SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF THE [TI2(OC2H5)8CL]2MG2(MU-CL)2 COMPLEX

The reaction between Ti(OC2H5)4 and MgCl2 in the 2:1 stoichiometric ratio yields the title bimetallic complex from which single crystals were obtained after recrystallization from n-heptane solution. The molecular structure was determined by X-ray diffraction. The molecule crystallizes in the monoclinic, space group P2(1)/n system, with two molecules per unit cell and a = 13.900(9), b = 14.624(8), c = 13.982(8) angstrom and beta = 95.05(4)-degrees, V = 2831(3) angstrom, D(calc) = 1.292 g/cm3. A high degree of position disorder affecting some ethyl groups limits the accuracy of the refinement and causes a rather high final discrepancy factor R of 0.076. The molecule is centrosymmetric and lies on a crystallographic centre of symmetry. The asymmetric unit in the cell, i.e. half molecule, is built up by three face-shared pseudooctahedra centered on the two Ti and Mg atoms and is surrounded by the eight terminal ethyl groups. The two asymmetric parts of the molecule are bonded to each other by a double chlorine bridge between the two Mg atoms. Some speculations on a possible way to form the complex are presented.