Enantiopure tris-helicenic chiral-at-iridium complexes have been prepared, constituting the first examples of organometallic metal-tris-helicenes. Thanks to their Ir(III)-based multihelicenic architecture, the complexes display strong electronic circular dichroism and optical rotation along with long-lived yellow phosphorescence.

When synthesis is performed with an enantiopure helicenic precursor (either (P) or (M)), the octahedral complex can be statistically obtained in 4 different configurations, due to the chirality-at-iridium (DIr/LIr) and the two coordination geometries (meridional = mer / facial = fac).

Only 3 configurations were found experimentally. They were separated using HPLC, and the complete NMR studies (1H, 13C, 2D homonuclear and heteronuclear NMR, performed on 500 MHz or 900 MHz spectrometers) of the optically pure stereoisomers were conducted in CD2Cl2. The analysis of the resulting NMR signals with reference to the calculated geometries of such molecular configurations enabled their stereochemistries to be definitively assigned.