Synthesis of 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1) and a Spectroscopic and Structural Study of [Ni(L1)(ClO 4 )](ClO 4 ) and of the Macrobicyclic Precursor Diamide Complex, [Ni(HL2)](ClO 4 ); Chloride Substitution Kinetics of the Corresponding [Ni(III)(L1)] 3+ Species