Substitution reactions of rhenium-chloride bonds in [Re2(DMAA)4Cl2], (DMAA=2′,6′-dimethylacetanilido);: synthesis and characterisation of [Re2(DMAA)4X2] (X = NCO, NCS, N3) and [Re2(DMAA)4Ln][SbF6]2 (n=2, L = pyridine;: n=1, L=4,4′-bipyridine)

Substitution of chloride ligands in [Re-2(DMAA)(4)Cl-2] (1), (DMAA = 2',6'-dimethylacetanilido) in a mixture of dichloromethane-methanol affords [Re-2(DMAA)(4)X-2] complexes with X = [N-3](-), 2 . CH2Cl2, [SCN](-), 3, or [NCO](-), 4 . CH2Cl2 in yields of 84, 72 and 76%, respectively. The reaction of 1 and Ag[SbF6] in air affords [Re-2(DMAA)(4)(H2O)(2)][SbF6](2) . H2O, 5 . H2O (71%). The aquo ligands in 5 can be displaced by pyridine or 4,4'-bipyridine to produce [Re-2(DMAA)(4)(pyridine)(2)][SbF6](2) (6) (68%), and [Re-2(DMAA)(4)(4,4'-bipyridine)][SbF6](2). CH2Cl2 (7) (42%). All new compounds were characterised with C, H and N chemical analysis, FTIR and, except for 7, H-1 and C-13 NMR spectroscopies. Additionally, single crystal X-ray crystallography was used to establish the molecular structures of 2.CH2Cl2 and 3.0.83CHCl(3). Principal distances and angles are: rhenium-rhenium distances in 2 and 3 of 2.2477(3) and 2.2324(5) Angstrom, respectively; rhenium to azido nitrogen distances in 2 of 2.158(5) and 2.166(6) Angstrom, and rhenium to isothiocyanato nitrogen distances in 3 of 2.208(8) and 2.210(6) Angstrom; essentially linear azido and isothiocyanato ligands with N-N-N angles of 178.4(10) and 179.1(9)degrees and N-C-S angles of 177.9(10) and 179.7(9)degrees, and Re-N-X angles (X = N for 2 and C for 3) of the rhenium. pseudo-halide bonds of 139.8(6) and 128.6(5)degrees in 2 and 151.9(7) and 169.1(9)degrees in 3, respectively. (C) 2003 Elsevier Science Ltd. All rights reserved.