Bonding of the chain structure for novel boranes B3k+pH−5k+p+3

The molecular orbitals obtained from conventional quantum chemistry calculations, are expressed in terms of symmetrized valence bond functions of fragment, and a direct picture of chemical bonding can be drawn easily. This method is utilized, together with extended Huckel calculations, to interpret the bonding properties of a centipede-like chain structure for novel laser-producing boranes B_3k+pH^?_5k+p+3 which is constructed from the repeated unit B₃H₅ halted to each other by three B—H—B bonds.     

H3+O和H3+O(H2O)n(n=1,2,3)阳离子振动力场和光谱频率的理论计算

本文利用多原子分子振动力场的模型势函法对H₃⁺O和H₃⁺O(H₂O)_n(n=1～3)阳离子的振动力场作了理论计算,并对其光谱频率进行了预测.H₃⁺O和H₉⁺O₄的振动频率的结果优于从头算梯度法的结果.本文首次给出了H₅⁺O₂、H₇⁺O₃伸缩振动频率的理论预测值.     

Localized molecular orbital studies on B_4C1_4,1,5-C_2B_3H_5 and B_nH_n~(2-)(n = 6-10, 12)

The wave functions, level energies and Mulliken population analysis of localized molecular orbitals (LMO's) for B4Cl4, 1,5-C2B3H5 and the closo-BnHn2- (n = 6-10, 12) are calculated by using the Edmiston-Reudenberg energy localization scheme under the CNDO/2 approximation in order to reveal the nature of quasi-aromaticity of the closo-BnHn2- (n > 5). It has been found that all the B-H or B-Cl LMO's are highly localized between the B and H (or Cl) atoms, corresponding to B-H or B-Cl o-bond, while the Bn framework bonding is formed mainly by the three-centered two-electron B-B-B bonds on the polyhedral faces. In the cases of B4Cl4 and 1,5-C2B3H5, these three-centered B-B-B bonds just fill their polyhedral faces; however, for the framework bonding of the closo-BnHn2- (n > 5), the valence electron deficiency leads to the delocalization of their three-centered B-B-B bonds, and as delocalizability of this three-centered B-B-B bond increases, some three-centered B-B-B bonds are further delocalized to become a f     

Quantum Study on the Hydrogen Bonding Interaction of Luteolin-（CH_3OH）_n

The optimized geometries and vibration frequencies of luteolin,methanol and luteolin-(CH3OH)n complexes have been investigated by density functional theory using B3LYP method.Four stable luteolin-CH3OH complexes,six stable luteolin-(CH3OH)2 complexes and four stable luteolin-(CH3OH)3 complexes have been obtained.The theories of atoms in molecules(AIM) and natural bond orbital(NBO) have been used to analyze the hydrogen bonds of these compounds,and their interaction energies corrected by basis set superposition error are between-8.046 and-76.124 kJ/mol.The calculation results indicate strong hydrogen bonding interactions in the luteolin-(CH3OH)n complexes.Then the nuclear magnetic resonance(NMR) and electronic absorption spectrum of luteolin have been calculated,and the results are in agreement with the experimental data.     

新手性源5-(l-孟氧基)-3-溴-2(5H)-呋喃酮的合成和结构

文中深入研究了5-(l-孟氧基)-3-溴-2(5H)-呋喃酮新手性源(5a)的合成方法及其不对称合成反应。5a不仅制备方法简便,光学纯度单一,而且它作为稳定的Michael受体,可与碳、氧、氮、硫等不同的亲核试剂发生串联的Michael加成/分子内亲核取代反应,制备得到含有多个手性中心的双环[3.3.0^3^,^7]-5-辛烯类化合物、双环[3.1.0^3^,^5]-己烷类化合物和螺-环丙烷类化合物。本文报道了该手性呋喃酮5a的合成和构型测定。     

Theoretical study of the interaction mechanism of single-electron halogen bond complexes H_3C…Br-Y(Y=H,CN,NC,CCH,C_2H_3)

The characteristics and structures of single-electron halogen bond complexes H3C…Br-Y(Y = H,CCH,CN,NC,C2H3) have been investigated by theoretical calculation methods.The geometries were optimized and frequencies calculated at the B3LYP/6-311++G level.The interaction energies were corrected for basis set superposition error(BSSE) and the wavefunctions obtained by the natural bond orbital(NBO) and atom in molecule(AIM) analyses at the MP2/6-311++G level.For each H3C…Br-Y complex,a single-electron Br bond is f...     

Synthesis and X－ray Structure of Solvated Mono－cyclopentadienyl Samarium Dichloride（C_5H_5）SmCl_2（THF）_3

ＳｙｎｔｈｅｓｉｓａｎｄＸ－ｒａｙＳｔｒｕｃｔｕｒｅｏｆＳｏｌｖａｔｅｄＭｏｎｏ－ｃｙｃｌｏｐｅｎｔａｄｉｅｎｙｌＳａｍａｒｉｕｍＤｉｃｈｌｏｒｉｄｅ（Ｃ_５Ｈ_５）ＳｍＣｌ_２（ＴＨＦ）_３￥ＱｉａｎＣｈａｎｇ－Ｔａｏ；ＺｈｕＤｕｎ－Ｍｉｎｇ；ＳｕｎＪ...     

(C6H8N3)+I3-和[(Cu3I4)(C8H17N2)]配体原位合成与结构表征

在溶剂热条件下, 以原位反应为基础合成了两个碘化物(C6H8N3)+I3-(1, C6H8N3=2,3-dihydroimi-dazo[1,2-a]pyrimidin-1-ium, 2,3-二氢咪唑[1,2-α]-嘧啶鎓阳离子)和[(Cu3I4)(C8H17N2)](2, C8H17N2=N-ethyl-4-aza-1-azonia-bicyclo[2.2.2]octane, N-乙基三乙烯二铵阳离子). 用元素分析、粉末X射线衍射及单晶X射线衍射等对化合物进行了表征. 结果表明, 化合物1属于三斜晶系, P1空间群, a=0.74281(15) nm, b=0.84241(17) nm, c=0.9993(2) nm, α=82.02(3)°, β=83.30(3)°, γ=82.92(3)°, V=0.6114(2) nm3. 化合物2属于单斜晶系, P21/c空间群, a=0.68924(14) nm, b=1.0786(2) nm, c=2.2779(5) nm, β=94.84(3)°, V=1.6874(6) nm3. 在两个化合物合成中存在两种不同类型的配体原位合成反应, 即化合物1的2-氨基嘧啶和乙醇的成环反应与化合物2的三乙烯二胺和乙醇的烷基化反应.     

Synthesis and Crystal Structure of[C_6H_5CH_2C_5H_4ErCl_2(THF)_3]·THF

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ［Ｃ_６Ｈ_５ＣＨ_２Ｃ_５Ｈ_４ＥｒＣｌ_２（ＴＨＦ）_３］·ＴＨＦＧａｏＦｕ－Ｘｉｎｇ；ＷｅｉＧｅ－Ｃｈｅｎｇ；ＪｉｎＺｈｏｎｇ－Ｓｈｅｎｇ；ＣｈｅｎＷｅｎ－Ｑｉ（ＣｈａｎｇｃｈｕｎＩｎｓｔｉ?..     

Tensor polarizability of cadmium atoms in the excited state (5s5p)3 P 1

The tensor polarizability of the (5s5p)³ P ₁ level of cadmium atoms in a vapour cell were measured using level crossing technique and opto-magnetic double resonance in parallel electric and magnetic fields. The value of the tensor polarizability obtained from the level crossings is: ₂=1.33±0.04 kHz/(kV/cm)² and from the double resonance is: ₂=1.27±0.06 kHz/(kV/cm)². These results were compared with previous theoretical and experimental data of other authors.This work was supported in part by the Committee for Scientific Research under grant No. 2 0226 91 01     

手性4-膦酸二酯基-3-卤-2(5H)-呋喃酮的合成与结构

手性呋喃酮1a-1b与亚磷酸三酯2a-2b通过串联的不对称Michael加成/分子内Michalis-Arbazov重排反应,得到了含磷官能团的新手性化合物,5-(S)-(l-孟氧基)-4-膦酸二酯基-3-卤素-2(5H)-呋喃酮4a-4d。该反应具有条件温和,产率高(86%-95%),光学纯度单一(d.e.≥98%)的特点。通过元素分析,IR,UV,^1HNMR,^1^3CNMR,MS,[α]~D^2^0波谱分析数据以及X射线四圆衍射数据确定了它们的化学结构和绝对构型。     

Cr(CNR)_3Cl_3和Cr(CNR)_3Cl_2B(C_8H_5)_4·H_2O(R=CH_2C_8H_5)的合成和性质研究

长期以来人们对羰基配合物进行了较为充分的研究,但忽略了与之对应的异腈配合物领域。本文在四氢呋喃溶剂中制得两个过渡金属异腈配合物,初步研究了它们的性质,并讨论了它们的红外光谱和热重分析。 1 实验部分 1。1 试剂和仪器 CrCl_3(thf)_3按文献合成。CNCH_2C_6H_5和NaB(C_6H_5)_4购自Aldrich试剂     

Air‐Stable (CAAC)CuCl and (CAAC)CuBH4 Complexes as Catalysts for the Hydrolytic Dehydrogenation of BH3NH3

The first stable copper borohydride complex [(CAAC)CuBH₄] [CAAC=cyclic(alkyl)(amino)carbene] bearing a single monodentate ligand was prepared by addition of NaBH₄ or BH₃NH₃ to the corresponding [(CAAC)CuCl] complex. Both complexes are air‐stable and promote the catalytic hydrolytic dehydrogenation of ammonia borane. The amount of hydrogen released reaches 2.8 H₂/BH₃NH₃ with a turnover frequency of 8400 mol mol_cat^?1 h^?1 at 25 °C. In a fifteen‐cycle experiment, the catalyst was reused without any loss of efficiency.     

Solvothermal Syntheses and Crystal Structures of Two New Nonmetal Borates:C_4H_(10)N_2·B_6O_8(OH)_2 and (NH_3CH_2CH_2NH_3)B_5O_8(OH)

Two new borate compounds,C4H10N2·B6O8(OH)2 1 and (NH3CH2CH2NH3)B5O8-(OH) 2,have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction,IR,elemental analysis and thermal analysis. Compound 1 crystallizes in the monoclinic system,space group P21/c,with a=8.3318(17),b=6.2118(12),c=12.479(3) ,β=108.96(3)o,V=610.8(2) 3,Mr=313.02,Z=2,Dc=1.702 g/cm3,μ=0.150 mm-1,F(000)=320,R =0.0387 and wR =0.0924. Its layered structure is linked by infinite covalently coordinated neutral sheets with 3,20-membered window system,which are built up from alternative B6O8(OH)2 subunits donated by two piperzazine nitrogen donors. 2 crystallizes in monoclinic,space group Cc,with a=6.7207(13),b=11.481(2),c=12.564(3) ,β=95.25(3)o,V=965.4(3) 3,Mr=261.18,Z=4,Dc=1.797 g/cm3,μ= 0.164 mm-1,F(000)=536,R=0.0396 and wR=0.0752. Its oxoborate structure is generated from the sheets of 3,9-membered boron rings bonded diamine molecules through electrostatic and H-bonding interactions to form a two-dimensional layered network.     

Metallaboranes of the Early Transition Metals: Direct Synthesis and Characterization of [{(eta5-C5Me5)Ta}2BnHm] (n=4, m=10; n=5, m=11), [{(eta5-C5Me5)Ta}2B5H10(C6H4CH3)], and [{(eta5-C5Me5)TaCl}2B5H11

Reaction of [Cp*TaCl4] (Cp*=eta5-C5Me5) with a sixfold excess of LiBH(4)thf followed by BH3thf in toluene at 100 degrees C led to the isolation of hydrogen-rich metallaboranes [(Cp*Ta)2B4H10] (1), [(Cp*Ta)2B5H11] (2), [(Cp*Ta)2B5H10(C6H4CH3)] (3), and [(Cp*TaCl)2B5H11] (4) in modest yield. Compounds 1-3 are air- and moisture-sensitive but 4 is reasonably stable in air. Their structures are predicted by the electron-counting rules to be a bicapped tetrahedron (1), bicapped trigonal bipyramids (2, 3), and a nido structure based on a closo dodecahedron 4. Yellow tantalaborane 1 has a nido geometry with C2v symmetry and is isostructural with [(Cp*M)2B4H8] (M=Cr and Re); whereas 2 and 3 are C3v-symmetric and isostructural with [(Cp*M)2B5H9] (M=Cr, Mo, W) and [(Cp*ReH)2B5Cl5]. The most remarkable feature of 4 is the presence of a hydride ligand bridging the ditantalum center to form a symmetrical tantalaborane cluster with a long Ta--Ta bond (3.22 A). Cluster 4 is a rare example of electronically unsaturated metallaborane containing four TaHB bonds. All these new metallaboranes have been characterized by mass spectrometry, 1H, 11B, and 13C NMR spectroscopy, and elemental analysis, and the structural types were unequivocally established by crystallographic analysis of 1-4.     

Synthesis and crystal structure of a novel mixed valence tri-iron complex salt: [hexakis(thiazole)iron(II)][μ-oxo- bis(trichloroiron(III))]

The title compound, [Fe(tz)₆][Fe₂OCl₆] (1) (tz = thiazole) has been synthesized under argon by the reaction of anhydrous FeCl₃ with thiazole in ethanol. 1 crystallises in the cubic space group (no. 205) with a = 15.001(5) Å, V = 3375(2) ų, Z = 4, R = 0.061 and R_w = 0.073. 1 consists of a face-centered cubic array of [Fe(tz)₆]² cations, with the oxo-bridged [Fe₂OCl₆]²⁻ anion occupying the cell and edge centres.     

A novel stibium phosphate,LiBa(SbO)2(PO4)3: synthesis,crystal structure and RE3+‐activated (RE = Tb3+ and Eu3+) fluorescence performance

A new stibium phosphate, lithium barium bis(antimony oxide) tris(phosphate), LiBa(SbO)₂(PO₄)₃, was prepared by the molten salt method with LiF as the flux. The crystal structure consists of an original three‐dimensional anionic framework of [(SbO)₂(PO₄)₃]_∞ built from PO₄ tetrahedra sharing their corners with SbO₆ octahedra. This framework delimits one‐dimensional tunnels where the lithium(I) and barium(II) ions are located. The UV–Vis spectrum shows that LiBa(SbO)₂(PO₄)₃ was transparent from 350 to 800 nm, and is thus suitable as a luminescent host matrix. We then used Tb³⁺ and Eu³⁺ activators to test its luminous performance and the purities of the prepared phosphors were studied by powder X‐ray diffraction analysis with Rietveld refinements. Photoluminescence (PL) studies reveal that the emission spectra of 1 mol% RE³⁺‐doped (RE = Tb and Eu) samples can be excited by 371 and 394 nm light, emitting green and orange–red light, respectively, for Tb³⁺ and Eu³⁺. The CIE coordinates were measured to be (0.295, 0.571) and (0.6027, 0.3967), and the luminescent lifetimes were calculated as 0.178 and 1.159 ms, respectively.     

Synthesis and Structureof［（C_2H_5）_4N］［Mo_3（μ_3－O）（μ－Cl）_3（μ－CH_3CH_2COO）_3Cl_3］

ＳｙｎｔｈｅｓｉｓａｎｄＳｔｒｕｃｔｕｒｅｏｆ［（Ｃ_２Ｈ_５）_４Ｎ］［Ｍｏ_３（μ_３－Ｏ）（μ－Ｃｌ）_３（μ－ＣＨ_３ＣＨ_２ＣＯＯ）_３Ｃｌ_３］ＺｈｕａｎｇＨｏｎｇ－Ｈｕｉ；ＷｕＤｉｎｇ－Ｍｉｎｇ；ＨｕａｎｇＪｉａｎ－Ｑｕａｎ；ＨｕａｎｇＪｉｎ－Ｌ...