9: Acid-Base and Donor-Acceptor Chemistry
- Page ID
- 279032
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- 9.1: Acid-Base Models as Organizing Concepts
- The concept of acids and bases is often associated with the movement of hydrogen ions from one molecule or ion to another. However, a host of acid base concepts have been developed to help chemists organize and make sense of a wide range of reactions
- 9.3: Brønsted-Lowry Concept
- 9.3.1: Rules of Thumb for thinking about the relationship between Molecular Structure and Brønsted Acidity and Basicity*
- 9.3.2: The acid-base behavior of binary element hydrides is determined primarily by the element's electronegativity and secondarily by the element-hydrogen bond strength.*
- 9.3.3: Brønsted-Lowry Superacids and the Hammett Acidity Function
- 9.3.4: Thermodynamics of Solution-Phase Brønsted Acidity and Basicity
- 9.3.5: Thermodynamics of Gas Phase Brønsted Acidity and Basicity
- 9.3.6: The Acidity of an Oxoacid is Determined by the Electronegativity and Oxidation State of the Oxoacid's Central Atom*
- 9.3.7: High Charge to Size Ratio Metal Ions Act as Brønsted Acids in Water
- 9.3.8: The Solvent System Acid Base Concept
- 9.3.9: Acid-Base Chemistry in Amphoteric Solvents and the Solvent Levelling Effect
- 9.3.10: Non-nucleophilic Brønsted-Lowry Superbases
- 9.4: Lewis Concept and Frontier Orbitals
- 9.4.1: The frontier orbital approach considers Lewis acid base reactions in terms of the donation of electrons from the base's highest occupied orbital into the acid's lowest unoccupied orbital.
- 9.4.2: All other things being equal electron withdrawing groups tend to make Lewis acids stronger and bases weaker while electron donating groups tend to make Lewis bases stronger and acids weaker
- 9.4.3: The electronic spectra of charge transfer complexes illustrate the impact of frontier orbital interactions on the electronic structure of Lewis-Acid base adducts.
- 9.4.4: Substances' solution phase Lewis Basicity towards a given acid may be estimated using the enthalphy change for dissociation of its adduct with a reference acid of similar hardness.
- 9.4.5: In the boron triflouride affinity scale the enthalphy change on formation of an adduct between the base and boron triflouride is taken as a measure of Lewis basicity.
- 9.4.6: Lewis base strength may also be estimated by measuring structural or energy changes on formation of a Lewis acid-base complex, as illustrated by efforts to spectroscopically assess of the strengths of halogen bonds
- 9.4.7: Bulky groups weaken the strength of Lewis acids and bases because they introduce steric strain into the resulting acid-base adduct.
- 9.4.8: Frustrated Lewis pair chemistry uses Lewis acid and base sites within a molecule that are sterically restricted from forming an adduct with each other.