New organometallic derivatives of helicenes containing platinum and ruthenium centers have been prepared and theirs chiroptical properties have been studied. In the first chapter, we sum up most of works based on helicene chemistry that have been reported since 60 years and in particular the original properties of these helical π-conjugated molecules. We also describe some applications where we can find helicenes. The second chapter is focused on the description on a new family of helicenes, the platinahelicenes. Platinahelicenes are phosphorescent at room temperature thanks to the orthoplatinated cycle. The synthesis, the photophysical and chiroptical properties of five platinahélicènes are reported in this chapter. In the third chapter, we describe the evolution of photophysical and chiroptical properties of platinahelicenes when we change the oxidation state or/and the ligand of the platinum center. We also report the heterochiral and homochiral assembly of two platina[6]helicenes. Isomerisation of the heterochiral assembly to the homochiral one has been studied. The last chapter deals with the hydroruthenation of ethynyl-helicene and diethynyl-helicene. Two complexes of ruthenium-vinyl-helicene have been obtained and their photophysical, chiroptical and electrochemical properties have been studied. Proof of the redox-triggered chiroptical switching ability of these complexes are reported in this chapter.
Organometallic derivatives of helicenes: impact of the metal center on the chiroptical properties.