Reaction of CuCl2 ·2H2O and 2,4,6‐tris(phosphorylmethyl)mesitylene (H6tpmm) in H2O?DMF solution at room temperature afforded green crystals of [Cu6(H2tpmm)3(H2O)9]·3H2O ( 1 ), which were characterized by Fourier transform infrared (FT‐IR), thermogravimetric (TG) analysis, and powder X‐ray diffraction (PXRD). The solid‐state structure of 1 reveals a one‐dimensional chain array of M4L2 ‐metallocages constituted by the connection of two kinds of metallocage units, namely MC‐A (phosphonate/water‐bridged) and MC‐B (phosphonate‐bridged only), via μ2‐O(phosphonate)? Cu bonds in ABAABA order. The tris‐phosphonate ligand H6tpmm is partially deprotonated to form H2tpmm4?, which displays a cis,cis,cis conformation to bridge six Cu(II) centers via two monodentate phosphonate groups in a η0:η0:η1‐bonding mode and one tridentate phosphonate group in a μ4, η1:η1:η2‐bondingng mode. 相似文献
The title complex [(C12H8N2)2Bi(O2NO)3] was synthesized by reaction of 1,10-phenanthroline (phen) and Bi(NO3)3·5H2O. The structure of the complex was characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. An advanced solution-reaction isoperibol microcalorimeter was applied to determine the standard molar enthalpies of formation at 298.15 K of the complex and Bi(NO3)3·5H2O, giving –(798.92 ± 5.99) and –(1986.87 ± 0.20) kJ mol−1, respectively. The biological effect of the complex was evaluated by microcalorimetry on the growth of Schizosaccharomyces pombe (S. pombe). According to thermogenic curves, the corresponding thermokinetics and thermodynamic parameters were derived. The complex had good bioactivity on the growth metabolism of S. pombe, with the value of IC50 being 2.8 × 10−5 mol L−1.
[reaction: see text] Lanosterol synthase converts oxidosqualene to the tetracyclic sterol precursor lanosterol. The mutation experiments described here show that an active-site valine residue in lanosterol synthase contributes to cyclization control through steric effects. Mutating to smaller alanine or glycine residues allows formation of the monocyclic achilleol A, whereas the leucine and isoleucine mutants make exclusively lanosterol. The phenylalanine mutant is inactive. 相似文献
A novel mixed‐tribridged dimolybdenum(I) compound [Bn4N][Mo2(μ‐SPh)2(μ‐Cl)(CO)6] (1) has been synthesized from the reaction of Mo2(CO)3(SPh)2 with BU4NCl. Compound 1 was characterized by IR, UV‐Vis and 1H, 13C, 95Mo NMR spectroscopic analyses. The electrochemical behavior was measured by cyclic voltammetry, indicating a quasi‐reversible two‐electron transfer in one step. The crystal structure determined by X‐ray crystallography shows that 1 contains a [Mo2(μ‐S)2(μ‐Cl)]? core with a planar Mo2S2unit and a Cl bridge. The Mo? Mo distance is 0.28709(7) nm, and the Mo‐Cl‐Mo angle is 66.44(4)°. A newface‐sharing bioctahedral structure is discussed. 相似文献
Hydrothermal reactions of different lanthanide(III) salts with an amino-diphosphonate ligand (H4L=C6H5CH2N(CH2PO3H2)2) led to two series of lanthanide phosphonates, namely, Ln(H2L)(H3L) (Ln=La, 1; Pr, 2; Nd, 3; Sm, 4; Eu, 5; Gd, 6; Tb, 7). Compounds 1-5 feature a one-dimensional (1D) chain structure in which dimers of two edge-sharing LnO8 polyhedra are interconnected by bridging phosphonate groups, such 1D arrays are further interlinked via strong hydrogen bonds between non-coordinated phosphonate oxygen atoms into a two-dimensional (2D) layer with the phenyl groups of the ligands orientated toward the interlayer space. Compounds 6 and 7 also show a different 1D array in which the LnO6 octahedra are bridged by phosphonate groups via corner-sharing, such chains are also further interlinked by hydrogen bonds into a 2D supramolecular layer. Compounds 5 and 7 emit red and green light with a lifetime of 2.1 and 3.7 ms, respectively. 相似文献
Elevated heart rate has been proposed as an independent risk factor for cardiovascular diseases, but their interrelationships are not well understood. In this study, we performed a genome-wide linkage scan in 1,026 individuals (mean age 30.6 years, 54.5% women) from 73 extended families of Mongolia and determined quantitative trait loci that influence heart rate. The DNA samples were genotyped using deCODE 1,039 microsatellite markers for 3 cM density genome-wide linkage scan. Correlation analysis was carried out to evaluate the correlation of the covariates and the heart rate. T-tests of the heart rate were also performed on sex, smoking and alcohol intake. Consequently, this model was used in a nonparametric genome-wide linkage analysis using variance component model to create a multipoint logarithm of odds (LOD) score and a corresponding P value. In the adjusted model, the heritability of heart rate was estimated as 0.32 (P<.0001) and a maximum multipoint LOD score of 2.03 was observed in 77 cM region at chromosome 18. The second largest LOD score of 1.52 was seen on chromosome 5 at 216 cM. Genes located on the specified locations in chromosomes 5 and 18 may be involved in the regulation of heart rate. 相似文献
Metal selenites and tellurites are a class of very important compounds. In this paper, the structures and properties of metal selenites or tellurites combining with transition-metal (TM) ions with the d (0) electronic configuration or tetrahedral MO 4 building blocks of post-transition main-group elements were reviewed. Most compounds in the alkali or alkaline-earth-d (0) TM-Se (IV) (or Te (IV))-O systems exhibit extended anionic architectures composed of distorted octahedra of (d (0)) TM cations and tellurite or selenite groups. The distortion of the octahedron is always away from the lone-pair cation, and some of them exhibit excellent second-order nonlinear optical properties due to the adductive effects of two types of bond polarizations. Because of the high coordination number of Ln (III) ions, most of compounds in the Ln-d (0) TM-Se (IV) (or Te (IV))-O systems are not second-harmonic-generation active; however, they are able to emit strong luminescence in the visible or near-IR region; also in most cases, the d (0) TM cations are in tetrahedral geometry and are well separated from selenite or tellurite groups. It is also interesting to note that the selenite group is normally "isolated", whereas the TeO x ( x = 3-5) can be polymerized into a variety of discrete polynuclear anionic clusters or extended architectures via Te-O-Te bridges. 相似文献
We investigated electronically excited states of caffeine and its 1:1 complex with water by using resonant two-photon ionization (R2PI) and UV-UV hole-burning techniques. Strong vibronic coupling between a pair of close-lying pi-pi* and n-pi* transitions is proposed to be responsible for the broad spectral feature observed. By comparing the experimental results with those of theoretical calculations, both the O-bonded and N-bonded forms were suggested to be initially produced for the 1:1 complex. The electronic transitions of the O-bonded complex were blueshifted in the R2PI spectrum. For the N-bonded complex, the excited state undergoes an ultrafast decay process, followed by dissociation on a repulsive potential energy surface, which gives rise to a characteristically anomalous cluster distribution in nanosecond experiments. 相似文献