摘要:

Valence-electron shake-up satellite bands in the ionization spectra of carbon dioxide, nitrous oxide, and tetrafluoroethene have been calculated with a modified version of the HAM/3 program. The results are compared with experiment and with the computations based on two-particle-hole Tamm-Dancoff approximation Green's function method. Because of the limitation of such Green's function procedures for inner-valence electrons, the results can often be inferior to those from the present HAM/3 calculations.

ISSN:0008-4042    

DOI:10.1139/v83-001

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

1-Methyl and 1-benzyl-1,2,3,10b-tetrahydro-5,6,8,9-tetramethoxyindeno[1,2,3-ij]isoquinoline have been synthesized from the corresponding 8-phenyl-3,4-dihydro-1(2H)isoquinolinones by treatment with POCl3under Vilsmeier conditions followed by borohydride reduction. The isoquinolinones were prepared in six steps from 2-(2,3,4-trimethoxyphenyl)-4,4-dimethyl-2-oxazoline. This sequence of reactions provides a new route to dihydro and tetrahydroindeno[1,2,3-ij]isoquinoline

ISSN:0008-4042    

DOI:10.1139/v83-002

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

We present a modification of a supermolecule model of a general chlorophyll dimer, and calculate the excited state electronic Raman selection rules between the various singlet states. The model utilizes the electronic part of the total wavefunction within the strong intermolecular coupling scheme. Under this condition and the neglect of underlying orbitals, the electronic wave function of the dimer is reduced to a four orbital function with each monomer contributing one HOMO and one LUMO. Using a Hückel type molecular orbital calculation, the one electron orbital energies and coefficients of the ground and excited state wavefunctions of the dimer are obtained and are shown to depend explicitly on the ground and excited state intermolecular interaction terms. The resulting Raman activity calculation between the various excited state configurations yields two types of tensor elements: (1) contains only coordinates of the individual monomer α1(molecule 1) and α2(molecule 2) and are called spatially localized elements and (2) labelled spatially delocalized and contains coordinates of both monomer molecules simultaneously (α3and α4).

ISSN:0008-4042    

DOI:10.1139/v83-003

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

A penta-2,4-dienylphosphine oxide is easily obtained by reaction of methylmagnesium iodide with 1-oxa-2-phosphacyclo-hepta-4,6-diene followed by two more intermediate steps. The corresponding phosphine may be obtained either by trichlorosilane reduction of the oxide or nickelocene reduction–complexation of the sulfide. It seems that the dienic part of penta-2,4-dienylphosphines cannot be involved in a η4-complexation for steric reasons. The oxides are valuable precursors for conjugated trienes through Wittig–Horner reactions with carbonyl compounds.

ISSN:0008-4042    

DOI:10.1139/v83-004

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

The1H nmr spectral parameters are extracted for a 4 mol% solution of 2-methylthiobenzaldehyde in CCl4at 305 K. The long-range spin–spin coupling constants involving the aldehydic and methyl protons are consistent only with a preferred conformation in which all heavy atoms are coplanar, as are the chemical shifts of the ring and methyl protons. This conclusion contradicts previous interpretations of the dipole moment, the nmr parameters, and of the infrared data for CCl4solutions. The present data show that theO-synandO-antiforms of the compound are present in roughly equal proportions.

ISSN:0008-4042    

DOI:10.1139/v83-005

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

A complete analysis of the1H nmr spectrum of 2-fluorotoluene yieldsthe spin–spin coupling constant between19F and the methyl protons, as 1.99 Hz. Analysis of nmr spectra of 21 other derivatives of 2-fluorotoluene shows thatcan vary between 1.69 and 2.55 Hz. This strong dependence on substitution contrasts with the near invariance of other long-range couplings such as,,The substituent dependence is discussed in terms of coupling mechanisms. INDO MO FPT calculations ofare inadequate. By means of appropriate model compounds, an adequate empirical conformational dependence is deduced forwhich can be used to reproduce some observed couplings. INDO MO FPT computations, in which certain off-diagonal Fock matrix elements are suppressed, are used to show that spin polarization via interacton of the methyl hydrogen orbitals is a major source of the discrepancy between theory and experiment. Some STO 3G MO calculations are reported for 2-fluorotoluene conformations.

ISSN:0008-4042    

DOI:10.1139/v83-006

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

Solubility and freezing point data are presented for the system sulfur dioxide –N-methyl-2-pyrroIidinone (NMP). The enthalpy and entropy of solution are determined as −33.7 kJ mol−1and −94.6 J K−1 mol−1, respectively. The freezing point diagram shows maxima at, suggesting the presence of 2:1 and 1:1 NMP:SO2complexes. The existence of such complexes in the liquid state is supported by viscosity and permittivity data. Nuclear magnetic resonance and Raman spectroscopic data suggest an overall shift of electron density from the nitrogen and the carbonyl carbon of NMP to the O of SO2, with weakening of the CO bond of NMP.

ISSN:0008-4042    

DOI:10.1139/v83-007

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

The STO-3G optimized structures of three series of carbon acids, CHnX4−n, wheren = 1, 2, or 3 and X = F, CN, or NO2and their corresponding conjugate bases are compared with the limited number of experimentally determined structures. The 6-31G* equilibrium geometries ofare included as a check on the reliability of the STO-3G structures of the anions. Although the effects of successive substitutions on the STO-3G structures are generally systematic, a few apparent anomalies are readily explained in terms of resonance stabilization. Calculations at the 3-21G level, on the STO-3G optimized structures, indicate that the stabilization energy associated with increasing the number of orbitals in the basis set is approximately additive. The stabilization energies are 0.865 ± 0.007 au per fluorine substituent, 0.661 ± 0.008 au per cyano substituent, and 1.561 ± 0.027 au per nitro substituent.

ISSN:0008-4042    

DOI:10.1139/v83-008

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

The structures ofcis-2-(m-nitrophenyl)cyclopropanecarboxylic acid (1) and 1-phenyl-2-methylcyclopropene-3-carboxylic acid (2) have been determined by X-ray methods. Crystals of1are triclinic, space group, witha = 7.422,b = 8.615,c = 9.499 Å, α = 60.24, β = 63.76, γ = 71.36°, and two molecules in the unit cell. Crystals of2are monoclinic, space groupP21/c, with four molecules in a unit cell of dimensionsa = 9.345,b = 13.286,c = 8.187 Å, and β = 98.22°. The carboxyl group of1approaches the bisecting conformation. The phenyl group is 37° from this conformation, by contrast with the unhindered compound 2-(p-nitrophenyl) cyclopropyl methyl ketone. In2the carboxyl group bisects the three-membered ring, indicating that carbonyl-cyclopropene π interactions can occur if sterically allowed. The two rings are essentially coplanar, permitting maximum interaction of the phenyl group and the double bond. In both compounds, the carbonyl oxygen of the carboxyl is the nearer oxygen to the three-membered ring.

ISSN:0008-4042    

DOI:10.1139/v83-009

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

Mononuclear and binuclear copper(II) complexes of the potentially tetradentate binucleating ligands 1,4-di(3′-methyl-2′-pyridyl)aminophthalazine (PAP3Me) and 1,4-di(5′-methyl-2′-pyridyl)aminophthalazine (PAP5Me) are reported. In the case of the ligand 1,4-di(4′,6′-dimethyl-2′-pyridyl)aminophthalazine (PAP46DiMe) only binuclear derivatives were obtained. The mononuclear complexes, involving protonated ligand, result from the sensitivity of these ligands to mildly acidic conditions in aqueous solutions of certain copper salts. Binuclear, neutral ligand, complexes are also formed when the pH increases. Hydroxy bridged binuclear structures exist in all the binuclear complexes described with the exception of one acetate bridged derivative. Sub normal magnetic moments are observed for all the binuclear complexes (< 1.74 BM) indicating spin coupled systems with very low values (< 0.88 BM) for binuclear complexes of PAP46DiMe, indicating the possibility of strong antiferromagnetic exchange between the metal centres.

ISSN:0008-4042    

DOI:10.1139/v83-010

出版商:NRC Research Press    

年代:1983

数据来源: NRC