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O: Fachverband Oberflächenphysik
O 103: Poster Session VIII: Surface reactions II
O 103.1: Poster
Thursday, March 4, 2021, 13:30–15:30, P
Enhancement of homochirality in on-surface designed indenofluorene polymers — •Cristina Martín Fuentes, Jose Ignacio Urgel, Jose Maria Gallego, Jose Santos, Rodolfo Miranda, Nazario Martín, and David Écija — IMDEA nanociencia, Cantoblanco 28049, Madrid, Spain
A crucial aspect in polymer science is to find out route to enhance homochirality when the monomer precursor is chiral or prochiral.
Inspired by our recent results regarding the homocoupling of acene species exploiting the =CBr2 functional group and its reactivity on surfaces, we synthesized a prochiral precursor molecule presenting an indenofluorene backbone with two CBr2 groups. Upon sublimation on surfaces the homocoupling reaction took place at room temperature. Three different substrates were employed: Au(111), Ag(111) and Ag(100), to elucidate the chemical role of the metal and of the substrate termination.
On all the surfaces, long polymers were found based on cumulene bridges. On Au(111) the polymers display racemic segments, a result of the random mixture the two molecular enantiomers. However, on Ag(100) and Ag(111), the polymers display more homochiral segments than the ones formed on Au(111) by a factor of 2. We can conclude that, depending on the substrate, it is possible to steer the homochirality of the designed molecular wires. Our results represent a step further towards a better control of the on-surface synthesis of homochiral polymers.