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51.
52.
The Complexes [Pd(PEt
3)2
dtc]X (1) and Pd(PR
3)Xdtc (2, 3) (dtc=S2CNEt
3;X=Cl, Br, I;R=Et, Ph) have been prepared. Conductivity, susceptibility, UV and IR measurements show that the cations [Pd(PEt
3)2
dtc]+ of1 and the complexes2, 3 have square-planar structure. 相似文献
53.
Mechanistic insight on the reversible binding of NO to Fe(II) chelate complexes as potential catalysts for the removal of NO from effluent gas streams has been obtained from the temperature and pressure parameters for the "on" and "off" reactions determined using a combination of flash photolysis and stopped-flow techniques. These parameters are correlated with those for water exchange reactions on the corresponding Fe(II) and Fe(III) chelate complexes, from which mechanistic conclusions are drawn. Small and positive Delta V(++) values are found for NO binding to and release from all the selected complexes, consistent with a dissociative interchange (I(d)) mechanism. The only exception in the series of studied complexes is the binding of NO to [Fe(II)(nta)(H(2)O)(2)](-). The negative volume of activation observed for this reaction supports the operation of an I(a) ligand substitution mechanism. The apparent mechanistic differences can be accounted for in terms of the electronic and structural features of the studied complexes. The results indicate that the aminocarboxylate chelates affect the rate and overall equilibrium constants, as well as the nature of the substitution mechanism by which NO coordinates to the selected complexes. There is, however, no simple correlation between the rate and activation parameters and the selected donor groups or overall charge on the iron(II) complexes. 相似文献
54.
Jochanan Blum Yaron Cohen Shulamit Levin Andrea Katschak Hansruedi Glatt 《Journal of heterocyclic chemistry》1998,35(1):39-43
Racemic K-region imines of benz[a]anthracene, 7-methylbenz[a]anthracene, chrysene and benzo[a]pyrene ( 1–4 , respectively) have been resolved by high performance liquid chromatography on a column packed with amylose tris(3,5-dimethylphenylcarbamate) on silica gel. The absolute configuration of the resolved aziridines was assigned by comparison of their circular dichromism spectra to those of the corresponding enantiomerically pure arene oxides. The mutagenicity of the enantiomers of the arene imines was investigated using Salmonella typhimurium strains TA98 and TA100. Although all arene imines investigated were potent mutagens, quantitative and qualitative differences in the mutagenic activity were observed between enantiomers. 相似文献
55.
New anisotropic ESR spectra of Co2+ doped sapphire, different from hitherto known, are reported. The new spectra which are observed, beside the well-known spectra of α-Al2O3:Co2+, are shown to form two sets, each one consisting of six spectra (1–6) and (7–12). The spectra of both sets are proven to be interrelated by B3a symmetry. g and A tensors for each set will be given. Evidence is given that the two sets are to be assigned to the defects α-Al2O3:Co2+,H+ and α-Al2O3:Co2+,X+. The former is concluded to consists of a Co2+ ion at the substitutional site (c) and a proton located in a potential minimum along a straight line between O2- ions situated in O2+ triangles above and below the CO2+ ion. The potential function for the proton has been calculated by quantum-chemical calculations to clucidate the geometrical structure of the paramagnetic center. The α-Al2O3:Co2+,X+ could not be fully analyzed but some evidence is presented, that X+ might be alkali ions. 相似文献
56.
The syntheses of the K-imine derivatives of carcinogenic benzo[c]phenanthrene and 7,12-dimethylbenz-[a]anthracene are described. Treatment of trans-5-azido-5,6-dihydrobenzo[c]phenanthren-6-ol ( 3 ) and trans-6-azido-5,6-dihydrobenzo[c]phenanthren-5-ol ( 5 ) with thionyl chloride yielded the corresponding β-chloro azides, which in turn, were reacted with lithium aluminium hydride to give 4b,5a-dihydro-5H-benzo[3,4]-phenanthro[1,2-b]azirine ( 2 ). In a similar manner trans-5-azido-5,6-dihydro-7,12-dimethylbenz[a]anthracen-6-ol ( 11 ) and trans-6-azido-5,6-dihydro-7,12-dimethylbenz[a]anthracen-5-ol ( 13 ) were transformed to the respective chloro azides and, converted into 1a,11b-dihydro-6,11-dimethyl-1H-benz[3,4]anthra[1,2-b]azirine ( 10 ). 相似文献
57.
Blum AS Ren T Parish DA Trammell SA Moore MH Kushmerick JG Xu GL Deschamps JR Pollack SK Shashidhar R 《Journal of the American Chemical Society》2005,127(28):10010-10011
Reported in this contribution are the synthesis, characterization, and charge transport properties of wire-like Ru2(ap)4(OPEn), where ap is 2-anilinopyridinate and OPE is -(CCC6H4)nSCH2CH2SiMe3 with n = 1 (1) and 2 (2). Scanning tunneling microscopy (STM) measurements of compound 2 inserted into a SAM of C11 thiol reveal that molecule 2 exhibits (i) the stochastic switching characteristic of wire molecules embedded in insulating SAMs and (ii) higher conductivity than the C11 thiol SAM. More importantly, analysis of the molecular electronic decay constant (beta) exhibits a decrease of at least 15% as compared to purely organic molecular analogues. Hence, the transport characteristics of molecules can be significantly improved for nanoscale electronics through the incorporation of a Ru2 fragment into conjugated backbone. 相似文献
58.
59.
Summary The chlorobenzaldehydes, 2-bromo-4-tolualdehyde and 2-iodobenzaldehyde react with IrCl(CO)(PPh3)2 at 190 to 220° to give PhIrCl2(CO)(PPh3)2,p-tolyl IrBr2(CO)(PPh3)2 and PhIrCl2(CO)(PPh3), respectively. Iodo-and bromobenzene form PhIrCl(Hal)(CO)(PPh3)2 complexes, whereas chlorobenzene does not react under these conditions. Halogen transfer from the aromatic to the metal atom in the reaction of halobenzaldehydes, and halogen extrusion in various homogeneously catalyzed processes, are assumed to follow similar reaction patterns. 相似文献
60.
The syntheses of the K-imine derivatives of benzo[h]quinoline ( 1 ), benzo[f]quinoline ( 2 ) and 1,10-phenanthroline ( 3 ) are described. The parent nitrogen heterocycles were oxidized with sodium hypochlorite to the corresponding K-oxides, 4, 6 and 8 , which in turn were reacted with sodium azide. The resulting azido alcohols were then cyclized with triethyl phosphite to the title compounds 5, 7 and 9 . The oxirane ring cleavage in benzo[h]quinoline 5,6-oxide ( 4 ) and in benzo[f]quinoline 5,6-oxide ( 6 ) by sodium azide proceeded by the predicted regioselectivity: 4 gave trans-5-azido-5,6-dihydro-6-benzo[h]quinolinol ( 11 ) and trans-6-azido-5,6-dihydro-5-benzo[h]quinolinol ( 10 ) as the major and minor products respectively, and 6 yielded solely trans-6-azido-5,6-dihydro-5-benzo[f]quinolinol ( 12 ). The latter compound proved by X-ray analysis to crystallize as a hydrogen bonded dimer. 相似文献