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A debromination–chain polymerization–debromination (DPD) route to poly( p -phenylene vinylene) (PPV) derivatives is reported. In contrast to existing chain polymerization routes for the preparation of PPV derivatives, this route takes advantage of a symmetric monomer to preclude head-to-head or tail-to-tail coupling that ultimately leads to alkyne or alkyl defects in the polymer chain. Mechanistic studies were performed and revealed that the DPD route can be carried out with the desirable intermediacy of a soluble, isolable polymer precursor. Unsubstituted PPV, poly( p -(2,5-dihexyloxyphenylene)vinylene) and a PPV derivative with a sterically encumbering side chain were all readily prepared by the new DPD route.

Fourteen chromophores of the form 1-(4-X-styryl)-4-(4-nitrostyryl)benzene or 1-(4-X-styryl)-4-(4-nitrostyryl)fluorene have been synthesized with X = CF3, Cl, I, H, CH3, OCH3, or OCH(CH3)3. An innovative synthetic route was developed in the course of this work wherein phosphonium-phosphonate ester bifunctional precursors were employed. By exploiting steric considerations and the difference in acidity of protons in the position alpha to the phosphonium and phosphonate ester, target asymmetric chromophores were assembled in a straightforward fashion with high selectivity. The photophysical characteristics of the chromophores are described, including notable solvatochromism revealed by measuring photophysical properties in acetonitrile, dichloromethane, tetrahydrofuran, and toluene. Electrochemical analysis by cyclic voltammetry, along with DFT calculations (B3LYP-6-31G*) were employed to reveal the HOMO and LUMO distributions and energies, thus providing further understanding of the properties of these materials and the similarities/differences between phenylene-centered and fluorenylene-centered chromophores.

An air-stable primary phosphine, 2,6-diphosphinonaphthalene-1,5-diol (4), has been synthesized and structurally characterized. A series of π-conjugated heteroacenes containing two phosphaalkene (P═C) units, 2,7-R2-naphtho[1,2-d:5,6-d′]bi(soxaphosphole)s [R2-NBOP, R = tBu (5a), Ad (5b), and Ph (5c)], have been synthesized from reactions of 4 and benzimidoyl chlorides. These novel fluorescent analogues of organic acenes were characterized by multinuclear NMR, UV–vis, and fluorescence spectroscopy, cyclic voltammetry, and single-crystal X-ray diffraction experiments.

The synthesis, characterization, and photoinduced CO-release reactivity of [(6-Ph2TPA)Pb(3-Hfl)]ClO4 (1; 6-Ph2TPA = N,N-bis((6-phenyl-2-pyridyl)methyl)-N-((2-pyridyl)methyl)amine; 3-Hfl = anion of 3-hydroxyflavone) is reported and compared with Group 12 analogues ([(6-Ph2TPA)M(3-Hfl)]ClO4 (M = Hg(II) (2), Cd(II) (3), Zn(II) (4)). The Pb(II) complex exhibits unique features within this group of complexes in terms of its structural and spectroscopic features involving the coordinated flavonolate ligand. Similar to the Group 12 compounds, irradiation of 1 at 300 nm in an O2-containing environment results in the quantitative release of CO and the formation of a Pb(II) O-benzoylsalicylate (O-bs, depside) complex via a photoinduced dioxygenase-type reaction. Comparison of the quantum yield for the reaction of the Pb(II) flavonolate complex (Φ = 0.21(6)) versus the reactions of the structurally-related Group 12 metal complexes (6-Ph2TPA)M(3-Hfl)]ClO4 (M = Hg(II) (2, Φ = 0.31(2)), Cd(II) (3, Φ = 0.28(2)), Zn(II) (4), Φ = 0. 09(1)) revealed that flavonolate complexes of a heavy metal ion (Cd(II), Hg(II), Pb(II)) exhibit a higher reaction quantum yield than the Zn(II) derivative. Both Pb(II) and Zn(II) flavonolate complexes were found to be catalysts for the oxidative photoinduced degradation of 3-hydroxyflavone. The combined results of these investigations suggest that metal contaminants typically present in soil, including toxic heavy metal ions, might facilitate the oxidative decomposition of plant-derived flavonols via photoinduced reactions.

Irradiation of 3-hydroxyflavonolato (3-Hfl) complexes of MnII, CoII, NiII and CuII (1–4) at 300 nm under aerobic conditions results in dioxygenase-type reactivity and the formation of the corresponding divalent metal O-benzoylsalicylato (O-bs) complexes 8–11 and CO. The latter were characterized by using multiple methods, including elemental analysis, X-ray crystallography, NMR and/or EPR spectroscopy, mass spectrometry and IR spectroscopy. Compounds 1–4 serve as catalysts for the photoinduced reactivity of 3-hydroxyflavonol (3-HflH) to produce O-benzoylsalicylic acid as the major product. Spectroscopic studies (UV/Vis and 1H NMR) show that each O-benzoylsalicylato complex 8–11 reacts with one equiv. of 3-hydroxyflavonol to regenerate 1–4 and enable turnover reactivity. Unlike what is observed for free 3-HflH, photoinduced reactions involving 1–4 and excess flavonol show only minor amounts of flavonol isomerization reactivity. These results indicate that the presence of a metal ion, whether under stoichiometric or catalytic conditions, facilitates the photoinduced degradation of 3-HflH to produce a carboxylic acid and CO as products.

A facile synthetic route allowed access to 1,4-dimethyl-9,9-dihexylfluorene (3) with no monoalkyl defects. Compound 3 was subsequently transformed to monomers for incorporation of 9,9-dihexyl-1,4-f...

A series of 1,4-distyrylfluorene derivatives (III) is synthesized via a Wittig—Horner type condensation.

A series of nine 1,4-distyrylfluorene derivatives (2) functionalized with substituents of variable electron-donating or -accepting capabilities was synthesised. The photophysical properties of the molecules were investigated, including UV/vis absorption, photoluminescence emission, and fluorescence quantum yields. Photophysical properties of chromophores 2 were found to exhibit significant solvatochromic effects, especially in the Stokes shift and photoluminescence maxima. The electrochemical properties of series 2 were also assessed by cyclic voltammetry and differential pulse voltammetry. Results of photophysical and electrochemical analyses were further supported by DFT calculations (B3LYP/6-31G*) and single crystal X-ray diffraction on select molecules. The contributions of intermolecular π-stacking and hydrogen bonding to crystal packing are discussed. A series of nine 1,4-distyrylphenylene derivatives (3) were also synthesised and similarly characterized for comparison to photophysical and solvatochromic effects observed in series 2. Properties of similarly-substituted molecules in series 2 and 3 were compared to one another in order to assess the influence of the 1,4-fluorenylene unit.

Seven new fluorescent 2-R-naphtho[2,3-d]oxaphospholes (R-NOPs) (4a–g; R = tBu (a), Ad (b), C(6)H(5) (c), 4-MeC(6)H(4) (d), 4-ClC(6)H(4) (e), 4-BrC(6)H(4) (f ), 4-MeOC(6)H(4) (g)), have been synthesized by cyclocondensation reactions of benzimidoyl chlorides with 3-phosphino-2-naphthol (3). The compounds were characterized by multinuclear NMR, UV-vis, and fluorescence spectroscopy. Compounds 4a–d and 4g were characterized by cyclic voltammetry experiments. The solid state structures of compounds 4b and 4d were also determined by single-crystal X-ray diffraction experiments.

Three new poly(p-phenylenevinylene) derivatives were synthesized via the Horner–Wittig condensation polymerization. The new polymers (P3–P5) incorporate recently developed 9,9-dihexyl-1,4-fluorenylene repeat units copolymerized with three different functional groups that are of interest for optoelectronic applications of organic semiconducting polymers (triphenylamine (P3), thiophene (P4) and carbazole (P5). The electrochemical properties were probed via cyclic voltammetry and differential pulse voltammetry for new polymers P3–P5, as well as previously reported but not electrochemically characterized poly(p-phenylene vinylene) derivatives P1 and P2. The electronic absorption and photoluminescence properties of all five 1,4-fluorenylene-containing copolymers were characterized in solution and were compared to other poly(p-phenylenevinylene) copolymers with similar functional groups.

Exposure of 3-hydroxyflavonolate complexes of the group 12 metals to UV light under aerobic conditions results in oxidative carbon-carbon bond cleavage and CO release. This reactivity is novel in that it occurs under mild reaction conditions and suggests that light-induced CO-release reactivity involving metal flavonolate species may be possible in biological systems.