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Metallo-phthalocyanines ( MPc ) are common photosensitizers with ideal photophysical and photochemical properties. Also, these molecules have shown to interact with non-canonical nucleic acid structures, such as G-quadruplexes, and modulate oncogenic expression in cancer cells. Herein, we report the synthesis and characterisation of two metallo-phthalocyanines containing either zinc ( ZnPc ) or nickel ( NiPc ) in the central aromatic core and four alkyl ammonium lateral chains. The interaction of both molecules with G-quadruplex DNA was assessed by UV–Vis, fluorescence and FRET melting experiments. Both molecules bind strongly to G-quadruplexes and stabilise these structures, being NiPc the most notable G-quadruplex stabiliser. In addition, the photosensitizing ability of both metal complexes was explored by the evaluation of the singlet oxygen generation and their photoactivation in cells. Only ZnPc showed a high singlet oxygen generation either by direct observation or by indirect evaluation using a DPBF dye. The cellular evaluation showed mainly cytoplasmic localization of ZnPc and a decrease of the IC 50 values of the cell viability of ZnPc upon light activation of two orders of magnitude. Graphical abstract Two metallo-phthalocyanines containing zinc and nickel within the aromatic core have been investigated as G-quadruplex stabilizers and photosensitizers. NiPc shows a high G4 binding but negligible photosensitizing ability while ZnPc exhibits a moderate binding to G-quadruplex together with a high potency to generate singlet oxygen and photocytotoxicity. The interaction with G4s and capacity to be photosensitized is associated with the geometry adopted by the central metal core of the phthalocyanine scaffold.

Highly effective electrocatalysts promoting CO 2 reduction reaction (CO 2 RR) is extremely desirable to produce value-added chemicals/fuels while addressing current environmental challenges. Herein, we develop a layer-stacked, bimetallic two-dimensional conjugated metal-organic framework (2D c -MOF) with copper-phthalocyanine as ligand (CuN 4 ) and zinc-bis(dihydroxy) complex (ZnO 4 ) as linkage (PcCu-O 8 -Zn). The PcCu-O 8 -Zn exhibits high CO selectivity of 88%, turnover frequency of 0.39 s −1 and long-term durability (>10 h), surpassing thus by far reported MOF-based electrocatalysts. The molar H 2 /CO ratio (1:7 to 4:1) can be tuned by varying metal centers and applied potential, making 2D c -MOFs highly relevant for syngas industry applications. The contrast experiments combined with operando spectroelectrochemistry and theoretical calculation unveil a synergistic catalytic mechanism; ZnO 4 complexes act as CO 2 RR catalytic sites while CuN 4 centers promote the protonation of adsorbed CO 2 during CO 2 RR. This work offers a strategy on developing bimetallic MOF electrocatalysts for synergistically catalyzing CO 2 RR toward syngas synthesis. Effective electrocatalyst is crucial in promoting CO 2 reduction to address current energy/environmental issue. Here, the authors develop bimetallic layered two-dimensional conjugated metal-organic framework to synergistically and efficiently electro-catalyze CO 2 to CO toward syngas synthesis.

Most current research is devoted to electrochemical nitrate reduction reaction for ammonia synthesis under alkaline/neutral media while the investigation of nitrate reduction under acidic conditions is rarely reported. In this work, we demonstrate the potential of TiO 2 nanosheet with intrinsically poor hydrogen-evolution activity for selective and rapid nitrate reduction to ammonia under acidic conditions. Hybridized with iron phthalocyanine, the resulting catalyst displays remarkably improved efficiency toward ammonia formation owing to the enhanced nitrate adsorption, suppressed hydrogen evolution and lowered energy barrier for the rate-determining step. Then, an alkaline-acid hybrid Zn-nitrate battery was developed with high open-circuit voltage of 1.99 V and power density of 91.4 mW cm –2 . Further, the environmental sulfur recovery can be powered by above hybrid battery and the hydrazine-nitrate fuel cell can be developed for simultaneously hydrazine/nitrate conversion and electricity generation. This work demonstrates the attractive potential of acidic nitrate reduction for ammonia electrosynthesis and broadens the field of energy conversion. Research on electrochemical nitrate reduction to ammonia in acidic conditions has been less extensive than that conducted in alkaline conditions. Here, the authors report a hybrid of iron phthalocyanine and TiO 2 catalyst with improved efficiency toward acidic nitrate reduction and its application in Zn-nitrate batteries and high-voltage pollutes-based fuel cell.

Iron phthalocyanine (FePc) is a promising non-precious catalyst for the oxygen reduction reaction (ORR). Unfortunately, FePc with plane-symmetric FeN 4 site usually exhibits an unsatisfactory ORR activity due to its poor O 2 adsorption and activation. Here, we report an axial Fe–O coordination induced electronic localization strategy to improve its O 2 adsorption, activation and thus the ORR performance. Theoretical calculations indicate that the Fe–O coordination evokes the electronic localization among the axial direction of O–FeN 4 sites to enhance O 2 adsorption and activation. To realize this speculation, FePc is coordinated with an oxidized carbon. Synchrotron X-ray absorption and Mössbauer spectra validate Fe–O coordination between FePc and carbon. The obtained catalyst exhibits fast kinetics for O 2 adsorption and activation with an ultralow Tafel slope of 27.5 mV dec −1 and a remarkable half-wave potential of 0.90 V. This work offers a new strategy to regulate catalytic sites for better performance. Iron phthalocyanine with a 2D structure and symmetric electron distribution around Fe-N 4 active sites is not optimal for O 2 adsorption and activation. Here, the authors report an axial Fe–O coordination induced electronic localization strategy to enhance oxygen reduction reaction performance.

Chlorine‐coordinated iron phthalocyanine is designed and synthesized for 4 e− pathway oxygen reduction reaction (ORR). Iron phthalocyanine (FePc) is a promising nonprecious catalyst for the ORR. Unfortunately, FePc with plane‐symmetric Fe‐N4 site usually exhibits an unsatisfactory ORR activity due to its poor O2 adsorption and activation. In this work, Chlorine‐coordinated iron phthalocyanine (Cl‐FePc) has been studied as a catalyst for the electrochemical ORR. Coordination of iron phthalocyanine with chlorine introduces additional active sites for ORR, improving its catalytic activity. The chlorine atoms enhance the electron transfer process and facilitate the ORR validated by in situ Raman spectroscopy. The obtained catalyst exhibits fast kinetics for O2 adsorption and activation with an ultralow Tafel slope of 30 mV dec−1 and a remarkable half‐wave potential of 0.80 V. This work offers a new strategy to regulate catalytic sites for better performance ORR. In situ Raman spectroscopy confirms Cl‐FePc is an effective oxygen reduction reaction catalyst, with distinct vibrational modes at 685 cm−1 (FeOOH) and 833 cm−1 (OH−) demonstrating the preferred 4e− pathway. These spectral fingerprints verify the critical role of iron‐oxyhydroxide and hydroxyl intermediates in achieving complete oxygen‐to‐water conversion, highlighting the catalyst's superior performance.

Copper and nickel phthalocyanines incorporating four polyethylene glycol (PEG) chains were synthesized for PEG of 200, 400 and 600 molecular weights. The functionalized phthalocyanines were incorporated into a resorcinol-formaldehyde polymer which was converted to a hierarchically porous macroporous-mesoporous carbon by pyrolysis. The pyrolysis released metal atoms from the phthalocyanines which agglomerated to give metal nanoparticles. Particle sizes were determined by SEM and TEM. Phthalocyanines with PEG of 400 molecular weight gave the smallest nanoparticles, in the 3–10 nm range. Catalytic activity for cyclohexene oxidation (for copper phthalocyanines) and p -nitrophenol reduction (for nickel phthalocyanines) were studied, and found not to correlate well with nanoparticle size, likely reflecting differences in accessibility of the nanoparticles on the carbon surface vs. nanoparticles formed within the carbon matrix. Highlights Phthalocyanines functionalized with polyethylene glycol chains (MPEGPCs) of varying lengths were prepared. MPEGPCs plus resorcinol and formaldehyde polymer gave a porous polymer that was pyrolyzed. Longer chain length (MW  ≥  200) MPEGPCs were well dispersed in carbon after pyrolysis. MW = 400 MPEGPC gave smallest metal nanoparticles (3–10 nm). MW = 400 MPEGPC nanoparticles were mostly confined within carbon not on surface.

The cover picture shows the selective internalization of molecules of a di‐galactosyl zinc(II) phthalocyanine into a cancer cell. Upon light irradiation, these molecules are excited and interact with the endogenous oxygen to generate highly reactive singlet oxygen, which oxidatively damages the cellular components, leading to cell death eventually. More information can be found in the Research Article by Dennis K. P. Ng, and co‐workers.

Metal phthalocyanines (MePcs) have been considered as promising catalysts for CO 2 reduction electrocatalysis due to high turnover frequency and structural tunability. However, their performance is often limited by low current density and the performance of some systems is controversial. Here, we report a carbon nanotube (CNT) hybridization approach to study the electrocatalytic performance of MePcs (Me = Co, Fe and Mn). MePc molecules are anchored on CNTs to form the hybrid materials without noticeable molecular aggregations. The MePc/CNT hybrids show higher activities and better stabilities than their molecular counterparts. FePc/CNT is slightly less active than CoPc/CNT, but it could deliver higher Faradaic efficiencies for CO production at low overpotentials. In contrast, the catalytic performance of MePc molecules directly loaded on substrate is hindered by molecular aggregation, especially for FePc and MnPc. Our results suggest that carbon nanotube hybridization is an efficient approach to construct advanced MePc electrocatalysts and to understand their catalytic performance.

Single-atom catalysts supported on solid substrates have inspired extensive interest, but the rational design of high-efficiency single-atom catalysts is still plagued by ambiguous structure determination of active sites and its local support effect. Here, we report hybrid single-atom catalysts by an axial coordination linkage of molecular cobalt phthalocyanine with carbon nanotubes for selective oxygen reduction reaction by screening from a series of metal phthalocyanines via preferential density-functional theory calculations. Different from conventional heterogeneous single-atom catalysts, the hybrid single-atom catalysts are proven to facilitate rational screening of target catalysts as well as understanding of its underlying oxygen reduction reaction mechanism due to its well-defined active site structure and clear coordination linkage in the hybrid single-atom catalysts. Consequently, the optimized Co hybrid single-atom catalysts exhibit improved 2e − oxygen reduction reaction performance compared to the corresponding homogeneous molecular catalyst in terms of activity and selectivity. When prepared as an air cathode in an air-breathing flow cell device, the optimized hybrid catalysts enable the oxygen reduction reaction at 300 mA cm −2 exhibiting a stable Faradaic efficiency exceeding 90% for 25 h. Difficulties in elucidating active sites and the role of the support hamper the development of high-efficiency two-electron oxygen reduction electrocatalysts. Here, the authors develop hybrid single-atom catalysts by rational experimental and theoretical screening for hydrogen peroxide production.