Tetrathia[7]helicene Phosphane Derivatives: Properties and Characterization

Tetrathia[7]helicenes (7-TH) are polyconjugated π-systems in which four thiophene rings are orthofused to alternating arene rings to generate a non-planar, chiral, stable helix, allowing the existence of M and P enantiomers.1 In the course of our studies on the synthesis of 7-TH phosphorus derivatives as potential innovative chiral ligands in asymmetric organometallic catalysis2, novel 7-TH-dialkylsubstituted phosphane derivatives 1 and 2 (Figure 1) have been synthesized and fully characterized. Figure 1 Chiroptical properties of borane adducts 1 have been investigated along with the electrochemical properties of phosphine ligands 2.