IONIZATION OF YCL3 IN TETRAHYDROFURAN - CRYSTAL-STRUCTURES OF THE [TRANS-YCL2(THF)(5)][TRANS-YCL4(THF)(2)] SALT AND POLYMERIC [YCL(3)CENTER-DOT-2THF]INFINITY COMPOUNDS

The [trans-YCl2(THF)(5)][trans-YCl4(THF)(2)] salt (1) and polymeric [Y Cl3.2THF](infinity) (2) were prepared by recrystallization of YCl3.3.5 THF from tetrahydrofuran (THF) and from dichloromethane, respectively. Both species have been structurally characterized. Complex 1 crystall izes in the space group C2/c with a = 12.503(4) Angstrom, b = 11.493(3 ) Angstrom, c = 27.212(8) Angstrom, and beta = 91.41(3)degrees. Compou nd 2 belongs to the space group P $$($) over bar 1 with a = 8.248(3) A ngstrom, b = 8.408(3) Angstrom, c = 9.993(4) Angstrom, alpha = 83.89(4 )degrees, beta = 67.73(3)degrees, and gamma = 86.02(3)degrees. In the [trans-YCl2-(THF)(5)](+) cation of 1, the yttrium atom is seven-coordi nated by five pentagonal oxygen atoms of THF molecules and two trans c hlorine atoms. The structure of 2 includes seven-coordinated Y(III) ce nters (separated by Y...Y distances of 4.422(1) and 4.436(1) Angstrom) , which are linked by double chlorine bridges to form the polymeric sp ecies. Two THF molecules and one terminal chlorine atom complete the p entagonal bipyramidal coordination sphere of the yttrium atom. Catalyt ic activity was found for ethylene polymerization by 1 and 2.