Preparation and Characterization of fac-[Rh(tacn)Cl3], fac-[Rh(tacn)(H2O)3](CF3SO3)3, [Rh(tacn)2]Br3.2.8H2O and fac-[Co(tacn)(H2O)3](CF3SO3)3.H2O. The Acid Dissociation Constants of fac-[M(tacn)(H2O)3]3+ (M = CrIII, CoIII, RhIII and IrIII; tacn = 1,4,7-triazacyclononane).