HYDROGEN-BONDING AND SIZE EFFECTS OF CATIONS ON THE COORDINATION GEOMETRY OF METAL-IONS - TETRAHALOCOBALTATES(II) OF THE N-ETHYLPIPERIDINE, 2-ETHYLPIPERIDINE, AND 4-BENZYLPIPERIDINE CATIONS - CRYSTAL AND MOLECULAR-STRUCTURE OF BIS(4-BENZYLPIPERIDINIUM) TETRACHLOROCOBALTATE(II)

Some compounds of the type (LH)2CoX4 (LH = TV-ethyl-, 2-ethyl-, and 4-benzylpiperidinium cations; X=CI, Br, I) were prepared and characterized by means of magnetic moments and X-ray powder, electronic, and infrared spectra. For one of them, bis (4-benzylpiperidinium) tetrachlorocobaltate (II), the crystal structure was determined by three-dimensional X-ray diffraction. The substance crystallizes in space group P21 with lattice constants a=13.469 (3) υ, b=8.416 (2) υ, c=12.169 (3) υ, β=97.54 (5)°, and Z=2. The intensity data were collected with a Philips PW 1100 automatic four-circle diffractometer using Mo Ka radiation. The structure was solved by three-dimensional Patterson and Fourier methods, and parameters were refined by least-squares calculations to a conventional R factor of 4.8% for 1209 independent reflections [1 > 3π(I)]. The structure consists of discrete CoCl42- and 4-benzylpiperidinium ions; the slightly distorted tetrahedral anions are bridged by hydrogen bonds involving the NH2 groups of the cations. The magnetic moments and electronic and far-IR spectra of the complexes indicate distorted tetrahedral environments in the 4-benzylpiperidinium complexes greater than those in the Ar-ethyl-and 2-ethylpiperidinium complexes. The far-IR spectrum of the bis(4-benzylpiperidinium) tetrachlorocobaltate (II) complex is interpreted on the basis of a C2 symmetry. © 1979, American Chemical Society. All rights reserved.