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11.
The complex of 2,6-diacetylpyridinedihydrazone (L) with lead(II) and azide has been characterized by elemental analyses, FTIR, and single-crystal X-ray analysis. The Pb(C9H13N11) (1) crystallized in the monoclinic space group C2/c. The coordination of 1 exhibits a gap around the lead(II), possibly occupied by a stereochemically active electron lone pair on lead(II) resulting in a hemidirected complex. Antimicrobial activity of the complex is higher than the free ligand.  相似文献   
12.
设计合成了4种对称的以不同供/吸电子基团为共轭桥、两端连接meso位苯或噻吩取代的新型氟化硼二吡咯甲川(BODIPY)衍生物;通过1H NMR,13C NMR和MS等手段对其进行了结构表征;并采用紫外吸收光谱、荧光发射光谱及循环伏安(CV)等方法研究了其光电性能.紫外光谱数据表明,BODIPY结构具有明显的特征吸收,中间的桥联基团无论是强供电子的苯并二噻吩(BDT)还是强吸电子的苯并噻二唑(BT)均不能使整个分子产生明显的分子内电子迁移(ICT).另一方面,meso位的取代基可与BODIPY核产生微弱的ICT,且meso位噻吩取代的分子比meso位苯环取代的分子表现出更强的ICT.紫外光谱数据和电化学测试结果表明,meso位噻吩取代的分子比meso位苯环取代的分子具有更低的氧化电位和更窄的能隙.  相似文献   
13.
本文报道了对一种电子给体-受体化合物(E)-(5-(4-(二苯基胺)苯乙烯基)二噻吩并[2,3-b∶3′,2′-d]噻吩基)-2-亚甲基丙二腈(TPA-DCST)的合成与光谱学行为的研究。化合物TPA-DCST的分子结构中含有强电子给体(三苯胺)与强电子受体(二氰基乙烯)两个部分,并由二噻吩并[2,3-b∶3′,2′-d]噻吩作为共轭桥将电子给体与受体相连接。在合成方面,采用Wittig反应将三苯胺通过双键与二噻吩并[2,3-b∶3′,2′-d]噻吩相连接、醛基化,并与并二腈经Knoevenagel缩合反应合成目标产物。产物通过了核磁氢谱、碳谱、红外以及高分辨率质谱的确认。光谱方面,主要考察了该化合物的吸收与荧光行为。其最大吸收峰位在412nm左右,归属于π-π*跃迁。在非极性溶剂正己烷中表现出来自分子间聚集而形成的聚集态荧光(550nm),并通过了单分子在CTAB胶束([c]=1.02×10-2 mol/L)的发光(460nm)试验得到验证。溶剂效应表明,该化合物没有出现典型的ICT态的发光现象,其原因在于电子给体与受体相连的共轭桥单元,即二噻吩并[2,3-b∶3′,2′-d]噻吩不具有有效的共轭效应。浓度效应与温度效应进一步表明TPA-DCST分子易于产生分子间聚集态的发光。在THF-H_2O二元溶剂体系中呈现典型的聚集诱导(AIE)发光现象,发光峰位为692nm。随着TPA-DCST分子间的聚集程度的增加,聚集态的荧光出现大范围的红移,直至固体发光红移到710nm。TPA-DCST分子的聚集因素可能来自于疏脂作用、偶极-偶极相互作用等。  相似文献   
14.
Within the scope of this paper, nine π-expanded mono-substituted 5,8,11,14,17-pentakis-(tert-butyl)-hexa-peri-hexabenzocoronenes (HBC) are introduced. 2-Iodo-5,8,11,14,17-pentakis-(tert-butyl)-hexa-peri-hexabenzocoronene served as precursor and was reacted with ethynyltrimethylsilane in a Sonogashira coupling reaction. The acetylene unit is used as a linker and can undergo another Sonogashira coupling reaction combining different phenyl coupling partners with the HBC core. The electron-withdrawing groups such as nitrile, pyridine and carbonyl species (aldehyde, methylester, carboxylic acid) as well as the three quinoxaline based species (diphenylquinoxaline, dibenzo[a,c]phenazine, phenanthro[4’,5’-a,b,c]phenazine) serve as substitution moieties. Their influence on the optoelectronic properties were investigated by UV/Vis absorption spectroscopy demonstrating a maximum redshift of 7 nm compared to starting compound 2-Iodo-5,8,11,14,17-pentakis-(tert-butyl) HBC. As for the phenanthro[4’,5’-a,b,c]phenazine substituted HBC a dramatic decrease in the intensity of the absorption of the UV/Vis spectrum was observed. The fluorescence spectroscopy pointed out that the dibenzo[a,c]phenazine and phenanthro[4’,5’-a,b,c]phenazine substitution changed the spectra to one broad peak departing from the characteristic HBC-like emission pattern.  相似文献   
15.
The tetranuclear manganese(II) complex [Mn4(ppi)6](BPh4)2 ( 2 ) (Hppi = 2‐pyridylmethyl‐2‐hydroxy phenylimine) is prepared by using the precursor complex [Mn(ppi)2]·H2O ( 1 ). Based on UV/Vis‐ and IR‐spectroscopy data in combination with mass spectrometry it has been concluded that 1 is a mononuclear neutral MnII complex, in which two ppi ligands chelate the manganese atom. Compound 2 crystallizes in the triclinic space group P1¯ (no. 2), with a = 17.500(3), b = 17.955(4), c = 19.101(4) Å, α = 113.79(3)°, β = 111.33(3)°, γ = 93.91(3)°, V = 4950(2) Å3 and Z = 2. In the tetranuclear [Mn4(ppi)6]2+ complex cation Mn(1), Mn(2), and Mn(3) are equivalently coordinated by two deprotonated Hppi ligands leading to a N4O2 donor set. The environment of the central Mn(4) is formed by coordination of three [Mn(ppi)2] fragments resulting in a phenoxo bridged star‐shaped Mn4O6 core motif. The average distance of directly adjacent manganese ions is 3.310 Å, whereas the average distance of Mn(1), Mn(2), and Mn(3) among each other is 5.732 Å.  相似文献   
16.
色谱法测定催化剂中碳含量操作条件研究   总被引:1,自引:1,他引:1  
根据燃烧-色谱法的原理建立了催化剂碳含量的测定方法并开发了催化剂高温定碳仪,通过考察燃烧温度、载气流速、桥流等对催化剂碳含量测定的影响,确定了测定催化剂碳含量的最佳操作条件。实验结果表明,在确定的最佳操作条件下,测定的催化剂碳含量与化学法基本相同。  相似文献   
17.
Three new binudear cobalt (II) complexes with extended te-tracarboxylato- bridge have been synthesized and characterized, namely [Co2 (PMTA) (bpy)4] (1), [Co2(PMTA)-(phen)4] (2) and [Co2(PMTA) (NO2phen)4] (3), where PMTA represents the tetraanion of pyroniellitic acid, and bpy, phen, NO2-phen denote 2,2'-bipyridine, 1,10-phenan-throline; 5-nirto-1, 10-plienanthroline, respectively. Based on elemental analyses, molar conductivity measurements, IR and electronic spectra studies, it is proposed that these complexes have PMTA-bridged structures and consist of two cobalt (II) ions, each in a distorted octahedral environment. These complexes were further characterized by variable temperature magnetic susceptibility measurements (4-300 K) and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, giving the exchange integral J = - 1.02 cm-1 for 1, J = -1.21 cm-1 for 2 and J = - 1.18 cm-1 for 3, respectively. These results revealed the operation of antiferromagneti  相似文献   
18.
    
This study extends the upstream flux‐splitting finite‐volume (UFF) scheme to shallow water equations with source terms. Coupling the hydrostatic reconstruction method (HRM) with the UFF scheme achieves a resultant numerical scheme that adequately balances flux gradients and source terms. The proposed scheme is validated in three benchmark problems and applied to flood flows in the natural/irregular river with bridge pier obstructions. The results of the simulations are in satisfactory agreement with the available analytical solutions, experimental data and field measurements. Comparisons of the present results with those obtained by the surface gradient method (SGM) demonstrate the superior stability and higher accuracy of the HRM. The stability test results also show that the HRM requires less CPU time (up to 60%) than the SGM. The proposed well‐balanced UFF scheme is accurate, stable and efficient to solve flow problems involving irregular bed topography. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
19.
Six novel μ-oxamido heterobinuclear complexes, namely Cu(oxae)Ln(Me2bpy)2-(ClO4)3 (Ln=La, Nd, Gd, Tb, Ho, Er), where oxae denotes N, N'-bis(2-aminoethyl)oxamido dian-ion, Me2bpy is 4,4'-dimethyl-2,2'-bipyridyl, have been synthesized and characterized by elemental analyses, IR, conductivity measurements and electronic spectra. The temperature dependence of the magnetic susceptibility of Cu(oxae)Gd(Me2bpy)2(ClO4)3 has been meaured over the range 4-300 K. The least-squares fit of the experimental susceptibilities yielded J - 1.87 cm-1.The observed Gd(Ⅲ)-Cu(Ⅱ) coupling is ferromagnetic. One plausible mechanism that can cause a ferromagnetic coupling between Gd(Ⅲ) and Cu(Ⅱ) is discussed in terms of spin-polarization.  相似文献   
20.
All methionine aminopeptidases exhibit the same conserved metal binding site. The structure of this site with either Co2+ions or Zn2+ions was investigated using density functional theory. The calculations showed that the structure of the site was not influenced by the identity of the metal ions. This was the case for both of the systems studied; one based on the X-ray structure of the human methionine aminopeptidase type 2 (hMetAP-2) and the other based on the X-ray structure of the E. colimethionine aminopeptidase type 1 (eMetAP-1). Another important structural issue is the identity of the bridging oxygen, which is part of either a water molecule or a hydroxide ion. Within the site of hMetAP-2 the results strongly indicate that a hydroxide ion bridges the metal ions. By contrast, the nature of the oxygen bridging the metal ions within the metal binding site of eMetAP-1 cannot be determined based on the results here, due to the similar structural results obtained with a bridging water molecule and a bridging hydroxide ion.  相似文献   
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