Divalent paramagnetic counterions site binding in polyelectrolyte solutions. Analysis of the frequency dependence of the water protons magnetic relaxation and the characteristic parameters of “site binding”

Water in the formation of biogenic minerals: Peeling away the hydration layers

“…In actuality the strong binding of counterions such as Mn 2+ and Co 2+ to a polyacid such as polyphosphate results in only half of the counterions undergoing complete dehydration leading to covalent site binding, the other half of the counterions are territorially bound (Karenzi et al, 1979; Manning, 1979; Spegt and Weill, 1976). Additionally, since the polyion is seen as a large ligand with a distributed charge density, the initial interaction between the polyion and the incoming counterion is primarily a territorial binding event (Manning, 1979).…”

Counterion binding in polyelectrolyte theory

“…The order given correlates well with extents of dehydration measured by dilatometry for these systems,5 and, in particular, the value near zero for poly(styrenesulfonate) is consistent with the wellknown inability of this "fat" polyion to produce significant dehydration of conterions bound to it. 15 The validity of the results discussed here are limited to the domain of validity of eq 13 for µ, which may be defined by « 1 (see eq 3 and 4 and the discussion immediately following them). In practice this restriction may not be severe, since even when c, = 1 , = 0.56 for DNA in 1:1 salt.…”

“…Magnetic and spin resonance signals are sensitive to the close approach of a polyion and a counterion; counterions giving rise to signals altered from a standard reference state (absence of polyion, for example) can be called bound to the polyion. [13][14][15][16][17] In a typical competitive binding experiment, a polyelectrolyte salt immersed in excess aqueous 1:1 salt is brought into equilibrium with a solution containing a multivalent counterion, whereupon the latter competes with the univalent counterions for binding interactions with the polyion. In an equilibrium dialysis (membrane equilibrium) experiment, long-range ionically screened interactions of the multivalent counterion with the polyion are eliminated by the presence of excess 1:1 salt, and the difference in number of multivalent counterions on the "polyion side" of the membrane compared to that on the other side of the membrane is the number of multivalent counterions bound to the polyions.7,18 '19 Another possibility is the use of an indicator dye in a solution containing polyelectrolyte salt, 1:1 salt, and multivalent counterions.20 Knowledge of Gerald S. Manning was born In New York in 1940.…”

“…Suppose, then, that pure solvent be added to the system sufficiently slowly for the continuous maintenance of equilibrium. This procedure (suggested by C. F. Anderson) provides the operational meaning of the mathematical statement µ = 0 (15) ca-*0 Note that the condition of excess salt, if initially satisfied, remains satisfied throughout the limiting process. Since x82 is of order cs, it follows from application of eq 13 to eq 15 that a unique value = N~H 1 -N-'ir1) (16) is required if µ is not to have limiting values of ±m.…”