Phthalocyanine-Gold Nanoparticle Hybrids: Modulating Quenching with a Silica Matrix Shell

Stable Cu Catalysts Supported by Two-dimensional SiO2 with Strong Metal-Support Interaction

Cu-based catalysts exhibit excellent performance in hydrogenation reactions. However, the poor stability of Cu catalysts under high temperatures has restricted their practical applications. The preparation of stable Cu catalysts supported by SiO₂ with strong metal-support interaction (SMSI) has thus aroused great interest due to the high abundance, low toxicity, feasible processability, and low cost of SiO₂ . The challenge in the construction of such SMSI remains to be the inertness of SiO₂ . Herein, a simple and scalable method is developed to prepare 2D silica (2DSiO₂ ) supported Cu catalysts with SMSI by carefully manipulating the topological exfoliation of CaSi₂ with CuCl₂ and thereafter calcination. The prepared Cu-2DSiO₂ catalysts with the unique encapsulated Cu nanoparticles exhibit excellent activity and long-term stability in high-temperature CO₂ hydrogenation reactions. This feasible and low-cost solution for stabilizing Cu catalysts might shed light on their realistic applications.

Effect of Solvent and Catalyst Types on Stability and Properties of Zinc Phthalocyanine in the Organic–Inorganic Hybrid Materials

Hybrid materials, i.e., the organically modified silicates (ORMOSIL) based on zincphthalocyanine (ZnPc) and silica glass matrix were synthesized by the sol-gel method using protic solvents (methanol, ethanol, isopropanol, butanol) and aprotic solvent (N,N-dimethylformamide; DMF). The effect of an alkaline environment with NaOH addition (a single-stage process) and acid–alkaline environment with CH3COOH-NH4OH and HCl-NaOH (a two-stage process) was analyzed. UV-Vis spectroscopy was used to study the stability of ZnPc in the sol. The highest stability of zinc phthalocyanine in the glass was obtained for synthesis with isopropanol in the presence of the alkaline catalyst. The lowest stability of ZnPc was observed when the aprotic solvent was used. The structure and optical properties of the gels were studied by SEM, FTIR, and XRD techniques and optically stimulated luminescence (OSL) and thermoluminescence (TL), respectively. The thermal stability of the materials was analyzed by TG-DSC methods.

The nucleobase assisted pyrene functionalization of gold nanoparticles

Gold nanoparticles were functionalized with a pyrene fluorophore without compromising the functional behaviour of the fluorophore.

Electrochemical Sensors Modified with Combinations of Sulfur Containing Phthalocyanines and Capped Gold Nanoparticles: A Study of the Influence of the Nature of the Interaction between Sensing Materials

Voltametric sensors formed by the combination of a sulfur-substituted zinc phthalocyanine (ZnPc^RS) and gold nanoparticles capped with tetraoctylammonium bromide (AuNP^tOcBr) have been developed. The influence of the nature of the interaction between both components in the response towards catechol has been evaluated. Electrodes modified with a mixture of nanoparticles and phthalocyanine (AuNP^tOcBr/ZnPc^RS) show an increase in the intensity of the peak associated with the reduction of catechol. Electrodes modified with a covalent adduct-both component are linked through a thioether bond-(AuNP^tOcBr-S-ZnPc^R), show an increase in the intensity of the oxidation peak. Voltammograms registered at increasing scan rates show that charge transfer coefficients are different in both types of electrodes confirming that the kinetics of the electrochemical reaction is influenced by the nature of the interaction between both electrocatalytic materials. The limits of detection attained are 0.9 × 10⁻⁶ mol∙L⁻¹ for the electrode modified with the mixture AuNP^tOcBr/ZnPc^RS and 1.3 × 10⁻⁷ mol∙L⁻¹ for the electrode modified with the covalent adduct AuNP^tOcBr-S-ZnPc^R. These results indicate that the establishment of covalent bonds between nanoparticles and phthalocyanines can be a good strategy to obtain sensors with enhanced performance, improving the charge transfer rate and the detection limits of voltammetric sensors.

Tailored porphyrin–gold nanoparticles for biomedical applications

In this review we present an updated survey of the main synthesis methods of gold nanoparticles (AuNPs) in order to obtain various tailored nanosystems for biomedical imaging. The synthesis approach significantly impacts on the AuNPs properties such as surface chemistry, biocompatibility and cytotoxicity. In recent years, nanomedicine emphasized the development of functionalized AuNPs for biomedical imaging. AuNPs are a good option for used as delivery photosensitizer agents for PDT of cancer. For example, the complex formed from AuNPs functionalized with PEGylate porphyrins presents several advantages in the medical field such as a better use in photodynamic therapy because of high triplet states and singlet oxygen quantum yield efficiency of porphyrin molecules.

Excited-State Charge Transfer in Covalently Functionalized MoS2 with a Zinc Phthalocyanine Donor-Acceptor Hybrid

The functionalization of MoS₂ is of paramount importance for tailoring its properties towards optoelectronic applications and unlocking its full potential. Zinc phthalocyanine (ZnPc) carrying an 1,2-dithiolane oxide linker was used to functionalize MoS₂ at defect sites located at the edges. The structure of ZnPc-MoS₂ was fully assessed by complementary spectroscopic, thermal, and microscopy imaging techniques. An energy-level diagram visualizing different photochemical events in ZnPc-MoS₂ was established and revealed a bidirectional electron transfer leading to a charge separated state ZnPc^.+ -MoS₂ ^.- . Markedly, evidence of the charge transfer in the hybrid material was demonstrated using fluorescence spectroelectrochemistry. Systematic studies performed by femtosecond transient absorption revealed the involvement of excitons generated in MoS₂ in promoting the charge transfer, while the transfer was also possible when ZnPc was excited, signifying their potential in light-energy-harvesting devices.