Acid-base approach

Perhaps the greatest area in which the Lewis acid-base approach is most useful is that of coordination chemistry. In the formation of coordination compounds, Lewis acids such as Cr3+, Co3+, Pt2+, or Ag+ bind to a certain number (usually 2, 4, or 6) of groups as a result of electron pair donation and acceptance. Typical electron pair donors include H20, NH3, F , CN , and many other molecules and ions. The products, known as coordination compounds or coordination complexes, have definite structures that are predictable in terms of principles of bonding. Because of the importance of this area of inorganic chemistry, Chapters 16 through 22 in this book are devoted to coordination chemistry. 

Pearson, R. G. (1963). /. Am. Chem. Soc. 85, 3533. The original publication of the hard-soft acid-base approach by Pearson. 

An additional example includes the intracellular transcription and translation of virally encoded genes during intracellular viral replication. In all such instances, the medical consequences of such inappropriate gene (over)expression could be ameliorated/prevented if this expression could be down-regulated. A nucleic-acid-based approach to achieve just this is termed antisense technology . 

The Lewis acid/base complex is formed via an overlap between a doubly occupied orbital of the donor D and vacant orbital of the acceptor A. This acid/base approach was extended by Pearson who divided Lewis acids and bases into two groups, hard and soft, according to their electronegativity and polarizability (principle of hard and soft acids and bases (HSAB concept). Hard acids (e.g., H, Lf, Na, BF3, AICI3, hydrogen-bond donors HX) and hard bases (e.g., F", CL, HO, RO, H2O, ROH, R2O,... 

Nucleic acid-based approaches and the use of microsatellites are proving of considerable value for investigating genetic variation, the molecular epidemiology and population... 

Van Oss and colleagues [14] have adapted the Lewis acid-base approach to address the spatial implications of non-DLYO interactions. The surface tension measurements discussed in Sec. I. C can be converted to free energies... 

In this case, the Lewis acid-base approach has been assumed to account for all non-DLVO interactions. The exponential-decay expressions [Eq. (27)] deriving from the work of Pashley and Quirk [51], or other quantitative expressions for non-DLVO interactions, similarly could have been inserted. A major advantage of the Lewis acid-base approach is that all parameters in the expression can be determined a priori, whereas the exponential-decay... 

Nucleic acid-based approaches are both sensitive and specific, and have been fielded as part of demonstrations and tests. Nucleic acid approaches cannot detect purified biological toxins but may be able to identify associated residues from the organism. The time required to perform a nucleic acid test is decreasing, and for some instruments it is now less than 10 minutes. Instrument packaging is also being dramatically reduced currently, suitcase-sized systems can be purchased. A nucleic acid approach to medical diagnostics is also showing promise... 

Other molecular entities (e.g., nucleic acid-based approaches) have advantages as well (e.g., higher specificity of antisense drugs based on the high diversity and selection process), but will have to prove their potential given recent setbacks (e.g., Genasense,... 

In the broadest form, an acid is an electrophile whereas a base is a nucleophile. When these species are regenerated during reactions then they become catalytic. For general reading see Michael B. Smith Organic Chemistry. An Acid-Base Approach CRC Press October 2010, ISBN 10 1420079204,13 9781420079203. 

Professor Smith is also the author of Volumes 6-12 of the Compendium of Organic Synthetic Methods, the author of the 5 , 6 , and 7 editions of March s Advanced Organic Chemistry, and the author of Organic Synthesis, U , 2", and 3" editions as well as several monographs. Professor Smith is also the author of an undergraduate textbook. Organic Chemistry An Acid-Base Approach, published by CRC Press. 

Kwok, D.Y., Li, D., and Neumann, A.W., Evaluation of the Lifshitz-van der Waals/acid-base approach to determine interfacial tensions, Langmuir, 10, 1323, 1994. 

In order to obtain surface tensions of ABA/ANA copolymers, van Oss and Good s Lifshitz-van der Waals-Acid-Base approach (3-Uquid LWAB method) is used. We chose diiodomethane as the apolar liquid and water-glycerol as the... 

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