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1.
Optical absorption and emission spectra are reported for single crystals of the cubic elpasolite Cs2NaSmCl6. The variable temperature spectra obtained at high resolution are assigned using energies and relative intensities. Transitions from the ground level, 6H to cystal fi levels of 6H-, 6F-, 4G-, 4F,, 4I, and 6P, are located and characterized. Intensity calculations are reported for magnetic dipole allowed transitions. The dominance of vibronic intensity in 6H→6F - and 6P, transitions is accounted for qualitatively through the ligand polarization model involving quadrupole metal (Sm3+)-ligand (Cl?) interaction mechanisms. The Eu″(6H)→E′(6H) Eu′(6F) no-phonon transition is postulated to be pure electric quadrupole allowed. The ground state magnetic moment is determined to be very small from magnetic circular dichroism (MCD) spectra.This study has led to the assignment of nearly all of the crystal field levels in the visible and IR region for Cs2NaSmCl6. A total of 27 such levels were identified, 17 from no-phonon transitions and the rest from vibronic transitions. The magnetic dipole intensity calculated using intermediate coupling Oh wavefunctions along with a crystal field analysis of the splitting pattern was used in the assignment of the levels. Vibronic bands were observed for all transitions and their vibrational symmetries were tentatively assigned. MCD data were used to determine the magnet moment of the ground state. 相似文献
2.
H. Krause K. Sille H.-D. Hausen J. Weidlein 《Journal of organometallic chemistry》1982,235(3):253-264
Reactions of urotropine (C6H12N4) with trimethylmetal derivatives of Al, Ga, In und Tl in various () molar ratios lead to stable and monomeric , or adducts in good yields, but no addition product could be isolated. The vibrational spectra (IR and Raman) of all compounds are recorded and partly assigned. Some characteristic frequencies of the C6N4-skeletons clearly show the symmetry changes in the series of the → → adducts (C3ν → C2ν → C3ν). The X-ray structure determinations of C6H12N4·.GaMe3 (MeCH3) and C6H12N4·.2GaMe3, are in good agreement with the vibrational spectra. Both compounds crystallize in monoclinic space groups (P21 and C2/c). The GaN distances are around 214 pm, and the values for the C6N4-skeletons are not significantly different from those for free urotropine. 相似文献
3.
R.J. Bertino B.A.W. Coller G.B. Deacon I.K. Johnson 《Journal of fluorine chemistry》1975,5(4):335-357
The lithium polyfluorobenzenesulphinates, Li O2SR (R = C6F5, -HC6F4, -HC6F4, or -HC6F4), and the dilithium tetrafluorobenzenedisulphinates, - and -(LiO2S)2C6F4, have been prepared by reaction of the appropriate polyfluoroaryllithium compounds with sulphur dioxide. All compounds were isolated as hydrates and gave the corresponding -benzylthiouronium salts on treatment with -benzylthiouronium chloride. From reactions of the lithium sulphinates with suitable mercuric salts in water, generally at room temperature, the derivatives RHgX (R = C6F5, X = Cl, Br, CH3CO2, or PhSO2; R = -HC6F4, X = Cl, Br, or CH3CO2; R = -HC6F4, X = Cl or Br; R = -HC6F4, X = Cl), -(XHg)2C6F4 (X = Cl, Br, or CH3CO2), and -(XHg)2C6X4 (X = Cl or Br) have been prepared. Similarly, the bispolyfluorophenylmercurials R2Hg (R = C6F5, -HC6F4, or -HC6F4) have been prepared from the corresponding lithium sulphinates and either mercuric salts or polyfluorophenylmercuric halides in aqueous -butanol. A possible mechanism for the sulphur dioxide elimination reactions is discussed. 相似文献
4.
Ronald E. Banks Ismail M. Farhat Roy Fields Robin G. Pritchard Mohamad M. Saleh 《Journal of fluorine chemistry》1985,28(3):325-340
The nitrosoarenes ArNO (Ar = C6H5, 2-MeC6H4, 2,4,6- Me3C6H2 and C6F5) have been condensed with 4-(dichloroamino)- tetrafluoropyridine to provide the azoxy-compounds pyFN()Ar (pyF = 2,3,5,6-tetrafluoro-4-pyridyl); de-oxygenation of the first three with triphenylphosphine or triethyl phosphite gave the corresponding azo-compounds, and the reverse reaction was achieved in the case of pyFNNC6H2Me3-2,4,6 using peroxytrifluoroacetic acid. Thermolysis of 4-azidotetrafluoropyridine in the presence of pentafluoronitrosobenzene provided the perfluorinated azoxy-compound pyFN()C6F5. X-Ray methods have been used to determine the molecular geometry of pyFN()C6H2Me3-2,4,6. 相似文献
5.
The crystal structure of Ca6Eu2Na2(PO4)6F2 has been determined by single crystal X-ray diffraction. The unit cell constants are and the space group is . The structure was refined by normal full matrix least squares techniques. The final value of the refinement indicator is R = 0.065, based on 419 reflections.The structure of Ca6Eu2Na2(PO4)6F2 contains disordered cations in both the triangle and column positions. The occupation of the six triangle sites is and and of the four column sites , and . 相似文献
6.
A sequence of formylation followed by a carbene insertion reaction has led to the stepwise introduction of additional ethano bridges into 4,5,7,8- tetramethyl [22](1,4)cyclophane (), providing syntheses of 5,7,8-trimethyl- [23](l,2,4)cyclophane (), a mixture of 5,8-dimethyl[24(1,2,4,5)cyclophane () and 5,7-dimethyl[24(1,2,3,5)cyclophane (, and-4-methyl[25](1,2,3,4,5)-cyclophane (). This route to completes a formal eight-step synthesis of [26](1,2,3,4,5,6)cyclophane (, superphane) with an overall yield of 17%. A Birch reduction of readily gave 12,15-dihydro-5,7,8-trimethyl[23](1,2,4)-cyclophane () in 85% yield. 相似文献
7.
J.R. Wiesenfeld 《Chemical physics letters》1973,21(3):517-520
The rate coefficients for the collisional deactivation of Tl(62P) by several gases has been determined at 300°K. This data is compared with that previously obtained at higher temperatures and the Arrhenius parameters calculated. Both the overall rate coefficients and temperature effects display trends similar to those observed for 1(52P) relaxation. The deactivation of Tl(62P) by O2 is shown to proceed by a process involving an equilibrium with Tl(62P) and electronically excited oxygen, probably O2(1Δg). 相似文献
8.
The vapour phase reaction of ammonia and hexafluoroacetylacetone leads to the formation of the new β-keto-amine C5H3F6NO. Crystals of the compound are monoclinic, space group 21/, = 10.01(2), = 19.33(3), = 8.40(1) Å, β = 82.27(6)°; final R = 0.044. 相似文献
9.
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
10.
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
11.
Comparative study on the proton and carbon NMR spectra for a series of - and -acyl substituted monohydroxypyridines (C5H4NO: =-H, -CHO, -COCH3, -COC(CH3)3, -COCF3, -COC6H5, -SO2CH3, -SO2C6H4CH3 is reported. p]Characteristic 1H, 13 NMR and IR spectral features allow simple and unambiguous distinction between the isomeric - and/or -acyl-derivatives of 2-, 3- and 4-hydroxypyridines, so that both forms can clearly be identified when tautomeric equilibria occur, since the tautomerism rate is slow on the NMR time scale 相似文献
12.
LDA-induced cyclization of yields , the -isomer of which undergoes dehydration using Ph2S[OC(CF3)2Ph]2 to give the pyrethroid amide . 相似文献
13.
BF3-OEt2 decompostion of azides or leads to the coupling product Schiff base imine intermediates. 相似文献
14.
The RPX2·AlX3 complex () reacts with unsaturated ketones and imines to give novel 7-oxa and 7-aza-2-phosphabicyclo[2.2.1]heptanes (compounds and respectively).A new 1,3-dipolar addition of (CH3)2 CCH2P?XR to nArN=C=S was disclosed resulting in the formation of the 2-imino-1,3-thiaphospholanes (). 相似文献
15.
Janina Karolak-Wojciechowska Marian Mikołajczyk Andrzej Zatorski Katarzyna Kiec-Kononowicz Alfred Zejc 《Tetrahedron》1985,41(20):4593-4602
The crystal and molecular structures of the title isomeric compounds and , obtained by intramolecular N,S--dialkylation of 5,5-diphenyl-2-thiohydantoin with 1,2-dibro-moethane, have been determined from X-ray diffractometer data. 2,3-Dihydro-6,6-diphenylimidazo-[2,1-b]-thiazol-5(6H)-one crystallizes in space group P212121 with a=11.376(3), b=12,255(5), c=8.434(3) Å and Z=4. Crystals of , containing one molecule of benzene, are monoclinic,space group P21/c with a=11.539(6), b=10.242(3), c=16.353(5) Å, β=95.45(5)° and Z=4. In both cases a planar geometry of the two fused five-membered heterocyclic rings was found. The selected bond lengths in and , as well as those analogous imidazothiazinones and , were used to calculate EHOSE (Harmonic Oscillation Stabilization Energy). The problem of stability and chemical reactivity of compounds to is also discussed. 相似文献
16.
The structure of [Pt2Cl(CO) (μ-Ph2PCH2PPh2)2] [PF6] was determined by -ray methods and refined to = 0.082, using diffractometric intensities of 5646 independent reflections. The crystals are monoclinic, space group 21/, = 12.919(3), = 15.576(6), = 25.151(5)Å, β = 94.82(3)°, = 4. They are built of octahedral hexafluorophosphate anions and dinuclear platinum(I) cations. The latter contain PtCl and PtCO fragments linked to one another by a PtPt σ-bond and by two bridging bis(diphenylphosphino)methane ligands. The platinum atoms are in square planar environments and the dihedral angle between the two coordination planes is 40.1°. Selected bond lengths are: PtPt 2.620(1), PtCl 2.384(5), PtC 1.89(3) and PtP 2.291(5) – 2.308(5)Å. 相似文献
17.
William R. Cullen Mangayarkarasy Williams Frederick W.B. Einstein Anthony C. Willis 《Journal of organometallic chemistry》1978,155(2):259-270
The β-chlorovinylphosphines R2PF2)3 (R = C6H5, C6H11) react with Fe(CO)5 yielding compounds of stoichiometry . The crystal structure of one of these (R = C6H11) has been determined from X-ray diffraction data and refined by least-squares to = 0.037 (2313 reflections with > 2.3σ). Crystals are triclinic, space group , = 10.253(5), = 15.590(7), = 9.390(4)Å, α = 99.88(3), β = 103.21(2), γ = 92.02(2)°, = 2. The fluorinated π-allyl group is σ-bonded to one Fe atom and π-bonded to the other. 相似文献
18.
The results of complete X-ray single-crystal structure determinations of the isostructural compounds Cs2NaCrF6 and Cs2NaFeF6, crystallizing in a 12 L-structure in space group , as well as of 2 L-Cs2LiGaF6 (space group ), are reported. The structures, which contain face sharing octahedra, are discussed in comparison to the hexagonal fluoroperovskites. The mean distances observed, CrF = 1.910 Å, FeF = 1.926 Å, GaF = 1.93 Å, are compared to recently published data. 相似文献
19.
The synthesis of a PGH2 analog 5-(2(Z), 6-(1E)-3-diazo-5-(7-hydroxy-2-heptenyl)-6-(3-hydroxy-1-octenyl)bicyclo[2.2.1]heptan-2-one 2 is described. 相似文献
20.
Results of studies of the nucleophilic aroylation of PhCO2Me, Me3CCO2Me and Ph2CO by several low temperature ArLi/CO systems (Ar =C6H5, p-CH3C6H4, -CH3C6H4, 2,6-(CH3)2C6H3 and 2,4,6-(CH3)3C6H2) are reported. The experiments with C6H5Li were unsuccessful and the best results were obtained with 2,6-(CH3)2-C6H3Li. 相似文献