The competition of C-X⋯O=P halogen bond and π-hole⋯O=P bond between halopentafluorobenzenes C6F5X (X=F, Cl, Br, I) and triethylphosphine oxide

Calculation predicted the interacting forms of halopentafluorobenzene C₆F₅X (X=F, Cl, Br, I) with triethylphosphine oxide which is biologically interested and easily detected by ³¹P NMR. The interaction energy and geometric parameters of resultant halogen or π-hole bonding complexes were estimated and compared. Moreover, the bonding constants were determined by ³¹P NMR. Both theory and experiments indicated the C₆F₆ and C₆F₅Cl interact with triethylphosphine oxide by π-hole bonding pattern, while C₆F₅I by halogen/σ-hole bonding form. For C₆F₅Br, two interactions are comparative and should coexist competitively. The calculated interaction energies of σ-hole bonding complexes, ?5.07 kcal mol^?1 for C₆F₅Br?O=P and ?8.25 kcal mol^?1 for C₆F₅I?O=P, and π-hole bonding complexes, ?7.29 kcal mol^?1 for C₆F₆?O=P and ?7.24 kcal mol^?1 for C₆F₅Cl?O=P, are consistent with the changing tendency of bonding constants measured by ³¹P NMR, 4.37, 19.7, 2.42 and 2.23 M^?1, respectively.

Density functional and Møller–Plesset studies of cyclobutanone⋯HF and ⋯HCl complexes

The molecular structure (hydrogen bonding, bond distances and angles), dipole moment and vibrational spectroscopic data [vibrational frequencies, IR and vibrational circular dichroism (VCD)] of cyclobutanone?HX (X?=?F, Cl) complexes were calculated using density functional theory (DFT) and second order Møller–Plesset perturbation theory (MP2) with basis sets ranging from 6–311G, 6–311G^**, 6–311 + + G^**. The theoretical results are discussed mainly in terms of comparisons with available experimental data. For geometric data, good agreement between theory and experiment is obtained for the MP2 and B3LYP levels with basis sets including diffuse functions. Surface potential energy calculations were carried out with scanning HCl and HF near the oxygen atom. The nonlinear hydrogen bonds of 1.81 Å and 175° for HCl and 1.71 Å and 161° for HF were calculated. In these complexes the C=O and H–X bonds participating in the hydrogen bond are elongated, while others bonds are compressed. The calculated vibrational spectra were interpreted and the band assignments reported are in excellent agreement with experimental IR spectra. The C=O stretching vibrational frequencies of the complexes show red shifts with respect to cyclobutanone.     

How do halogen bonds (S–O⋯I,N–O⋯I and C–O⋯I) and halogen–halogen contacts (C–I⋯I–C,C–F⋯F–C) subsist in crystal structures? A quantum chemical insight

Thirteen X-ray crystal structures containing various non-covalent interactions such as halogen bonds, halogen–halogen contacts and hydrogen bonds (I?N, I?F, I?I, F?F, I?H and F?H) were considered and investigated using the DFT-D3 method (B97D/def2-QZVP). The interaction energies were calculated at MO62X/def2-QZVP and MP2/aug-cc-pvDZ level of theories. The higher interaction and dispersion energies (2nd crystal) of ?9.58 kcal mol^?1 and ?7.10 kcal mol^?1 observed for 1,4-di-iodotetrafluorobenzene bis [bis (2-phenylethyl) sulfoxide] structure indicates the most stable geometrical arrangement in the crystal packing. The electrostatic potential values calculated for all crystal structures have a positive σ-hole, which aids understanding of the nature of σ-hole bonds. The significance of the existence of halogen bonds in crystal packing environments was authenticated by replacing iodine atoms by bromine and chlorine atoms. Nucleus independent chemical shift analysis reported on the resonance contribution to the interaction energies of halogen bonds and halogen–halogen contacts. Hirshfeld surface analysis and topological analysis (atoms in molecules) were carried out to analyze the occurrence and strength of all non-covalent interactions. These analyses revealed that halogen bond interactions were more dominant than hydrogen bonding interactions in these crystal structures.

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Graphical Abstract Molecluar structure of 1,4-Di-iodotetrafluorobenzene bis(thianthrene 5-oxide) moelcule and its corresponding molecular electrostatic potential map for the view of σ-hole.

     

Biosynthesis,isolation, purification and separation of nivalenol,fusarenone — X and zearalenone

Fusarium, graminearum KF 370 isolate is able to simultaneous biosynthesis of three toxic metabolites, namely: fusarenone-X (FUS), nivalenol (NIV) and zearalenone (F-2). After metabolites extraction with methanol — water (3:1) and defatting with n-heptane toxins were partitioned into chloroform layer. Purification of the? compounds was performed on Celite 545 — charcoal — Aluminiumoxid 90 column then metabolites were separated on Kieselgel 60 (200–300 mesh) column with developing solvent chloroform — methanol. This way FUS, NIV and F-2 were obtained as crystalline or high purity standards.     

Structures and aromaticity of X2Y 2 − (X = C, Si, Ge and Y = N, P, As) anions

The equilibrium geometries, total energies, and vibrational frequencies of anions X₂Y₂ ⁻ (X = C, Si, Ge and Y = N, P, As) are theoretically investigated with density functional theory (DFT) method. Our calculation shows that for C₂N₂ ⁻ species, the D _2h isomer is the most stable four-membered structure, and for other species the C _2v isomer in which two X atoms are contrapuntal is the most stable structure at the B3LYP/6-311 +G_* level. Wiberg bond index (WBI) and negative nucleus-independent chemical shift (NICS) value indicate the existence of delocalization in stable X₂Y₂ ⁻ structures. A detailed molecular orbital (MO) analysis further reveals that stable isomers of these species have strongly aromatic character, which strengthens the structural stability and makes them closely connected with the concept of aromaticity.     

45,X/46,X,idic(X)/47,X,idic(X),idic(X)嵌合体核型的研究

最常见的人类X染色体的结构异常是长臂等臂X染色体,以及X染色体与常染色体之间的易位。关于idic(X)染色体结构异常的病例较为罕见。国外Chapella等曾有研究,国内周氏等首次报道了有关idic(X)染色体结构异常的病例。     

Comparison of the directionality of the halogen,hydrogen, and lithium bonds between HOOOH and XF (X = Cl,Br, H,Li)

Detailed electrostatic potential (ESP) analyses were performed to compare the directionality of halogen bonds with those of hydrogen bonds and lithium bonds. To do this, the interactions of HOOOH with the molecules XF (X?=?Cl, Br, H, Li) were investigated. For each molecule, the percentage of the van der Waals (vdW) molecular surface that intersected with the ESP surface was used to roughly quantify the directionality of the halogen/hydrogen/lithium bond associated with the molecule. The size of the region of intersection was found to increase in the following order: ClF?<?BrF?<?HF?<?LiF. The maximum ESP in the region of intersection, V _{S, max}, was observed to become more positive according to the sequence ClF?<?BrF?<?HF?<?LiF. For ClF and BrF, the positive electrostatic potential was concentrated in a very small region of the vdW molecular surface. On the other hand, for HF and LiF, the positive electrostatic potential was more diffusely scattered across the vdW surface than for ClF and BrF. Also, the optimized geometries of the dipolymers HOOOH···?XF (X?=?Cl, Br, H, Li) indicated that halogen bonds are more directional than hydrogen bonds and lithium bonds, consistent with the results of ESP analyses.

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Graphical abstract Electrostatic potential (ESP) contour maps in the xz plane of ClF and BrF

     

Theoretical investigations of the H···π and X (X = F,Cl, Br,I)···π complexes between hypohalous acids and benzene

The H···π and X (X = F, Cl, Br, I)···π interactions between hypohalous acids and benzene are investigated at the MP2/6-311++G(2d,2p) level. Four hydrogen-bonded and three halogen-bonded complexes were obtained. Ab initio calculations indicate that the X···π interaction between HOX and C₆H₆ is mainly electrostatically driven, and there is nearly an equal contribution from both electrostatic and dispersive energies in the case of XOH–C₆H₆ complexes. Natural bond orbital (NBO) analysis reveals that there exists charge transfer from benzene to hypohalous acids. Atom in molecules (AIM) analysis locates bond critical points (BCP) linking the hydrogen or halogen atom and carbon atom in benzene.     

45,X/46,XY qh? Karyotype and Aspermia. A case report

A 41-years old male with short stature, abnormal male sex differentiation, aspermia and schizoid character disorder is described. The patient was studied from clinical, endocrinological and genetic perspectives. Cytogenetical analysis revealed a chromosomic mosaicism formed by two normal lines 45X and 46,XY qh^?. Molecular studies on AZF region evidenced that it was conserved. The correlation of the symptoms with the cytogenetic finding is discussed.     

Discovery, synthesis and SAR of azinyl- and azolylbenzamides antagonists of the P2X₇ receptor

The discovery, of a series of 2-Cl-5-heteroaryl-benzamide antagonists of the P2X(7) receptor via parallel medicinal chemistry is described. Initial analogs suffered from poor metabolic stability and low Vd(ss). Multi parametric optimization led to identification of pyrazole 39 as a viable lead with excellent potency and oral bioavailability. Further attempts to improve the low Vd(ss) of 39 via introduction of amines led to analogs 40 and 41 which maintained the favorable pharmacology profile of 39 and improved Vd(ss) after iv dosing. But these analogs suffered from poor oral absorption, probably driven by poor permeability.     

Two X family DNA polymerases, λ and μ, in meiotic tissues of the basidiomycete, Coprinus cinereus

The X family DNA polymerases λ (CcPolλ) and μ (CcPolμ) were shown to be expressed during meiotic prophase in the basidiomycete, Coprinus cinereus. These two polymerases are the only members of the X family in the C. cinereus genome. The open reading frame of CcPolλ encoded a predicted product of 800 amino acid residues and that of CcPolμ of 621 amino acid residues. Both CcPolλ and CcPolμ required Mn²⁺ ions for activity, and both were strongly inhibited by dideoxythymidine triphosphate. Unlike their mammalian counterparts, CcPolλ and CcPolμ had no terminal deoxynucleotidyl transferase activity. Immunostaining analysis revealed that CcPolλ was present at meiotic prophase nuclei in zygotene and pachytene cells, which is the period when homologous chromosomes pair and recombine. CcPolμ was present in a slightly wider range of cell stages, zygotene to diplotene. In analyses using D-loop recombination intermediate substrates, we found that both CcPolλ and CcPolμ could promote primer extension of an invading strand in a D-loop structure. Moreover, both polymerases could fully extend the primer in the D-loop substrate, suggesting that D-loop extension is an activity intrinsic to CcPolλ and CcPolμ. Based on these data, we discuss the possible roles of these polymerases in meiosis.     

Frequency of the ΔF508 deletion and G551D,R553X and G542X mutations in Yugoslav CF patients

Summary A study was undertaken to find the frequency of the F508 deletion and those of the G551D, R553X and G524X mutations among the mainly Slavic population of Serbia, Bosnia, Herzegovina, and Montenegro and compare the frequencies determined with those in other European populations. The F508 mutation was found to account for about 70% of CF genes in central Jugoslavia, where its frequency is significantly higher than elsewhere in Southern European populations.     

A B3LYP and MP2(full) theoretical investigation into cooperativity effects,aromaticity and thermodynamic properties in the Na+⋯benzonitrile⋯H2O ternary complex

In this work the growth of a graphene monolayer on copper substrate, as typically achieved via chemical vapor deposition of propene (C₃H₆), was investigated by first-principles and kinetic Monte Carlo calculations. A comparison between calculated C1s core-level binding energies and electron spectroscopy measurements showed that graphene nucleates from isolated carbon atoms adsorbed on surface defects or sub-superficial layers upon hydrocarbon fragmentation. In this respect, ab initio nudged elastic band simulations yield the energetic barriers characterizing the diffusion of elemental carbon on the Cu(111) surface and atomic carbon uptake by the growing graphene film. Our calculations highlight a strong interaction between the growing film edges and the copper substrate, indicative of the importance of the grain boundaries in the epitaxy process. Furthermore, we used activation energies to compute the reaction rates for the different mechanisms occurring at the carbon–copper interface via harmonic transition state theory. Finally, we simulated the long-time system growth evolution through a kinetic Monte Carlo approach for different temperatures and coverage. Our ab initio and Monte Carlo simulations of the out-of-equilibrium system point towards a growth model strikingly different from that of standard film growth. Graphene growth on copper turns out to be a catalytic, thermally-activated process that nucleates from carbon monomers, proceeds by adsorption of carbon atoms, and is not self-limiting. Furthermore, graphene growth seems to be more effective at carbon supersaturation of the surface—a clear fingerprint of a large activation barrier for C attachment. Our growth model and computational results are in good agreement with recent X-ray photoelectron spectroscopy experimental measurements.     

Interplay between halogen and chalcogen bonding in the XCl∙∙∙OCS∙∙∙NH3 (X = F,OH, NC,CN, and FCC) complex

The interplay between halogen and chalcogen bonding in the XCl???OCS and XCl???OCS???NH₃ (X = F, OH, NC, CN, and FCC) complex was studied at the MP2/6-311++G(d,p) computational level. Cooperative effect is observed when halogen and chalcogen bonding coexist in the same complex. The effect is studied by means of binding distance, interaction energy, and cooperative energy. Molecular electrostatic potential calculation reveals the electrostatic nature of the interactions. Cooperative effect is explained by the difference of the electron density. Second-order stabilization energy was calculated to study the orbital interaction in the complex. Atoms in molecules analysis was performed to analyze the enhancement of the electron density in the bond critical point.     

Genome-wide profiling of liver X receptor, retinoid X receptor, and peroxisome proliferator-activated receptor α in mouse liver reveals extensive sharing of binding sites

The liver X receptors (LXRs) are nuclear receptors that form permissive heterodimers with retinoid X receptor (RXR) and are important regulators of lipid metabolism in the liver. We have recently shown that RXR agonist-induced hypertriglyceridemia and hepatic steatosis in mice are dependent on LXRs and correlate with an LXR-dependent hepatic induction of lipogenic genes. To further investigate the roles of RXR and LXR in the regulation of hepatic gene expression, we have mapped the ligand-regulated genome-wide binding of these factors in mouse liver. We find that the RXR agonist bexarotene primarily increases the genomic binding of RXR, whereas the LXR agonist T0901317 greatly increases both LXR and RXR binding. Functional annotation of putative direct LXR target genes revealed a significant association with classical LXR-regulated pathways as well as peroxisome proliferator-activated receptor (PPAR) signaling pathways, and subsequent chromatin immunoprecipitation-sequencing (ChIP-seq) mapping of PPARα binding demonstrated binding of PPARα to 71 to 88% of the identified LXR-RXR binding sites. The combination of sequence analysis of shared binding regions and sequential ChIP on selected sites indicate that LXR-RXR and PPARα-RXR bind to degenerate response elements in a mutually exclusive manner. Together, our findings suggest extensive and unexpected cross talk between hepatic LXR and PPARα at the level of binding to shared genomic sites.     

45,X/46,XXr嵌合体

本文报告一例45,X/46,XXr嵌合体。患者徐××,表型女性,25岁,未婚。继发闭经,因阴蒂肥大而要求入院手术,维持女性。术中发现子宫为幼儿型,小而薄。右侧卵巢和输卵管缺如。左侧圆韧带薄而松弛。左侧输卵管长度正常但很细,卵巢小而薄。     

A phenotypic male with karyotype 45,X/45,X,ace+(?Yq-)

Summary A phenotypical normal 22-year-old male with the sex chromosome constitution 45,X/45,X,ace+(?Yq-) and an atypical endogenous depression has been studied. The chromosome aberration and the depression are most probably not aetiologically connected.The patient presented no physical signs of male Turner phenotype, except for short stature. His personality development was, however, in several ways similar to what is characteristic for females with Turner's syndrome and karyotype 45,X and he had some dermatoglyphic signs similar to females with Turner's syndrome.The cytogenetic findings in leucocytes as well as fibroblast cultures indicated that the small acentric chromosome fragment found in approximately half of the cells was made up of the short arms of a Y chromosome. The finding of only short arms Y chromosome in approximately half of the cells in a phenotypically normal male with testes of normal size supports indications from previous studies that the genes necessary for the development of testes are located in the short arms Y. The finding further indicates that if homologous gene loci for the short arms X are present in the Y chromosome, they must be located in the short arms, and deletion long arms Y is most probably not an aetiological factor in the development of the so-called male Turner phenotype.

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Zusammenfassung Es wird ein phänotypisch normaler 22jähriger Mann mit der Geschlechtschromosomenkonstitution 45,X/45,X,ace+(?Yq-) und einer atypischen endogenen Depression beschrieben. Die Chromosomenaberration und die Depression stehen sehr wahrscheinlich in keinem ätiologischen Zusammenhang.Der Patient zeigte keine körperlichen Veränderungen im Sinne der männlichen Turner-Phänotype, mit Ausnahme von Kleinwuchs. Seine Persönlichkeitsentwicklung jedoch ließ sich in mehreren Punkten mit den Charakteristika, wie man sie bei Frauen mit Turner-Syndrom und der Karyotype 45,X sieht, vergleichen; und er hatte einige dermatoglyphische Zeichen, ähnlich wie bei Frauen mit Turner-Syndrom.Die cytogenetischen Untersuchungsergebnisse sowohl an Leukocyten als auch an Fibroblastenkulturen deuteten an, daß das kleine azentrische Chromosomenfragment, welches sich in ungefähr der Hälfte der Zellen fand, von den kurzen Armen des Y-Chromosoms gebildet wurde. Der Fund von lediglich den kurzen Armen des Y-Chromosoms in ungefähr der Hälfte der Zellen bei einem phänotypisch normalen Mann mit normaler Testisgröße unterstützt die Vermutungen vorangegangener Untersuchungen, daß die Gene, die für die Entwicklung der Testis notwendig sind, auf den kurzen Armen des Y-Chromosoms lokalisiert sind. Das Ergebnis der Untersuchung deutet weiterhin an, wenn homologe Genloci für die kurzen Arme X im Y-Chromosom vorhanden sind, diese auf den kurzen Armen lokalisiert sein müssen und daß eine Deletion der langen Arme des Y-Chromosoms sehr wahrscheinlich kein ätiologischer Faktor in der Entwicklung der sogenannten männlichen Turner-Phänotype ist.