12,52-二羟基-15,55-二甲基-14,16,34,36,54,56,74,76-八硝基-2,4,6,8-四氧桥连-1,3,5,7（1,3）-杯[4]芳烃的合成

以1,5-二氟-2,4-二硝基苯和3,4,5-三甲氧基甲苯为起始原料,经环化、甲基化、硝化和去甲基化反应，合成了一种新型杯芳烃衍生物，其结构经¹H NMR，¹³C NMR，¹⁵N NMR和元素分析表征。      

BF分子X1∑+,A1∏和B1∑+电子态的势能函数

使用SAC/SAC-CI和D95++,6-311++g,6-311++g**及D95(d)基组,分别对BF分子的基态X1∑+、第一简并激发态A1∏和第二激发态B1∑+的平衡结构和谐振频率进行优化计算.对所有计算结果进行比较,得出6-311++g**基组为最优基组.运用6-311++g**基组和SAC方法对基态X1∑+,SAC-CI方法对激发态A1∏和B1∑+进行单点能扫描计算,并用正规方程组拟合Murrell-Sorbie函数,得到相应电子态的势能函数解析式,由得到的势能函数计算了与X1∑+,A1∏和B1∑+态相对应的光谱常数,结果与实验数据较为一致.     

Palladium-catalyzed syntheses of condensed cyclopentanes. The crystal and molecular structure of 3-benzylidenpentacyclo[9.2.1.5,8.11,11.02,10.04,9]-pentadecane

New syntheses of condensed cyclopentanes are described, based on insertion into a sufficiently stable PdC bond of molecules able to provide an easy reductive elimination step. These reactions are highly stereoselective. Interesting features are revealed by the X-ray investigation of the title compound, which was obtained in good yield from β-bromostyrene and norbornene. The structural parameters are reported; the molecule adopts the conformation with the bridging carbon atoms of the two norbornanes trans with respect to the mean plane of the cyclopentylidene ring. The condensed cyclopentane system is highly symmetric. The phenyl group is twisted out of the plane of the cyclopentylidene ring by 25.3°.     

Molecular structure of methyl-10,14,19,19-tetramethyl-4-oxo-20-oxahexacyclo [15.3.1.16.18.06.15.09.14017.21]docosane-10-carboxylate

The synthesis of methyl-10,14,19,19-tetramethyl-4-oxo-20-oxahexacyclo[15.3.1.1^6.18.0^6.15.0^9.140^17.21] docosane-10-carboxylate III is performed and its molecular structure is determined. Compound III C₂₇H₄₀O₄ crystallizes in the monoclinic system with the cell parameters as follows: a = 12.8081(11) ?, b = 7.0384(6) ?, c = 12.8904(12) ?, β = 105.828(2)^o, P2₁ space group, Z = 2, d = 1.273 mg/m³.     

Molecular and crystal structure of 23,24,25,26,27,29,30-heptamethyl-19,28-oxahexacyclo[15.13.18.017,18.013,14.08,9.05,10]tetracos-3-yl acetate

The molecular structure of 23,24,25,26,27,29,30-heptamethyl-19,28-oxahexacyclo[15.13.18.0^17,18.0^13,14.0^8,9.0^5,10]tetracos-3-yl acetate III. Compound III C₃₂H₅₂O₃ crystallizes in the monoclinic crystal system with the unit cell parameters a = 13.265(15) ?, b = 6.481(7) ?, c = 32.274(4) ?, β = 99.333(2)°, space group C2, Z = 4, d = 1.176 g/cm³. Original Russian Text Copyright ? 2009 by N. I. Medvedeva, O. B. Flechter, and A. A. Korlyukov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 399–401, March–April, 2009.     

Potential energy curve of 1Σ+ Li+/He

The potential energy curve of the system Li⁺/He has been determined with moderately large basis sets for 0.5 ? r ? 10.0 a₀ both at the SCF level and including correlation. The present SCF results predict a deeper well (?0.00248 au) at a smaller r(3.66 a₀) compared with earlier calculations. Correlation deepens the well further (?0.00274 au), but pulls it inward slightly (3.63 a₀). In the repulsive part the calculated curve lies above the experimental one, especially at shorter distances. A similar behavior has been noted in the systems Li⁺/H₂, Li⁺/CO and Li⁺/N₂, suggesting that the experimental determinations may underestimate the interaction in this region by 10–20%.     

Radiative lifetimes of the CO a′3Σ+, b3Σ+, c3Π, d3Δ and B1Σ+ states. Absolute emission cross sections for t

Radiative lifetimes have been measured for the CO a′³Σ⁺(ν′=4–9), b³Σ⁺(ν′= 0), c³Π(ν′=0), d³Δ(ν′=1–16) and B¹Σ⁺(ν′= 0) states. Our experimental values, arranged in the same order, are 7–10 μs, 56 ns, 16 ns, 3–7.5 μs, 34 ns. Some of these values disagree with the results of previous experiments. To our opinion this is due to an incomplete identification of the emission spectrum in regions where many bands may overlap, dependent on the applied spectral resolution. For the a′Σ⁺?a³Π and d³Δ?a³Π emissions effective cross sections for quenching by CO molecules are given. In connection with the identification of the spectrum, absolute emission cross sections for electrons incident on CO have been measured for the b³Σ⁺?a³Π and c³Π?a₃Π transitions. For an electron energy, corresponding to the maximum of the excitation function we find cross sections of 5.94 (?1.2) × 10^?18 cm² and 0.630 (? 0.13) × 10^?18 cm², respectively.     

η3:η1⇌η2-tautomerism in carbonyliron complexes. Thermodynamic characteristics

The thermodynamic characteristics of the equilibrium between the chelate tricarbonylmethyl-π-allyl-σ-R-carbamoyliron complex (R = c-C₆H₁₁) and its π-olefinic isomer in hexane and in hexane/dichloromethane were determined. The observed values fit fairly well with the thermodynamic scale of tautomerism and allow a quantitative conclusion on the influence of solvent, temperature and polarity on the relative stabilities of the tautomeric forms to be reached.     

Molecular structure of 8-carboxy-18-chloro-14-hydroxy-20-isopropyl-16-methoxy-4,8-dimethyl-15-oxaoctacyclo-[11.7.1.03,1204,9012,19014,18016,21017,20]henicosane

The structure of 8-carboxy-18-chloro-14-hydroxy-20-isopropyl-16-methoxy-4,8-dimethyl-15-oxaoctacyclo[11.7.1.0^3,120^4,90^12,190^14,180^16,210^17,20]henicosane has been determined by single crystal X-ray diffraction. Original Russian Text Copyright ? 2008 by R. R. Fazlyev, G. F. Vafina, and F. Z. Galin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 6, pp. 1179–1181, November–December, 2008.     

Asymmetrical nitrogen-40;1 Geminal systems-261 N-chlorohydrazines3

The factors determining the kinetic and thermodynamic stabilities of N-chlorohydrazines are discussed. Acyclic N-chlorohydrazines exist only as trialkyldiazenium chlorides 3a,b. Chlorination of 2-acyl-1, 1-dimethylhydrazines 6a,b gave 1,4-diacyl-2,3-dimethylhexahydro-1,2,4,5-tetrazines 7a,b via hydrazyl radical intermediates, and chlorination of a 1-phenylpyrazolidin-5-one 8 gave phenylazoisovaleric esters 9a,b. Stable N-chlorohydrazines were obtained from bicyclic hydrazines; viz. the 2-chloro-1,2-diazabicyclo [2.2.2]octan-3-one 12 and 7-chloro-1,7-diazabicyclo[2.2.1]heptane 16. The restricted inversion of N(7) in 16 and its 1-methyl quaternary salt 21 were observed in the ¹³C-NMR spectra. The acyclic N-chloro-hydrazinium salt 25 was isolated.     

A 1Π ← χ1Σ+ resonance-enhanced multiphoton ionization of jet-cooled CO

We report the observation of two-photon resonance enhancement in the four-photon tunable dye laser-induced multiphoton ionization spectrum of CO. The observed structure is readily assigned to the rotational bands of the A ¹Π ← χ¹Σ⁺ (3,0) transition of CO.     

η3:η1⇌η2-tautomerism in carbonyliron complexes. Influence of substituents

A number of chelate η³-allylcarbamoyl iron complexes (I) with different substituents (R in the allyl ligand and R′ at the nitrogen atom) were synthesized. The influence of structural features on the equilibrium between the complexes I and their η²-azadiene tautomers (II) was studied by IR spectroscopy. It was established that the equilibrium position is determined in the first place by steric factors. When R is a bulky substituent the equilibrium is shifted towards the cyclic form I, whereas the branching of the alkyl substituent R′ at the nitrogen atom favours the open olefinic form II. Furthermore π-σ-(N) rearrangement of complexes II to σ-(N) derivatives (III), and the conversion of III into η⁴-azadiene complexes (IV) also depend on the steric requirements of the substituents R and R′.     

Molecular structure of methyl 20-isopropyl-15(E)-hydroxyimino-5,9-dimethyl-18-oxahexacyclo [12.4.0.22,13.118,20.05,10.04,13]heneicosane-9-carboxylate

Methyl 20-isopropyl-15(E)-hydroxyimino-5,9-dimethyl-18-oxahexacyclo[12.4.0.2^2,13.1^18,20.0^5,10.0^4,13]-heneicosane-9-carboxylate is synthesized and its molecular structure is determined. Compound IIa of C₂₇H₄₁NO₄ crystallizes in the acentric P2₁ space group with the following unit cell parameters: a = 7.6511(7) ?,b = 12.0698(11) ?, c = 12.9182(12) ?, β = 95.257(2)°.