The synthesis and structural characterization of ZnLX2 (X = H2O(1), N-3(-)(2), and NCS-(3); L = 2,5,9,12-tetramethyl-1,4,8,11-tetraazacyclotetradecane) complexes are reported. The crystal structure analysis was employed to determine solid state structures. The crystal structures of these complexes have an axially elongated octahedral geometry with two axial ligands and adopt the trans-III conformation. The long Zn-O bond distance of 2.343(5) Angstrom in complex 1 has a high pK(a) value of 11.2. (C) 1998 Elsevier Science Ltd. All rights reserved.