Columnar Discotic Mesophases from Novel Non-symmetrically Substituted (Octylsulfanyl) Porphyrazines

Belviso, Sandra; Amati, Mario; Bonis, Margherita De; Lelj, Francesco

doi:10.1080/15421400701834088

Cited by 12 publications

(23 citation statements)

References 20 publications

(62 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[81] Such approach affords a very clean reaction, easy purification procedures, yielding non-symmetrically substituted product. The subsequent bromination of 2 leads to the bromo derivative 3, [82] which, through Pd-catalysed Suzuki [93,94] coupling reaction, [79,83] provides the pyrene-substituted thioethyl porphyrazine PzPy in 45% yield. Supramolecular interactions between aromatic systems and nanocarbons are usually determined by noncovalent - interactions [68,95] which, being highly directional, [96] are strictly dependent on shape and mutual orientation of the interacting molecules.…”

Section: Synthesis and Structural Characterization The Pyrene-substit...mentioning

confidence: 99%

“…In particular, thioalkyl porphyrazines, having thioethereal moieties at the -position of the macrocycle, are rather interesting. In fact, the presence of sulfur atoms imparts outstanding optical and electrochemical properties [77][78][79][80][81][82][83] to these compounds, promoting coordination sites out and above the molecular plane, favoring the presence of columnar discotic liquid-crystalline mesophases. [77][78][79][80] This is a relevant feature because highly ordered materials such as liquid crystals assist both exciton and charge carrier mobilities.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, the presence of sulfur atoms imparts outstanding optical and electrochemical properties [77][78][79][80][81][82][83] to these compounds, promoting coordination sites out and above the molecular plane, favoring the presence of columnar discotic liquid-crystalline mesophases. [77][78][79][80] This is a relevant feature because highly ordered materials such as liquid crystals assist both exciton and charge carrier mobilities. [1,[84][85][86] One of the key research effort in optoelectronic devices is devoted to increase the spectral response of the photoactive layer, obtaining panchromatic light absorbers, which can be ideal candidates for both photodetecting and energy harvesting applications.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thioethyl‐Porphyrazine/Nanocarbon Hybrids for Photoinduced Electron Transfer

Belviso

Capasso

Santoro

et al. 2018

Adv Funct Materials

Self Cite

View full text Add to dashboard Cite

Running title: Hybrids of thioalkyl-porphyrazines with nanocarbons ABSTRACTWe designed a novel pyrene-substituted thioethyl-porphyrazine (PzPy) and the formation of supramolecular assembly with nanocarbons demonstrating photoinduced electron transfer ability. As revealed by spectroscopic and electrochemical studies, PzPy displays wide spectral absorption in the visible range, charge separation upon photoexcitation, as well as bandgap and highest occupied/lowest unoccupied molecular orbital (HOMO/LUMO) energy values, matching the key requirements of organic optoelectronic. Moreover, the presence of a pyrene moiety promotes attractive interactions with -conjugated systems. In particular, theoretical calculations show that in the PzPy the HOMO and LUMO are localized on different positions of the molecule, i.e., the HOMO on the pyrene moiety and the LUMO on the macrocycle. Therefore, HOMO-LUMO excitation gives rise to a charge separation, preventing excitons recombination. Two kinds of non-covalent hybrid composites are prepared by mixing the PzPy with single wall carbon nanotubes (SWNTs) and graphene nanoflakes (GNFs), respectively, and used for photocurrent generation through charge transfer processes between PzPy and nanocarbons. Photoconduction experiments show photocurrent generation upon visible light irradiation of both PzPy/SWNT and PzPy/GNF composites (0.78 and 0.71 mA/W at 500 nm, respectively), demonstrating their suitability for optoelectronic applications and light harvesting systems.widely used for this purpose. [12] More recently, carbon nanotubes (CNTs) have also been reported as acceptors, [13][14][15] and the use of graphene is rapidly raising too. [16][17][18][19][20][21] In particular, single wall carbon nanotubes (SWNTs) have been proposed as acceptor material since they possess nanoscale diameter and large aspect ratio in combination with favorable electrical transport properties. [14,19] Furthermore, SWNTs show unique optoelectronic properties, electrochemical stability, and energy levels that can be suitably coupled to those of conjugated polymers with long-range charge transport properties to make efficient composites for optoelectronic devices. [19] Similarly, graphene has high electron and hole mobility at room temperature, with reported values exceeding 15000 cm 2 V -1 s -1 . [20][21][22] Graphene is also electrochemically stable, with a very high specific surface area (∼ 2630 m 2 g −1 ), surpassing that of both SWNTs and graphite. [23,24] Moreover, graphene has an optical transmittance over the visible range of 97.7%, [25] and its work function (∼ 4.5 eV) [26] can be matched to the energy levels of organic donor materials. [22] Moving from these motivations, both SWNTs and functionalized graphene have been used as electron acceptors in combination with conjugated polymer donors, such as poly(3-octylthiophene) (P3OT), or poly(pphenylenevinylenes), and poly(3-hexylthiophene) (P3HT), [14,19,27,28] especially in organic bulk heterojunction (BHJ) solar cell devices. [19] Amongst the non-poly...

show abstract

Section: Synthesis and Structural Characterization The Pyrene-substit...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thioethyl‐Porphyrazine/Nanocarbon Hybrids for Photoinduced Electron Transfer

Belviso

Capasso

Santoro

et al. 2018

Adv Funct Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…The key step was the replacement of one alkylthio tail to give the nonsymmetrical β‐H‐substituted porphyrazines 2a , b , followed by bromine substitution to yield 3a , b . Pd‐catalyzed Suzuki coupling reactions[29d], finally provided the pyrene‐substituted alkylthioporphyrazines PzPy and PzPy‐octyl , respectively. To the best of our knowledge, no Pd II –alkylthioporphyrazine complexes have been reported in the literature so far.…”

Section: Resultsmentioning

confidence: 99%

Stereochemical Stability and Absolute Configuration of Atropisomeric Alkylthioporphyrazines by Dynamic NMR and HPLC Studies and Computational Analysis of HPLC‐ECD Recorded Spectra

et al. 2018

Self Cite

View full text Add to dashboard Cite

The conformational and stereodynamic properties of a pyrene‐substituted ethylthioporphyrazine (PzPy), promising as a dye for organic optoelectronic applications and light‐harvesting systems, have been investigated by DFT computations and variable‐temperature NMR and HPLC. In PzPy, rotation around the pyrene–macrocycle bond is hindered and the molecule displays atropisomerism, existing as a pair of enantiomers, thus representing the first chiral alkyl‐porphyrazine to be reported in the literature. The rotational barrier (ΔG‡ ≈ 22.0 kcal mol–1), measured by variable‐temperature HPLC experiments, allows chromatographic separation of the enantiomers on a chiral stationary phase below 0 °C, whereas racemization spontaneously occurs at room temperature. The absolute configurations of the eluted enantiomers were also determined by computational analysis of their electronic circular dichroism spectra. The influence of alkyl chain length and metal complexation on the molecular stereodynamic properties have also been investigated by studying its novel octylthio derivative (PzPy‐octyl) and PdII complex (PdPzPy), respectively. The latter also is the first example of a PdII–alkylthioporphyrazine complex. Given that PzPy has been used in the preparation of hybrid materials with nanocarbons for optoelectronic applications, the presence of an axial chirality element may play a key role in its interaction with semiconducting chiral nanotubes.

show abstract

“…16 Despite the lack of the results, the first Suzuki cross-coupling arylation of Pzs giving access to highly non-symmetrical aryl-substituted thioalkyl-porphyrazines has been performed by Belviso, Lelj and their co-workers. 17,18 In our research, we focused on the synthesis of Pzs with different 5-membered ring heteroaromatic groups. Although this type of Pzs periphery has been reported previously by Luo et al.…”

Section: Introductionmentioning

confidence: 99%