Comparison of 2‑Arylnaphtho[2,3‑<i>b</i>]phospholes and 2‑Arylbenzo[<i>b</i>]phospholes: Effects of 2‑Aryl Groups and Fused Arene Moieties on Their Optical and Photophysical Properties

Suzuki–Miyaura cross-coupling reactions were used in the divergent synthesis of a series of 2-arylnaphtho­[2,3-<i>b</i>]­phosphole <i>P</i>-oxides and their benzo­[<i>b</i>]­phosphole counterparts. We elucidated the electronic and steric effects of the 2-aryl groups and fused arene moieties on the optical and photophysical properties of these two types of phosphole-based π-systems

Synthesis of 3,5-Disubstituted BODIPYs Bearing <i>N</i>‑Containing Five-Membered Heteroaryl Groups via Nucleophilic C–N Bond Formation

Aromatic substitution reactions were applied to the divergent synthesis of a series of symmetrically and unsymmetrically 3,5-disubstituted BODIPYs bearing <i>N</i>-heteroaryl groups. Furthermore, the effect of <i>N</i>-heteroaryl substituents at the 3- and 5-positions on the optical and photophysical properties of the BODIPY π-electron system was elucidated

Acrostichum flagelliferum

The synthesis, structures, optical and electrochemical properties, and aromaticity of a series of 5,15-diaza-10,20-dimesitylporphyrins (M–DAP; M = Pb, H₂, Ni, Pd, Pt, Zn; mesityl = 2,4,6-trimethylphenyl) are reported. Treatment of mesityl-substituted bis­(5,5′-dibromodipyrrin) with sodium azide in the presence of lead­(II) acetylacetonate afforded Pb–DAP, which was quantitatively converted to H₂–DAP by acidolysis. The free base H₂–DAP reacted with palladium­(II), platinum­(II), and zinc­(II) salts to give Pd–DAP, Pt–DAP, and Zn–DAP, respectively. The crystal structures, optical and electrochemical properties, and aromaticities of these β-unsubstituted M–DAPs were comprehensively investigated by X-ray crystallography, UV–vis absorption/fluorescence spectroscopy, nanosecond flash photolysis, cyclic and differential pulse voltammetry, NMR spectroscopy, and density functional theory calculations. The obtained data show that replacement of the 5- and 15-methine carbons with nitrogen atoms alters the intrinsic properties of the porphyrin 18π system as follows: (i) the coordination spheres at the N₄ core become contracted while keeping high planarity; (ii) the Q bands are red shifted and largely intensified; (iii) the electron-accepting ability is enhanced, whereas the electron-donating ability is reduced; (iv) the radiative decay rates from the S₁ state are enhanced; and (v) the aromaticity of the 18π circuit is slightly reduced in terms of both geometric and magnetic criteria. These optical and electrochemical properties of M–DAPs stem from their characteristic frontier orbitals; two HOMOs and two LUMOs are nondegenerate as a result of the incorporation of the electronegative nitrogen atoms at the two meso positions. In addition, the group 10 metals incorporated at the core finely tune the fundamental properties of DAP π systems through inductive effects as well as dπ–pπ antibonding orbital interactions; the HOMO–LUMO gaps of the group 10 metal complexes increase in the order Ni–DAP < Pd–DAP < Pt–DAP

Synthesis of 2‑Alkenyl- and 2‑Alkynyl-benzo[<i>b</i>]phospholes by Using Palladium-Catalyzed Cross-Coupling Reactions

Heck, Stille, and Sonogashira reactions of 2-bromobenzo[<i>b</i>]phosphole <i>P</i>-oxide afforded a series of 2-alkenyl- and 2-alkynyl-benzo[<i>b</i>]phosphole <i>P</i>-oxides. The charge-transfer character of the new benzo[<i>b</i>]phosphole π-systems in the excited state is enhanced by the terminal electron-donating substituents. Furthermore, the C–Sn cross-coupling of the bromide was applied to the facile synthesis of a new Stille-coupling precursor, 2-stannylbenzo[<i>b</i>]phosphole

Phosphole–Thiophene Hybrid: A Dual Role of Dithieno[3,4‑<i>b</i>:3′,4′‑<i>d</i>]phosphole as Electron Acceptor and Electron Donor

We have synthesized dithieno­[3,4-<i>b</i>:3′,4′-<i>d</i>]­phosphole derivatives as a new type of thiophene-fused phospholes. These dithienophospholes were found to show intramolecular charge transfer interactions by introducing electron-donating or -withdrawing groups on the peripheral aryl groups. Namely, they exhibit the unique hybrid character of electron-withdrawing phosphole and electron-donating thiophene

Phosphole–Thiophene Hybrid: A Dual Role of Dithieno[3,4‑<i>b</i>:3′,4′‑<i>d</i>]phosphole as Electron Acceptor and Electron Donor

We have synthesized dithieno­[3,4-<i>b</i>:3′,4′-<i>d</i>]­phosphole derivatives as a new type of thiophene-fused phospholes. These dithienophospholes were found to show intramolecular charge transfer interactions by introducing electron-donating or -withdrawing groups on the peripheral aryl groups. Namely, they exhibit the unique hybrid character of electron-withdrawing phosphole and electron-donating thiophene

Synthesis and Charge-Carrier Transport Properties of Poly(phosphole <i>P</i>‑alkanesulfonylimide)s

A new class of polyphospholes bearing alkanesulfonylimino moieties on the phosphorus(V) centers was prepared by the Pd–CuI-promoted Stille coupling reaction to investigate the charge-carrier transport properties of the π-networks of polyphospholes. Time-of-flight measurements have revealed that the poly(phosphole <i>P</i>-imide)s possess ambipolar charge-carrier mobilities of up to μ_electron = 6 × 10^–3 cm² V^–1 s^–1 and μ_hole = 4 × 10^–3 cm² V^–1 s^–1

Synthesis and Charge-Carrier Transport Properties of Poly(phosphole <i>P</i>‑alkanesulfonylimide)s

A new class of polyphospholes bearing alkanesulfonylimino moieties on the phosphorus(V) centers was prepared by the Pd–CuI-promoted Stille coupling reaction to investigate the charge-carrier transport properties of the π-networks of polyphospholes. Time-of-flight measurements have revealed that the poly(phosphole <i>P</i>-imide)s possess ambipolar charge-carrier mobilities of up to μ_electron = 6 × 10^–3 cm² V^–1 s^–1 and μ_hole = 4 × 10^–3 cm² V^–1 s^–1

Correction to “Segregated Donor–Acceptor Columns in Liquid Crystals That Exhibit Highly Efficient Ambipolar Charge Transport”

Correction to “Segregated Donor–Acceptor Columns in Liquid Crystals That Exhibit Highly Efficient Ambipolar Charge Transport

Excited-State Proton Transfer of Cyanonaphthols in Protic Ionic Liquids: Appearance of a New Fluorescent Species

Excited-state proton transfer (ESPT) of 5-cyano-2-naphthol (5CN2) and 5,8-dicyano-2-naphthol (DCN2) in three different protic ionic liquids (PILs), triethylammonium trifluoromethanesulfonate ([N₂₂₂H]­[CF₃SO₃]), triethylammonium methanesulfonate ([N₂₂₂H]­[CH₃SO₃]), and triethylammonium trifluoroacetate ([N₂₂₂H]­[CF₃COO]), was studied by time-resolved fluorescence. In [N₂₂₂H]­[CF₃SO₃], both 5CN2 and DCN2 showed fluorescence only from ROH* (normal form of substituted naphthol in the excited states), indicating that no ESPT occurred in [N₂₂₂H]­[CF₃SO₃]. For 5CN2 in [N₂₂₂H]­[CH₃SO₃], fluorescence bands from ROH* and RO^–* (anionic form of substituted naphthol in the excited states) were observed, indicating that 5CN2 could dissociate proton to surrounding solvents and form RO^–*. More interestingly, 5CN2 in [N₂₂₂H]­[CF₃COO] and DCN2 in [N₂₂₂H]­[CH₃SO₃] and [N₂₂₂H]­[CF₃COO] showed an anomalous fluorescence band around 470 nm (5CN2) or around 520 nm (DCN2) which has not been reported previously. The kinetics of each fluorescent component of 5CN2 and DCN2 was analyzed on the basis of the time profile of fluorescence intensity. Plausible ESPT schemes of 5CN2 and DCN2 were discussed on the basis of the kinetics and the basicity of anion in PILs