Ion-assisted reaction

Exchange of the bromine atoms in 142 and 145 for other halides or hetero-atomic groups is similarly facile [100]. Among those listed in Scheme 31, the triazides 154 and 158 are interesting because of their further conversion. Reduction of 154 with lithium aluminium hydride furnishes the C3v-symmetrical triamine 155 [105] (cf. Scheme 33 for the Cs-symmetrical isomer). The homologue 158 was converted into unusual heterocycles by thermolysis [100] (cf. Scheme 43). Three-fold bridgehead ethers such as 159 and 160 were obtained by alcoholysis of 142, and Ag1 ion assisted reaction of 142 with tert-butyl hydroperoxide afforded the tris(peroxide) 161 [100]. 

Another aspect of catalysis at metal ion sites on enzymes is the selectivity exhibited by some enzymes for the type of cation (monovalent versus divalent) and/or the oxidation state (-l- 2 versus + 3) of the cation. Model studies of metal ion-assisted reactions and of metal-ligand structures will be reviewed to establish trends for these types of reactions and features that direct metal ion preference for certain ligand environments. 

Role of the Counterion in Silver Ion Assisted Reactions of Ethyl Iodide... 

Surface chemistry, especially ion-assisted reactions, recombination, or polymerization that might occur. 

The last two theories described (chemical and thermodynamic) are intimately linked together because both of them induce a modification of the chemical composition at the surface. On the one hand, this modification can change the thermodynamic parameters (wettability) of the surface. On the other, changes in chemical composition influence the chemical adhesion established between the adherend and the adhesive layer. Numerous treatments are available for surface modification with coronas [8], plasmas [9, 10], lasers [11, 12], ion-assisted reactions [13], or coupling agents [14, 15]. All these treatments do not only change the chemical composition they can also affect the roughness, the orientation of macromolecular chains, and the mechanical behavior. 

In a similar [94] way L1367 (yield 52%) [98] and L1368 (yield 89%) [99] were prepared in DMF through the caesium ion-assisted reaction of 2-mercaptoethyl sulphide with 3,6-dithiaoctane-l,8-diyl bis(methanesulphonate) and 1,11-dichloro-3,6,9-trithiaundecane with 3-thiapentane-l,5-dithiol, respectively (Eq. 6.29). 

It is useful to note that reaction Rl competes with reaction R2 for the available CIONO2 on liquid aerosol surfaces. Thus if HCl has been depleted, the rate of the latter reaction increases, so that effective heterogeneous activation of chlorine is not dependent upon both HCl and CIONO2 being present. Further, the reactions of HCl with HOCl (R3) are also quite efficient on liquid aerosol under moderately cold and/or wet conditions. CIONO2 hydrolysis may proceed via nucleophilic attack at Cl by a lattice water molecule of ice in concert with proton transfer. It is also possible that Cl is formed on ice surfaces, allowing an ion-assisted reaction with C10N02. ... 

Generally, improvement of surface energy by ion assisted reactions in a reactive gases environment is mainly due to the polar force [90]. The measured dependence of the polar component of the free surface energy (j/g) on the irradiation fluence, for the 40 keV Ar ions irradiated PE sample [73], is shown in Fig. 11. The polar component of the free surface energy is... 

Lee JH, et al. Improvement of adhesion between plastic substrates and antireflection layers by ion-assisted reaction. Thin Solid Films. 2004 449 147-151. 

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