COORDINATION GEOMETRIES IN BIS(DI-2-PYRIDYLAMINE)COPPER(II) COMPLEXES- CRYSTAL-STRUCTURES OF [CUL(2)](PF6)(2)' [CUL(2)(NO3)(2)](L=DI-2-PYRIDYLAMINE)

The crystal structures of three compounds containing bis(di-2-pyridyla mine)-copper(II) complex units have been determined by X-ray crystallo graphic methods; [Cu(dpa)(2)](PF6)(2) (1), [Cu(dpa)(2)(NO3)(2)] (2) an d CS)(1.5)-(ClO4)(0.5)][Cu(dpa)(2)(NCS)](2)(ClO4)(2) (3). Compound 1 c rystallizes in space group Fddd with cell dimensions a=9.418(2), b=13. 472(3), c=40.834(5) Angstrom; compound 2 in space group P2(1)/c with a =8.413(2), b=17.096(2), c=7.603(1) Angstrom, beta=94.18(1)degrees; com pound 3 in space group P2(1)/c with cell dimensions a=12.758(1), b=14. 459(2), c=19.397(3) Angstrom, beta=93.81(1)degrees. The structures wer e refined by full-matrix least-squares methods to R-values of 0.049, 0 .031 and 0.060 for compounds 1, 2 and 3, respectively, using 1110, 163 1 and 4760 reflections collected at room temperature with monochromate d MoK alpha radiation. In compound 1 the anions are uncoordinated, and the complex features the compressed tetrahedral geometry. In compound 2 the complex unit is centrosymmetric and octahedrally elongated, wit h the anions coordinating in axial positions. Two crystallographically independent molecules are found in compound 3, one complex unit being centrosymmetric and octahedrally elongated, the other close to square -based pyramidal with one of the dipyridylamine ligands occupying the apical and one of the equatorial positions.