CHIRAL METAL-COMPLEXES .45. THE STRUCTURE OF TRAAZATRICYCLO-[13,3,1,1(6,10)]EICOSANE)COPPER(II)

The crystal and molecular structure of chloro-{6S,15S-(4R, methyl)-1,5 ,10,14-tetraazatricyclo[13,3,1,1(6,10)] eicosane}copper(II)perchlorate , [Cu(S-mac6)Cl]ClO4, has been determined by X-ray analysis, Crystal d ata: C18H36N4O4Cl2Cu is orthorhombic, space group P2(1)2(1)2(1), a = 1 1.915(2), b = 12.290(2), c = 15.705(6) Angstrom 2 = 4. The structure w as refined by full-matrix least-squares procedures to R = 0.040 for 24 77 unique non-zero (I > 1.5 sigma(I)) reflections and with eta = 1.02( 7) confirming the absolute configurations of the chiral centres. The N -4 macrocycle coordinates to the copper atom in a square-planar arrang ement with Cu-N-sec of 2.005(5) and Cu-N-tert of 2.060(4) Angstrom, an d a square-based pyramidal geometry is completed by a chloride ion, Cu -Cl 2.711(2) Angstrom. Folding of the non-chelate six-membered rings p roduces a conformation such that only one face of the complex ion is a vailable for axial coordination of unidentate ligands.