摘要:

AbstractThe effect of higher‐order photo‐excitation on the angular distribution of photo‐dissociated molecular fragments is studied. A general formalism is derived that will cover non‐linear as well as linear polyatomic molecules and will permit comparison of the processes of different orders. Some of the higher‐order processes, e.g., magnetic dipole and electric quadrupole, will give rise to azimuthal‐angle (Φ) besides polar‐angle (θ) dependence of the fragments. Using a molecule of D3h, Symmetry as an example, a comprehensive study is made of all possible excitations allowed by symmetry in this point group for one‐photon electric/magnetic dipole and three‐photon electric‐dipole transitions. Plane wave approximation is used for the relative motion of the random and non‐rotating molecules which dissociate instantaneously with a velocity large compared with thermal motion. These basic angular factors may be used in future extensions to rotating and vibrating molecules and to time‐delayed dissociations and to vibronically exc

ISSN:0009-4536    

DOI:10.1002/jccs.198900013

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractMolecular structures of the two title compounds were investigated to reveal the relationship between the structure of the reaction intermediates and the reaction pathways in the transition metal‐mediated cycloaddition reaction between tetrafluorodisilacyclobutene and conjugated dienes. The structures were determined by X‐ray diffraction. Both cyrstals are orthorhombic. Compound I. C14H18O2Si2F4Fe. is of space group P212121with Z=4; a=6.862(7) Å. b=10.9560(10) Å. c=23.597(25) Å. and Dc=1.562 gcm−1. Compound II, C15H18O3Si2F4W, is of space group Pbca with Z=8; a=16.999(8) Å, b=15.948(6), c=14.045(7) Å, and Dc=1.962 gcm−1. Both structures were solved by heavy‐atom methods and refined by full‐matrix least‐squares using anisotropic temperature factors for all non‐hydrogen atoms to R values of 0.092 for 1544 observed reflections and 0.078 for 2751 observed reflections, respectively, for compound I and compound II. The butadiene segment of the cyclohexadiene ligand is essentially planar in compound I while it is twisted with a torsional angle of 22° (2) in compound II. The five‐membered disilametallacycle ring is planar in compound II while ii is in an envelope comformation in compound I. The coordination geometry of the iron atom may be considered as a distorted tetragonal‐pyramidal with the diene unit occupying the apical site, That of tungsten is a distorted seven‐coordinated pentagonal‐bipyramidal with the two axial carbonyl groups displaced toward the disilabutene ligand. The disilabutene of compound I lies almost parallel andcisto the plane of the butadiene segment while that of compound II orients almost perpendicular to the diene group. The differences in the structural features of the two complexes explain clearly their product patterns and the reactions are

ISSN:0009-4536    

DOI:10.1002/jccs.198900014

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

Abstract[Cu(C8H22N4)]·(ClO4)2.H2O, Mr= 454.80, orthorhombic C2221, a = 15.481(5), b = 7.404(1), c = 14.827(3)Å, V = 1699.5(8)Å3, Z = 4, Dx= 1.78 g/cm3, λ(MoKα) = 0.71073Å, μ = 16.5 cm−1. F(000) = 940, T = 22°C, R = 6.86%, Rw= 7.66% for 820 observed reflections (I>2.5σ (I)). The coordination number for the copper(II) ion is five, and the coordination geometry about copper(II) ion is a buckled square pyramid with the tetraamine equatorial and a perchlorate ion axial. The tetraamine is coordinated in a square‐plannar manner with slight tetrahedral distortions. The four Cu‐Ndistances span a very narrow range, 1.990(1

ISSN:0009-4536    

DOI:10.1002/jccs.198900015

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractSome New azo sulphonamide derivatives containing 8‐hydroxyquinoline moiety and their complexes with some transition metal ions vz. Fe+3, Co+2, Ni+2, Cu+2, and Hg+2have been prepared and characterised. The stereochemistry as well as the type of bonding around the metal ions were determined on the basis of microanalysis, IR and UV‐VIS spectra, conductivity and magnetic moment measurements; the thermal behaviour of the complexes was also studied. The metal ions coordinate exclusively to the 8‐hydroxyquinoline moiety. The biological activity of the complexes was tested against a number of bacteria. Chelation of the metal ions to the ligands induces a remarkable increase in their antimicrobial act

ISSN:0009-4536    

DOI:10.1002/jccs.198900016

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe kinetics of the bromate oxidation of tris(1,10‐phenanthroline)iron(II) (Fe(phen)32+) and aquoiron(II) (Fe2+(aq)) have been studied in aqueous sulfuric acid solutions at μ = 1.0M and with Fe(II) complexes in great excess. The rate laws for both reactions generally can be described as ‐d [Fe(II)]/6dt = d[Br−]/dt = k[Fe(II)][BrO−3] for [H+]0= 0.428–1.00M. For [BrO−3]0= 1.00 × 10−4M. [Fe2+]0= (0.724–1.45)x 10−2M, and [H+]0= 1.00M, k = 3.34 ± 0.37 M−1s−1at 25°. For [BrO−3]0= (1.00–1.50) × 10−4M, [Fe2+]0= 7.24 × 10−3M ([phen]0= 0.0353M), and [H+]0= 1.00M, k = (4.40 ± 0.16) × 10−2M−1s−1at 25°. Kinetic results suggest that the BrO−3‐Fe2+reaction proceeds by an inner‐sphere mechanism while the BrO−3‐Fe(phen)32+reaction by a dissociative mechanism. The implication of these results for the bromate‐gal

ISSN:0009-4536    

DOI:10.1002/jccs.198900017

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe crystal and molecular structure of BFL‐TCNQ has been determined by single‐crystal X‐ray diffraction analysis. The complex crystallizes in the monoclinic space group C2/c, a=17.915(3), b=12.238(3), c=13.531(3) Å, β = 115.16(1)°, and Z=4. The complex has a mixed‐stacked crystal structure in which BFL molecules exist in a twisted conformation and TCNQ molecules are dimensionally similar to uncomplexed TCNQ. The complex is diamagnetic and is an insulator with a room‐temperature conductivity less than 10−9s cm−1. The FT‐IR spectrum of the BFL‐TCNQ complex reveals that the degree of charge transfer between the two component molecules

ISSN:0009-4536    

DOI:10.1002/jccs.198900018

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe velocity distributionsP(v)of pulsed molecular beams are conventionally measured via TOF techniques. To account for the finite pulse widths of beam valves, a convoluted TOF distribution functionP(t)is derived. TOF data on Ar pulsed beams are analyzed accordingly.

ISSN:0009-4536    

DOI:10.1002/jccs.198900019

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractUnder certain circumstance, natural orbitals of excited states have quite unusual hybrid behavior, which is drastically different from that of the familiar cononical orbitals, and gives ambiguous results for the one‐electron properties. We show that a simple 2×2 density matrix obtained from a multiconfiguration self‐consistent‐field calculation is sufficient to reveal the NO behavior in this sit

ISSN:0009-4536    

DOI:10.1002/jccs.198900020

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractN‐Hydroxy‐3‐arylsydnone‐4‐carboxamide oximes (7) were prepared from the corresponding 3‐arylsydnone‐4‐carbohydroximic acid chlorides (6) and hydroxylamine in high yield. The chemical reactivity of compound (2) is somewhat different from 3‐arylsydnone‐4‐carboxamide oximes (2) in that the former compounds reacted with both aromatic and aliphatic aldehydes in the presence of acid catalyst to give 3‐aryl‐4‐(5‐aryl‐1,2,4‐oxadiazol‐3‐yl)sydnones (5) and 3‐aryl‐4

ISSN:0009-4536    

DOI:10.1002/jccs.198900021

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractSelective synthesis of the title compounds from the corresponding sulfenyldienes is described.

ISSN:0009-4536    

DOI:10.1002/jccs.198900022

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY