Synthesis, characterization, and preceramic properties of π-conjugated polymers based on Ni(II) complexes of goedken's macrocycle

Abstract

Nickel(II) complexes of Goedken's macrocycle bearing alkyne substituents were copolymerized with 2,7-dibromo-9,9-dihexylfluorene, 2,5-dibromo-3-hexylthiophene, and 1,4-dibromo-2,5-bis(hexyloxy)benzene via microwave-induced Sonogashira cross-coupling reactions to produce copolymers 6F, 6T, and 6B. The spectroscopic and electrochemical properties of the copolymers were examined and compared to model compounds. Specifically, each polymer exhibited a nickel-based absorption centered at about 589 nm and two π → π* transitions between 272 and 387 nm. While the copolymers did not exhibit extended π conjugation, the nature of the organic spacer did affect the high energy transitions. Furthermore, each copolymer underwent two ligand-based one-electron oxidations at potentials of about 0.24 V and about 0.75 V relative to the ferrocene/ferrocenium redox couple. Postpolymerization functionalization of the alkyne group in 6F with Co2(CO)8 afforded a novel heterobimetallic copolymer that yielded amorphous nanomaterials containing Ni/Co when pyrolyzed at 800 °C for 3 h under an atmosphere of N2/H2 (95:5). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3257–3266