Kinetics of structural rearrangement accompanying the substitution reaction on complex (Co(terpy)(hmpa)3)2+(terpy=2,2':6',2"-terpyridine) in hexamethylphosphoric triamide.

The reaction of structural rearrangement accompanying the substitution of hexamethylphosphoric triamide (HMPA) for 2,2′: 6′,2″-terpyridine (terpy) from octahedral [Co(terpy)(hmpa)3]2+ to tetrahedral [Co(hmpa)4]2+ proceeds through a five-coordinated intermediate in HMPA. The following values for the first-order rate constant at 25 °C, ΔHd\eweq, and ΔSd\eweq were obtained: kd=3.55×10−5 s−1, ΔHd\eweq=105.4 kJ mol−1 and ΔSd\eweq=+15.9 J K−1 mol−1.