A. A. Macdowell

The breakdown of the one‐electron picture in the ligand XPES of Mo2 (O2CH)4, Mo2 (O2CCH3)4, and Cr2 (O2CCH3)4

The C1s and O1s photoelectron spectra of gaseous Mo2(O2CH)4, Mo2(O2CCH3)4, and Cr2(O2CCH3)4 are reported. An intense satellite peak is associated with C1s ionization in Mo2(O2CH)4 and Mo2(O2CCH3)4, but is absent in the other spectra. These observations are interpreted using ab initio MO calculations, together with initial and final state correlation effects. The intense satellite is associated with the transition δ→Lpπ, where δ is a metal–metal bonding orbital and Lpπ is an orbital of the same symmetry localized on the ligand from which ionization has occurred.

Correlation of metal-metal bond lengths and metal orbital ionization energies in dichromium(ii) and dimolybdenum(ii) complexes

Abstract The difference between the metal- metal δ and π orbital ionization energies for the complexes M 2 (O 2 CCF 3 ) 4 , M 2 (O 2 CCH 3 ) 4 , M 2 (C 3 H 5 ) 4 , and M 2 (MHP) 4 (where M = Cr or Mo and H{MHP} = 6-methyl-2-hydroxypyridine) increases, within each series, as the metal-metal bond length decreases. The variation in the metal-metal bond length is more marked for the Cr 4+ 2 complexes where the magnitude of the metal-metal ionization energies decrease as the Cr-Cr separation contracts, thus suggesting that the coulombic repulsion between these metal atoms is a prime factor which determines their separation in these complexes.

Core electron ionization energies and electronic structure of Ti(NO3)4 and Cu(NO3)2

Abstract Gas phase X-ray photoelectron spectra of Ti(NO 3 ) 4 and Cu(NO 3 ) 2 are reported and discussed in terms of the molecular charge distributions. No measurable splitting is observed between the 1 s ionization energies of the chemically distinct oxygen atoms in either molecule. Ab initio calculations for Cu(NO 3 ) 2 suggest that this is due in large measure to differential orbital relaxation occurring upon core electron ionization.

Intense satellite peaks in the carbon 1s photoelectron spectra of Mo2(O2CH)4 and Mo2(O2CCH3)4

Abstract The C 1s PES of Mo 2 (O 2 CH) 4 AND Mo 2 (O 2 CCH 3 ) 4 and Mo 2 (O 2 CCH 3 ) 4 , reported here, show an intense satellite peak close to the main C 1s line. This is assigned, by means of ab initio calculations, to a b 1 (δ) → b 1 (C2pπ) transition of the core hole ion. The lack of an intense satellite in the O 1s spectrum is discussed.

Crystal structure and u.v. photoelectron spectra of tetrakis-(6-methyl-2-oxopyridinato)dirhodium

Rh2(mhp)4(where Hmhp = 6-methyl-2-hydroxypyridine) has been prepared and characterised by X-ray crystallography and shown to involve a metal–metal separation of 2·359(1)A; the He I and He II photoelectron spectra of Rh2(mhp)4 provide evidence for the presence of a metal–metal single bond.