CP-ASTERISK-RU(DMSO)2CL AND CP-ASTERISK-R U(TMEDA)CL - SYNTHESIS AND MOLECULAR-STRUCTURE OF 2 CP-ASTERISK-RU COMPLEXES WITH HARD SIGMA-DONOR COLIGANDS

Reaction of [CpRuCl]4 with DMSO and TMEDA respectively gave the compl exes CpRu(DMSO)2Cl (1) and Cp*Ru(TMEDA)Cl (2a) and Cp*Ru(TMEDA)Br (2b ) as rare examples of CpRu complexes with only hard sigma-donor colig ands. The crystal and molecular structure of 1 (space group P2(1)/n (N r. 14), a 8.250(3), b 15.204(8), c 14.33(l) angstrom, beta 93.91(5)-de grees, Z = 4); and 2a (space group P2(1)/n (Nr. 14), a 10.480(5), b 14 .133(5), c 12.349(4) angstrom, beta 90.42(3)-degrees, Z = 4) was deter mined. Whereas the molecular geometry of 1 is largely as expected, ver y long Ru-C] (2.5116(9) angstrom) and Ru-N (2.262(4) and 2.295(3) angs trom) bonds are characteristic for 2a. Solution dynamics in 2a,b gener ating a mirror plane through the TMEDA ligand with equivalent CH2- and N-Me protons on the NMR timescale are explained by facile dissociatio n to a 16 VE cation [CpRu(TMEDA)]+.