SYNTHESIS OF CATIONIC HALF-SANDWICH RHODIUM(I) COMPLEXES OF 1,4,7-TRITHIACYCLONONANE ([9]ANES3) - THE SINGLE-CRYSTAL STRUCTURES OF [RH([9]ANES3)(C2H4)2]PF6, [RH([9]ANES3)-(C8H12)]BF4 AND [RH([9]ANES3)(C4H6)]PF6-CENTER-DOT-0.25OET2

Reaction of [Rh2L2L'2Cl2] {L, L' = C2H4, 1/2cod or 1/2nbd; L = C2H4, L' = PPr(i)3 or P(C6H11)3; cod = cycloocta-1,5-diene, nbd = norbornadiene (bicyclo[2.2.1]hepta-2,5-diene)} with 2 molar equivalents of 1,4,7-trithiacyclononane([9]aneS3) in the presence of NaBF4 or NH4PF6 at 293 K, or treatment of [Rh(C4H6)2Cl] or [Rh(CO)Cl(PPh3)2] with 1 molar equivalent of [9]aneS3 and NH4PF6 afforded [Rh([9]aneS3)L(L')]X [L, L' = C2H4, 1/2cod, 1/2nbd or 1/2C4H6; L = C2H4, L' = PPr(i)3 P(C6H11)3; L = CO, L' = PPh3; X = BF4 or PF6] in moderate yields. The crystal structure of the complex [Rh([9]aneS3)(C2H4)2]PF6 has been determined: monoclinic, space group P2(1)/n, a = 11.487(3), b = 9.459(3), c = 15.745(6) angstrom, beta = 105.54(3)degrees and Z 4. The cation adopts a trigonal-bipyramidal geometry, with one equatorial and one axial ethene ligand. The complex [Rh([9]aneS3)(cod)]BF4 crystallises in the triclinic space group P1BAR with a = 11.491(13), b = 12.803(6), c = 13.377(15), alpha = 88.12(7), beta = 70.30(8), 7 = 74.68(7)degrees and Z = 4. The two molecules in each asymmetric unit also adopt distorted trigonal-bipyramidal stereochemistries, with the conformation in molecule 1 being related to that of molecule 2 by a 6-degrees rotation of the macrocyclic ring about the central M-[9]aneS, axis. The complex [Rh([9]aneS3)(C4H6)]PF6 crystallises in the monoclinic space group C2/c with a = 18.612(6), b = 8.679(5), c = 23.756(5), beta = 96.844(18)degrees and Z = 8. The structure shows a quasi-square-pyramidal complex cation. Treatment of [Rh2(CO)4Cl2] with [9]aneS3 and NH4PF6 yielded the dimeric complex [Rh2([9]aneS3)2(mu-CO)3] [PF6]2. Reaction of [Rh([9]aneS3) (C2H4)L]+ [L = C2H4 or P(C6H11)3] with halogenated substrates afforded insoluble [Rh([9]aneS3)X3] (X = Cl or l), while no reaction was observed with C6H6 or SiEt3H. Spectroscopic, structural and chemical evidence indicates that the [Rh([9]aneS3)]+ fragment has a high electrophilic character.