In the search for new bis(imidazole)thioether (BIT) copper complexes that accurately mimic the electronic and reactivity features of the Cum site of-copper hydroxylase enzymes, a set of tripodal BIT ligands 4a,b-6a,b has been synthesized that vary according to the imidazole C-(Ph or H) and N-(H or Me) substituents, as well as the position (2-or 4-) of the tripodal attachment. Corresponding [(BIT)Cu(L)](PF6) complexes 7a,b', 8a,b', and 9a',b' [L = CO (a), CH3CN (b)] have been prepared and characterized spectroscopically. The IR spectra of 7a-9a (L = CO), specifically nu(CO), show little variation (2090-2100 cm(-1)), suggesting a similar electronic character of the Cu centers. In contrast, cyclic voltammetric analysis of these compounds (L = CH3CN) reveals quasi-reversible oxidation waves with significant variation of E-pa in the range of + 0.45-0.57 V vs Fc/Fc(+), depending on the imidazole substituents. Each of the [(BIT)Cu(CH3CN)]PF6 complexes reacts with dioxygen to form. [(BIT)Cu-2(II)(mu-OH)(2)](PF6)(2) derivatives, 10-12, but they vary considerably in their relative reactivity, following the same trend as the ease of their electrochemical oxidation, that is, [(2-BITNMe)Cu(CH3CN)](+) (9b') > [(4-BITPh,NMe)Cu(CH3CN)](+) (8b') > [(2-BITPh2,NMe)Cu(CH3CN)](+) (1a') > [(4-BITPh,NH)Cu(CH3CN)](+) (7b'). Thus, N-Me substitution and 4-tethering on the imidazole unit increase oxidation and oxygenation reactivity, while Ph-substitution and 2-tethering decrease reactivity. PM3 and DFT calculations are employed to analyze the relative stability, the electronic features, the Cu-CO vibrtional frequency, and the electrochemical and oxidative reactivity of the complexes.