Abstract
The synthesis, structure and spectroscopic properties of a family of Zn complexes containing a dinucleating hexaazamacrocyclic ligand (L) and anionic ligands (X) of general formula [Zn~2~(X)~4β~~n~(L)]^n^^+^ (1β8; L = H2p, H3p, Me2p, Me2m, Me3p, Me3m; X = Cl, n = 0; X = NO~3~, n = 2) have been investigated. The solidβstate structural characterisation has been performed by means of Xβray diffraction analysis for complexes 3, 5, 7Β·1/3CH~2~Cl~2~ and 8. The Zn complexes 5, 7Β·1/3CH~2~Cl~2~ and 8 containing chloride ligands present a distorted N~2~Cl~2~ tetrahedral coordination with two nonβcoordinated N atoms of the macrocyclic ligand. On the other hand, complex 3, which contains nitrate ligands, displays an N~3~O~2~ pentacoordination with all the N atoms of the macrocyclic ligand bonded to the metal centres. The different factors governing the relative ZnβZn disposition are discussed. NMR spectroscopy in solution reveals the presence of fluxional behaviour and a completely different structural arrangement than in the solid state. In particular, evidence for the formation and breaking of ZnβN bonds involving all the macrocyclic ligand aminic N atoms is obtained for the chloride complexes 2 and 4β8. Finally, complexes 1, 3, 5 and 7 hydrolyse pβnitrophenyl acetate (NA) with secondβorder rate constants ranging from 0.045 to 0.193 M^β1^s^β1^, thus manifesting the influence of the ligands over the hydrolytic activity. (Β© WileyβVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)