Halogen complexes origins

The nitrosonium cation bears a formal relationship to the well-studied halogens (i.e. X2 = I2, Br2, and Cl2), with both classes of structurally simple diatomic electron acceptors forming an extensive series of intermolecular electron donor-acceptor (EDA) complexes that show well-defined charge-transfer absorption bands in the UV-visible spectral region. Mulliken (1952a,b 1964 Mulliken and Person, 1969) originally identified the three possible nonbonded structures of the halogen complexes as in Chart 7, and the subsequent X-ray studies established the axial form II to be extant in the crystals of the benzene complexes with Cl2 and Br2 (Hassel and Stromme, 1958, 1959). In these 1 1 molecular complexes, the closest approach of the... 

The product of substitution reactions of alkanes with the halogens is typically a complex mixture of haloalkanes (halogenated alkanes). One way to limit the production of the more highly substituted alkanes is to use a large excess of the alkane then most reactions take place with the original hydrocarbon rather than with any haloalkanes produced in the reaction. 

VO(acac)2 < VO(Et-acac)2 VO(Me-acac)2 BMOV. Conversion rates for all hydrolysis products were faster than for the original species. Both EPR and visible spectroscopic studies of solutions prepared for administration to diabetic rats ocumented both a salt effect on the species formed and formation of a new halogen-containing complex. The authors concluded that vanadium compound efficacy with respect to long-term lowering of plasma glucose levels in diabetic rats traced the concentration of the hydrolysis product in the administration solution. 

Boudreau AE, Mathez EA McCallum IS (1986) Halogen geochemistry of the Stillwater and Bushveld complexes evidence for transport of the platinum-group elements by Cl-rich fluids. J Pet 27 967-986 Boudreau AE, Stewart MA, Spivack AJ (1997) Stable Cl isotopes and origin of high-Cl magmas of the Stillwater Complex, Montana. Geology 25 791-794... 

Cy, Me, Bu X = CN), can lead to a different origin of the optical behavior [17,18]. For example, in the case of the halogen derivatives, as in the previous case, the complexes show different supramolecular organization chains, dimers and isolated molecules. 

Of more interest to coordination chemists is the Du Pont halogen tin process which is based on halo complexes of tin(II). The presence of fluoride is considered to form [SnF3], but much chloride is present to enhance the conductivity. Inhibitors are required to control the oxidation of tin(II) to tin(IV) and the consequent separation of the sparingly soluble Na2[SnF6] as a sludge. The process was originally introduced in 1942 for the continuous electrotinning of steel strip. 

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