NOVEL SQUARE PYRAMIDAL COPPER(II) COMPLEXES OF THE STEREOSPECIFIC LINEAR NSNN TETRADENTATE LIGAND, N-[(2-PYRIDYL)METHYL]-2-[(2-AMINOETHYL)THIO] ACETAMIDE (PYGEH) - THE CRYSTAL-STRUCTURES OF [CU(PYGE)BR], [CU(PYGE)N3]

The preparations of complexes of type [Cu(pyge)X] and [Cu(pyge)(OH2)]BF 4, where pygeH is N-[(2-pyridyl)methyl]-2-[(2-aminoethyl)thio]acetamide and X is Br, N3, NCO, NCS, OC6H4NO2-p, and NO2, are described. The new complexes have been characterized by elemental analysis, IR and electronic spectroscopy, magnetic moment, and in two cases (X = Br and OC6H4NO2-p), EPR spectroscopy. The available data suggest that the complexes are of tetragonal, probably square pyramidal geometry in solution. X-ray structural analyses of [Cu(pyge)Br] (1) and [Cu(pyge)N3] (2) were undertaken. Complex 1 crystallized in the monoclinic space group P21/n, a = 9.676(2), b = 9.147(2), c = 15.171(3) Å, β = 106.73(2)°, V = 1286.0(5) Å3, Z = 4. Refinement was based on 1594 reflections and converged at R = 0.059, Rw = 0.058. Complex 2 crystallized in the monoclinic space group P21/c, a = 9.925(2), b = 9.354(3), c = 15.141(4) Å, β = 106.96(2)°, V = 1344.3(6) Å3, Z = 4. Refinement was based on 1196 reflections and converged at R = 0.065, Rw = 0.065. The geometry of the complexes is best described as very slightly distorted square pyramidal, with the terminal amino group of the tetradentate ligand occupying the apical site. Origins of the observed stereospecificity and structural comparisons to octahedral [Co(pyge)(NO2) 2] are discussed. © 1990.