An atomic electronegative distance vector and carbon-13 nuclear magnetic resonance chemical shifts of alcohols and alkanes

A novel atomic electronegative distance vector (AEDV) has been developed to express the chemical environment of various chemically equivalent carbon atoms in alcohols and alkanes. Combining AEDV and Y parameter, four five-parameter linear relationship equations of chemical shift for four types of carbon atoms are created by using multiple linear regression. Correlation coefficients are R = 0.9887, 0.9972, 0.9978 and 0.9968 and roots of mean square error are RMS = 0.906, 0. 821, 1.091 and 1.091 of four types of carbons, i.e., type 1, 2, 3, and 4 for primary, secondary, tertiary, and quaternary carbons, respectively. The stability and prediction capacity for external samples of four models have been tested by cross-validation.     

一个新的分子电性距离矢量(MEDV)

有机化合物通常由电性各异的碳、氢、氧、氮、硫等元素以共价键相互连接而成。我们提出了一个称为分子电性距离矢量(简称MEDV)的新描述来表征有机分子结构。以含有环、饱和与不饱和键及碳氧氮等元素的色氨酸分子为例,说明构建MEDV的基本方法。开发设计了计算有机MEDV分子的TrueBASIC语言程序。不借用其他任何描述子,仅用MEDV建立了烷、醇、多环芳烃等多种有机化合物包括沸点、密度、保留指数等多种性质的定量结构-性质相关(QSPR)模型,相关系数均达0.98以上。     

分子电性距离矢量用于多溴联苯醚分子结构表达及色谱保留时间预测

应用分子电性距离矢量(MEDV)对多溴联苯醚(PBDEs)的209种同系物进行结构表征.通过多元线性回归的方法,建立了PBDEs定量结构-色谱保留(QSRR)关系的6个变量和5个变量的两种模型.两种模型的建模计算值复相关系数R均为0.995;用留一法(LOO)进行了交互检验,其复相关系数(R2cv)分别为0.987和0...     

Synthesis and properties of aminomethoxy derivatives of 1-(ethylsulfanyl)alkanes

Mannich condensation of 1-(ethylsulfanyl)alkan-2-ols, formaldehyde, and secondary amines taken in equimolar amounts was used to obtain new amino derivatives of 1-(ethylsulfanyl)alkanes. The structure of the thus synthesized compounds was confirmed by elemental analysis, IR and ¹H NMR spectroscopies, and mass spectrometry. It is shown that the obtained compounds can be used as antimicrobial additives to lubricating oils and antiseptic substances against bacteria and fungi.     

Cobalt(II) tetraphenylporphyrin-catalyzed isomerization of electronegative substituted quadricyclanes

Co(II)TPP¹ - catalysed isomerization of a series of electronegative substituted quadricyclanes($\text{1}$) to the corresponding norbornadiene($\text{2}$) was found to proceed via radicophilic attack of the metal to $\text{1}$.     

Polyfuryl(aryl)alkanes and their derivatives. 14. Halochromism of polyfuryl(aryl)alkanes

It was concluded on the basis of the similarity between the electronic spectra of difurylarylmethanes and trifurylalkanes and the spectra of the corresponding arylfurylcarbinols and difurylcarbenium perchlorates in concentrated sulfuric acid that the appearance of color in the solutions of polyfuryl(aryl)alkanes in concentrated sulfuric acid results from their disproportionation at the carbon-carbon bond with the elimination of the furan ring. The disproportionation of difurylalkanes, containing a methine hydrogen atom at the central carbon atom, under these conditions is accompanied by hydride transfer.For Communication 13, see [1].Kubansk State Technological University, Krasnodar. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 738–741, June, 1996. Original article submitted February 21, 1996.     

Molecular geometry and boiling related thermodynamic properties

Boiling related thermodynamic properties are important parameters in research. In this study, a model integrating both additive groups and non-additive molecular geometric factors has been developed for the calculation of boiling enthalpy, entropy and temperature. The calculated values are in good agreement with the measured values of 470 compounds. This model provides a simple and accurate estimation of enthalpy of boiling, entropy of boiling and boiling temperatures with absolute average errors of 0.62 kJ/mol, 1.15 J/K · mol and 7.13 K respectively.     

双(二环己基膦基)烷烃双(四氟硼酸盐)的合成

以溴代环己烷和亚磷酸二乙酯为原料制得二环己基氧化膦(2),用四氢铝锂还原得二环己基膦氢,经锂化后依次与二氯烷烃和四氟硼酸反应合成了对空气稳定的1,3-双（二环己基膦基）丙烷双（四氟硼酸盐）(4a)和1,4-双（二环己基膦基）丁烷双（四氟硼酸盐）(4b),收率分别为62%和65%,其结构经¹H NMR, ¹³C NMR, ³¹P NMR和元素分析表征。并对关键反应条件进行了优化。     

Chemometrics to chemical modeling: novel molecular distance-edge vector (λ) in alkanes and retention index of gas chromatography

Systematic studies are made on application of chemometrics to chemical modeling and/or molecular modeling as well as the regularity of retention index for gas chromatography (GC). A set of novel molecular graph theoretical parameters, called the molecular distance-edge (MDE) vector (λ), is proposed and found to be excellently correlated to retention index of GC for alkanes. The MDE parameters were tested by the multiple linear regression (MLR) estimation and prediction of the retention index of GC, and the results obtained are satisfactory.     

Molecular motion of isolated linear alkanes in nanochannels

The mobility of a series of linear alkanes in their inclusion compound with tris(o-phenylenedioxy)spirotriphosphazene is studied by high-resolution carbon-proton magic-angle spinning solid-state NMR spectroscopy. Two different carbon-proton dipolar recoupling experiments are compared with respect to their ability to yield precise site-specific, motion-averaged dipolar coupling constants. The most accurate results are obtained by analysis of extrema positions in Lee-Goldburg cross-polarization build-up curves. We present a comprehensive collection of coupling constants, which evidence a rotational motion of the all-trans chains around the channel axis, with some further averaging due to additional fluctuations, as previously found for alkanes in other host matrices such as urea. The order parameter increases toward the inner parts of the chains, and is largely independent of chain length. Notably, chains in a TPP host are not more ordered than in urea, even though the average TPP channel diameter is reported to be smaller. Significantly decreased order is found for highly filled short-alkane samples, which is interpreted in terms of an increased rate of mutual collisions. From residual dipolar couplings as well as carbon chemical shifts, we derive similar amounts of gauche conformers. Translational motions along the channels are further studied by proton double-quantum spectroscopy, which probes guest-host dipolar couplings. The extent of local-scale lateral motion is again correlated with the sample filling, and is a weak function of temperature, as expected from a case in which highly restricted single-file diffusion should dominate the mobility. Characteristic effects of sample aging are apparent in all our experiments.     

Extraction of scandium(III) by bis(diphenylphosphorylmethylcarbamoyl)alkanes

The extraction of trace amounts of scandium(III) from HCl,HNO₃, and HClO₄ solutions in the form of complexes with neutral polyfunctional organophosphorus compounds bis(diphenylphosphorylmethylcarbamoyl)alkanes [Ph₂P(O)CH₂C(O)NH]₂(CH₂) _n (n = 3, 5, 8) was studied. The effect of the structure of the extractant, the aqueous phase composition, and the nature of the organic solvent on the efficiency of transition of scandium(III) ions into the organic phase was considered, and the stoichiometry of the extracted complexes was determined. The studied ligands exhibit a higher extraction power toward scandium(III) ions than their analog Ph₂P(O)CH₂C(O)NHC₉H₁₉ containing only one bidentate carbamoylmethylphosphoryl moiety per molecule. Scandium(III) passes into the organic phase most efficiently in the presence of HClO4 in the aqueous phase. It was shown that scandium(III) can be selectively recovered and preconcentrated by a complexing adsorbent obtained by noncovalent immobilization of bis(diphenylphosphorylmethylcarbamoyl)pentane on a macroporous polymer matrix.     

Molecular chain properties of poly (N-isopropyl acrylamide)

A series of poly( N-isopropyl acrylamide) (PNIPAM) samples with molecular weight ranging from 2.23×10~4 to 130×10~4 and molecular weight distribution M_w/M_n≤1.28 were obtained by free radical polymerization and repeat precipitation fractionation. The molecular weight M_w, second virial coefficient A_2 as well as the mean-square-root radius of gyration 〈S~2〉 for PNIPAM samples in tetrahydrofuran (THF) were determined by light scattering, and the relations were estimated at A_2 ∞ M_w~0.25) and 〈S~2〉~(1/2)=1.56×10~(-9) M_w~(0.56). The intrinsic viscosity for THF solution and methanol solution of PNIPAM samples was measured and the Mark-Houwink equations were obtained as [η]=6.90×10~(-5) M~(0/73) (THF solution) and [η]=1.07×10~(-4) M~(0.71) (methanol solution). The above results indicate that both THF and methanol are good solvents for PNIPAM. The limit characteristic ratio C_∞ for PNIPAM in the two solutions was determined to be 10.6 by using Kurata-Stockmayer equation, indicating that the f     

Oxomolybdenum(V) complexes of bis-(2-benzimidazolyl) alkanes

Summary Oxomolybdenum(V) complexes of the type (LH₄) [MoOCl₅] (where LH₂ = dimethylene bis-2-benzimidazole or tetramethylene bis-2-benzimidazole), [MoOCl₃(LH₂)] (where LH₂ = tetramethylene bis-2-benzimidazole), [(Mo₂O₄Cl₂-(H₂O)₃)₂(LH₂)] (where LH₂ = dimethylene bis-2-benzimidazole, tetramethylene bis-2-benzimidazole or hexamethylene bis-2-benzimidazole) and [Mo₂O₃Cl₄(LH₂)₂] (where LH₂ = tetramethylene bis-5-nitro-2-benzimidazole) were prepared and characterised. The mononuclear complexes show u.v.-vis. absorptions characteristic of octahedral molybdenum(V). The dinuclear complexes do not absorb in the visible region, possibly due to the presence of an Mo₂O ₄ ^{2 +}} core, which is also indicated by their diamagnetic behaviour. The biological activities of the free ligands and their complexes have been studied.     

Mn(15-冠-5)(NCS)_2的晶体和分子结构

在碱金属离子或碱土金属离子与过渡金属离子共存的情况下，全氧冠醚一般选择前者与之配位［1，2］，而与过渡金属离子直接配位的情况则报道较少［3，4］我们在Na+与Mn2+共存的体系中制得了标题配合物的单晶体，并用四圆衍射仪测定了其晶体结构和分子结构．本文对进一步探讨全氧冠醚与过渡金属离子的配位性能及配位特点具有重要的意义．1实验部分1．1单晶生长在10mL称量瓶中，加入0．5gMnCI。·4H。0、08gNaSCN和5mL蒸馏水，溶解后再加入0．ig15一冠一5，搅拌均匀，静置于有机玻璃恒温箱中（25士0．SC），6h后长出无色棒状单晶．经红外…     

Crystal and Molecular Structure of BiCl3(15-Crown-5)

Single crystals of complex BiCl3(15-crown-5) were synthesized by gel method, and the structure was solved from X-ray diffraction data by direct and Fourier methods. The crystal is orthorhombic, space group is P212121 with unit cell parameters:a = 7. 677(4), 6=13. 254(6) and c= 15. 911(6) A , and 2=4. The final structural refinement converged with unweighted and weighted factors of 0. 053 and 0. 063 respectively for 1290 observed reflections. The structure consists of discrete BiCl3(15-crown-5) molecules in which bismuth atom is sandwiched between two essentially parallel planes, one of which contains five oxygen atoms and the other contains three chlorine atoms.     

Polyfuryl(aryl)alkanes and their derivatives

The reduction of 2-nitrophenyldifurylmethane with SnCl₂ leads to an indolenyl ketone as a result of intramolecular heterocycloaddition of the intermediately formed nitroso derivative. During the reduction of 2-nitroaryldifurylmethanes in the Zn+HCl or NH₂NH₂·H₂O+Pd/C systems, 2-aminoaryldifurylmethanes are formed; when treated with trityl perchlorate, their acetyl derivatives are converted into indolo[2,3-h]-1-oxazulenium perchlorates.For Communication 14, see [1].Kubansk State Technological University, Krasnodar. Severo-Osetinsk State University, Vladikavkaz. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1614–1621, December,1997.     

Intramolecular excimer of DI(1-pyrenylmethyleneoxycarbonyl) alkanes

Intramolecular excimer emission of a series of di(1-pyrenylmethyleneoxycarbonyl)alkanes (n = 0–22) has been studied under photostationary conditions. The intramolecular excimer formation rate constant decreases monotonously with increasing number of methylene units of the chains in the low temperature region. The temperature dependence of the rate constant for each sample was studied to give an apparent activation energy of ca. 5 kcal/mol.     

Convenient synthesis of bis(indolyl)alkanes and bis(pyrrolyl)alkanes by Cu(OTf)2-catalyzed addition of indole and pyrrole to acetylenic sulfone

Sulfonyl-containing bis(indolyl)alkanes and bis(pyrrolyl)alkanes were synthesized conveniently by Cu(OTf)₂-catalyzed double Michael addition of indole and pyrrole to acetylenic sulfone.     

Synthesis of bis(glycosylamino)alkanes and bis(glycosylamino)arenes

The condensation of D-mannose and D-galactose with aliphatic and aromatic diamines afforded a series of bis(glycosylamino)alkanes and-arenes. A possible mechanism was proposed for the formation of 1,2-bis(β-D-glycosylamino)benzenes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2793–2801, December, 2005.