Benzoylation and Properties of 14-π Nickel(II)-Tetraazaannulene Complexes with Substituents on the Phenyl Ring

Metal-containing polymers bearing pendant nickel(ii) complexes of Goedken's macrocycle

“…Crucially, through judicious we have shut down the oxidative dimerization pathway commonly associated with nickel(II) complexes of Goedken's macrocycle, as evidenced by the reversibility of the oxidation waves. An irreversible reduction was also observed for the monomer at a cathodic potential of −2.14 V, which has been previously attributed to the reduction of nickel(II) 32. The voltammogram of polymer 14 was quite similar.…”

“…S14). Furthermore, the polymer exhibited a reversible one-electron reduction wave associated with nickel(II), 32,50 at E red1 = −2.07 V, potentially indicating that the macromolecular nature of the polymer protects the metal centre, and prevents side reactions and/or metal expulsion from occurring.…”

“…31 Furthermore, the macrocyclic backbone can be benzoylated at the activated  carbons, providing a synthetic handle for the introduction of polymerizable groups and preventing oxidative dimerization. [32][33][34] Although derivatives of complex 8 have garnered significant interest from inorganic chemists for over five decades, [35][36][37][38][39][40][41] very little has been reported with respect to their incorporation into polymers. Prior to our recent work on main-chain polymers, [33][34] the only existing examples were produced in small quantities by electropolymerization.…”

Polymers Containing Nickel(II) Complexes of Goedken's Macrocycle: Optimized Synthesis and Electrochemical Characterization

“…[ 22 ] A similar absorption maximum (588 nm, ε = 6000 M −1 cm ), the latter being assigned to a π→π* transition associated with the π-conjugated organic spacer [-CO-benzenealkyne-(9,9-dihexylfl uorene)-alkyne-benzene- CO-] produced during the polymerization reaction. [ 22,23 ] Nearly identical spectral features were observed for a model compound 10 synthesized from mono-brominated 9,9-dihexylfl uorene and monomer 7 ( Figure S9-S11), demonstrating that polymer 9 does not possess a signifi cant degree of extended π-conjugation. We believe the intensity of the π→π* transitions found at 378 nm for polymer 9 has increased relative to monomer 7 as a result of the installation of 9,9-dihexylfl uorene spacer, and thus a drastic change in the π-systems appended to the nickel(II) complex of Goedken's macrocycle (an increase from 12 π electrons to 36 π electrons).…”

“…[ 15a , 24 ] Crucially, by derivatizing the 6 and 13 positions of the macrocyclic framework, we have precluded electropolymerization, which may allow for future exploitation of the redox properties observed for polymer 9 in materials-based applications. [ 23,25 ] Monomer 7 and model complex 10 are each oxidized twice at potentials of 0.25, 0.76 V and 0.24, 0.75 V, respectively (Figure 2 c and S12, Supporting Information). For each compound, the observed current responses for each oxidation wave were confi rmed as one-electron processes through comparison with the current generated by equimolar quantities of ferrocene.…”