1D Coordination π-d Conjugated Polymers with Distinct Structures Defined by the Choice of the Transition Metal: Towards a New Class of Antiaromatic Macrocycles.

Recently π-d conjugated coordination polymers have received a lot of attention due to their unique material properties, although synthesis of long and defect free polymers remains challenging. Here we introduce a novel on-surface synthesis of coordination polymers with quinoidal ligand under ultra-high vacuum conditions, which enables formation of flexible coordination polymers with lengths up to hundreds of nanometers. Moreover, this procedure allows the incorporation of different transition metal atoms tuning their coordination between four and two-fold. Remarkably, the two-fold coordination mode revealed the formation of wires constituted by (electronically) independent 12-membered antiaromatic macrocycles linked together through two C-C single bonds.