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For metal complexes of macrocyclic tetraaza ligands, a number of configurational isomers are possible owing to the chiral nitrogen of the macrocycle.1 Miyamura et al. reported the synthesis and structure of Ni(II) complex of C-meso- 1,5,8,12-tetramethyl-1,4,8,11-tetraazacyclotetradecane. 2 In the present study we report the structure of the title compoud ( Fig. 1) by single crystal X-ray analysis.The ligand, C-meso-1,5,8,12-tetramethyl-1,4,8,11tetraazacyclotetradecane, was prepared according to the method of Miyamura et al.2 Equimolar quantities of Cu(ClO 4 )·6H 2 O and the ligand were mixed in aqueous methanol (v/v=1/1) solution and allow to react for 4 h at room temperature. The resulting solution was placed in a refrigeratopr for several days, whereupon red crystals were formed.The molecular structure of the title compound is shown in Fig. 2. Two molecules of different configurations occupy the same position with the same occupancy. The structure contains the two diastereomers, (A) and (B). The Cu(II) ion is located at an inversion center. The Cu(II) ions in these two diastereomers are coordinated with four N atoms of the equitorial ligand and two O atoms of the perchlorate axial group. The quadridentate ligand has two five-membered chelate rings in gauche conformation and two six-membered

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The stereochemistry of Zn(II) complexes varies from linear to dodecahedral with coordination numbers 2 to 8, respectively.1 Since there is no ligand field-stabilization effect in the Zn(II) ion due to its completed d shell, the stereo chemistry is determined by a consideration of the size, electrostatic forces and covalent-bonding forces with the ligands. Here, we report on the crystal structure of [Zn(tmc)H 2 O](ClO 4 ) 2 monohydrate based on an X-ray structural analysis.The ligand 1,4,8,11-tetraazatetramethylcyclodecane was prepared according to the literature.2 Equimolar quantities of Zn(ClO 4 ) 2 ·6H 2 O and the ligand were mixed in a methanolic solution to react for 1 h at room temperature. The resulting solution was dried using a rotary evaporator. Colorless crystals were obtained by recrystallization using acetone and 5 M NaClO 4 as solvents by slow evaporation.The coordination about the Zn(II) ion is five coordinated in a distorted trigonal bipyramid and the