Halogen surface bond

Bagus et were the first to give a detailed ab initio description of the halogen-silver bond using Hartree-Fock wave functions. The silver surface was modeled as a four- or ten-atom cluster exposing the... 

The above-described ATRP mechanism is identical either if polymerization occurs in bulk or if started from a surface (i.e., surface-initiated). Many commercially available initiators (e.g., alkyl halides) can be used, as long as they present a weak halogen-heteroatom bond. The initiator will provide the polymer a surface with simple halogen as end groups, which is easily converted into useful functionalities. The transition metal complexes used (Ru, Cu, Fe, Ni, among others) are responsible for the conversion into useful functionalities, removing the halides from the polymer surface. The surface is then ready for polymerization [131]. 

Atom abstraction occurs when a dissociation reaction occurs on a surface in which one of the dissociation products sticks to the surface, while another is emitted. If the chemisorption reaction is particularly exothennic, the excess energy generated by chemical bond fomiation can be chaimelled into the kinetic energy of the desorbed dissociation fragment. An example of atom abstraction involves the reaction of molecular halogens with Si surfaces [27, 28]. In this case, one halogen atom chemisorbs while the other atom is ejected from the surface. 

Catalysis. Catalytic properties of the activated carbon surface are useful in both inorganic and organic synthesis. For example, the fumigant sulfuryl fluoride is made by reaction of sulfur dioxide with hydrogen fluoride and fluorine over activated carbon (114). Activated carbon also catalyzes the addition of halogens across a carbon—carbon double bond in the production of a variety of organic haUdes (85) and is used in the production of phosgene... 

Active halogen groups were bonded to a glass surface by nonhydrolyzable links using the reactions set out in Scheme (40) ... 

Femandez-Garcfa J.C., Orgiles-Barcelo, and A.C., Martm-Martmez J.M., 1991, Halogenation of styrene-butadiene rubber to improve its adhesion to polyurethanes, J. Adhes. Sci Technol, 5, 1065-1080. Oldfield D. and Symes T.E.F., 1983, Surface modification of elastomers for bonding, J. Adhes., 16, 77-96. Pastor-Bias M.M., Ferrandiz-Gomez T.P., and Martm-Martmez J.M., 2000, Chlorination of vulcanized styrene-butadiene rubber using solutions of trichloroisocyanuric acid in different solvents, J. Adhes. Sci. Technol, 14, 561-581. 

As well as the adsorption of halogen atoms or molecules, the adsorption of halide anions to gold surfaces has been extensively studied and a comprehensive review of the area has been published by Magnussen [168]. The degree of specific adsorption to gold surfaces increases in the order F < Cl < Br < 1 with only weakly specifically adsorbed. The presence of halide anions can also affect the electrodeposition of organic molecules such as pyridine on Au surfaces with chloride and bromide solutions suppressing the formation of ordered N-bonded pyridine layers [169]. 

The question 26-27> whether there is a preferred surface orientation for facile reduction of the carbon-halogen bond may also be answered by reference to the electrochemical behavior of 16-18. This question was investigated in two ways. The first method involved determination of the amount of iso-topically labelled chlorine remaining in 20 isolated from the electrochemical reduction of 16. This proportion was found to be 7 1 % under a variety of experimental conditions 25-29). This means that reduction of the exo chlorine... 

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