Chemical action at a distance

Ostwald drew attention to the fundamental condition for the production of current by a chemical reaction, which he attributes to J. W. Ritter only those chemical reactions can produce an electric current which can be divided into two parts taking place simultaneously but separately at two electrodes. One of these reactions is an oxidation (e.g. Zn = Zn + + 2 ) and the other is a reduction (e.g. Cu = Cu + 2 ). Faraday (see p. 126) had the idea that an electric current is transporting chemical affinity , and Schonbein spoke of this as chemical action at a distance (Fernewirkung) . 

We observe that the solvent is arranged as a one dimensional chain of hydrogen bonded water molecules, whose properties are considerably different than ordinary three dimensional water. For example, this linear water is a better ion solvent than three dimensional water in terms of solvation energy as a function of distance from the ion to the water. In addition, the 25 A long chain of waters tends to translate as a correlated unit, thus leading us to discuss the possibility of water structures in proteins acting as the intermediary for chemical action at a distance, particularly in allosteric effects in enzymes. ... 

Enzymes and chemical catalysts bind their substrates, not permanently, but transiently—for a brief time. There is no action at a distance involved. The portion of an enzyme that binds substrate and carries out the actual catalysis is termed the active site. 

Hormones are chemical messengers synthesized and secreted by specialized endocrine glands to act locally or at a distance, having been carried in the bloodstream (classic endocrine activity) or secreted into the gut lumen (lumocrine activity) to act on target cells that are distributed elsewhere in the body. Probably, to be more correct three actions should be defined, namely endocrine action when the hormone is distributed in circulation binds to distant target cells paracrine action in which the hormone acts locally by diffusing from its source to target cells in close proximity and autocrine action when the hormone acts upon the cell that actually produced it. 

At the early stages of the study of enzymatic catalysis many fanciful mechanisms were proposed, each of which attributed to the catalyst some special, hitherto unobserved, chemical property, such as the ability to act at a distance, or the ability to form unorthodox chemical bonds. The number of theories accounting for the catalytic properties of enzymes was narrowed down considerably when it was demonstrated that all enzymes are proteins. Furthermore, when other chemical compounds, such as cofactors or metal ions are also required for catalysis, enzymatic action is still intimately related to the intact tertiary structure of the protein. 

A spatial repellent is a chemical that deters mosquitoes at a distance and inhibits their ability to locate a host. Spatial repellency has been widely used to describe the action of coils, mats, and passive emanaters, which release vaporized chemicals that affect mosquitoes at a distance and cause knockdown, mortality, repellency, or inhibition of feeding. Componnds that mask attractive host odors and thereby impact mosquito host-finding behavior were snggested to be defined as attraction inhibitors. ... 

Because Berthollet considered chemical affinity to be a form of universal gravitation, the shapes of the interaction particles would be significant at the short distances of chemical action, as they were not at astronomical distances. In addition, the idea of universal attraction meant that affinities would not be satisfied or saturated by a single combination, but would be variable according to the quantities of all the material there. He thus arrived at the concept of chemical mass, which modified the conventional... 

Since any quenching action is a bimolecular process, it is essential that the molecules M and Q should be in relatively close contact, but not necessarily in hard sphere (van der Waals) contact. Theoretical models lead to the distance dependence of the quenching rate constants as exponentials or sixth powers of r, the centre-to-centre distance of M and Q. Since these distance dependences are very steep, it is convenient to define a critical interaction distance r at which the quenching efficiency is, this being the distance at which 50% of the molecules M decay with emission of light (or undergo a chemical reaction) and 50% are quenched by some nearby molecule Q. 

TTHE ACTION OF ULTRASONIC WAVES IN LIQUIDS can induce or accelerate a wide variety of chemical reactions (1, 2) The chemical effects of ultrasound have been explained in terms of reactions occurring inside, at the interface, or at some distance away from cavitating gas bubbles. In the interior of a collapsing cavitation bubble, extreme but transient conditions exist. Temper-... 

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