摘要:

AbstractIndividual members of a family of highly absorptive porphyrins bearing symmetrically positioned flexible side chains form discotic liquid crystalline mesophases at modest temperature ranges. The order of this phase is preserved when a thin layer of this self‐assembled material is cooled to room temperature. Exposure of such films to visible excitation, with or without an externally applied electrical field, produces photovoltaic effects and/or charge trapping. The latter effect constitutes the basis for optoelectronic information storag

ISSN:0009-4536    

DOI:10.1002/jccs.199300050

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe reaction between certain platinum(II) complexes and alky radicals produces an unstable organoplatinum(III) intermediate, {PtIII‐R}. The kinetics of this step were evaluated by laser flash photolysis with ABTS2(2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonate) ion) and TMPD (tetramethylphenylenediamine) as kinetic probes. The rate constants for PtCl42−are: kPt/108L mol−1s−1= 5.2, 2.8 and 0.27 for CH3,C2H5, and CH2Cl in aqueous solution at pH 1. Those with cis‐Pt(NH3)2Cl2are somewhat smaller, and those for Pt(NH3)42+too small to measure will) this technique. The product analysis indicates that the decomposition of organoplatinum takes place by hydrolysis and (for R = C2H5only) by β‐elimination, The kinetic isotope effect on die β‐elimination of DCH2CH2PtC4,2−is kH/kD= 1.2. The β‐elimination step produces a PtIII‐hydride that releases hydrogen gas and forms {PtIII‐OH}. The short‐lived Pt(III) intermediate may disproportionate or oxidize the CoIIcomplex that is pro

ISSN:0009-4536    

DOI:10.1002/jccs.199300051

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe rate coefficients of the reactions of CN and NCO radicals with O2and NO2at 296 K: (1) CN + O2→ products; (2) CN + NO2→ products; (3) NCO + O2→ products and (4) NCO + NO2→ products have been measured with the laser photolysis‐laser induced fluorescence technique. We obtained k1= (2.1 ± 0.3) × 10−11and k2= (7.2 ± 1.0) × 10−11cm3molecule−ts−1which agree well with published results. As no reaction was observed between NCO and O2at 297 K, an upper limit of k3<4 × 10−17cm3molecule−1S−1was estimated. The reaction of NCO with NO2has not been investigated previously. We measured k4= (2.2 ± 0.3) ×

ISSN:0009-4536    

DOI:10.1002/jccs.199300052

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe alkylation of ethylbenzene with methanol on various zeolites has been studied at atmospheric pressure, 300–500 °C and with ethylbenzene/methanol = 3 mol/mol in a fixed‐bed, integral‐flow reactor. The catalytic activity decreased in the order HZSM‐5>HY>HM. The optimum conditions for the formation of ethyltoluene were HY zeolite, 400 °C and W/F = 4.1 g‐cat h/g‐feed. The catalyst decay rate increased in the order HZSM‐5<

ISSN:0009-4536    

DOI:10.1002/jccs.199300053

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractA spectrophotometric method to determine palladium(II) at trace levels is based on the extraction of palladium(II) as a binary complex withN‐hydroxy‐N,N′‐diphenylbenzamidine (HDPBA) in chloroform at pH 5.0 ± 0.2. The complex shows maximum absorbance at 400 nm with molar absorptivity 6.4 × 103L mol−1cm−1. The sensitivity of the Pd(II)‐HDPBA complex was enhanced by the addition of l‐(2‐pyridylazo)‐2‐naphthol (PAN). The green coloured complex shows maximum absorbance at 620 nm with molar absorptivity 1.58 × 104L mol−1cm−1. Sandell's sensitivity and the detection limit of the method are 0.0067 μg cm−2and 0.1 μgPd(II) mL−1, respectively. Most common metal ions associated with palladium metal do not interfere. The effects of various analytical parameters on the ext

ISSN:0009-4536    

DOI:10.1002/jccs.199300054

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractFerrocenylaldimines (Fc‐CH=N‐R) were prepared by condensation of Schiff base of formylferrocene with polyacenylamines RNH2; R = naphthyl, anthracenyl and pyrenyl groups. This step was followed by oxidation with FeCl3to give [Fc‐CH=NR]‐FeCl3adducts. The electronic state of iron in these adducts was investigated by means of57Fe Mössbauer spectra except for [Fc‐CH=N‐Pyr]‐FeCl3showed that only a doublet was observed at ambient temperature. As the temperature was decreased below 200 K, additional magnetic hyperfine splitting was observed characteristic o

ISSN:0009-4536    

DOI:10.1002/jccs.199300055

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractAnionic iron(0) tetracarbonyl with terminal phenyltellurolate ligand PhTe−, [PhTeFe(CO)4]−, has been synthesized and characterized. The title compound was obtained by addition of (PhTe)2to [PPN][HFe(CO)4] THF solution dropwise. [PPN][PhTeFe(CO)4] crystallizes in the monoclinic space group C c, with a = 16.119(4) Å, b = 13.141(3) Å, c = 19.880(8) Å, β = 93.04(3)°, V = 4205(2) Å3, and Z = 4. The [PhTeFe(CO)4]−anion is a trigonal‐bipyramidal complex in which the phenyltellurolate ligand occupies an axial position with Fe‐Te bond length 2.630(5) Å and the Fe‐Te‐C(Ph) angle is 103.4(5)°. The neutral iron(0)‐telluroether compound, (PhTeMe)Fe(CO)4, was prepared by alkylation of the [PhTeFe(CO)4]−. Protonation of [PhTeFe(CO)4]−and reaction of H2Fe(CO)4and PhTe)2ultimately lead to formation of the known di

ISSN:0009-4536    

DOI:10.1002/jccs.199300056

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractAddition of NOBF4tofac‐[PPN][Fe(CO)3(TePh)3] in THF at ambient temperature results in formation of Fe2(μ‐TePh)2(NO)4lFe2(−TePh)2(CO)6and organic products. Methylation offac‐[PPN][Fe(CO)3‐ (TePh)3] by Mel or [Me3O][BF4] leads to the known dimer Fe2(μ.‐TePh)2(CO)6and organic products. Fe2(μ‐TePh)2(NO)4crystallizes in the orthorhombic space group P bca, with a = 12.701(5) Å, b = 6.7935(16) Å, c = 21.299(9) Å, V = 1837.8(11) Å3, and Z = 4. The core geometry of Fe2(μ‐TePh)2(NO)4is best described as a Fe2Te2planar rhombus with Te‐Fe‐Te bond angle 112.09(4)°. A Fe‐Fe bond (length 2.827(2) Å) is proposed for Fe2(μ‐TePh)2(NO)4on the basis of the 18‐electron rule. The iron atom adopts a distorted tetrahedral geometry with acute bridge Fe‐Te‐Fe angles 67.91(3)°, an

ISSN:0009-4536    

DOI:10.1002/jccs.199300057

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractReaction of dihydroxo(2,2′‐iminodiethanolato‐AWO′) germanium(IV) (A) or dihydroxo(2,2′‐methyliminodiethanolato‐N,O.O′) germanium(IV) (B) with bidentate ligands, e.g. diol, α‐hydroxy acid, oxalic acid, 2,6‐pyridinedicarboxylic acid, or 2‐aminophenol in a mixture of ethanol and xylene mixture yielded a series of unsymmetrical spiro‐germanium complexes 1‐6. These complexes were characterized by NMR, IR, mass spectra and elementary analysis. The1H NMR spectrums of all these compounds show the existence of an intramolecular N–Ge bond. X‐ray analysis of compound 6 sh

ISSN:0009-4536    

DOI:10.1002/jccs.199300058

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe total synthesis of (±)‐carnphor and (±)‐epicamphorenone from methylcyclopentadiene are desc

ISSN:0009-4536    

DOI:10.1002/jccs.199300059

出版商:WILEY‐VCH Verlag    

年代:1993

数据来源: WILEY