Semiconductive microporous hydrogen-bonded organophosphonic acid frameworks

Abstract

Herein, we report a semiconductive, proton-conductive, microporous hydrogen-bonded organic framework (HOF) derived from phenylphosphonic acid and 5,10,15,20-tetrakis[pphenylphosphonic acid] porphyrin (GTUB5). The structure of GTUB5 was characterized using single crystal X-ray diffraction. A narrow band gap of 1.56 eV was extracted from a UV-Vis spectrum of pure GTUB5 crystals, in excellent agreement with the 1.65 eV band gap obtained from DFT calculations. The same band gap was also measured for GTUB5 in DMSO. The proton conductivity of GTUB5 was measured to be 3.00 × 10 −6 S cm −1 at 75°C and 75% relative humidity. The surface area was estimated to be 422 m 2 g −1 from grand canonical Monte Carlo simulations. XRD showed that GTUB5 is thermally stable under relative humidities of up to 90% at 90°C. These findings pave the way for a new family of organic, microporous, and semiconducting materials with high surface areas and high thermal stabilities.

Arylphosphonate‐Tethered Porphyrins: Fluorescence Silencing Speaks a Metal Language in Living Enterocytes**

“…p-H 8 TPPA (Figure 1) and m-H 8 TPPA (Figure S1 in the Supporting information), were pretreated with various bivalent metal ions at a pH close to the cellular milieu (pH 7.4) before recording absorption and fluorescence spectra. The visible absorption of both sensors in the buffer-controlled treatment showed maxima in the range of 380-430 nm, with a typical Soret peak at around 416 nm, already observed in our recent studies [36,44] and also by others. [45] Ca 2 + or Mg 2 + treatment did not shift the position of the Soret maximum, but slightly raised the intensity of the absorption spectrum causing a higher fluorescence, characteristic for nonratiometric metal-ON fluorescence sensors.…”

Proton-Conducting Hydrogen-Bonded Organic Frameworks

“…Zorlu and Yucesan et al developed a 2D microporous HOF, GTUB5, using the multi-component approach involving H 8 -TPPA [tetrakis(p-phenylphosphonic acid)]porphyrin and phenylphosphonic acid (PPA) molecular tectons (Scheme 3j). 80 GTUB5 possesses high thermal stability up to 400 °C and a theoretical surface area of 422 m 2 g −1 . The phosphonic acid moieties incorporated in the porphyrin backbone can establish two types of H-bonds among the H 8 -TPPPA and PPA moieties.…”

Chemically Exfoliated Semiconducting Bimetallic Porphyrinylphosphonate Metal–Organic Layers for Photocatalytic CO2 Reduction under Visible Light

“…The latter corresponds to the Soret band of the porphyrin nucleus. 62,63 Meanwhile, the UPS spectrum (Figure 3b and Figure S20) shows that the valence band edge of 1-MOL comprises two major electron density states, the beginning of which are positioned at 1.1 eV (first HOMO) and 2.9 eV (2nd HOMO) below the Fermi level, respectively. Note that the density of state (DOS) of the former is significantly lower than that of the latter, coinciding with the weak UV−vis absorption at longer wavelengths.…”