HALOCUPRATES(II) OF THE N-PHENYLPIPERAZINIUM MONOCATIONS AND DICATIONS - CRYSTAL AND MOLECULAR-STRUCTURE OF N-PHENYLPIPERAZINIUM TETRACHLOROCUPRATE(II) - CORRELATION OF THE ELECTRONIC-SPECTRUM VS DISTORTION OF THE CUCL42- ANIONS FROM TETRAHEDRAL SYMMETR

The X-ray structure of N-phenylpiperazinium tetrachlorocuprate (II), (C10H16N2) CuC14, was determined by X-ray diffraction methods. Crystals are orthorhombic, P212121) with a=17.698 (2) υ, b=8.615 (1) υ, c=9.841 (1) υ, and Z=4. A final R value of 4.3 was obtained. The structure consists of [CuC14]2~ anions and N-phenylpiperazinium diprotonated cations. The [CuCl4]2-anions show a flattened tetrahedral geometry, the two larger Cl-Cu-Cl angles being 141.1 and 143.0° the dihedral angle is 51.6°. The Cu-Cl distances range from 2,23 to 2.27 υ. All four chlorine atoms are involved in Cl—N interactions, which may be responsible for the large distortion of the [CuCl4]2- ion from the tetrahedral configuration. The N-phenylpiperazinium dication shows the usual “chair” configuration. The spectroscopic and magnetic results of the [CuCl4]2- and [CuCl3Br]2-anions are in agreement with a high distortion of these ions from tetrahedral symmetry. A study of the d-d transition maximum vs. the distortion of the CuCl4 chromophore from the Td symmetry is also reported. Some compounds containing the monoprotonated amine such as (NPhpipzH)2Cu2X6 (X=CI, Br) and (NPhpipzH)2Cu2Cl2Br4 are also studied. Their spectroscopic data suggest the presence of dimeric species in them with highly distorted tetrahedral symmetry. © 1979, American Chemical Society. All rights reserved.