Photoelectron Spectra of Group V Compounds, III Methylhalogen Compounds MeEHal2 and Me2EHal

The He I photoelectron spectra of certain MeEHal2 and Me2EHal compounds (E = (N), P, As, Sb; Hal = (F), Cl, Br, J; Me = CH3) are interpreted in terms of a “composite molecule” approach derived for C3vCs systems. Although an “internal standard” is missing here, substituent group-orbitals (nHal, C—H) may be classified with respect to their orientations in space (R, V, T). Ionisation energies are assigned according to this assumption. PE data of the isoelectronic EMe3/EHal3 compounds and of related molecules (Me2EH, MePH2, CF3PBr2) as well as EHMO calculations with partial inclusion of spin orbit coupling are used to confirm the assignments given for Me2EHal/MeEHal2 series. Correlations between PE ionisation energies (e.g. nE (IE)) and molecular or atomic properties are critically revised and discussed

Photoelectron Spectra of Group V Compounds, VI. Methyl- and Trifluoromethyl-Cyanophosphines, MenP(CN)3-n and (CF3)nΡ(CN)3-n (n = 0, 1, 2, 3)

The He I photoelectron spectra of the series RnP(CN)3-n (R = Me, CF3; n = 0, 1, 2, 3) and of Me2ECN (E = N, P, As) are interpreted. The PE assignments are based on the comparison with the PE data of analogous halogeno and hydrogen derivatives as well as related cyano compounds and on simple MO considerations (composite molecule-approach). Hyperconjugative and inductive effects of the substituents CN, Me, F, Cl, and especially CF3 are assessed. The various effects of changing substituents or central atoms within the series are used to confirm the interpretation. The differing electronic structures of halogeno and cyano (pseudohalogeno) compounds are discussed on the basis of their PE spectra

Darstellung und Eigenschaften von Diacetylbis(methylimin) / Synthesis and Properties of Biacetylbis(methylimine)

Biacetylbis(methylimine) (1) is obtained by formic acid catalyzed condensation of biacetyl and methylamine. Photoelectron- and UV spectra, H NMR and 13C NMR data are compared with those of the new compound biacetylbis(isopropylimine) (2) and glyoxalbis(isopropylimine) (3)

Photoelectron spectra of group 5 compounds. 2, Conformational analysis of diphosphine (P2H4)

The photoelectron spectra of certain hydrazines, disulfides, peroxides, and aminophosphines have been assigned to a unique conformer, being present under normal PE spectroscopic conditions. In contrast, different rotamers could be detected in the PE spectra of hexahydropyridazines and tetrasubstituted diphosphines and diarsines and were assumed for polysilanes. The composition of the rotameric mixture (transgauche) obtained for tetramethyldiphosphine from the relative PE peak areas had to be revised

Electron transfer and ion pairing, 7 [1, 2]. Contact ion pairs of sulfur-containing radical anions

The structurally different radical anions M⊖ of peralkylated 1-sila-2,5-diazacyclopentane-3,4-dithione and of tetrakis(isopropylthio)-p-benzoquinone are generated by reduction with potassium/2.2.2-cryptand under aprotic conditions in THF solution. On addition of Li⊕B(C6H5)4⊖, both form hitherto elusive sulfur-containing contact ion pairs, which are characterized by their ESR/ENDOR spectra

Magnetic Exchange Interactions in Tetranuclear Copper(II) Complexes

Magnetic susceptibility measurements are reported for a series of tetranuclear copper (II) complexes [Cu 4OX 6L 4] (X = Br or Cl; L = Cl, Br, C 5H 5N, C 5H 5NO, tetramethylurea, or dimethyl sulphoxide). These data and literature data on other tetranuclear complexes describe a range of magnetic behaviour, varying from strong intramolecular antiferromagnetic interaction, through weak antiferromagnetic interaction, to apparent ferromagnetism. Intermolecular interactions are found to be negligible. The results are used to evaluate current theoretical models for such systems, and are consistent with the existence of a significant symmetric component in the pairwise exchange Hamiltonian