Cationic Organic Structures

Al-containing ITQ-21 zeolite ((Si+Ge)/Al=25, Si/Ge=20) was synthesized using N(16)-methyl-sparteinium cation (MSPT+) as the organic structure-directing agent in combination with fluoride anions and germanium as described in [1], The composition of the final synthesis gel was ... 

Cations other than Li+ can be introduced into the film by a simple ion-exchange procedure, and this may be a simple method for obtaining multilayered structures with any cation. Organic cations, e.g., cyanine dyes, can also be introduced into the film by this procedure. Perhaps this approach for the application of highly ordered thin LB films onto the surface of electrodes could yield some new results, such an improvement in response time, as was discussed in Section 7.3.7. 

Persistent Organic Cationic Complexes Structure and Reactivity... 

There are numerous publications on the chemistry of long-lived cationic complexes see, for example (7-70). Most of our recent results in this area have been published in Russian and are probably not easily accessible to most foreign researchers. It was for this reason that we enthusiastically accepted the invitation made by Prof. Ken Laali to contribute a brief review summarizing our recent studies on the structure and reactivity of long-lived cationic organic complexes. We limit this account to the data obtained after 2000 but include some earlier unpublished results that were not included in our earlier reviews (5, 77). 

R. L. Smith, R K. Chou, and H. I. Kenttamaa, Structure and reactivity of selected distonic radical cations , in Structure, Energetics and Dynamics of Organic Ions, T. Baer, C. Y. Ng, and I. Pawis, Eds., John Wiley Sons, Inc., New York, 1996, p. 197. 

For ionic compounds the coordination number is the number of anions that are arfang d about the cation in a organized structure. For example, NaCl has a coordination number of 6. In otherwords, 6 CF atoms surround 1 Na+ atom. The number of anions that can surround a cation is dependent (but not entirely) on the relative sizes of the ions involved. Table 2.15 illustrates thtnmlios of the radii of the ions and their coordination number. 

Early in the development of the field, compounds were often prepared to define the limits of both the synthetic methods and the stable products that could be formed. To date, many thousands of heteromacrocycles have been prepared. The dominant application of the vast family of host or receptor molecules has been to bind or complex a guest structure. The guests can be metal cations, organic cations, neutral substrates, anions, or complementary molecules. The complexation process can be understood from the simple example of 18-crown-6 complexing K+Cl- in solution. Ignoring structural and solvation/desolvation issues, the process can be described simply as... 

Koepsell H, Lips K, Volk C. Polyspecific organic cation transporters structure, function, physiological roles, and biopharmaceutical implications. Pharm. Res. 2007 24 1227-1251. 

Table 5. Structures, singlet energies (E ), reduction potentials (Erdn), and excited state reduction potentials (E rdn) of cationic organic acceptors .

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