A computational study of the electronic structure, bonding, and spectral properties of tripodal tetraamine Co(III) carbonate complexes.

Density functional calculations have been carried out on the experimentally characterized Co(III) [Co(N4)(O2CO)]+ carbonate complexes containing a tripodal tetraamine ligand (N4 = tpa, Metpa, Me2tpa, Me3tpa, pmea, pmap, tepa) and also the model [Co(NH3)4(O2CO)]+ system. Calculations on the model species, performed using both gas-phase and solvent-corrected procedures, have revealed that the inclusion of a condensed-phase environment is necessary to obtain generally satisfactory results for the structural and bonding properties in these systems. Using the solvent-corrected approach, the observed trends in structural parameters for the metal-ligand bonds, 59Co chemical shifts, and changes in visible absorption wavelengths have been satisfactorily reproduced for the [Co(N4)(O2CO)]+ complexes.

Stabilization of coordinated carbonate in aqueous acidic solution: steric inhibition of protonation in Co(III) complexes containing chelated carbonate.

The synthesis, characterization, X-ray crystal structures, and reactivity in aqueous acidic solution of the Co(III) carbonate complexes [Co(tpa)(O2CO)]ClO4.H2O, [Co(Me-tpa)(O2CO)]ClO4.0.