Other Oxidation State iii Studies

An 5 Nlcb mechanism is proposed for the base hydrolysis (loss of first Cl ) of /ra j-[Ru(L)4Cl2]+ ions [(L)4 = (NH3)4, (enjj, 2,3,2-tet, or cyclam]. The results are collected in Table 2. The reactions proceed with retention of configuration, and the rates increase with increased chelation. The c/5-[Ru(en)aCI ] ion 

An 5 Nlcb mechamism is also favoured for the stereoretentive base hydrolysis of /ra/ij-[Rh(cyclam)XY]+ ions (X, Y=Cl, Br, or I). The results are collected in Table 3. The /ra/i5-effect of I ion is evident, with A// for loss of Cl 6.1 kcal mol less with I rather than Br or Cl trans to the leaving group. Variations in the values of (rather than kou at a particular temperature) indicate that Rh ii is a class (b) or soft metal ion. At 25 °C, the relative rates of base hydrolysis of rra j-[M(cyclam)Cl2]+ ions are Co (/ oh=6.7 x 10 s, A/f = 13.4 

Rate data for the base hydrolysis of /ra j-[Rh(LL )Cl2]+ ions (LL — a range of substituted ethane-1,2-diamine molecules) are collected in Table 4. In general, A obs = A i-l-A 2[OH-] from studies in up to 1 M [OH ], with A 2=0 when LL = tmeda. This is consistent with the 5 Nlcb mechanism since there are no acidic protons when LL = tmeda.  

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