SYNTHESIS, SB-121-MOSSBAUER SPECTRA AND STRUCTURES OF [SBF3(18-CROWN-6)], [SBF3(18-CROWN-6)CENTER-DOT-CH3CN, AND [(SBF3)(2)(12-CROWN-4)]

The crown ether complexes SbF3(18-crown-6) (1), SbF3(18-crown-6) CH3CN (2) and (SbF3)(2)(12-crown-4) (3), have been prepared by reactions of SbF3 and the corresponding crown ether. They have been characterized by IR, Raman and Sb-121-Mossbauer spectroscopy, and by X-ray structure determinations. The s electron density at the Sb atom is diminished in these complexes. 1 and 2 show a symmetrical half-sandwich structure, with coplanar O atoms and Sb-O distances ranging from 298 to 321 pm. 3 has a band-like structure. The two metal centers adopt different stereochemistries. The Sb-O distances are in the range from 269 to 325 pm. One oxygen atom of 12-crown-4 has a bridging function. Crystal data for 1: space group P2(1)2(1)2(1), a = 823,1(1), b = 1146,1(2), c = 1807,0(3) pm, Z = 4; 2: space group P2(1)/c, n = 1257,7(3), b = 828,9(2), c = 1895,5(5) pm, beta = 93,68(2), Z = 4; 3: space group P2(1)/c, a = 805,6(1), b = 2143,1(4), c = 836,4(2) pm, beta = 90,98(1), Z = 4.