Spectroscopic evidence of a net formation of MV+ via photolysis of Ru(bpy)32+ and MV2+ adsorbed on porous Vycor glass

An Examination of the Role B2O3 Lewis Acid Sites in Electron Transport on Porous Vycor Glass

“…@R,,(I) maximizes at a loading corresponding to a mean separation between the Ru(bp~)3~+ reactions of 50 f 10 A and approaches zero at loadings corresponding to mean adsorbant spacings of 2200 and 1 1 3 A, respectively. The separation corresponding to the maximum yield agrees with electron migration distances on PVG,17,18 while the adsorbate spacing at higher loading, 5 13 A, correspondings to a contact interaction, Le., monolayer coverage? These data suggest that charge separation in this glass is a consequence of the immobility of the reactants and their distribution on the glass surface.…”

“…Unless otherwise specified, all measurements were carried out with samples at room temperature. The general procedure was to evacuate the sample to 5 Torr, record an initial spectrum, and then expose the sample to 1 atm of NH3. After reaching equilibrium, which occurs in a few minutes at room temperature, the sample was maintained under a dynamic vacuum (p I Torr), and spectra were recorded as a function of time to monitor NH3 desorption.…”

Photoinduced Electron Transfer in Porous Glass

“…The probability that an electron travels a distance r without interacting with another Ru(bpy)32+(ads) is F(r) = exp[-ar] (5) Equation 5 arises from the fact that for small Ar F(r+Ar)=F(r)[l-aAr] (6) where / -<z/Vis the probability that the electron moves a distance Ar without interacting. Rearranging equation 6 yields [F(r+Ar) -F(r)]/Ar = -aF(r) (7) and taking the limit of (7) as Ar -*• 0 yields F\r) = -aF(r) for some constant c. Since the probability of not interacting goes to one as r -» 0, c = 1 and…”

“…First, the electron populates only one surface acceptor site, and second, since these sites are energy wells with a depth of ca. 7 kcal/mol,35 activation from the site reduces the electron's energy and in turn reduces its maximum travel distance to r't (Figure 4). Even with these simplifying assumptions, however, the situation remains complex since all cases where the electron falls into a site after traveling a distance r0 < rtb and r0 > rth have to be treated separately.…”

Photoelectrochemistry in particulate systems. 7. Electron-transfer reactions of indium sulfide semiconductor colloids

“…This process is favored by the fact that particles that are stabilized by Nafion are negatively charged and repel the negatively charged ZVfrom the colloidal particle. Hence the negatively charged stabilizer (Nafion) plays two important roles in effecting the electron transfer in these particulate systems: (1) It facilitates the adsorption of the relay (ZV) species on the semiconductor particle.…”