Rates were measured for the association of CO, CH4, CH3F, NH3, ND3, CH3Cl, and CH3Br onto Ag+ and Cu+ at 298 K. In the order given above, the three-body association rate constants for Ag+ range from 2.5×10−30 to 3.9×10−27 cm6 s−1. The rate constants for Cu+ are about four to six times larger for a given neutral reactant. The rate constants display trends in the order expected considering the relative bond energies of the clusters, although the enormous range of reactivity is not reflected simply by differences in dipole moments and polarizabilities. There is a very large isotope effect, where the rate constant for ND3 association was found to be about three times greater than NH3 in the case of both ions. (Results for Na+ follow the same trend.) This suggests a coupling of ligand vibrations with orbiting motion which leads to enhanced lifetimes of the cluster intermediates. The trend found for the methyl halides also supports the involvement of this effect.

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MLCT state is higher in energy than remote. For all other complexes eq 6 is employed. For all 423-type complexes, the DQ2+ 2+/1+ reduction potential is -0.65 V, as shown in Table I. Once values of AG are known, estimation of k,, follows easily, using eq 11, with C = -104 mV, and b = -2022 mV. Estimates presented in this Appendix are listed in Table 111.(R~(bpy)~(42n-DQ~+))~+ Series. The onset of emission in the complex Ru(bpy)2(DMB)Z+ is 2.20 eV (Table IV), and the Ru 3+/2+ potential for R~( b p y )~( 4 2 3 -D Q~+ ) is +1.24 V ( Table I) .Equation 7 thus yields a value of 1.24 -2.20 = -0.96 V for the Ru 2+*/3+ potential in R u ( b p~)~( 4 2 3 -D Q~+ ) .With values of -0.65 V for the DQz+ 2+/1+ potential, and 0.05 V (50 mV) for E A R , eq 8 yields an estimate of AG equal to -0.96 + 0.65 -0.05 = -0.36 V or -360 mV. For R~( b p y )~( 4 2 2 -D Q~+ ) and Ru-( b p~)~( 4 2 4 -D Q~+ ) , DQ2+ 2+/1+ potentials (Table I) are -0.44 and -0.77 V, respectively, yielding respective AG estimates (Table 111) of -240 and -570 mV. For these complexes, k,, values are estimated as kr(obsd)/a(calcd), (a = 0.064). These ke-I estimates are found in Table 111.(4) Radecki, B. D.; Allison, J.