Synthesis, crystal structure, DFT calculations and Hirshfeld surface analysis of 3-butyl-2,6-bis­(4-fluoro­phen­yl)piperidin-4-one

The title compound, C21H23F2NO, consists of two fluoro­phenyl groups and one butyl group equatorially oriented on a piperidine ring, which adopts a chair conformation. The dihedral angle between the mean planes of the phenyl rings is 72.1 (1)°. In the crystal, N—H⋯O and weak C—H⋯F inter­actions, which form R22[14] motifs, link the mol­ecules into infinite C(6) chains propagating along [001]. A weak C—H⋯π inter­action is also observed. A Hirshfeld surface analysis of the crystal structure indicates that the most significant contributions to the crystal packing are from H⋯H (53.3%), H⋯C/C⋯H (19.1%), H⋯F/F⋯H (15.7%) and H⋯O/O⋯H (7.7%) contacts. Density functional theory geometry-optimized calculations were compared to the experimentally determined structure in the solid state and used to determine the HOMO–LUMO energy gap and compare it to the UV–vis experimental spectrum.




surface

2-[(2,4,6-Tri­methyl­benzene)­sulfon­yl]phthalazin-1(2H)-one: crystal structure, Hirshfeld surface analysis and computational study

The X-ray crystal structure of the title phthalazin-1-one derivative, C17H16N2O3S {systematic name: 2-[(2,4,6-tri­methyl­benzene)­sulfon­yl]-1,2-di­hydro­phthalazin-1-one}, features a tetra­hedral sulfoxide-S atom, connected to phthalazin-1-one and mesityl residues. The dihedral angle [83.26 (4)°] between the organic substituents is consistent with the mol­ecule having the shape of the letter V. In the crystal, phthalazinone-C6-C—H⋯O(sulfoxide) and π(phthalazinone-N2C4)–π(phthalazinone-C6) stacking [inter-centroid distance = 3.5474 (9) Å] contacts lead to a linear supra­molecular tape along the a-axis direction; tapes assemble without directional inter­actions between them. The analysis of the calculated Hirshfeld surfaces confirm the importance of the C—H⋯O and π-stacking inter­actions but, also H⋯H and C—H⋯C contacts. The calculation of the inter­action energies indicate the importance of dispersion terms with the greatest energies calculated for the C—H⋯O and π-stacking inter­actions.




surface

Crystal structure, Hirshfeld surface analysis and DFT studies of 6-bromo-3-(12-bromo­dodec­yl)-2-(4-nitro­phen­yl)-4H-imidazo[4,5-b]pyridine

The title compound, C24H30Br2N4O2, consists of a 2-(4-nitro­phen­yl)-4H-imidazo[4,5-b]pyridine entity with a 12-bromo­dodecyl substituent attached to the pyridine N atom. The middle eight-carbon portion of the side chain is planar to within 0.09 (1) Å and makes a dihedral angle of 21.9 (8)° with the mean plane of the imidazolo­pyridine moiety, giving the mol­ecule a V-shape. In the crystal, the imidazolo­pyridine units are associated through slipped π–π stacking inter­actions together with weak C—HPyr⋯ONtr and C—HBrmdc­yl⋯ONtr (Pyr = pyridine, Ntr = nitro and Brmdcyl = bromo­dodec­yl) hydrogen bonds. The 12-bromo­dodecyl chains overlap with each other between the stacks. The terminal –CH2Br group of the side chain shows disorder over two resolved sites in a 0.902 (3):0.098 (3) ratio. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯H (48.1%), H⋯Br/Br⋯H (15.0%) and H⋯O/O⋯H (12.8%) inter­actions. The optimized mol­ecular structure, using density functional theory at the B3LYP/ 6–311 G(d,p) level, is compared with the experimentally determined structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.




surface

Crystal structure and Hirshfeld surface analysis of 2-phenyl-1H-phenanthro[9,10-d]imidazol-3-ium benzoate

In the title compound, C21H15N2+·C7H5O2−, 2-phenyl-1H-phenanthro[9,10-d]imidazole and benzoic acid form an ion pair complex. The system is consolidated by hydrogen bonds along with π–π inter­actions and N—H⋯π inter­actions between the constituent units. For a better understanding of the crystal structure and inter­molecular inter­actions, a Hirshfeld surface analysis was performed.




surface

Crystal structure and Hirshfeld surface analysis of 4-{[(anthracen-9-yl)meth­yl]amino}­benzoic acid di­methyl­formamide monosolvate

The title compound, C22H17NO2·C3H7NO, was synthesized by condensation of an aromatic aldehyde with a secondary amine and subsequent reduction. It was crystallized from a di­methyl­formamide solution as a monosolvate, C22H17NO2·C3H7NO. The aromatic mol­ecule is non-planar with a dihedral angle between the mean planes of the aniline moiety and the methyl anthracene moiety of 81.36 (8)°. The torsion angle of the Car­yl—CH2—NH—Car­yl backbone is 175.9 (2)°. The crystal structure exhibits a three-dimensional supra­molecular network, resulting from hydrogen-bonding inter­actions between the carb­oxy­lic OH group and the solvent O atom as well as between the amine functionality and the O atom of the carb­oxy­lic group and additional C—H⋯π inter­actions. Hirshfeld surface analysis was performed to qu­antify the inter­molecular inter­actions.




surface

Crystal structure and Hirshfeld surface analysis of 6-benzoyl-3,5-di­phenyl­cyclo­hex-2-en-1-one

In the title compound, C25H20O2, the central cyclo­hexenone ring adopts an envelope conformation. The mean plane of the cyclo­hexenone ring makes dihedral angles of 87.66 (11) and 23.76 (12)°, respectively, with the two attached phenyl rings, while it is inclined by 69.55 (11)° to the phenyl ring of the benzoyl group. In the crystal, the mol­ecules are linked by C—H⋯O and C—H⋯π inter­actions, forming a three-dimensional network.




surface

Synthesis, crystal structure and Hirshfeld surface analysis of N-(4-chloro­phen­yl)-5-cyclo­propyl-1-(4-meth­oxy­phen­yl)-1H-1,2,3-triazole-4-carboxamide

The title compound, C19H17ClN4O2, was obtained via a two-step synthesis involving the enol-mediated click Dimroth reaction of 4-azido­anisole with methyl 3-cyclo­propyl-3-oxo­propano­ate leading to the 5-cyclo­propyl-1-(4-meth­oxy­phen­yl)-1H-1,2,3-triazole-4-carb­oxy­lic acid and subsequent acid amidation with 4-chloro­aniline by 1,1'-carbonyl­diimidazole (CDI). It crystallizes in space group P21/n, with one mol­ecule in the asymmetric unit. In the extended structure, two mol­ecules arranged in a near coplanar fashion relative to the triazole ring planes are inter­connected by N—H⋯N and C—H⋯N hydrogen bonds into a homodimer. The formation of dimers is a consequence of the above inter­action and the edge-to-face stacking of aromatic rings, which are turned by 58.0 (3)° relative to each other. The dimers are linked by C—H⋯O inter­actions into ribbons. DFT calculations demonstrate that the frontier mol­ecular orbitals are well separated in energy and the HOMO is largely localized on the 4-chloro­phenyl amide motif while the LUMO is associated with aryl­triazole grouping. A Hirshfeld surface analysis was performed to further analyse the inter­molecular inter­actions.




surface

Compressive strain formation in surface-damaged crystals

The mechanism of formation of residual strain in crystals with a damaged surface has been studied by transmission electron microscopy in GaAs wafers ground with sandpaper. The samples showed a dislocation network located near the sample surface penetrating to a depth of a few micrometres, comparable to the size of abrasive particles used for the treatment, and no other types of defects were observed. A simple model for the formation of a compressive strain induced by the dislocation network in the damaged layer is proposed, in satisfactory agreement with the measured strain. The strain is generated by the formation of dislocation half-loops at the crystal surface, having the same component of the Burgers vectors parallel to the surface of the crystal. This is equivalent to the insertion of extra half-planes from the crystal surface to the depth of the damaged zone. This model can be generalized for other crystal structures. An approximate calculation of the strain generated from the observed dislocation distribution in the sample agrees with the proposed model and permits the conclusion that this mechanism is in general sufficient to explain the observed compressive strain, without the need to consider other types of defects.




surface

Calcium-ligand variants of the myocilin olfactomedin propeller selected from invertebrate phyla reveal cross-talk with N-terminal blade and surface helices

Olfactomedins are a family of modular proteins found in multicellular organisms that all contain five-bladed β-propeller olfactomedin (OLF) domains. In support of differential functions for the OLF propeller, the available crystal structures reveal that only some OLF domains harbor an internal calcium-binding site with ligands derived from a triad of residues. For the myocilin OLF domain (myoc-OLF), ablation of the ion-binding site (triad Asp, Asn, Asp) by altering the coordinating residues affects the stability and overall structure, in one case leading to misfolding and glaucoma. Bioinformatics analysis reveals a variety of triads with possible ion-binding characteristics lurking in OLF domains in invertebrate chordates such as Arthropoda (Asp–Glu–Ser), Nematoda (Asp–Asp–His) and Echinodermata (Asp–Glu–Lys). To test ion binding and to extend the observed connection between ion binding and distal structural rearrangements, consensus triads from these phyla were installed in the myoc-OLF. All three protein variants exhibit wild-type-like or better stability, but their calcium-binding properties differ, concomitant with new structural deviations from wild-type myoc-OLF. Taken together, the results indicate that calcium binding is not intrinsically destabilizing to myoc-OLF or required to observe a well ordered side helix, and that ion binding is a differential feature that may underlie the largely elusive biological function of OLF propellers.




surface

Development of a scanning soft X-ray spectromicroscope to investigate local electronic structures on surfaces and interfaces of advanced materials under conditions ranging from low vacuum to helium atmosphere

A scanning soft X-ray spectromicroscope was recently developed based mainly on the photon-in/photon-out measurement scheme for the investigation of local electronic structures on the surfaces and interfaces of advanced materials under conditions ranging from low vacuum to helium atmosphere. The apparatus was installed at the soft X-ray beamline (BL17SU) at SPring-8. The characteristic features of the apparatus are described in detail. The feasibility of this spectromicroscope was demonstrated using soft X-ray undulator radiation. Here, based on these results, element-specific two-dimensional mapping and micro-XAFS (X-ray absorption fine structure) measurements are reported, as well as the observation of magnetic domain structures from using a reference sample of permalloy micro-dot patterns fabricated on a silicon substrate, with modest spatial resolution (e.g. ∼500 nm). Then, the X-ray radiation dose for Nafion® near the fluorine K-edge is discussed as a typical example of material that is not radiation hardened against a focused X-ray beam, for near future experiments.




surface

Synchrotron X-ray diffraction investigation of the surface condition of artefacts from King Henry VIII's warship the Mary Rose

Synchrotron X-ray diffraction (XRD) measured on the XMaS beamline at the ESRF was used to characterize the alloy composition and crystalline surface corrosion of three copper alloy Tudor artefacts recovered from the undersea wreck of King Henry VIII's warship the Mary Rose. The XRD method adopted has a dynamic range ∼1:105 and allows reflections <0.002% of the height of major reflections in the pattern to be discerned above the background without smoothing. Laboratory XRD, scanning electron microscopy–energy dispersive spectroscopy, synchrotron X-ray fluorescence and X-ray excited optical luminescence–X-ray near-edge absorption structure were used as supporting techniques, and the combination revealed structural and compositional features of importance to both archaeology and conservation. The artefacts were brass links believed to be fragments of chainmail and were excavated from the seabed during 1981 and 1982. Their condition reflects very different treatment just after recovery, viz. complete cleaning and conservation, chemical corrosion inhibition and chloride removal only, and distilled water soaking only (to remove the chlorides). The brass composition has been determined for all three at least in the top 7 µm or so as Cu(73%)Zn(27%) from the lattice constant. Measurement of the peak widths showed significant differences in the crystallite size and microstrain between the three samples. All of the links are found to be almost chloride-free with the main corrosion products being spertiniite, sphalerite, zincite, covellite and chalcocite. The balance of corrosion products between the links reflects the conservation treatment applied to one and points to different corrosion environments for the other two.




surface

Detailed surface analysis of V-defects in GaN films on patterned silicon(111) substrates by metal–organic chemical vapour deposition. Corrigendum

An error in the article by Gao, Zhang, Zhu, Wu, Mo, Pan, Liu & Jiang [J. Appl. Cryst. (2019), 52, 637–642] is corrected.




surface

Takagi–Taupin dynamical X-ray diffraction simulations of asymmetric X-ray diffraction from crystals: the effects of surface undulations

Dynamical X-ray diffraction simulations of very asymmetric diffraction from single crystals of silicon were made to accompany an experimental rocking-curve topography study reported in a seperate paper. Effects on rocking curves were found and are reported. The development of Uragami [(1969), J. Phys. Soc. Jpn, 27, 147–154] for Takagi–Taupin simulations was followed and applied to the case of both convex and concave surface undulations.




surface

Effects of surface undulations on asymmetric X-ray diffraction: a rocking-curve topography study

Very asymmetric crystal diffraction was obtained from a finely polished silicon crystal set to reflect in Bragg diffraction at grazing incidence for the (333) reflection. The angle of incidence to achieve Bragg diffraction was varied between 1.08° and 0.33° by changing the X-ray energy from 8.100 to 8.200 keV. Topographic images obtained as the crystal was rocked were used to identify the effects of surface undulations, and the results are compared with dynamical X-ray diffraction calculations made with the Takagi–Taupin equations specialized to a surface having convex or concave features, as reported in an accompanying paper.




surface

Last seen 140 years ago, deep sea worm resurfaces, delighting scientists

In 2009, during an expedition by a Russian research ship, a small length of yellow flesh about 5 centimeters long was dredged up from the […]

The post Last seen 140 years ago, deep sea worm resurfaces, delighting scientists appeared first on Smithsonian Insider.




surface

Structure of P46, an immunodominant surface protein from Mycoplasma hyopneumoniae: interaction with a monoclonal antibody

Mycoplasma hyopneumoniae is a prokaryotic pathogen that colonizes the respiratory ciliated epithelial cells in swine. Infected animals suffer respiratory lesions, causing major economic losses in the porcine industry. Characterization of the immunodominant membrane-associated proteins from M. hyopneumoniae may be instrumental in the development of new therapeutic approaches. Here, the crystal structure of P46, one of the main surface-antigen proteins, from M. hyopneumoniae is presented and shows N- and C-terminal α/β domains connected by a hinge. The structures solved in this work include a ligand-free open form of P46 (3.1 Å resolution) and two ligand-bound structures of P46 with maltose (2.5 Å resolution) and xylose (3.5 Å resolution) in open and closed conformations, respectively. The ligand-binding site is buried in the cleft between the domains at the hinge region. The two domains of P46 can rotate with respect to each other, giving open or closed alternative conformations. In agreement with this structural information, sequence analyses show similarities to substrate-binding members of the ABC transporter superfamily, with P46 facing the extracellular side as a functional subunit. In the structure with xylose, P46 was also bound to a high-affinity (Kd = 29 nM) Fab fragment from a monoclonal antibody, allowing the characterization of a structural epitope in P46 that exclusively involves residues from the C-terminal domain. The Fab structure in the complex with P46 shows only small conformational rearrangements in the six complementarity-determining regions (CDRs) with respect to the unbound Fab (the structure of which is also determined in this work at 1.95 Å resolution). The structural information that is now available should contribute to a better understanding of sugar nutrient intake by M. hyopneumoniae. This information will also allow the design of protocols and strategies for the generation of new vaccines against this important swine pathogen.




surface

LDL uptake-dependent phosphatidylethanolamine translocation to the cell surface promotes fusion of osteoclast-like cells [RESEARCH ARTICLE]

Victor J. F. Kitano, Yoko Ohyama, Chiyomi Hayashida, Junta Ito, Mari Okayasu, Takuya Sato, Toru Ogasawara, Maki Tsujita, Akemi Kakino, Jun Shimada, Tatsuya Sawamura, and Yoshiyuki Hakeda

Osteoporosis is associated with vessel diseases attributed to hyperlipidemia, and bone resorption by multinucleated osteoclasts is related to lipid metabolism. In this study, we generated low-density lipoprotein receptor (LDLR)/lectin-like oxidized LDL receptor-1 (LOX-1) double knockout (dKO) mice. We found that, like LDLR single KO (sKO), LDLR/LOX-1 dKO impaired cell-cell fusion of osteoclast-like cells (OCLs). LDLR/LOX-1 dKO and LDLR sKO preosteoclasts exhibited decreased uptake of LDL. The cell surface cholesterol levels of both LDLR/LOX-1 dKO and LDLR sKO osteoclasts were lower than the levels of wild-type OCLs. Additionally, the amount of phosphatidylethanolamine (PE) on the cell surface was attenuated in LDLR/LOX-1 dKO and LDLR sKO pre-OCLs, while the PE distribution in wild-type OCLs was concentrated on the filopodia in contact with neighboring cells. Abrogation of the ATP binding cassette G1 (ABCG1) transporter, which transfers PE to the cell surface, caused decreased PE translocation to the cell surface and subsequent cell-cell fusion. The findings of this study indicate the involvement of a novel cascade (LDLR~ABCG1~PE translocation to cell surface~cell-cell fusion) in multinucleation of OCLs.




surface

A hot new island has just surfaced in the Red Sea. What’s going on? Smithsonian scientists explain.

The new island visible in the satellite photograph is the top of a giant shield volcano located on the rift axis in the Red Sea where the continental plates of Africa and Arabia are pulling apart.

The post A hot new island has just surfaced in the Red Sea. What’s going on? Smithsonian scientists explain. appeared first on Smithsonian Insider.




surface

Streams damaged by too many hard surfaces in urban areas

How do you diagnose a sick stream? Count its insects, according to Smithsonian biologist Don Weller.

The post Streams damaged by too many hard surfaces in urban areas appeared first on Smithsonian Insider.




surface

Crystal structure and Hirshfeld surface analysis of 4,4'-(propane-1,3-diyl)bis(4H-1,2,4-triazol-1-ium) penta­fluorido­oxidovanadate(V)

In the structure of the title salt, second-order Jahn–Teller distortion of the coordination octa­hedra around V ions is reflected by coexistence of short V—O bonds and trans-positioned long V—F bonds, with four equatorial V—F distances being inter­mediate in magnitude. Hydrogen bonding of the anions is restricted to F-atom acceptors only, with particularly strong N–H⋯F inter­actions [N⋯F = 2.5072 (15) Å] established by axial and cis-positioned equatorial F atoms.




surface

Crystal structure, Hirshfeld surface analysis and DFT studies of 2-(2,3-di­hydro-1H-perimidin-2-yl)phenol

The asymmetric unit of the title compound contains two independent mol­ecules, consisting of perimidine and phenol units, which are linked through an N—H⋯O hydrogen bond. Intra­molecular O—H⋯N hydrogen bonds are observed in both independent mol­ecules.




surface

The crystal structure and Hirshfeld surface analysis of 1-(2,5-di­meth­oxy­phen­yl)-2,2,6,6-tetra­methyl­piperidine

The title compound, 1-(2,5-di­meth­oxy­phen­yl)-2,2,6,6-tetra­methyl­piperidine, was synthesized as a side-product during the synthesis of the inter­mediate, methyl 3,6-dimeth­oxy-2-(2-meth­oxy-2-oxoeth­yl)benzoate, necessary for the total synthesis of the isocoumarin 5,8-dimeth­oxy-3-methyl-1H-isochromen-1-one.




surface

Crystal structure and Hirshfeld surface analysis of 1,3-diethynyladamantane

The title compound exhibits exceptionally weak inter­molecular C—H⋯π hydrogen bonding of the ethynyl groups, with the corresponding H⋯π separations [2.91 (2) and 3.12 (2) Å] exceeding normal vdW distances. This bonding compliments distal contacts of the CH (aliphatic)⋯π type [H⋯π = 3.12 (2)–3.14 (2) Å] to sustain supra­molecular layers.




surface

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di­chloro-1-[(E)-(4-fluoro­phen­yl)diazen­yl]ethen­yl}-N,N-di­methyl­aniline

The dihedral angle between the two aromatic rings of the title compound is 64.12 (14)°. The crystal structure is stabilized by a short Cl⋯H contact, C—Cl⋯π and van der Waals inter­actions.




surface

Co-crystal structure, Hirshfeld surface analysis and DFT studies of 3,4-ethyl­ene­dioxy­thio­phene solvated bis­[1,3-bis­(penta­fluoro­phen­yl)propane-1,3-dionato]copper(II)

The title complex, Cu(L)2 or [Cu(C15HF10O2)2], comprising one copper ion and two fully fluorinated ligands (L−), was crystallized with 3,4-ethyl­ene­dioxy­thio­phene (EDOT, C6H6O2S) as a guest mol­ecule to give in a di­chloro­methane solution a unique co-crystal, Cu(L)2·3C6H6O2S.




surface

Crystal structure and Hirshfeld surface analysis of 4-{2,2-dichloro-1-[(E)-(4-fluorophenyl)diazenyl]ethenyl}-N,N-dimethylaniline

In the title compound, C16H14Cl2FN3, the dihedral angle between the two aromatic rings is 64.12 (14)°. The crystal structure is stabilized by a short Cl...H contact, C—Cl...π and van der Waals interactions. The Hirshfeld surface analysis and two-dimensional fingerprint plots show that H...H (33.3%), Cl...H/H...Cl (22.9%) and C...H/H...C (15.5%) interactions are the most important contributors towards the crystal packing.




surface

Crystal structure and Hirshfeld surface analysis of 1,3-diethynyladamantane

The title compound, C14H16, exhibits exceptionally weak intermolecular C—H...π hydrogen bonding of the ethynyl groups, with the corresponding H...π separations [2.91 (2) and 3.12 (2) Å] exceeding normal vdW distances. This bonding complements distal contacts of the CH (aliphatic)...π type [H...π = 3.12 (2)–3.14 (2) Å] to sustain supramolecular layers. Hirshfeld surface analysis of the title compound suggests a relatively limited significance of the C...H/H...C contacts to the crystal packing (24.6%) and a major contribution from H...H contacts accounting 74.9% to the entire surface.




surface

Crystal structure, Hirshfeld surface analysis and DFT studies of 2-(2,3-dihydro-1H-perimidin-2-yl)phenol

The asymmetric unit of the title compound, C17H14N2O, contains two independent molecules each consisting of perimidine and phenol units. The tricyclic perimidine units contain naphthalene ring systems and non-planar C4N2 rings adopting envelope conformations with the C atoms of the NCN groups hinged by 44.11 (7) and 48.50 (6)° with respect to the best planes of the other five atoms. Intramolecular O—H...N hydrogen bonds may help to consolidate the molecular conformations. The two independent molecules are linked through an N—H...O hydrogen bond. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (52.9%) and H...C/C...H (39.5%) interactions. Hydrogen bonding and van der Waals interactions are the dominant interactions in the crystal packing. Density functional theory (DFT) optimized structures at the B3LYP/ 6–311 G(d,p) level are compared with the experimentally determined molecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.




surface

The crystal structure and Hirshfeld surface analysis of 1-(2,5-dimethoxyphenyl)-2,2,6,6-tetramethylpiperidine

In the title compound, C17H27NO2, the piperidine ring has a chair conformation and is positioned normal to the benzene ring. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming chains propagating along the c-axis direction.




surface

Crystal structure and Hirshfeld surface analysis of 4,4'-(propane-1,3-diyl)bis(4H-1,2,4-triazol-1-ium) pentafluoridooxidovanadate(V)

In the structure of the title salt, (C7H12N6)[VOF5], second-order Jahn–Teller distortion of the coordination octahedra around V ions is reflected by coexistence of short V—O bonds [1.5767 (12) Å] and trans-positioned long V—F bonds [2.0981 (9) Å], with four equatorial V—F distances being intermediate in magnitude [1.7977 (9)–1.8913 (9) Å]. Hydrogen bonding of the anions is restricted to F-atom acceptors only, with particularly strong N–H...F interactions [N...F = 2.5072 (15) Å] established by axial and cis-positioned equatorial F atoms. Hirshfeld surface analysis indicates that the most important interactions are overwhelmingly H...F/F...H, accounting for 74.4 and 36.8% of the contacts for the individual anions and cations, respectively. Weak CH...F and CH...N bonds are essential for generation of three-dimensional structure.




surface

Comparison of azimuthal plots for reflection high-energy positron diffraction (RHEPD) and reflection high-energy electron diffraction (RHEED) for Si(111) surface

Features of azimuthal plots for RHEED and its new counterpart, RHEPD, are discussed. The plots, for both electrons and positrons, are determined using dynamical diffraction theory.




surface

New kind of interference in the case of X-ray Laue diffraction in a single crystal with uneven exit surface under the conditions of the Borrmann effect. Analytical solution

The analytical solution of the problem of X-ray spherical-wave Laue diffraction in a single crystal with a linear change of thickness on the exit surface is derived. General equations are applied to a specific case of plane-wave Laue diffraction in a thick crystal under the conditions of the Borrmann effect.




surface

Surface Pro not responding to stylus OR finger




surface

Bad_system_config_info Surface RT version 6.2




surface

Statement Regarding National Academies Study on Potential Health Risks of Living in Proximity to Surface Coal Mining Sites in Central Appalachia

In an August 18 letter, the U.S. Department of the Interior’s Office of Surface Mining Reclamation and Enforcement informed the National Academies of Sciences, Engineering, and Medicine that it should cease all work on a study of the potential health risks for people living near surface coal mine sites in Central Appalachia.




surface

Aerosols strongly influence sea surface temperature

Sea surface temperatures in the North Atlantic may be significantly influenced by air pollution, with knock-on effects for climatic events, such as drought and hurricanes, according to a new study. The findings indicate that estimates of man-made aerosol emissions over coming decades should be refined within climate models to improve predictions of future climate change.




surface

Surface Laptop 3 screens with spontaneous cracks now fixed for free

Microsoft is now stating that they will fix mysterious and spontaneous cracks in Surface Laptop 3 displays as they may have been caused by a "foreign particle" introduced during manufacturing. [...]




surface

Quiet road surfaces may have financial as well as acoustic benefits

A recent report has reviewed research on the effectiveness of low-noise road surfaces, taking into account acoustic performance, safety, skidding resistance and cost. It concludes they could have substantial acoustic and financial benefits, but their durability and safety must be taken into account.




surface

Extracting water from the ground affects water on the surface

Water extraction from the ground using pumps and wells may have significant impacts on the flow of water in streams on the surface, according to new research. Results suggest that groundwater pumping has caused total stream flow in one Hawaiian stream to decline by 5.4mm per year since 1960.




surface

Fracking: a serious concern for surface water as well as groundwater

While the ecological impact of shale gas exploration and extraction on groundwater has received considerable attention, the implications for surface water and terrestrial ecosystems is often overlooked, according to a new US study. Although more data are needed, preliminary results suggest that regulations based on proximity to surface water could be necessary to protect valuable ecosystems.




surface

Protecting surface waters from combined effects of chemical contaminants

Surface water is considered to be of good ecological quality if the Maximum Permissible Concentrations (MPCs) of contaminants in the water are not exceeded. However, new research suggests that even when each individual contaminant does not exceed its MPC, water quality may be compromised by the combined effects of contaminants.




surface

New method for assessing organic pollutant risks in surface waters

A new approach to assessing the risk posed by 500 organic chemicals potentially found in the surface waters of river basins across Europe has been developed. It allows pollutants of concern, including emerging substances, to be identified and prioritised by Member States for monitoring and action as required by the Water Framework Directive.




surface

Aerosols strongly influence sea surface temperature

Sea surface temperatures in the North Atlantic may be significantly influenced by air pollution, with knock-on effects for climatic events, such as drought and hurricanes, according to a new study. The findings indicate that estimates of man-made aerosol emissions over coming decades should be refined within climate models to improve predictions of future climate change.




surface

21st miner: Chilean miner&#39;s mistress at surface; wife boycotts rescue

Video: Newscasters say relationship may be old news, but it does add a new twist to a day of reunions.



  • Wilderness & Resources

surface

A cat has the surface area of a Ping-Pong table

And that information isn't as useless as it may seem.



  • Research & Innovations

surface

More than 55 percent of Earth&#39;s ocean surface is occupied by industrial fishing vessels

Using satellite data and machine learning, researchers have mapped the movements of over 70,000 industrial fishing vessels.



  • Wilderness & Resources

surface

Kinect-like technology turns any surface into a touchscreen

Technology projects a touchscreen onto your hand, clothes, a wall, or any surface, so you can operate your phone without removing it from your pocket.



  • Gadgets & Electronics

surface

World&#39;s deepest fish discovered 5 miles under the ocean surface

The unknown species is believed to be a snailfish with 'large wing-like fins and a head resembling a cartoon dog.'