Iodine anion

Strong base treatment of the spiro salt 49 gives a benzyne (107) from which the isolated products were produced by further reaction. For example, with n-butyllithium and furan in tetrahydrofuran, 108 is produced after hydrogenation and acid treatment via 109. Reaction with phenyllithium gives 110 (R == Ph and Me) by subsequent addition of phenyl or methyl anion to the benzyne, respectively, and 110 (R = I) by subsequent reaction with iodine anion. Similarly the 9,9-diphenyl salt 111 gives 112 with phenyllithium. Pyrolysis of the spiro salt 49 gives 50. 

The observed femtosecond dynamics of this dissociative CT reaction is related to the nature of bonding. Upon excitation to the CT state, an electron in the highest occupied molecular orbital (HOMO) of benzene (ir) is promoted to the lowest occupied molecular orbital (LUMO) of I2 (a ). Vertical electron attachment of ground state I2 is expected to produce molecular iodine anions in some high vibrational levels below the dissociation limit. In other words, after the electron transfer, the I—I bond is weakened but not yet broken. While vibrating, the entire I2 and benzene complex begins an excursion motion within die coulombic field and the system proceeds... 

Good, M.L., Purdy, M.B. and Hoering, T. (1958) The anion-exchange separation of iodine anions./. Inorg. Nucl. Chem., 6, 73-75. 

It can easily be seen that the total yield of partial chemical reactions (2.182) and (2.19]) is zero. This is caused by the presence of the third, low-mobile component (iodine anions I ). Because of their presence, rubidium and silver cations are unable to move in the lattices of the growing Rb 2AgI3 and RbAg4J5 compounds independently of each other. The fluxes of these cations should necessarily be balanced since partial chemical reactions (2.18]) and (2.192) are mutually dependent. In this respect, the system under consideration and other similar systems differ from binary ones in which all four partial chemical reactions taking place at layer interfaces are independent of each other unless any diffusional constraints arise (see the next chapter). 

Riveros, J. M. Ingemann, S. Nibbering, N. M. M. Formation of gas phase solvated bromine and iodine anions in ion/molecule reactions of halobenzenes. Revised heat of... 

An analogous process has been developed for unbranched aldehydes which can be transformed into a-amino ketones when oxidized in the presence of an secondary amine and iodine, as the mediator, in aqueous terf-butanol. The actual reactive species is probably the enamine which is attacked by iodine cations and subsequently by water. Carbonyl transposition reaction releases iodine anions which can be anodically reoxidized [197]. 

Examples of such systems include alkali metal atoms solvated by ammonia and by water four solvent molecules appear to fill the first solvation layer. Thus, in Li(H20) , when > 4, the valence electron appears to move out into the second solvation layer, forming Li+(H20) . Another example is solvated iodine anions [such as I (CH3CN) photoexcitation leads to the transfer of an electron to the solvent even for n = 2. The nature of the excited state is determined by the entire arrangement of the solvent molecules, as expected for a CTTS state. 

In the first two parts of this chapter, electron transfer (ET) from atomic donors, e.g., alkali metals or the iodine anion, to an accepting unit composed of simple molecular or atomic solvents was discussed. It was demonstrated that even for a molecule without a stable anionic state or large dipole moment, e.g., water and ammonia, an ensemble of a relatively small number of the molecules can act as an electron acceptor. In the case of the solvated alkali metal atom clusters, ET takes place spontaneously as the number of solvent molecules increases, while the ET in the solvated 1 clusters is induced by photoexcitation into the diffuse electronic excited states just below the vertical detachment thresholds. These ET processes in isolated supermolecular systems resemble the charge delocalization phenomena in condensed phases, e.g., excess-electron ejection from alkali metals into polar solvents and the charge transfer to solvent in a solution of stable anions. 

The addition of iodine anion (Nal) to an aqueous solution of [Co(sep)]5+ cation led to spectral changes the CTB shifted to the... 

The Sb centre in the structurally characterized complex [H(py)2][Sbl4(dmpe)] (py = pyridine, dmpe=l,2-bis(dimethylphosphino)ethane] shows significant distortions from octahedral geometry which are discussed in terms of an arrested double S 2 transition state for the nucleophilic substitution of two iodine anions by dmpe. ... 

Guest rattling was also analyzed by means of the Raman spectroscopy. It was shown that in Si44lio (= [Si44l2]Ig) two peaks at 75 and 101 cm can be assigned to vibrations of guest iodine anions inside the cationic framework [61]. 

Zinc iodide. The zinc cation Zn and the iodine anion I combine to form zinc iodide. To make the charges add up to zero, there have to be twice as many I ions as Zn ions. Therefore, the formtrla for zinc iodide is Znl2. 

For a more detailed look at this reaction, iodomethane reacts with lithium metal, which is assumed to exist as a simple dimer (Li-Li). The products are lithium iodide and CHgLi (methyllithium, 33). When the lithium dimer comes close to the C-I bond of iodomethane, the polarized C-I bond induces a polarized Li-Li structure (an induced dipole) and the transition state of the reaction is taken to be 31. Rather than transferring two electrons, the Li-Li bond breaks with transfer of only one electron (homolytic cleavage remember that Li is in group 1), which leads to formation of a methyl radical ( 0113) and a lithium radical ( Li), as well as a lithium cation and an iodine anion (see 32). Transition state 31 represents the transfer of single electrons to generate radicals. When the methyl radical and the lithium radical combine, each donates... 

The ferric color test for thiocyanates is not applicable in the presence of iodides because the iodine liberated by the redox reaction 2 Fe+ + 2 I -> 2 Fe+2 -f I2 makes it impossible to see the red ferric thiocyanate. The iodine-azide test may be carried out without modification if only small amounts of iodide are present. For reasons that are not yet clear, large amounts of iodide considerably reduce the sensitivity of the test. This interference can be obviated by the addition of mercuric chloride. The reaction Hg+2 + 4 1 [Hgl4] 2 produces complex mercuri-iodine anions which do... 

In the 1980s, Andrieux et al. [83] studied the electrochemical behavior of alkyl halides in DMF using cyclic voltammetry. For Fbutyl iodide, two separate waves were recorded, each one related to the exchange of one electron. The first one was attributed to the reduction of the halide with cleavage of the C-I bond to give a t-butyl radical and an iodine anion. The second one is the reduction of this radical into the t-butyl anion. For sec-butyl iodide, both peaks are very close... 

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