A study of linkage isomerization for the five-membered cyclic CN4 tetrazole ligand system from the carbon-adjacent-N1-bonded (5-methyltetrazolato)pentaamminecobalt(III) to its N2-bonded form in 11 different solvents is reported. The solvents include both protic and aprotic solvents as well as the hydroxylic solvents water and methanol. Rate constants in the various solvents were successfully correlated to solvent properties by using Reichardt's acceptor parameter ET and Gutmann's donor parameter DN in the equation In k = In k0 + αET + βDN with α = 0.0557, β = 0.0794, and In k0 = -18.70. Alternatively, the equation ln k = ln k0 + aα + bβ + cπ* due to Kamlet and Taft can be used to model the solvent effects. Here α measures the ability of a solvent to act as a hydrogen-bond donor, β measures the solvent's hydrogen-bond-accepting ability, and π* measures the solvent's dipolarity/polarizability and its ability to stabilize a charge dipole. The fit to these solvent parameters was also successful for all 11 solvents with In k0 = -17.35, a = 0.92, 6 = 2.16, and c = 1.98. These fits are discussed in terms of specific solvent interactions with the complex, and solvent effects on the rate constants for linkage isomerization of the tetrazolato system are compared to solvent effects in the nitrito system.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry