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161.
The mechanism and stereochemistry of δ-C atom functionalisation in the reactions of secondary straight-chain aliphatic alcohols with lead tetraacetate, ceric ammonium nitrate, and heavy metal (Pb4+, Hg2+, Ag+) salts (AcO)?1, O2?, CO32?-halogen (I2, Br2, Cl2) combinations are discussed. By demonstrating the intermediacy of 5-bromo-2-hexanol, it was confirmed that the dark silver oxidebromine induced cyclisation of 2-hexanol (and alcohols in general) involves (as the other hypohalite reactions) intramolecular 1,5-hydrogen abstraction by alkoxy radicals and formation of δ-bromohydrins. A novel and simple procedure for obtaining tetrahydrofurans from alcohols by way of the hypochlorite reaction, using silver or mercuric salts and chlorine, is described. 相似文献
162.
The title compound crystallizes in the orthorhombic space group P212121 with 4 molecules in the unit cell (cell dimensions: a 9.778(2), b 10.639(2) and c 12.423(4) Å). The structure was solved by means of the heavy atom method. The rhodium atom is linked to both olefinic double bonds. The terpene carbonyl group does not participate in coordination to rhodium. Unlike the endocyclic olefinic group, which is approximately perpendicular to the coordination plane of rhodium, the exocyclic Cz.sbnd;C double bound shows a considerable deviation from this arrangement. The π-complexation of carvone with rhodium proceeds diastereospecifically. The absolute configuration of (+)-carvone is 4S in agreement with the assignment derived by indirect chemical correlation. 相似文献
163.
The kinetics of the reaction between organocobaloximes, RCo(DH)2H2O, and iodine have been investigated. They reveal the participation of an RCo(DH)2H2O · I2 intermediate which undergoes intramolecular transalkylation and acts as an electrophile towards a second organocobaloxime molecule. The trend in reactivity as the R group is varied is discussed. 相似文献
164.
消除夹带溶胀的新液膜操作法曹汉瑾,褚莹,何彦涛,吴子生,严忠(东北师范大学化学系长春130024)关键词液膜,油/水乳液,溶胀,夹带,包裹消除液膜操作中的夹带溶胀对液膜的工业化具有重要意义,夹带溶胀分为包裹溶胀和再液化溶胀。前者是乳状液滴上浮时将水相... 相似文献
165.
A new series of group 6 carbonyl complexes of N-[(2-pyridyl)methyliden]-α (or β)-aminonaphthalene (α/β-NaiPy) are described in this work. The complexes are formulated as cis-[M(CO)4(α/β-NaiPy)] by elemental, mass and other spectroscopic data. The complexes show emission spectra at room temperature and their quantum yield lies between 0.4 and 0.5. All the complexes exhibit negative solvatochromism. Cyclic voltammetry shows metal centred oxidation and ligand reductions. 相似文献
166.
167.
The metalation of allyl benzyl thioether involves the benzylic or the allylic hydrogens. The benzylic carbanion undergoes a rapid[2,3] sigmatropic shift whereas the allylic carbanion gives rise to various rearrangements, among them migration of the allylic unit to the para position with allylic inversion. The temperature dependence of the ratio of products arising from the benzylic carbanion vs those from the allylic carbanion shows that the allylic-to-benzylic carbanion transformation occurs only under special conditions: (a) with slow addition of the base; (b) with thioether in excess relative to the base, and (c) on raising the temperature of the reaction medium from ?78° to ?15°. In the last instance, the proton transfer is intramolecular as shown with labeled thioethers. The extent of the different rearrangements depends on the temperature and solvent. A choice of mechanism cannot be made at this time for the para migration 5→9a. A leaving group effect on the reaction regioselectivity of the carbanion from allyl methyl thioether with benzyl halides has been noticed. The presence of dibenzyl indicates that, in addition to SN2 reactions, some electron transfer process is occurring. 相似文献
168.
Michael Stavola J.M. Friedman R.A. Stepnoski Mark G. Sceats 《Chemical physics letters》1981,80(1):192-194
Cooperative vibronic spectra involving Gd3+ electronic transitions and the vibrational transitions of nearby water molecules are used to determine the stretching spectrum for isotopically dilute OH in a solution of GdCl3 in D2O. The OH stretching spectrum of water molecules in the first hydration sphere is shifted to lower energy than that of the bulk liquid. 相似文献
169.
Lemi Türker 《Journal of Molecular Structure》2004,680(1-3):47-51
Semiempirical quantum chemical calculations at the level of AM1 (restricted Hartree–Fock) have been performed on a fullerene derivative, C54N4, theoretically obtained from C60 and its mono and diprotonated forms. All these structures are stable, but endothermic in nature. Some calculated geometrical and physicochemical properties of these have also been reported. 相似文献
170.
Jolanta Olkowska‐Oetzel Dieter Fenske Petra Scheer Andreas Eichhfer 《无机化学与普通化学杂志》2003,629(3):415-420
Syntheses and Thermal Properties of Cluster Molecules, formed from Groups 11‐13‐16 Elements In the presence of PPh3, CuX (X = Cl, CH3COO) or AgOC(O)C6H5 and GaCl3 react in THF with S(SiMe3)2 or Se(SiMe3)2 to yield [Cu6Ga8Cl4S13(PPh3)6] ( 1 ), [Cu6Ga8Cl4Se13(PPh3)6] ( 2 ), [Ag6Ga8Cl4S13(PPh3)6] ( 4 ) and [Ag6Ga8Cl4Se13(PPh3)6] ( 5 ). The use of PnPr2Ph instead of PPh3 and subsequent layering with n‐hexane leads to the formation of the cluster [Cu6Ga8Cl4Se13(PnPr2Ph)12] ( 3a , 3b ). Reaction of CuCl, GaCl3 and PnPr3 with Se(SiMe3)2 in THF results in the crystallisation of the ionic cluster (HPnPr3)2[Cu2Ga4Cl4Se6(PnPr3)4] ( 6 ). The structures of 1 — 6 were determined by X‐ray single crystal structure analysis. Thermogravimetric measurements of the cluster molecules and powder diffraction patterns of the remaining powders reveal the potential use of them as single source precursor compounds for the synthesis of the related ternary solid state materials. 相似文献