Solvent-metal interactions

The general picture emerging from the pzc in aqueous solutions is that the major variation of <7-0 between two metals is due to with a minor contribution from AX that is governed by metal-solvent interactions. If this is also the case in nonaqueous solvents, a similar picture should be obtained. This is confirmed by Fig. 20 in which the data in DMSO are reported. As in aqueous solution, all points lie to the left of the point of Hg. Bi, In(Ga), and Tl(Ga) lie with Hg on a common line deviating from the unit slope. As in aqueous solution, Ga is further apart. Au is in the same position, relatively close to the Hg line. Finally, the point of Pt is (tentatively) much farther than all the other metals. 

In fact, the orientation of water at the potential of zero charge is expected to depend approximately linearly on the electronegativity of the metal.9 This orientation (see below) may be deduced from analysis of the variation of the potential drop across the interface with surface charge for different metals and electrolytes. Such analysis leads to the establishment of a hydrophilicity scale of the metals ( solvophilicity for nonaqueous solvents) which expresses the relative strengths of metal-solvent interaction, as well as the relative reactivities of the different metals to oxygen.23... 

The metal-solvent interactions were put into the model of Price and Halley93 in a later paper by Halley and co-workers,97 which also remedied some of the deficiencies of the original model, such as the inability to calculate the slope of a plot of (Cc) 1 versus qM and the dependence of the compact-layer capacitance on crystal face. One can show in general [see Eq. (40)] that... 

Some information about the metal-solvent interaction can be obtained from measurements of the contact (Volta) potential difference at the metal/solvent interface... 

The metal-solvent interaction is expected to depend on the donicity of the solvent the higher the donor number of the solvent the stronger the solvent-metal interaction should be. Hence, a correlation between the contact potential difference A>// (a = 0) and the donor number of the solvent should be observed. However, this correlation for the Hg electrode is rather poor, with the most deviant point having been found for water, that is, for the case of the strongest dipole-dipole interaction in the bulk. The correlation is better when acceptor numbers of solvents are taken into account. ... 

When there is no adsorption, only solvent molecules are present in this layer. Then the variation of the inner-layer capacity vs. charge density gives information on the metal-solvent interactions [see Section V.3(i). The short-range interactions change the solvent properties. 

When there are organic neutral substances on the metal side of the oHp, there is also substitution of solvent molecules by neutral molecules and metal-neutral substances interactions are observed, they could also alter the metal-solvent interactions in some cases the adsorption-desorption peaks can be observed [see Section... 

From so few results it is difficult to draw precise conclusions on the influence of the co on the metal-solvent interactions. It was foreseen that Ag(dip), the change of the contribution to the metal-solution electrode potential drop due to preferential orientation of water dipoles, increases as the work function of the metal surfaces decreases, i.e., is larger for the (110) face than for the (100) face (of the fee system) this was observed for silver faces in KPF (Fig. 30). 

The origin of these peaks can be discussed. Obviously, when metal-ion interactions are weak, the effects of the metal-solvent interactions should still be observable. On the contrary, when the metal-to-ion interactions are strong, the metal-solvent interaction effects become obscured. Intermediate cases will be difficult to analyze. 

It was proposed, for determination of the roughness factor, that the value of the capacity at very negative density of charge (where there is no longer adsorption of anions) be compared to that of mercury. This does not take into account that at such negative density of charge there are metal-solvent interactions and these are not only metal specific but also face specific. 

Trassati, S. Metal-Solvent Interaction at Electrode/Solution Interfaces. Holland, Elsevier Pub. Co. 1980, in press... 

In a polar medium, the partial charge transfer depends on two additional contributions due to the ion-solvent and metal-solvent interactions. Following the theory of electrochemical adsorption by Schmickler [232], the adsorbate energy level in solution, e is given by... 

The interaction between an atom or a cluster, even when neutral, and a solvent is noticeable and induces specific properties that between a ligand and a metal is even stronger than the metal-solvent interaction. Thus the complexation has a marked influence on the reaction rate-constants and on the thermodynamics of the... 

Taylor, C.D., The transition from metal-metal bonding to metal-solvent interactions during a dissolution event as assessed from electronic structure. Chemical Physics Letters, 2009. 469 (1-3) p. 99-103. 

Metal-solvent interactions can be conveniently considered in terms of the hard-soft acid-base (HSAB) principle (Chapter 1). For example, palladium(II) is a soft metal center and so the hard oxygen donor solvent, diethyl ether, interacts only poorly with it. Simple valence bond models have been presented that adequately explain such soft metal-hard base interactions. In this chapter complexes containing coordinated halocarbons are treated in a separate section (3.7) from those that contain other "hard bases" since such species have only been recognized as well-defined complexes in recent years and their potential for exploitation in coordination chemistry merits special attention. 

With an exception of [THA][DHSS] and [TOMA] [Sal], the cesium nitrate solubility in RTIL is much less than in water, the metal-solvent interaction is likely to be stronger in water, than in RTIL, i.e. less energy is needed for breaking the metal-(RTIL anion) bonds. Thus the... 

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