Negative fragments

Ion-pair formation. An ionization process in which a positive fragment ion and a negative fragment ion are the only products. 

A final example in Table X shows the log P computation which CLOGP-3 performs on atrazine. If the three Isolating Carbon atoms in the ring were truly isolating, the negative fragments would predominate and a value of -1.15 would be obtained. The... 

Figure 9. Top. Negative fragment ion formed from the substituted sulfonamide by laser desorption using pulsed CC>2 laser. Bottom. Dissociation upon irradiation with a cw CO2 laser, all other conditions identical to those in the top spectrum.

Because of the limited volatihty of most organomagnesium and -berylhum compounds, there have been fewer mass spectrometric data reported. With Cp2Mg, positive and negative fragment ions from cleavage of the metal ring bonds are observed. Mass spectra of Mc2Be vapor show the presence... 

Uasymmetrical reagents add to olefins in such a way that the more negative fragment appears on the carbon atom carrying the smaller number of hydrogen atoms. (Markownikoff s rule,) In terms of hyperconjugation theory, this is the more positive atom (see p. 32). 

Arrhenius is a Swedish chemist. In 1903 he won the Nobel Prize for his work with solutions. He explained why some solutions conduct electricity. In his theory, Arrhenius concluded that the molecule breaks apart into a positive fragment and negative fragment, called ions. He also explained weak and strong electrolytes according to the ratio of the ions in solutions. 

Ionic chain polymerizations are especially sensitive to traces of moisture and other impurities which can terminate ions. Water and other similar compounds terminate ions by transferring a proton or negative fragment (see Chapter 8) For example, in the cationic polymerization of styrene, the cationic chains are effectively terminated by proton transfer to water molecule ... 

Various transfer agents (denoted here by TA or S) present as a solvent, impurity, or deliberately added to the system can bring about termination of the growing polymer chain by transfer of a negative fragment A . In general terms, the reaction can be represented by... 

Firstly, consider the fragmentation (disconnection) of the TM - noting that the TM is an ester. The fact that the target molecule is an ester helps in suggesting the most useful disconnection of the molecule into positive and negative fragments (synthons) - see below. 

Chain transfer of the propagating carbenium ion to a negative fragment from the counter-ion (e.g., transfer of OH or Cl from AlCl OH ) or solvent or some other component (e.g., water) of the reaction system are also important. 

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