Nanohybrid Assemblies of Porphyrin and Au10 Cluster Nanoparticles

Trapani, Mariachiara; Castriciano, Maria Angela; Romeo, Andrea; Luca, Giovanna De; Machado, Nelson; Howes, Barry D.; Smulevich, Giulietta; Scolaro, Luigi Monsù

doi:10.3390/nano9071026

Cited by 17 publications

(18 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[11][12][13][14][15][16][17][18] Usually, chiroptical properties could arise from the presence of stereogenic centers in the basic building blocks, [19][20][21][22][23][24][25] or induced by a chiral scaffold or chemical template, such as simple chiral compounds, polymers and biomolecules. [26][27][28][29][30][31][32][33][34][35] Many examples of J-aggregated TPPS4 exhibiting optical activity under the presence of chemical [36][37][38][39][40][41][42][43][44][45][46][47] or physical chiral bias [48][49][50][51][52][53][54][55] have been reported so far. The occurrence of spontaneous symmetry breaking during the growth process has been related to kinetics and in particular to mixing protocols.…”

Section: Introductionmentioning

confidence: 99%

Controlling J-Aggregates Formation and Chirality Induction through Demetallation of a Zinc(II) Water Soluble Porphyrin

Occhiuto

Castriciano

Trapani

et al. 2020

IJMS

Self Cite

View full text Add to dashboard Cite

Under acidic conditions and at high ionic strength, the zinc cation is removed from its metal complex with 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS4) thus leading to the diacid free porphyrin, that subsequently self-organize into J-aggregates. The kinetics of the demetallation step and the successive supramolecular assembly formation have been investigated as a function of pH and ionic strength (controlled by adding ZnSO4). The demetallation kinetics obey to a rate law that is first order in [ZnTPPS4] and second order in [H+], according to literature, with k2 = 5.5 ± 0.4 M−2 s−1 at 298 K (IS = 0.6 M, ZnSO4). The aggregation process has been modeled according to an autocatalytic growth, where after the formation of a starting seed containing m porphyrin units, the rate evolves as a power of time. A complete analysis of the extinction time traces at various wavelengths allows extraction of the relevant kinetic parameters, showing that a trimer or tetramer should be involved in the rate-determining step of the aggregation. The extinction spectra of the J-aggregates evidence quite broad bands, suggesting an electronic coupling mechanism different to the usual Frenkel exciton coupling. Resonance light scattering intensity in the aggregated samples increases with increasing both [H+] and [ZnSO4]. Symmetry breaking occurs in these samples and the J-aggregates show circular dichroism spectra with unusual bands. The asymmetry g-factor decreases in its absolute value with increasing the catalytic rate kc, nulling and eventually switching the Cotton effect from negative to positive. Some inferences on the role exerted by zinc cations on the kinetics and structural features of these nanostructures have been discussed.

show abstract

Section: Introductionmentioning

confidence: 99%

Controlling J-Aggregates Formation and Chirality Induction through Demetallation of a Zinc(II) Water Soluble Porphyrin

Occhiuto

Castriciano

Trapani

et al. 2020

IJMS

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is well known that the diacid form of this porphyrin in solution under the opportune experimental conditions is able to self-organize into highly ordered chiral J-aggregates with or without the assistance of chiral species [33][34][35]. Indeed, in the absence of a chiral bias, TPPS could be assembled into chiral aggregates showing a dichroic signal characterized by a positive bisignate Cotton effect [34,[36][37][38][39][40][41] whose shape and magnitude is strictly related to the experimental conditions used for the preparation of the aggregates [34,37,[42][43][44][45][46]. The formation of chiral supramolecular assemblies from achiral building blocks is a particularly interesting phenomenon [47][48][49][50][51] for the possible correlation with homochirality observed in nature.…”

Section: Introductionmentioning

confidence: 99%

Influence of Magnetic Micelles on Assembly and Deposition of Porphyrin J-Aggregates

et al. 2020

Self Cite

View full text Add to dashboard Cite

Clusters of superparamagnetic iron oxide nanoparticles (SPIONs) have been incorporated into the hydrophobic core of polyethylene glycol (PEG)-modified phospholipid micelles. Two different PEG-phospholipids have been selected to guarantee water solubility and provide an external corona, bearing neutral (SPIONs@PEG-micelles) or positively charged amino groups (SPIONs@NH2-PEG-micelles). Under acidic conditions and with specific mixing protocols (porphyrin first, PF, or porphyrin last, PL), the water-soluble 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin (TPPS) forms chiral J-aggregates, and in the presence of the two different types of magnetic micelles, an increase of the aggregation rates has been generally observed. In the case of the neutral SPIONs@PEG-micelles, PL protocol affords a stable nanosystem, whereas PF protocol is effective with the charged SPIONs@NH2-PEG-micelles. In both cases, chiral J-aggregates embedded into the magnetic micelles (TPPS@SPIONs@micelles) have been characterized in solution through UV/vis absorption and circular/linear dichroism. An external magnetic field allows depositing films of the TPPS@SPIONs@micelles that retain their chiroptical properties and exhibit a high degree of alignment, which is also confirmed by atomic force microscopy.

show abstract

“…TPPS J-aggregates are characterized by a linear arrangement of the chromophores and stabilized by electrostatic interactions between the negatively charged benzenesulfonate groups and the positively charged nitrogen atoms of the pyrrole rings, as well as by hydrogen bonds and stacking interactions [35][36][37][38][39][40]. Aggregation kinetics and final supramolecular structures are strictly related to the different experimental parameters, such as the nature of the acid [41], the ionic strength [38,39], organic or inorganic scaffold [42][43][44][45][46][47][48] or the reagent mixing order protocol [49,50]. In this work, the effect of different wt percentages of TPPS in s-PEEK membranes with a medium DS (50%) has been investigated.…”

Section: Introductionmentioning

confidence: 99%

Novel Polymeric Composite TPPS/s-PEEK Membranes for Low Relative Humidity PEFC

et al. 2020

Self Cite

View full text Add to dashboard Cite

Composite membranes based on different wt percentages of meso-tetrakis-(4-sulfonatophenyl)porphyrin (TPPS) embedded in a medium sulfonation degree (50%) sulfonated poly(etheretherketone) (s-PEEK) were investigated. The successful introduction of porphyrin into the membranes and the characterization of its different species into the membrane ionic domains were carried out by spectroscopic techniques. Moreover, the effect of TPPS arrangement was investigated in terms of water retention, proton conductivity and fuel cell performance at low relative humidity (RH). It was found that the introduction of this porphyrin induces a variation of the chemical-physical parameters, such as ion exchange capacity (IEC), water up-take (Wup %) λ and proton concentration ([H+]), attributable to the interactions that occur between the sulfonic groups of the polymer and the nitrogen sites of TPPS. The TPPS, in its J-aggregated form, actively participates in the proton conduction mechanism, also maintaining the adequate water content in more drastic conditions (80 °C and 50% RH). A maximum power density value of 462 mW cm−2 was obtained for the s-PEEK membrane, with a 0.77 wt % content of TPPS. This evidence suggests that the presence of J-aggregates in the proton conduction channels maintains a good hydration, even if a drastic reduction of the RH of the reactant gases occurs, preventing the membrane from a dry-out effect.

show abstract

Nanohybrid Assemblies of Porphyrin and Au10 Cluster Nanoparticles

Cited by 17 publications

References 64 publications

Controlling J-Aggregates Formation and Chirality Induction through Demetallation of a Zinc(II) Water Soluble Porphyrin

Controlling J-Aggregates Formation and Chirality Induction through Demetallation of a Zinc(II) Water Soluble Porphyrin

Influence of Magnetic Micelles on Assembly and Deposition of Porphyrin J-Aggregates

Novel Polymeric Composite TPPS/s-PEEK Membranes for Low Relative Humidity PEFC

Contact Info

Product

Resources

About