Charged dimers

The donors are in fact organized in + 1 charged dimers which stack to form regular chain... 

The ionization and protonation equilibria for the doubly charged dimer have been determined in 3.0 M NaC104 medium but the values for these equilibrium constants can be expected to be affected by the great changes in ionic medium required (71)... 

A further ion detected at m/z 362 was assigned as the dimer [2M + H + K]2+. Since it was the only doubly charged dimer observed, it seemed that the combination of two Ci2-CAPB molecules with one proton and one potassium cation yielded a particularly stable species. 

Figure 2 Absorption spectra of silver atom Ag° (top) and charged dimer Agj (bottom) complexed by CN [37], EDTA [37], and NH3 [36,47] in solution. The spectra of uncomplexed Ag° and AgJ are shown for comparison. (From Ref. 35.)...

Table 1 Formation Rate Constants (mol 1 sec and Optical Absorption Maxima of Metal Atoms, Hydrated or Complexed, and of the Corresponding Charged Dimers in Water [19]...

The N-methyl stretch absorptions are often weaker in methyl groups attached to electronegative atoms . Spin density on the nitrogen in the pyridinyl radical reflects a positive charge dimerization of the radical would diminish the transfer of charger into another group, as whon with resonance forms (see below). 

This index is provided so that the reader might locate information about a particular complex of interest. It is organized as follows The first section contains the neutral binary complexes, followed by charged dimers, and then by larger complexes in the last section. Within each section, the complexes are ordered by the type of molecules contained. The order is as follows XH, YH2, ZH3, carbonyl, carboxyl, imine, amide, nitrile, alkyne, alkene, alkane, others. (X refers to any halogen F, Cl, Br, I Y to O, S, etc. and Z to N, P, etc.) Any alkylated or similar substitutions follow immediately after their parent group. 

Fig. 5. 250.13 MHz H NMR spectrum of the lithium dianion of azulene (152 ) in [2H8]tetrahydro-furan. Residual signals are due to the doubly charged dimer I92...

Figure 3.41 MALDI-TOF mass spectrum of insulin and (3-lactoglobulin, A mixture of S pmol each of insulin (I) and 3-lactoglobulin (L) was ionized by MALDI, which produces predominately singly charged molecular ions from peptides and proteins—the insulin ion (I + H] and the lactoglobulin ion (L -F H)". FHowever, molecules with multiple charges as well as small quantities of a singly charged dimer of insulin (2 1 + H) also are produced. [After J. T. Watson, Introduction to Mass Spectrometry, 3d ed. (Lippincott-Raven, 1997), p. 282.]...

Recombination of charged dimer molecules during HB lifetime... 

Two oppositely charged dimer molecules vibrate elastically... 

This picture of molecular events implies that a noticeable concentration (about 40%) of short-lived charged dimer molecules is commensurable with concentration of all water molecules. Hence, microscopically small charged regions of the fluid are assumed to be constantly substituted by the regions composed of neutral water molecules, and vice versa. 

Formation rate constants (mol 1 s ) and optical absorption maxima of metal atoms, hydrated or complexed, and of the corresponding charged dimers in water. 

Soon after absorption of the irradiation pulse by a solution containing the monovalent solvated cation M+, the population of atoms is created by the reaction depicted in Eq. (2). Formation of the atom is correlated with the decay of the solvated electron and this correlation enables determination of the rate constant of the reaction. The silver ion aqueous solution was the first system thoroughly studied by pulse radiolysis and has recently been revisited (Fig- 2). The optical absorption spectra of transient silver atoms and charged dimers produced by the reaction depicted in Eq. (10) have been observed by pulse radiolysis in various solvents, for example water (Table 1). The rate constants are generally diffusion-controlled, as are those for the corresponding reactions for formation of Tl and... 

Metal ion Rate constant of atom formation, V (L mol" s )I I Absorption maxima of atoms, A (nm) Rate constant of charged dimer formation k o, q, (Lmol" s" ) Absorption maxima of charged dimers, A (nm)... 

As already observed in the pulse radiolysis of hydrated Ag", the formation of the atom in the presence of CN is followed by formation of the charged dimer.f ... 

After association of this complexed atom with an excess ion, the spectrum of the complexed charged dimer (Ag2", xY" ") has three bands at 310, 340, and 400 nm (Fig. 3). ... 

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