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1.
Laser excitation of equilibrium vapor mixtures ErCl3(s)-ACl3(g) (A = Al, Ga, In) at 475–1100 K gives rise both to resonance fluorescence from the f → f Er3+ transitions of the Er-Cl-A vapor complexes, and to Raman scattering due to the vibrational modes of the ACl3 vapor. The laser-induced fluorescence from the 4F, 4S and 2H states has been investigated at different temperatures and excitation. 相似文献
2.
Acid catalyzed cyclization of ()-HCO-(CH2)-4-CH=C(Me)-CH(SPh)SiMe3 affords -2-substituted cyclohexanol, while () compound affords the isomer. Those cyclized products are transformed to the corresponding α-methyl γ-lactones. 相似文献
3.
Synthesis and properties of C5H5(CO)2Mn-N2H4-Cr(CC)5, C5H5(CO)2Mn-N2H2-Cr(CO)5 and C5H5(CO)2Mn-N2-Cr(CO)5 are reported. , and constitute the first series of heteronuclear complexes in which N2, N2H2 and N2H4 are bound to identical metal centers. and are obtained by reacting C5H5Mn(CO)2N2H4 respectively with Cr(CO)5THF, by oxidation of . disproportionates by addition of base yielding and H2. The IR Spectrum of allows the assignment of five normal vibrations of the diazene ligand; in the IR spectrum of the deuterated analogue all six normal vibrations can be assigned. The 1H-NMR spectrum of yields the coupling constant of protons on NN double bonds for the first time; the value of 3JHH 23,5 Hz points to a trans structure of . 相似文献
4.
R. Schwesinger K. Piontek W. Littke O. Schweikert H. Prinzbach C. Krüger Y.-H. Tsay 《Tetrahedron letters》1982,23(24):2427-2430
According to X-ray crystal structure analyses “cis-benzenetrisimine” () and “cis-benzenetrioxide” () act as tridentate ligands in their 2:1- and 4:1-complexes (Co(C6H9N3)2(NO3)3) and (Ba(C6H6O3)4(ClO4)2), resp. The latter is the rare example of an organic complex with the (approximate) T-symmetry. 相似文献
5.
Jiro Tsuji Yuichi Kobayashi Hideaki Kataoka Takashi Takahashi 《Tetrahedron letters》1980,21(15):1475-1478
Methyl 3-oxo-8-phenoxy-6-octenoate () was cyclized using Pd(OAc)2-PPh3 as a catalyst to give 2-carbomethoxy-3-vinylcyclopentanone () and 2-carbomethoxy-4-cycloheptenone (). The former was the main product in acetonitrile. 2-Alkylated 3-oxo-8-phenoxy-6-octenoates were converted mainly to the five-membered ketones. Based on this cyclization method, methyl dihydrojasmonate () was prepared from methyl 2-pentyl-3-oxo-8-phenoxy-6-octenoate (). Methyl 3-oxo-9-phenoxy-7-nonenoate (10) was subjected to the palladium-catalyzed cyclization to afford 2-carbomethoxy-3-vinylcyclohexanone (11) selectively without forming the eight-membered ketone (12). 相似文献
6.
Josefina Garcia Robert Greenhouse Joseph M Muchowski Jose Antonio Ruiz 《Tetrahedron letters》1985,26(15):1827-1830
2-Alkyl-3-cyanoindoles are obtained when 1-alkylmethyl-2-chloro-(or 2-phenylsulfonyl)-3-phenylsulfonylindoles are reacted with excess azide ion (90°/DMF). The reaction is considered to occur by a fragmentation recombination process in which the Schiff's base is of central importance. This proposal is supported by the formation of 2-substituted indole-3-carboxylates from aldehydes and the α-phenylsulfonyl--aminophenylacetic acid ester derivative . 相似文献
7.
Boźenna Golankiewicz Piotr Januszczyk Maria Gdaniec Zofia Kosturkiewicz 《Tetrahedron》1985,41(24):5989-5994
2-Acylamino-2-cyanoacetic acid ethyl esters react with 2,4-bis (4-methoxyphenyl)-1, 3, 2, 4-dithiadiphosphetane 2,4-disulfide in refluxing benzene with formation of 2-alkyl(aryl)-5-aminothiazole-4-carboxylic acid ethyl esters . Structure was established by spectroscopic means and an X ray crystallographic investigation of . X-Ray analysis revealed that the thiazole ring, exocyclic nitrogen and carbonyl group forming a hydrogen-bonded cycle are nearly coplanar. A resonance interaction is manifested by distinctly shortened /1.447 (3)/ C(carbonyl)-C(thiazole) distance. 相似文献
8.
The anion of dimethyl homophthalate adds to imidazolinium and tetrahydropyrimidinium salts () to yield imidazolidine and tetrahydropyrimidine adducts corresponding to methylenetetra-hydrofolate models (). These models transfer the carbon fragment 2-(MeOOC)C6H4CH(COOMe)CHXXX to tryptamine to give an enamino ester intermediate which is cyclized, in two steps to the yohimboid skeleton. 相似文献
9.
The reactions (I) Hg2Cl2(s) + Br2(g) and (II) HgCl2(s) + HgBr2(s) have been investigated by an X-ray method. Both the reactions yield two forms of the mixed halide HgClBr, designated as α-HgClBr and β-HgClBr. The cell parameters of the two are as follows:α-HgClBr: , , , z = 4, ? = 5.91 g/cm3. The powder pattern and cell parameters are similar to that of HgCl2. Therefore it is probable that the chlorine atoms, in the linear halogenHghalogen molecules of HgCl2 structure have been replaced by bromines, and since the radius of the bromine atom is larger than that of chlorine, the lattice is larger in this case.β-HgClBr: , , , z = 4, ? = 5.40. These parameters are the same as those reported in the literature for β-Hg(ClBr)2, and its X-ray powder pattern is similar to HgCl2. Therefore this phase also has linear halogenHghalogen molecules but the distribution of Cl and Br atoms is perhaps random.Heating the products (I) and (II) up to the melting point increases the amount of α phase and decreases the β phase, whereas crystallization increases the β phase. DTA study has supported the X-ray findings. 相似文献
10.
11.
- The corresponding - and -methyl- and -benzyl-5,6- and 4,5-tetramethylenetetrahydro-l,3-oxazines were synthesized from - and -methyl and-benzyl-2- aminomethyl-1-cyclohexanols , from - and -methyl- and benzyl -2-hydroxymethyl-1-cyclohexylamines by reaction with formaldehyde. The aminoalcohols and were prepared in considerably higher yields than in earlier procedures. NMR spectroscopy showed that the isomers of the synthesized oxazines were conformationally homogeneous in solution, and their preferred conformation (inside or outside) depended on the steric requirement of the groups attached to the anellation points, whereas a bulky C-2 substituent had no influence on the predominant conformation. The structure of -benzyl--4,5-tetramethylenetetrahydro-1,3-oxaziniumpicrate . determined by X-ray diffraction analysis, was in agreement with the predominant N-outside conformation of the corresponding base, established by means of NMR spectroscopy. 相似文献
12.
Structured emission spectra have been observed from ND3 excited at 2139 Å and 2144 Å. The emission is short-lived (τ < 10?10 s) and has been assigned to the ND3() → ND3() fluorescence transition. 相似文献
13.
The extraction of Co(II) with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one ((H)PMBP) and tri-n-octylamine (TOA) is investigated in order to explore the influence of diluents and inorganic anions with synergistic acidic extractant + liquid anion exchanger systems. Although it is proved that the same species [HTOA]+ [Co(PMBP)3]? is extracted from various inorganic media, with toluene as the diluent, the presence of ClO4? SO42? or Cl? anion modifies the distribution of the anions which are associated to (HTOA)+ in the organic phase, leading to different synergistic equilibria; with Cl? or SO42?: + ,PMBP?) ?,Co(PMBP)3? (log K = 6.10) and with ClO4? : + + ,ClO4? ? ,Co(PMBP)3? + H+ + ClO4? (log K = 2.34) The same synergistic equilibrium is observed for the extraction of Ni(II) from ClO4? medium, with a comparable value of the constant (log K = 2.45). The synergistic effect is cancelled in n-octanol. 相似文献
14.
The dimers & b) of dimethyl- and diethylcyclopentadienone ketals( & b) undergo a novel 1,3-alkoxy-rearrangement to (a & b). Mild hydrolysis of or gives the monoketones (a or b). On strong acid catalysed hydrolysis , or afford the cyclopentadienone-dimer(. 相似文献
15.
The complexes trans-[PdCl{(ME)=NR'} (PPh3)2] (R=C6H11,p-C6H4OMe; R=p-C6H4OMe, Me) containing a σ-bonded 1,4-diaza-3-menthyl-butadiene-2-yl group with different substituents on the nitrogen atoms have been prepared by two routes. The first involves initial methylation of the mixed isonitrile complex [PdCl2(CNR)(CNR')]by HgMe2, followed by reaction with PPh3 (molar ratio ). The second method involves condensation of primary aliphatic amines with the carbonyl group of the 1-azabut-1-en-3-one-2-yl moiety of the complex trans-[PdCl{(Me) = 0} (PPh3)2]. The 1,4-diaza-3-methylbutadiene-2-yl derivatives act through their imino nitrogen atoms as chelating ligands towards anhydrous metal chlorides MCl2 (M = Co, Ni, Cu, Zn). Magnetic moment measurements and the far-infrared and electronic spectra of these adducts indicate an essentially pseudo-tetrahedral configuration at M in the solid and in solution. With the ZnCl2 adducts, the 1H NMR pattern for the phenyl protons of the p-methoxyphenyl N-substituents dependss upon the position of the substituent i the 1,4-diazabutadiene chain. 相似文献
16.
As a part of a systematic study of the synergic extractions of metals with mixtures of acidic chelating extractants and lipophilic anion-exchangers (B, X with X?6 inorganic anion), the extractions of M Cd and Zn from perchlorate, nitrate and sulphate media with 1-phenyl-3-methyl-4-benzoyl-pyrazol-5- one (HL) and tri-n-octylammonium salts (TOAH.X) or aliquat 336 (TOMA.X) in toluene have been investigated. Three key equilibria describe the extractions: (a) M2++2?+2H+. (b) +?+H++X? with B efficiency TOMA < TOAH and X efficiency ClO4 < NO3 < SO4. (c) +? with B efficiency toma > TOAH and Ni ~ Co > Cd > ZN.As a consequence of the conflicting orders of efficiencies of TOMA and TOAH in equilibria b and c, TOAH.X is a better synergic extractant from perchlorate medium than TOMA.X whereas the inverse is observed from nitrate and sulphate media. Equilibrium c is independent of the inorganic anions. Constants of equilibria a, b and c are given. B.ML3 species are not extracted in 1-octanol. 相似文献
17.
Brian J. Brisdon Dennis A. Edwards James W. White 《Journal of organometallic chemistry》1978,156(2):427-437
A series of carbonylmetallate anions -[MX(CO)3L2]?, where M = Mo or W, X = Cl, Br or I and L2 = 1,10-phenanthroline(phen) or 2,2′-bipyridine(bipy) have been prepared from the corresponding -M(CO)4L2 complexes. No evidence of -to -isomerisation was evident on dissolution, although in MeCN solvolysis occurred with the formation of -M(CO)3L2(MeCN). Reaction of the anions with various allyl halides resulted in high yields of η3-allyl complexes [MX(CO)2(η3-RC3H4)L2]. The significance of these observations for the mechanism of the allyl oxidative-addition reaction are discussed. 相似文献
18.
Toschitake Iwamoto 《Journal of Molecular Structure》1981,75(1):51-65
Based on the structural features of Hofmann-type clathraces M(NH3)2M'(CN)4 · 2G (M = a divalent metal in six-coordination, M' = a divalent metal in square-planar coordination, G = a small aromatic guest molecule), several series of the analogous clathrates have been derived by appropriate replacements of the host moieties. These clathrates are designated with a general formula Cd (diam)M'(CN)4 ·G where diam refers to diammine, an ambident diamine or monoethanolamine (mea), or a pair of unidencate mea's, M'(CN)4 is a square-planar or a tetrahedral tetracyanometallate(II), and G is a small aromatic guest molecule. The number of guest molecules, , varies stepwise from 2 through to 1 depending on the bulkiness of diam ligand which builds up the host structure. Their structural features are discussed on the two- and three-dimensional networks of the metal complex hosts. The historical background is also reviewed briefly. 相似文献
19.
Moktar Ferid Mahmoud Dogguy Néjia Kbir-Ariguib Melika Trabelsi 《Journal of solid state chemistry》1984,53(2):149-154
The MIPO3Sm(PO3)3(MI = Li, Na, Ag) systems were studied. Differential thermal analysis and X-ray diffraction were used to investigate the liquidus and solidus relations. Three compounds LiSm(PO3)4, NaSm(PO3)4, and AgSm(PO3)4 were obtained which melt incongruently at 1248, 1143, and 1078 K, respectively. These compounds are isomorphous with their homologs LiLn(PO3)4, NaLn(PO3)4, AgLn(PO3)4 (Ln = Ce, La, Nd). They belong to the monoclinic system. The LiSm(PO3)4 unit cell parameters refined by least squares method are a = 16.43(3) Å, b = 7.16(1) Å, c = 9.65(3) Å, β = 125,9°(1), with the space group and Z = 4. NaSm(PO3)4 and AgSm(PO3)4 are isotypic; they cristallize in the space group, Z = 4; their unit cell parameters are, respectively, a = 12.18(1) Å, b = 13.05(1) Å, c = 7.25(5) Å, β = 126,53°(4), , b = 13.06(1) Å, c = 7.201(9) Å, β = 126,57°(7). The ir spectra of the last two compounds indicate that these phosphates are chain phosphates. 相似文献
20.
The crystal structures of the apatites Ba10(PO4)6F2(I), Ba6La2Na2(PO4)6F2(II) and Ba4Nd3Na3(PO4)6F2 (III) have been determined by single-crystal X-ray diffraction. All three compounds crystallize in a hexagonal apatite-like structure. The unit cells and space groups are: I, a = 10.153(2), c = 7.733(1)Å, Å, ; III, a = 9.786(2), c = 7.281(1)Å, . The structures were refined by normal full-matrix crystallographic least squares techniques. The final values of the refinement indicators Rw and R are: I, Rw = 0.026, R = 0.027, 613 observed reflections; II, Rw = 0.081, R = 0.074, 579 observed reflections; III, Rw = 0.062, R = 0.044, 1262 observed reflections.In I, the Ba(1) atoms located in columns on threefold axes, are coordinated to nine oxygen atoms; the Ba(2) sites form triangles about the F site and are coordinated to six oxygen atoms and one fluoride ion. The fluoride ions are statistically displaced ~0.25 Å from the Ba(2) triangles. This displacement of the F ions is analogous to the displacement of OH ion in Ca10(PO4)6(OH)2.The structures of II and III contain disordered cations. In II there is disorder between La and Na in the column cation sites as well as triangle sites. In III, Nd and Na ions are ordered in the column sites, but there is disorder among Ba and the remaining Nd and Na ions in the triangle sites to give an average site population of . The coordination of the rare earth ions and Na ions in the ordered column sites are nine and six oxygens, respectively, in accord with the greater charge of the rare earth ions as compared with Na. The F ions in both II and III suffer from considerable disorder in position, and their locations are not precisely known. 相似文献