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981.
CrystalandMolecularStructureofaNewMono-substitutedTitanoceneComplex,{(η~5-Cp)[η~5-(1-(4-OCH_3)C_6H_4)C_6H_(10)Cp](TiCl_2)}·0.3(n-...  相似文献   
982.
X-Ray Crystal Structure Determination of 1,3-Bis(diethylamino)-1,3-dibenzyl-2,4-diphenyl-1λ5, 3λ5-diphosphete Benzylidene-diethylamino-benzylfuorophosphorane, 1 , reacts with lithium bis(trimethylsilyl)amide to give the title compounds 2 and 1-diethylamino-2,3-diphenylphosphirane, 3 . Only one of the stereoisomers of 2 is formed in which the two benzyl groups are located on the same side of the planar four-membered ring. 2 crystallizes in the monoclinic space group P21/n.  相似文献   
983.
Comparative molecular similarity indices analysis (CoMSIA), a three-dimensional quantitative structure activity relationship (3D QSAR) paradigm, was used to examine the correlations between the calculated physicochemical properties and the in vitro activities (3'-processing and 3'-strand transfer inhibition) of a series of human immunodeficiency virus type 1 (HIV-1) integrase inhibitors. The training set consisted of 34 molecules from five structurally diverse classes: salicylpyrazolinones, dioxepinones, coumarins, quinones, and benzoic hydrazides. The data set was aligned using extrema of molecular electrostatic potentials (MEPs). The predictive ability of the resultant model was evaluated using a test set comprised of 7 molecules belonging to a different structural class of thiazepinediones. A CoMSIA model using an MEP-based alignment showed considerable internal as well external predictive ability (r2(cv) = 0.821, r2(pred) = 0.608 for 3'-processing; and r2(cv) = 0.759, r2(pred.) = 0.660 for 3'-strand transfer).  相似文献   
984.
Pyrrolidine dithio carbamate (pdtc) cobalt(III) chelate has been used as a coprecipitation matrix for obtaining preconcentration factors of 100 or more for analytical estimation of trace metals in natural waters. This chelate, suitable for bivalent and trivalent ions, crystallizes as dark green crystals in monoclinic space group C2/c with unit cell parametersa = 28.89 ?,b = 14.39 ?,c = 16.17 ? andΒ = 104.2‡. X-ray crystallographic analysis of these crystals reveals that threepdtc are coordinated to a Co 0 3 + atom through their sulphur atoms, the six sulphur atoms forming a distorted octahedra around the metal atom at an average distance of 2.26 ?. The thiocarbamate part of the ligands is nearly planar but the pyrrolidine rings are puckered.  相似文献   
985.
The crystal of [Co(H2O)6]·(Hnip)2·(H2nip)2·(OMA)2·(H2O)8 has been cultured using direct method and characterized by X-ray single crystal diffractometry, elemental analysis and FTIR spectroscopy. It crystallizes in triclinic system, P-1 space group with the cell parameters of a=0.7012(1) nm, b=1.1378(2) nm, c=1.6612(3) nm, α= 84.92(3)°, β=85.19(3)°, γ=85.91(3)°, V= 1.3128(5) nm^3, Z=1, Dc= 1.573 g·cm^-3. Final R indices [1〉2σ(I)] are: R1 =0.0279, wR2=0.0765 while R indices for all data are: R1 =0.0327, wR2=0.0806. The Co coordination octahadra are each surrounded by two Hnip, two H2nip, two DMA and eight water molecules that are linked by hydrogen bonds and π-π stacking interactions. Thermal analyses of DSC and TG-DTG have been performed on the complex to predict its thermal decomposition mechanism and determine the most probable kinetic model function using Kissinger, Ozawa, integral and differential methods.  相似文献   
986.
Ba3N2 reacts at 950°C under pure N2 with Zr to yield dark red, air-sensitive Ba[ZrN2]. This new compound crystallizes in the tetragonal space group P4/nmm with a = 416.10(2), c = 839.2(1) pm and Z = 2. The crystal structure was solved and refined using X-ray and neutron powder diffraction data. In the nitrido zirconate [ZrN2]2? the Zr atoms exhibit a square-pyramidal coordination by five N atoms at distances of 201(3) and 220.2(2) pm. The pyramids share all the edges in the basal plane to form layers parallel to (001) with their apices alternately pointing up and down. The Ba2+ cations are integrated into these layers at the levels of the pyramidal apices. The structure can be interpreted as a stuffed PbFCl type. Ba2[NbN3] is formed by the reaction of Ba3N2 and NbN or of Ba and Nb at 1 000°C under N2. Isostructural to Ba2[TaN3] it crystallizes in the monoclinic space group C2/c with a = 613.2(3), b = 1 176.8(3), c = 1 322.9(4) pm, β = 91.65(2)°, Z = 8. The nitrido niobate anions form chains of corner sharing NbN4 tetrahedra with distances Nb? N between 188(1) and 199.9(9) pm.  相似文献   
987.
The reaction of alkali metal hexacyanoferrate(II/III) with (CH2)6N4 (hexamethylenetetramine, abbreviated HMT) in an acidic medium yielded crystalline compounds of stoichiometries HK2[Fe111(CN)6]·2HMT·4H2O, H2K2[Fe11(CN)6]·2HMT·4H2O, and HNa2[Fe111(CN)6]· 2HMT·5H2O. Their crystal structures are based on a packing of three molecular components: neutral and/orprotonated HMT, hexacyanoferrate, and an alkali metal ion-water cluster. The resulting three-dimensional supramolecular framework is constructed from the coordination of the alkali metal ion by aqua ligands as well as [Fe(CN)6]{n–} and HMT units, and further stabilization is achieved by hydrogen bonding between water molecules and the noncoordinated nitrogen atoms of HMT and hexacyanoferrate.  相似文献   
988.
CrIII Phthalocyaninates: Synthesis, Properties, and Crystal Structure of l-Bis(triphenylphosphine)iminium trans-Di(nitrito(O))phthalocyaninato(2–)chromate(III) [Cr(H2O)2Pc2?]Ix reacts with excess (PNP)NO2 in dimethylformamide to yield less soluble greenblack l-bis(triphenylphosphine)iminium trans-di(nitrito(O))phthalocyaninato(2–)chromate(III), l(PNP)trans[Cr(ONO)2Pc2?], which crystallizes in the triclinic space group P1 (No. 2) with Z = 2. The Cr atom is in the center of the Pc2? ligand and the two nitrite ions are monodentate O-coordinated in a mutually trans arrangement to the Cr atom. The Cr? O and Cr? Niso bond distances are 1.9898(14) und 1.981(2) Å, respectively. The geometric data of the coordinated nitrite ion are: d(N? O) = 1.307(2) Å; d(N? O) = 1.205(2) Å; ?(O? N? O) = 113.7(2)°; ?(Cr? O? N) = 116.85(12)°. The non-bonding O atoms are trans to the Cr atom. The Pc2? ligand is slightly saddled. Three weak spin-allowed trip-quartet(TQ) transitions (in 103 cm?1): TQ1 (8.20) < TQ2 (11.3) < TQ3 (20.33) and the characteristic π-π* transitions of the Pc2? ligand: B (14.68) < Q1 (27.1) < Q2 (29.0) < N (35.4) are observed in the UV-VIS-NIR spectrum. Prominent luminescence spectra are obtained by excitation within the TQ1 region, in which the spin-forbidden trip-sextet transition at 7376 cm?1 dominates at low temperatures (T < 50 K). The vibrational spectra are discussed. In coincidence of the excitation lines with TQ3, vs(Cr? O) at 378 cm?1 is selectively resonance Raman (RR) enhanced. vas(Cr? O) is observed in the FIR spectrum at 391 cm?1. The following internal vibrations (in cm?1) of the nitrito ligand are in the MIR spectrum: vas(N? O)/1447 > vas(N? O)/1018/1029 > δ(O? N? O)/828 and in the RR-spectrum: vs(N? O)/1410 > vs(N? O)/952, the last followed by three overtones.  相似文献   
989.
合成了两个二价的过渡金属磺酸化合物,并通过X-射线衍射单晶结构分析进行结构表征。化合物犤Ni(cyclam)(1,5nds)犦·1/3H2O(1)以P2(1)/c空间群结晶,晶胞参数为a=8.583(5),b=10.533(6),c=12.946(7)?,β=92.433(9)°。犤Ni(cyclam)犦2+与两个磺酸基团形成弱配位,从而构筑了一维的配聚物。犤Ni(cyclam)犦2+与磺酸基团之间的作用还通过O2S-O…H-N型氢键进一步被加强。化合物犤Co(cyclam)(H2O)2犦(1,5nds)·2H2O(2)以P1珔空间群结晶,晶胞参数为a=8.738(5),b=9.324(5),c=10.118(5)?,α=81.382(8),β=64.868(8),γ=62.999(8)°。在该化合物中,磺酸基团没有与Co2+形成配位键,而是以平衡离子的形式存在并与配离子形成氢键,构筑了有序的三维结构。  相似文献   
990.
1 INTRODUCTION Orotic acid (H3dtpc), an important pyrimidine derivative as the effective precursor in the biosynthesis of pyrimidine base of nucleic acids in living organisms, plays a unique role in bioinorganic and pharmaceutical. Aside from the biological interest, orotic acid is also interesting in coordination chemistry. Its ketonic and enolic tautomers along with asymmetric geometry make it to be a very good versatile polydentate ligand[1~5]. The incorporation of metals into supram…  相似文献   
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