Charge transfer, bonding

These iridium(IV) complexes have UV-visible spectra dominated by intense absorptions around 500 nm (X = Cl) and 700 nm (X = Br) assignable to 7tx —> Ir(t2g) ligand-to-metal charge-transfer bonds. 

The quantitative effects of steric encumbrance on the electron-transfer kinetics reinforce the notion that the inner-sphere character of the contact ion pair D+, A- is critical to the electron-transfer paradigm in Scheme 1. Charge-transfer bonding as established in the encounter complex (see above) is doubtless an important consideration in the quantitative treatment of the energetics. None the less, the successful application of the electron-transfer paradigm to the... 

O. Hassell, Structural Aspects of Interatomic Charge-Transfer Bonding, Nobel Lectures Chemistry 1963-1970 (New York, Elsevier, 1972), pp. 295-331. 

The colour formed on mixing the two solutions, of magnesium and haem, arises from a charge-transfer bond. The resultant spectrum contains a broad, intense band that we call a metal-to-ligand charge transfer transition, or MLCT for short. 

O. Hassel, Structural aspects of interatomic charge-transfer bonding. Science 170, 497-502 (1970)... 

When charge-transfer bonds are obscured by those of the original donors and acceptors, one may find of value a difference method [1] (e.g., Forster s tandem method [70]). Four cuvets of equal path length are used, two containing the charge-transfer complex solutions in series in the indicator beam of a double-beam spectrophotometer, and two cuvets, one with the unreacted donor and the other with unreacted acceptor solution, also in series in the reference beam. A difference spectrum is thus obtained which, however, needs special care in its interpretation. 

Weak Chemical Coordination/Complexation/ Charge-Transfer Bonding 2-50... 

Two novel, remarkable polymeric halochalcogenates(IV) with inter-molecular charge-transfer bonding were reported recently. The first, in a compound with the empirical composition [(CH3)3NH ]2[SeBr8 ] (f 72,276), was obtained from SeBr4 and trimethylammonium bromide... 

CHARGE CLOUDS particular atoms charge-transfer bonds hydrogen bonds Ionic bond bonds between polarized ions Ionic-covalent bonds... 

For these systems Ajg -o- l2g spin conversion leads to a drastic change of the relevant physical properties. An abrupt change of color accompanies the spin transition in absence of allowed metal-to-ligand charge-transfer bonds hiding the much less intense parity-forbidden d-d bands. This pronounced thermochromism... 

Tablo 32. Charge-transfer bonds for 4-X-substituted pyridinium iodides... 

Studies of the character of the bonding between the adsorbate and the surface have not yet yielded a final pattern, although the available evidence suggests that the chemical bonds may be charge transfer bonds of the Mul-liken type. Further developments in this direction are badly needed to clarify the picture that has been delineated from the studies of electron-transfer processes. 

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