Charge-transfer complexation

Photoinduced copolymerization of donor-acceptor monomer pairs (Scheme 1) can be either self initiated by excitation of the charge transfer complex (charge transfer initiation) or by polymerization of the charge transfer complex/monomer equilibrium... 

The above formulas may become inapplicable for systems with adsorption processes or/and coupled chemical steps in solution whose characteristic times are comparable with the inverse frequency within the impedance measurement interval. In this case the charge-transfer resistance, Rct, must be replaced by a complex charge-transfer impedance, Zct. Another restriction of this treatment is its assumption of the uniform polarization of the m s interface which requires to ensure a highly symmetrical configuration of the system. Refs. [i] Sluyters-Rehbach M, Sluyters JH (1970) Sine wave methods in the study of electrode processes. In Bard A/ (ed) Electroanalytical chemistry, vol. 4. Marcel Dekker, New York, p 1 [ii] Bard A], Faulkner LR (2001) Electrochemical methods, 2nd edn. Wiley, New York [iii] Retter U, Lohse H (2005) Electrochemical impedance spectroscopy. In Scholz F (ed) Electroanalytical methods. Springer, Berlin, pp 149-166 [iv] Bar-soukov E, Macdonald JR (ed) (2005) Impedance spectroscopy. Wiley, Hoboken... 

If the hydroxonium ions migrated only hydrodynam-ically A° 85 cm2 would be expected, which value can easily be derived by using the -> Stokes law and the known values of the -+ self-diffusion coefficient of water, the radius of the ion and the - viscosity. (See also proton, - Eigen complexes, - Zundel complexes, charge transfer, - Dahms-Ruff theory.)... 

Miscellaneous Binuclear Complexes Charge-Transfer Spectra... 

This is responsible for the characteristic color of the complex. It is seen that for weakly interacting complexes, that is, for a b, the excited state will be essentially ionic. The ionic character in either case arises from at least a partial transfer of electrons from the donor D to acceptor A partial in this context means that on the average, the electron will spend more time in the vicinity of A than in the proximity of D. For high stability of the complex, charge transfer must be incomplete [10]. 

Charge transfer complexes, see Complexes Charge transfer spectra, see Electronic spectra... 

Comenic acid, bromination, 58, 297 Complex induced proximity effect, in heterocyclic metalations, 56, 160 Complexes, charge transfer tetraphenyl-4,4 -bithiopyranylidene with lj +, -,60, 78,91... 

Complexes, charge-transfer of fused 1,2-dichalcogenoles, 58, 73 of phenoxachalcogenins with acceptors formation, 58, 101 thermodynamic parameters, 58, 102 of tetratellurafulvalenes, 58, 81 Complexes, charge transfer, azonia-aromatics with TCNQ, 55, 352 Complexes, see also Ligands, coordinated, and the various metals Condensation reactions, forming vinylene betaines, 60, 216... 

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

R. D. Brown, B. H. James, and M. F. O Dvvycr, Tbeor. Chim. Acta, 17, 264 (1970). Molecular Orbital Calculations on Transition Element Compounds. W. T. A. M. V an der Lugt, hit. J. Quantum Chem., 6, 859 (1972). Molecular-Orbital Calculations on Transition-Metal Complexes, Charge-Transfer Spectra, and the Sequence of Metal and Ligand Orbitals. J. J. Kaufman and R. Predney, hit. J. Quantum Chem., Quantum Chem. Symp., 6, 231 (1972). Extension of INDO Formalism to d Orbitals and Parameters for Second-Row Atoms. 

As in silver-olefin complexes, charge transfer into anti-bonding ligand orbitals should result in a lengthening of the C=C bond and a decrease in vC C. 

Tetrathiafulvalenes form crystalline CT complexes (charge-transfer complexes, r-complexes) with e.g. 7,7,8,8-tetracyanoquinodimethane, which display high electric conductivity (organic metals) [65]. 

There are few direct spectroscopic probes for iron for instance, in most complexes charge transfer bands obscure the d-d transitions and magnetic measurements cannot provide information on low-spin iron(II) complexes. Therefore when the Mossbauer technique became generally available in the late 1960s, it was widely used for the study of iron complexes. The effect arises from the resonant absorption of y-rays by the Fe nucleus, which has a natural abundance of 2%. When the y-ray source and sample nuclei are in different environments, the shift in the energy of resonant absorption is expressed as a velocity relative to some arbitrary zero such as stainless steel or Na2[Fe(CN)5N0] 2H20. Whilst the value of the shift is temperature dependent, it is also affected by the electronic environment. 

In the case of covalency in a magnetic complex, charge transfer from ligand to partially filled metal orbitals results in a transfer of spin density in the opposite direction. The magnitude of the spin transfer, obtainable from LHFI, is directly related to the covalency parameters by the simple MO model (see Section II. B). 

However, the host does not have a polymeric structure like that of the Hofmann-type but comprises a discrete metal-complex molecule. The name Werner was used to differentiate the host as a coordination complex from other kinds of complexes, e.g., organic-organic or organic-inorganic molecular complex, charge - transfere omplex, etc. Hence, the name ofWerner is independent of molecular inclusion phenomena. 

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