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 owing to their unique material properties, although synthesis of long and defect-free polymers remains challenging. Herein we introduce a novel on-surface synthesis of coordination polymers with quinoidal ligands 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 with four- or two-fold coordination. 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.