Coordination of the macrocyclic thioether 1,4,7-trithiacyclononane (TTCN) to chromium(3+) and to dimolybdenum(2+) di-acetato bridged molecules
1989; Elsevier BV; Volume: 8; Issue: 13-14 Linguagem: Inglês
10.1016/s0277-5387(00)80638-5
ISSN1873-3719
AutoresHeinz‐Josef Küppers, Karl Wieghardt,
Tópico(s)Organometallic Complex Synthesis and Catalysis
ResumoAbstract Although chromium(III) is a hard acid and the macrocyclic thioether 1,4,7-trithiacyclonone (TTCN) a soft base, the following compounds could be synthesized: [Cr(TTCN)Cl3], [Cr(TTCN)(SO3CF3)3] and [Cr(TTCN)2]3+ (a rare example of a CrIII (thioether)6 coordination sphere). Comparison with the analogous 1,4,7-triazacyclononane (TACN) complexes shows that the bonding is relatively weak and the ligand-field splitting small. This is in contrast to the bonding properties of these ligands in “late” transition metals and results from the lack of π-donor capability of the Cr3+ centre. TTCN forms several dimeric di-acetato bridged complexes with the (Mo2)4+ unit. The unique interaction of steric and electronic effects of TTCN causes the unusual coordination of a tridentate ligand to the [MO2(μ-OAc)2]2+ unit.
Referência(s)