Tuned helical array of Rh^III/Ir^III Cp* complexes with polypyridyl ligands

Abstract

Reactions of the chloro-bridged dimeric complexes [{(η⁵-C₅Me₅)M(μ-Cl)Cl}₂] (M = Rh, Ir) with the polypyridyl ligands 2,3-di(2-pyridyl)pyrazine (dpp) and 2,4,6-tri(2-pyridyl)-1,3,5-triazine (tptz) in the presence of ammonium tetrafluoroborate gave the mononuclear complexes [(η⁵-C₅Me₅)MCl(κ²-dpp)]BF₄ [M = Rh (1), Ir (2)] and [(η⁵-C₅Me₅)MCl(κ²-tptz)]BF₄ [M = Rh (3), Ir (4)]. The complexes have been characterised by elemental analysis, FAB-MS, ESMS, IR, NMR, electronic and emission spectroscopic studies and the molecular structures of 1, 2 and 3 have been crystallographically determined. Structural studies on the complexes revealed the presence of helical superstructures resulting from C–H•••X (X = N, F, Cl and π) interactions.