共查询到20条相似文献,搜索用时 31 毫秒
1.
Reaction of 1,2-bis(diorganophosphino)ethanenickel dibromide (I) with 1,2,3,4-tetraphenyl-1,4-dilithiumbutadiene (II) at ?30°C yields diphosphannickelacyclopentadiene (III) which at elevated temperatures isomerizes to diphosphanecyclobutadienenickel(0) (IV). The thermodynamic and kinetic parameters of the rearrangement were determined. The structural and conformational analyses of III were carried out by means of 13C NMR, 31P NMR and Raman spectroscopy. The reactions of III and IV with CH3COOH, CO, RCCR and RNCNR have been axamined and the observed reactivities III ? IV are discussed. 相似文献
2.
Addition of nitroalkanes into n‐alkanes can lower the activation barriers of free‐radical production and accelerate the decomposition of n‐alkanes at relatively low temperatures. Four initial decomposition mechanisms of the n‐butane/nitroethane binary mixture were proposed for the promoting effect and considered theoretically at the B3LYP, BB1K, BMK, MPW1K, and M06‐2X levels with MG3S basis set. Energetics above was compared to high‐level CBS‐QB3 and G4 calculations. Calculated results confirm the feasibility of the four initial decomposition pathways: (I) the C? NO2 bond rupture of nitroethane to produce ethyl and ·NO2, (II) HONO elimination from nitroethane followed by decomposition to ·OH and ·NO, (III) rearrangement of nitroethane to ethyl nitrite which further dissociates into CH3CH2O· and ·NO, and (IV) direct hydrogen‐abstraction of nitroethane with n‐butane. 相似文献
3.
Analysis of ESR spectra of mechanoradicals from poly(methyl methacrylate) reveals that after mechanical degradation in vacuo at 77°K, the sample contains two types of primary radicals? CH2? C(CH3)(COOCH3) (I) and CH2? C(CH3)(COOCH3)? CH2 (II) produced by the breaking of the polymer chain, and secondary radicals ? CH2? C(CH3)(COOCH3)? CH? C(CH3)? (COOCH3)? CH2? (III). With increasing temperature, radical I remains stable while II reacts with methylene hydrogen of the polymer chain giving rise to the secondary radical III, which decays and finally disappears as the temperature rises. After admission of oxygen at 113°K, the polymer radicals react with oxygen with formation of polymer peroxy radicals ROO. and diamagnetic dimers. With increasing temperature the latter dissociate again to the original polymer peroxy radicals which gradually decay, if the temperature is increased further. The present results are compared with earlier ones obtained on poly(ethylene glycol methacrylate) (PGMA). 相似文献
4.
V. N. Odinokov V. R. Akhmetova R. G. Savchenko G. A. Tolstikov 《Chemistry of Natural Compounds》1987,23(4):500-502
(±)-15,19-Dimethyltritriacontane (II) — a component of the pheromone of the stable fly — has been obtained by a five-stage synthesis from dimethylcyclooctadiene (I). The coupling of 1,1-dimethoxy-4-methyl-8-oxonon-4Z-ene [the product of the ozonolysis of (I)] with n-C13H27CH=PPh3 (THF; ?30°, 2 h; 25°, 15 h; Ar) gave 1,1-dimethoxy-4,8-dimethyldocosa-4Z,8Z(E)-diene (III). The hydrolysis of (III) (TsOH·Py, H2O-Ac, boiling, 4 h) gave the corresponding aldehyde (IV). The condensation of (IV) with n-C10H21CH=PPh3 (THF; ?60° to ?30°C, 2 h, 25°C, 15 h) led to 15,19-dimethyltritriaconta-11Z(E),15Z,19Z(E)-triene (V), the exhaustive hydrogenation of which (ethanol, H2, 5% Pd/C, 25°C) gave (II). The substance, the yield in %, and Rf values are given, respectively: (II), 95, 0.92; (III), 29, 0.74; (IV), 80, 0.72; (V) 50, 0.8. The IR and PMR spectra of compounds (II)–(V) and the mass spectra of (II) and (III) are given. 相似文献
5.
The structure, thermal stability and decomposition of solutions of diallylzinc (I), bis(2-methylallyl)zinc (II), bis(3-methylallyl)zinc (III) and bis(3,3-dimethylallyl)zinc (IV) in deuterated solvents, have been investigated by1H NMR and by kinetic measurements at temperatures between ?125 and +180°C. At room temperature I, II, III and IV are dynamic systems and are best described as being rapidly equilibrating mixtures of all isomeric σ-allyl forms; the NMR spectra are averages weighted according to the relative concentrations of the respective forms. I displays a1H NMR spectrum of a static σ-allyl system only below ?125°C and II only below ?115°C. At temperatures above 100°C the thermal decomposition of I–IV results in coupling of the allyl groups, decomposition via radicals being the major process. The coupled products exhibit CIDNP, in which the multiplet polarisations confirm a decomposition via randomly diffusing allyl radicals. In the allyl radicals CH2CR1CR2R3 an alternating spin density was proved experimentally. The thermal stability decreases in the order I > II > III > IV. 相似文献
6.
Four Crystalline Forms of (Tetrahydrothiophene)trichloridogold(III): Polymorphism and Reversible Low‐temperature Phase Transitions
下载免费PDF全文
![点击此处可从《无机化学与普通化学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The title compound (tht)AuCl3, previously known to crystallize at –95 °C in space group C2 with Z = 4 (form I ), converts reversibly to form II (P21/n, Z = 8) at ca. –150 °C; the b axis doubles and the centering is lost. A few crystals of a rarer form III (Pna21, Z = 4) were also investigated; these transform reversibly to form IV (P21/c, Z = 4) at ca. –160 °C. In all forms, stacks of molecules are formed, with short Au ··· Cl contacts within the stacks. For forms I and II , adjacent stacks are connected by C–H ··· Cl interactions; more striking for forms III / IV are short Cl ··· Cl contacts between the stacks. Detailed physico‐chemical studies of the relationships between the various phases proved to be impossible, largely because form III could not be obtained reproducibly in significant quantities. 相似文献
7.
V. N. Odinokov V. R. Akhmetova Kh. D. Khasanov A. A. Abduvakhabov A. V. Kuchin N. I. Andreeva G. A. Tolstikov 《Chemistry of Natural Compounds》1989,25(5):610-613
A four-stage asymmetric synthesis of (+)-disparlure [(7R,8S)-(+)-cis-methyl-7,8-epoxyoctadecane (V)] has been effected from 8-methylnon-2Z-en-l-ol (I), obtained by the carboalumination of acetylene with tris(5-methylhexyl)aluminum using the Sharpless reaction. The asymmetric epoxidation of (I), (Ar, mol. sieve A, (+)-DET, (iOPr)4Ti, t-BuOOH, ?15°C, 20 h; H2O, 1 h, NaOH, ?7°C, 30 min) gave 8-methyl-2S,3R-epoxynonan-l-ol (II), which was oxidized (kieselguhr-CrO3-Py, 0°C, 2 h; 25°C, 2 h) to 8-methyl-2S,3R-epoxynonan-l-al (III). The coupling of (III) with n-C8H17CH=PPh3 (?78°C, 1 h; 25°C, 15 h) gave 2-methyl-7R,8S-epoxyoctadec-9Z-ene (IV), the hydrogenation (H2/5% Pd-C, 25°C, 5 days) of which led to (V) in admixture with an isomerization product. Compound (V) was isolated by HPLC. Substance, yield, [α] D 25 : (II), 73, ?2.75°; (III), 80, [80.8°; (IV), 50, +37.25°; (V), 50, +0.8°. The IR and PMR spectra of (II–IV), the13C NMR spectra of (II) and (III), and the mass spectrum of (IV) are given. 相似文献
8.
Fabian Gerson Joanna Jachimowicz Ichiro Murata Kazuhiro Nakasuji Kagetoshi Yamamoto 《Helvetica chimica acta》1975,58(8):2473-2483
The radical anion and the radical cation of azuleno[1,2,3-cd]phenalene (III) have been investigated by ESR. spectroscopy, along with the radical anion of 2-phenylazulene (IV). Also studied has been the neutral radical obtained by one-electron reduction of cyclohepta[cd]phenalenium-cation (VI⊕). Assignment of the proton coupling constants for the radical ions III. ·?, III ·⊕ and IV·⊕, and the radical VI · is supported by comparison with the ESR. spectra of specifically deuteriated derivatives III-d5 ·?, III-d5 ·⊕, IV-d2 ·? and VI-d1′. The experimental results are in full accord with qualitative topological arguments and predictions of HMO models. Whereas the radical anion III ·? exhibits α-spin distribution similar to that of IV ·?the corresponding radical cation III ·⊕ and the neutral radical VI · are related in this respect to phenalenyl (V·). It is noteworthy that oxidation of III by conc. H2SO4 yields a paramagnetic species (IIIa ·⊕) which has a similar – but not an identical – structure as the radical cation III ·⊕ produced from III with AlCl3 in CH3NO2. 相似文献
9.
《International journal of quantum chemistry》2018,118(18)
Elementary processes of the aromatic Claisen rearrangement were investigated by DFT calculations. First, rearrangements of four substrates Ph—O—CH2—CHCH2 [A], Ph—O—CH2—CHCH(OMe) [B], Ph—O—CH2—CHCH2····BF3 [C], and Ph—O—CH—CHCH(OMe)····BF3 [D] were examined. In these systems, the tautomerization is initiated by the intermolecular proton transfer involving the transient ion‐pair intermediate. An ignition‐propagation chain‐reaction mechanism in the tautomerization was suggested. For [A], the (ortho‐allyl phenol → α‐methyl‐dihydrobenzofuran (α‐methyl‐cumarane)) process was found to be ready and the product of the Claisen rearrangement seems to be the cumarane rather than the phenol. In [D] (activated both by the terminal methoxy group and by the BF3 catalyst), not the [3,3]‐sigmatropic shift but the tautomerization is the rate determining step. Second, the parent system, Ph—O—CH2—CHCH2, was investigated with (H2O) n (n = 2, 4, 6, and 10) systematically. The tautomerization takes place by the proton transfer via the water dimer or trimer. Except n = 2, similar changes of Gibbs free energies were obtained from the ether substrate to the cumarane. 相似文献
10.
The syntheses of dibenzo [b, f]-1, 4-oxazepin-11 (10 H)-ones (I) with electron-attracting substituents in position 2 by ring closure of the sodium salts of 2-halogeno-2′-hydroxy-benzanilides (II) are described. The reaction of II (R = SO2·N(CH3)2) in N-methylpyrrolidone also led, by SMILES rearrangement, to the isomeric minor product dibenzo [b, e]-1, 4-oxazepin-11 (5 H)-one (III; R = SO2·N(CH3)2), whose constitution was proven by synthesis from VI. In the case of II (R = SO2·CH3), the 5-methylsulfonyl-2-(2-hydroxyanilino)-benzoic acid (VI; R = SO2·CH3) was obtained directly after hydrolysis. The lactam I (R = NO2) was rearranged to the corresponding acid VI by heating with dilute caustic soda. 相似文献
11.
5-Aza(oxa, thia)-2, 8-dithia-1-stanna(II)-bicyclo[3.3.01,5]octanes — Intramolecular Stabilized Stannylenes By the reaction of tin(II) butoxide with mercaptanes of the general type E(CH2? CH2SH)2 (E ? N-t-Bu, NMe, O, S) at temperatures up to 50°C the 5-aza(oxa, thia)-2, 8-dithia-1-stanna(II)-bicyclo[3.3.01,5]octanes I—IV are obtained in high yields. The compounds are monomeric in solution. Contrary at higher reaction temperatures (80°C) the spiro-compounds of the type [E(CH2CH2S)2]2Sn ( V—VIII ) are formed. Some typical stannylene reactions of I—IV with BF3, Cr(CO)6, Br2, and PhS? SPh show the high reactivity of the compounds. Their structure is investigated by 1H, 13C, and 119Sn n.m.r., i.r., and Mössbauer spectroscopy. 相似文献
12.
Diana Yanover Menahem Kaftory 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(8):o365-o370
The lophine derivative 2‐(2‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole, C21H15N3O2, (I), crystallized from ethanol as a solvent‐free crystal and from acetonitrile as the monosolvate, C21H15N3O2·C2H3N, (II). Crystallization of 2‐(4‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole from methanol yielded the methanol monosolvate, C21H15N3O2·CH4O, (III). Three lophine derivatives of methylated imidazole, namely, 1‐methyl‐2‐(2‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole methanol solvate, C22H17N3O2·CH4O, (IV), 1‐methyl‐2‐(3‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole, C22H17N3O2, (V), and 1‐methyl‐2‐(4‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole, C22H17N3O2, (VI), were recrystallized from methanol, acetonitrile and ethanol, respectively, but only (IV) produced a solvate. Compounds (III) and (IV) each crystallize with two independent molecules in the asymmetric unit. Five imidazole molecules in the six crystals differ in their molecular conformations by rotation of the aromatic rings with respect to the central imidazole ring. In the absence of a methyl group on the imidazole [compounds (I)–(III)], the rotation angles are not strongly affected by the position of the nitro group [44.8 (2) and 45.5 (1)° in (I) and (II), respectively, and 15.7 (2) and 31.5 (1)° in the two molecules of (III)]. However, the rotation angle is strongly affected by the presence of a methyl group on the imidazole [compounds (IV)–(VI)], and the position of the nitro group (ortho, meta or para) on a neighbouring benzene ring; values of the rotation angle range from 26.0 (1) [in (VI)] to 85.2 (1)° [in (IV)]. This group repulsion also affects the outer N—C—N bond angle. The packing of the molecules in (I), (II) and (III) is determined by hydrogen bonding. In (I) and (II), molecules form extended chains through N—H...N hydrogen bonds [with an N...N distance of 2.944 (5) Å in (I) and 2.920 (3) Å in (II)], while in (III) the chain is formed with a methanol solvent molecule as the mediator between two imidazole rings, with O...N distances of 2.788 (4)–2.819 (4) Å. In the absence of the imidazole N—H H‐atom donor, the packing of molecules (IV)–(VI) is determined by weaker intermolecular interactions. The methanol solvent molecule in (IV) is hydrogen bonded to imidazole [O...N = 2.823 (4) Å] but has no effect on the packing of molecules in the unit cell. 相似文献
13.
Contributions to the Chemistry of Transition Metal Alkyl Compounds. XL. About Lithium Alkenylmanganates(II) MnCl2 reacts with vinyl, 2,2-dimethylvinyl, allyl, and methallyl lithium giving rise to alkenyl manganates(II). In a pure state the compounds Li2[Mn(CH?CH2)4] · 1.5 diox, Li2[Mn(CH?C(CH3)2)4] · 1.5 diox, Li2[Mn(CH2? CH?CH2)4] · 2.5 diox and Li3[Mn(CH2? C(CH3)?CH2)5] · 2 diox were isolated. The compounds were characterized by elementary analysis, EPR and IR spectra, magnetic moments, and reactions with iodine. 相似文献
14.
T. N. Fedotova G. G. Aleksandrov G. N. Kuznetsova 《Russian Journal of Inorganic Chemistry》2008,53(12):1862-1869
The Platinum(II) diamine with N,N-dimethylethylenediamine (N,N-dimeEn) [Pt{(CH3)2N(CH2)2NH2}Cl2] (I) was synthesized. The reaction of the diamine with pyridine gave Pt(II) tetramine [Pt{(CH3)2N(CH2)2NH2}Py2]Cl2 (II), which was oxidized with chlorine to give Pt(IV) triamine Pt{[(CH3)2N(CH2)2}PyCl3]Cl · H2O (III). The reaction of III with chlorine (chloroamidation) yielded chloroimide [Pt{(CH3)2N(CH2)2NCl}PyCl3] (IV). The IR spectra of complexes I–IV and UV/Vis spectra of III and IV were studied. X-Ray diffraction analysis was performed for III (monoclinic crystals, space group P21/c, a = 7.7437(6), b = 8.1100(7), c = 28.52992(2) Å, β = 93.7280(10)°, Z = 4, R hkl = 0.0420) and IV (orthorhombic crystals, space group Pna21, a = 15.7825(12), b = 7.4447(6), c = 12.3099(6) Å, Z = 4, R hkl = 0.0539). During oxidation of Pt(II) tetramine with chlorine, the pyridine molecule is removed from the cis position relative to the (CH3)2N group (trans position relative to the NH2 group) of N,N-dimethylethylenediamine. The reaction of chloroimide complex IV with concentrated HCl (dechloroamidation) at 20°C afforded the initial complex III; that at 100°C, gave triamine III together with Pt(IV) diamine [Pt(N,N-dimeEn)Cl4] (V) (monoclinic crystals, space group P21/n, a = 7.1278(5), b = 11.5384(8), c = 12.7501(9) Å, β = 93.23(10)°, Z = 4, R hkl = 0.0239). 相似文献
15.
Guerreiro C. T. R. Ribeiro C. A. Crespi M. S. Torres C. 《Journal of Thermal Analysis and Calorimetry》2002,67(2):419-424
Magnesium ion was reacted with 5,7-dibromo-, 5,7-dichloro-, 7-iodo-and 5-chloro-7-iodo-8-hydroxyquinoline, in acetone/ammonium
hydroxide medium under constant stirring to obtain (I) Mg[(C9H4ONBr2)2]·2H2O; (II) Mg[(C9H4ONCl2)2]·3H2O; (III) Mg[(C9H5ONI)2]·2H2O and (IV)Mg[(C9H4ONICl)2]·2.5H2O complexes. The compounds were characterized by elemental analysis, IR spectra, ICP, TG-DTA and DSC.
Through thermal decomposition residues were obtained and characterized, by X-ray diffractometry, as a mixture of hexagonal
MgBr2 and cubic MgO to the (I) compound at 850°C; cubic MgO to the (II), (III) and (IV) compounds at750, 800 and 700°C, respectively.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Xiang-Long Niu Lin Wei Jian-Cheng Liu Wan-He Jia Jian-Ping Ma Lei Wang Jian-Cheng Wang Yu-Bin Dong 《Acta Crystallographica. Section C, Structural Chemistry》2021,77(1):29-39
Semirigid organic ligands can adopt different conformations to construct coordination polymers with more diverse structures when compared to those constructed from rigid ligands. A new asymmetric semirigid organic ligand, 4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine ( L ), has been prepared and used to synthesize three bimetallic macrocyclic complexes and one coordination polymer, namely, bis(μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine)bis[dichloridozinc(II)] dichloromethane disolvate, [Zn2Cl4(C12H10N6)2]·2CH2Cl2, ( I ), the analogous chloroform monosolvate, [Zn2Cl4(C12H10N6)2]·CHCl3, ( II ), bis(μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine)bis[diiodidozinc(II)] dichloromethane disolvate, [Zn2I4(C12H10N6)2]·2CH2Cl2, ( III ), and catena‐poly[[[diiodidozinc(II)]‐μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine] chloroform monosolvate], {[ZnI2(C12H10N6)]·CHCl3}n, ( IV ), by solution reaction with ZnX2 (X = Cl and I) in a CH2Cl2/CH3OH or CHCl3/CH3OH mixed solvent system at room temperature. Complex ( I ) is isomorphic with complex ( III ) and has a bimetallic ring possessing similar coordination environments for both of the ZnII cations. Although complex ( II ) also contains a bimetallic ring, the two ZnII cations have different coordination environments. Under the influence of the I? anion and guest CHCl3 molecule, complex ( IV ) displays a significantly different structure with respect to complexes ( I )–( III ). C—H…Cl and C—H…N hydrogen bonds, and π–π stacking or C—Cl…π interactions exist in complexes ( I )–( IV ), and these weak interactions play an important role in the three‐dimensional structures of ( I )–( IV ) in the solid state. In addition, the fluorescence properties of L and complexes ( I )–( IV ) were investigated. 相似文献
17.
E. Santoro 《Journal of mass spectrometry : JMS》1973,7(5):589-599
The mass spectra of the following compounds have been studied: and the fragmentation pathways established with the aid of accurate mass measurements, metastable transition and appearance potential determination. The mass spectra show that the sulphur-containing compounds (II to IV) give a stronger molecular ion that that of compound I. A further significant difference is the low intensity, in the mass spectra of II to IV, of the fragments relative to the processes that occur in I, probably because the electron removed upon ionisation belongs to the sulpher atom in compounds II to IV and to the oxygen in compound I. The isomeric compounds, (III and IV) show quite different mass spectra, The radicals containing only Phosphorus and oxygen have an ionisation potential close to 9 eV and the presence of sulphur considerably lowes this value. The measured ionisation potentials of compounds I to IV are respectively, 10·70, 9·55, 9·20 and 9·00eV. The heats of formation of compounds II and III have been estimated as ?176 and ?118 Kcal mole?1, respectively. 相似文献
18.
Mild solvothermal synthesis, structures, thermal and magnetic properties of coordination complexes [Ln(PDA)2(PDAH2)] · (DMAH2)2(DMAH0.5)2(I–IV) (PDA = pyrdine-2,6-dicarboxylate anion, DMAH = dimethylamine, Ln = Ce, Nd, Sm, and Ho) are described. The DMAH molecules in I–IV, generated in situ from hydrolysis of N,N-dimethylformamide, are responsible to assemble three dimensional coordination polymers through N–H···O and C–H···O hydrogen bonds. Distorted tricapped trigonal prismatic LnO6N3 geometry having 14 triangular faces is attributed to mean deviation of dihedral angles while nitrogen shows fairly triangular faces having dihedral angle close to 60°C (CIF files CCDC nos. 872065 (I), 872070 (II), 872069 (III), and 872066 (IV)). Curie–Weiss law and the overall magnetic behavior are typical for the presence of antiferromagnetic exchange coupling interactions between lanthanide. Thermal decomposition analyses reveal removal of ammonia and resultant complexes showthermal stability. Complexes have been further characterized by using elemental analyzer and FT-IR spectroscopy. 相似文献
19.
The reactions of eaq−, CH2OH·, (CH3)2COH·, CO, OH· and N3· radicals with peroxo terpyridine complexes of Cu(II), Zn(II), and Cu(II) Zn(II) in aqueous solution were investigated by pulse radiolysis. The primary products from the reduction and oxidation of the macrocyclic complexes were assigned a radical nature by comparing their optical spectra with those of Cu(I), Zn(I), and Cu(III) species. Such metal–ligand radical products undergo disproportionation that does not lead to the formation of Cu(0) or colloidal copper. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 92–98, 2000 相似文献
20.
(C5H5)Co[2–6-η-(CH3)2Si(CHCH)2BC6H5(III) is prepared photochemically from (C5H5)Co(CO)2 and (CH3)2Si(CHCH)2BC6H5 (II). Acetylation of the new complex III with CH3COCl/AlCl3 and subsequent hydrolysis effect ring-opening new complex III with CH3COCl/AlCl3 and subsequent hydrolysis effect ring-opening to give (C5H5)Co[(1,2-η-(cis-CH3COCH)CH(η-CH2CH)Si(CH3)2] (IV) which slowly isomerizes (ΔG≠296 100 ± 2 kJ mol?1) to the corresponding trans-isomer (V).Pure (CH3)2Si(CHCH)2Sn(CH3)2 (I) can be obtained in preparative quantities via the new complex (CH3)2Si(CHCH)2Sn(CH3)2 · 2 CuCl. 相似文献