LAUSR

A poly(biphenylene–pyrazinylene) (PPz, Egopt = 3.10 eV) and a head-to-tail regioregular polypyridine (rr-P4Py, Egopt = 3.25 eV) equipped with 1-alkenyl side chains have been prepared and postfunctionalized by hydroboration with different hydroboranes (9H-BBN, (C6F5)2B-H (BPF-H), Cl2B-H) to give the corresponding ladder polymers featuring intramolecular coordinative N → B bonds. Characterization of the optical and electrochemical properties of the postfunctionalized polymers shows that the borylation strongly increases their electron affinity and lowers the optical gaps. Electron affinities between −3.75 eV (PPzBBN, Egopt = 2.16 eV) and −4.35 eV (PPzBPF, Egopt = 2.07 eV) can be reached for hydroborated PPz, while rr-P4Py-derivatives reach LUMO levels of −3.45 eV (P4PyBBN, Egopt = 2.88 eV), −3.85 eV (P4PyBPF, Egopt = 2.95 eV), and −4.15 eV (P4PyBCl2, Egopt = 2.95 eV). The potential of this class of compounds as electron acceptors is demonstrated by the investigation of the semiconducting properties of PPzBB...