THE KINETICS OF THE HG2-ASSISTED CHLORIDE RELEASE FROM SOME [MCL(RNH(2))(5)](2+) COMPLEXES (M=CO, CR)()

Activation parameters associated with the Hg2+-assisted chloride relea se reaction in 50:50 dioxane:aqueous HClO4(I=0.5 M) from [MCI(RNH(2))( 5)](2+) at 25 degrees C in the order (k(Hg), M(-1)S(-1);Delta H,kJ mo l(-1);Delta S,J K-1 mol(-1) are 0;M=Co,R=nPr:2.59,69.3,-5;M=Co,R=nBu: 2.15,70.2,-3. Similar data in aqueous HClO4 (I=1.0 M) are 15x10(-3),93 .2,+16.5M=Co,R=H:1.40x10(-1),65.1,-42; M=Co,R=Me:5.00,70.4,+5. The tre nds in activation entropy would rank MCl(RNH(2))(5)](2+) (R not equal H) at essentially the same position on an interchange mechanistic scal e, independent of M, and more associatively restricting than [MCl(NH3) (5)](2+).