Electronegativity optical

Optical electronegativity and nephelauxetic effect in oxide systems. J. A. Duffy, Struct. Bonding (Berlin), 1977, 32,148-166 (33). 

Drillon M, Darriet J (1992) Progress in Polymetallic Exchange-Coupled Systems, some Examples in Inorganic Chemistry. 79 55-100 Duffy JA (1977) Optical Electronegativity and Nephelauxetic Effect in Oxide Systems. 32 147-166... 

Duffy, J.A. Optical Electronegativity and Nephelauxetic Effect in Oxide Systems. Vol. 32, pp. 147—166. 

No bands were reported by Brown et al. corresponding to charge-transfer transitions, and their absence below 50 kK. was confirmed by Allen et al. Since the lowest Laporte-allowed band for the PdCle- anion is found close to 30 kK. (24), this is as would be expected from optical electronegativity considerations. 

For OsF6 the absorption appears to increase steadily from near 23 kK. to the first maximum at 35.7 kK. and we therefore take this value for the first n - -t2g excitation a similar assignment is also adopted for the 40.8 kK. maximum. The optical electronegativity values derived thereform, and from a similar treatment of the IrF6 and PtFg spectra, are discussed in Section 5 (q.v.). 

Similarly for MF ions D varies between the extremes of 3.5 and 4.2 kK., (72) so that in neither case is any sensible error involved in assuming constancy. However, the determination of D and the assignment of the Laporte-allowed charge-transfer bands also permits the evaluation of Jorgensen s (91) optical electronegativity parameters. These are obtained using the relationship... 

Table 30. Optical electronegativities and fitting parameters for 5 d systems...

The reducing character of the ligand is linearly related to the relative position of the first spin-allowed transition and the first electron transfer transition. Jorgensen 233) calculated the optical electronegativity of ethyl-dsep as 2.6 which is close to that of ethyl-dtp, 2.7. Jorgensen 233) has also discussed electron delocalization in M(X2P)3 (X = S, Se) chromophores in terms of a molecular orbital model. 

Optical Electronegativity and Nephelauxetic Effect in Oxide Systems... 

Correlation Between Nephelauxetic Effect and Optical Electronegativity. 157... 

The atom X is P, B, etc. and there will be other oxide(— II)s attached to it (also, for the HjO ligand X = 2 H). The atom X plays an important role in determining the chemical properties of a metal or non-metal oxide or oxyanion, and thus it is anticipated that the nature of X would influence the oxide(— II) moiety governing (i) the extent of electron donation to and (ii) the ease with which an electron may be transfered from oxide(— II) to an orbital essentially owned by M . In other words, both the nephelauxetic effect produced by the oxide(— II) and the optical electronegativity are expected to be influenced by atom X. 

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