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In physical organic chemistry, a free-energy relationship or ''Gibbs energy relation'' relates the logarithm of a reaction rate constant or equilibrium constant for one series of reactions with the logarithm of the rate or equilibrium constant for a related series of reactions. Establishing free-energy relationships helps in the understanding of the reaction mechanism for a chemical reaction and allows the prediction of reaction rates and equilibrium constants. The most common form of free-energy relationships are Linear Free-Energy Relationships (LFER). The Brønsted catalysis equation describes the relationship between the ionization constant of a series of catalysts and the reaction rate constant for a reaction on which the catalyst operates. The Hammett equation predicts the equilibrium constant or reaction rate of a reaction from a ''substituent constant'' and a ''reaction type constant''. The Edwards equation relates the nucleophilic power to ''polarisability'' and ''basicity''. The Marcus equation is an example of a Quadratic Free-Energy Relationship (QFER). IUPAC has suggested that this name should be replaced by linear Gibbs energy relation,〔(IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). ) Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. 〕 but at present there is little sign of acceptance of this change. The area of physical organic chemistry which deals with such relations is commonly referred to as 'Linear Free-Energy Relationships'. ==Chemical and physical properties== (詳細はM.H. Abraham and co-workers):〔M.H. Abraham ''et al.'', “Application of hydrogen bonding calculations in property based drug design”, ''Drug Discovery Today'' 7 (2002) 1056–1063〕〔C.F. Poole ''et al.'', “Determination of solute descriptors by chromatographics methods”, ''Analytica Chemica Acta'' 652 (2009) 32–53〕 :log SP = ''c'' + ''e''E + ''s''S + ''a''A + ''b''B + ''l''L 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Free-energy relationship」の詳細全文を読む スポンサード リンク
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