Pc Molecule Research Articles

Tuning the surface electronic structure of WS2 with Zn- and Cu-phthalocyanine for improved hydrogen evolution reaction: Experimental and DFT investigation

WS2 nanosheets have been successfully demonstrated to be promising materials for several important catalytic reactions including Hydrogen Evolution Reaction (HER) and Oxygen Reduction Reactions (ORR) either standalone or by functionalizing and as composites. Tungsten disulfide (WS2) is known to exist in two phases: 2H semiconducting and 1 T conducting. The 2H phase is commonly obtained by simple exfoliation of bulk WS2. Due to the semiconducting nature of the 2H phase, catalytic activity towards HER is very feeble compared to its 1 T counterpart. In this work, we have enhanced the activity of 2H WS2 nanosheets by interfacial modification through metal phthalocyanine (Pc) molecule (Cu-Pc and Zn-Pc) functionalization. We observe that the HER activity shows significant enhancement with the functionalization, with Zn-Pc showing better performance than the Cu-Pc. This functionalization creates an electronically coupled inorganic–organic heterostructure which shows improved response to HER. The WS2 functionalized nanosheets were studied in-depth with X-ray diffraction (XRD), X-ray photo electron spectroscopy (XPS) and High-Resolution Transmission Electron Microscopy (HRTEM) analyses. Electrochemical studies like linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) demonstrates that the heterostructures deliver enhanced charge transfer kinetics. The Zn-Pc functionalized nanosheets display an overpotential of 233 mV for attaining a current density of 10 mA.cm-2 and the overpotential decreased to 165 mV after cycling due to the surface reconstruction, when the stability was assessed with chronoamperometry. Density Functional Theory (DFT) studies reveal that the charge transfer due to the adsorption of Zn-Pc onto WS2 nanosheets is comparatively better than that of Cu-Pc. This work recounts that by simple metal phthalocyanine functionalization, charge transfer characteristics of WS2 can be markedly improved, thereby signifying the importance of interface modification in two-dimensional (2D) heterostructures.

New additive as Li+ source for charge transfer improvement at triple-cation perovskite/Spiro-OMeTAD interface

One of the main obstacles to perovskite solar cells (PSCs) entering the market is the doping-induced degradation of expensive hole transport materials (HTMs), which results in poor device stability. Although lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) and 4-tert-butylpyridine (4-tBp) as additives are commonly used in HTMs, they often lead to low device stability and reproducibility due to their hygroscopic and volatile nature. In this study, we incorporated the dilithium phthalocyanine (Li 2 Pc) molecule into the Spiro-OMeTAD precursor solution with Li-TFSI and 4-tBp to produce triple-cation PSCs with an n–i–p configuration operating with high efficiency and stability. The addition of the Li 2 Pc molecule not only improves the perovskite/Spiro-OMeTAD interface but also increases the π–π stacking in the thin-film phase according to the absorption and Raman results. Based on space-charge-limited current, photoluminescence, time-resolved photoluminescence and lifetime analysis measurements, charge transfer is improved with the Li 2 Pc molecule and charge recombination losses are reduced. As a result, the control device showed a power conversion efficiency (PCE) of 20.0% with J SC = 24.6 mA/cm 2 and fill factor (FF) = 72.7%, whereas the Li 2 Pc-doped device exhibited an improved PCE of 20.6% with J SC = 25.0 mA/cm 2 and FF = 73.6%. The addition of Li 2 Pc resulted in more stable and high-efficiency solar cells that maintained approximately 90% of the initial efficiency after 40 days. • The addition of the Li 2 Pc molecule can increase the π–π stacking in the thin-film phase. • Li 2 Pc can effectively passivate the defects at the triple-cation perovskite/Spiro-OMeTAD interface. • The efficiency of triple-cation perovskite solar cell is increased from 20.0% to 20.6%. • The device with Li 2 Pc retained about 90% of the initial efficiency after 40 days compared to the control device.

Experimental and computational studies of polycarboxylate dispersant effect on the properties of low‐rank coal water slurries

AbstractThe disadvantages of low‐rank coal in the preparation of coal water slurry (CWS) are well known, but the synthesis of suitable dispersants is a promising solution. Polycarboxylate dispersant (PC) is expected to be an efficient CWS dispersant due to its flexible and controllable structure. In this study, a series of binary PC dispersants were synthesized by controlling the ratio of acrylic acid (AA) to sodium styrene sulfonate (SSS), initiator fraction, and temperature, and the optimal PC was selected based on the apparent viscosity of 72# CWS at 100 s−1. The properties of 72# CWS were studied: This CWS exhibited shear‐thinning behavior, >14 static stability, and >55 wt% maximum solid loading, indicating the satisfactory performance of the optimal PC. The experimental results (including adsorption tests and zeta potential measurement) and molecular dynamics simulation showed that PC was effectively adsorbed on the surface of the coal particles by a horizontal multipoint adsorption mode, mainly through the interaction between the hydrophobic groups of the PC molecule and the hydrophobic areas of the coal particles. The hydrophilicity of the coal particles was therefore improved and the stability of their hydration layer was also enhanced, which accounted for the good static stability of 72# CWS. The amount of PC adsorption and the improved absolute zeta potential were associated with the decent properties of 72# CWS. This study is significant for promoting the molecular design of CWS dispersants based on their adsorption behavior.

Fluorescence Quenching of Carboxy-Substituted Phthalocyanines Conjugated with Nanoparticles under High Stoichiometric Ratios

Background: The search of the approaches towards a photosensitizer’s conjugation with multifunctional nanoparticles is an important step in the development of photodynamic therapy techniques. Association of photosensitizer molecules with nanoparticles that perform the delivery function can lead to a change in the functional state of the photosensitizer. Methods: We studied the effects observed upon incorporation of octa- and hexadeca-carboxyphthalocyanines of zinc(II) and aluminum(III) (Pcs) into the polymer shell of nanoparticles with a semiconductor CdSe/CdS/ZnS core with various spectral and optical methods. Results: First, the interaction of Pc with the polymer shell leads to a change in the spectral properties of Pc; the effect strongly depends on the structure of the Pc molecule (number of carboxyl groups as well as the nature of the central cation in the macrocycle). Secondly, upon incorporation of several Pc molecules, concentration effects become significant, leading to Pc aggregation and/or nonradiative energy transfer between neighboring Pc molecules within a single nanoparticle. Conclusions: These processes lead to the decrease of a number of the Pc molecules in an excited state. Such effects should be taken into account during the development of multifunctional platforms for the delivery of photosensitizers, including the use of nanoparticles as enhancers of photosensitizer activity by energy transfer.

The effect of the position of the trimethoxy groups as distant substituents on the spectral and acid sensing properties of phthalocyanines

In this study, alpha and beta substituted phthalonitrile derivatives were obtained by using 3,4,5-trimethoxyphenol and 2,4,6-trimethoxyphenol, and metal-free and Co2+ phthalocyanine molecules were synthesized using these starting compounds. After the phthalocyanine compounds were purified and characterized by classical methods, their detailed solubility, UV–Vis and FT-IR spectroscopy studies were performed and it was revealed how the positions of methoxy groups changed the spectroscopic properties of phthalocyanines. In addition, during detailed UV–Vis studies of Pcs, it was determined that alpha-substituted Pcs gave an extra peak in 1 × 10−5 M dichloromethane solution. It was determined that this peak was caused by acid impurities in dichloromethane in trace amounts and UV–Vis spectra in DCM solutions with different trifluoroacetic acid(TFA) concentrations for alpha substituted Pcs (5–8) were studied and their protonation behaviour was examined. It was determined that H2Pc(6) was sensitive to acid even at 1.8 × 10−3 mM concentration. Thus, acid sensor device can be developed by using this Pc molecule, if desired.

First - principles investigation of geometry, charge and magnetic states for metal Phthalocyanine (MPc, M = Sn and Pb) molecules

We have investigated the geometry, charge and magnetic states of the metal phthalocyanine (MPc, M = Sn and Pb) molecules using the first - principles method within the framework of density functional theory. We have shown that the inter - atomic bond distances of absorbed metals (M = Sn and Pb) on the Pc molecule are the different from each other due to the different atomic radii of absorbed metal atom. The absorbed metal atoms are affect to the charge state of system. The total magnetic moment generates to the metal Phthalocyanine molecules by absorbing metal atoms.PACS numbers: 31.15.E-, 31.15.Ne, 36.20.-r

Photoconductive NiOx hole transport layer for efficient perovskite solar cells

NiOx is widely applied in perovskite solar cells (PSCs) as a hole transport layer. However, its poor conductivity limits the further improvement of device performance. Motivated by photoconductive phenomenon, here we propose a photoconductive NiOx-Pc hole transport layer in PSCs through combining with phthalocyanine (Pc). Under illumination, Pc molecule absorbs light and will be excited. Then photogenerated charges on Pc molecule will transfer to NiOx spontaneously and increase the hole density of NiOx film, thus improving its conductivity. As a result, > 300% increase in conductivity is observed in NiOx-Pc film and its conductivity reaches 4.6 * 10-4 S m−1. PSCs with NiOx-Pc exhibit high efficiency of 21.68%, which is much higher than control devices (19.74%). In addition, device stability is also improved in PSCs with NiOx-Pc and over 95%of initial efficiency is retained after 85 °C for 800 h.

Phthalocyanine-Triggered Helical Dipeptide Nanotubes with Intense Circularly Polarized Luminescence.

Nanotubes with circularly polarized luminescence (CPL) are attracting much attention due to many potential applications, such as chiroptical materials, displays, and sensing. However, it remains a challenge to change the assemblies of ordinarily molecular building blocks into CPL supramolecular nanotubes. Herein, the regulation of quite common dipeptide (Fmoc-FF) assemblies into unprecedented helical nanotubes exhibiting intense CPL is reported by simply doping a few phthalocyanine (octakis(carboxyl)phthalocyaninato zinc complex (Pc)) molecules. Interestingly, altering the Fmoc-FF/Pc molar ratios over a wide range cannot change the nanotubes structures according to transmission electron microscopy (TEM) and atomic force microscope (AFM) measurements. Although molecular dynamics simulations suggest that the noncovalent interactions between Fmoc-FF and Pc are quite weak, few Pc molecules can still change the secondary structures of a large number of Fmoc-FF assemblies, which hierarchically form helical supramolecular nanotubes with long-range ordered molecular packing, leading to intense CPL signals with large luminescence dissymmetry factor (glum = 0.04). Consequently, the chiral reorganization of Fmoc-FF assemblies is dependent on the coassembly between Pc molecule and Fmoc-FF supramolecular architectures. These results open the possibility for the fine-tuning of helix and supramolecular nanotubes with CPL properties by using a small number of cofactors.

Tuning the Electrical and Thermoelectric Properties of Phthalocyanine and Metallo-Phthalocyanine Molecular Junction

In this work, a comparative study is presented that analyses the electrical and thermoelectrical properties of free base-Phthalocyanine (Bare-Pc) and Metallo-Phthalocyanine (MPc) molecule sandwiched between gold electrodes. The study investigates the transmission and conductance characteristics of Bare-Pc without central metal ion and with different transition metal ions at the centre of (Pc) such as (Mn, Co, Ni, and Zn) in two different molecular configurations, cis and trans. The results reveal that the conductance changed by varying the transition metal-centre in the order of Co > Ni > Zn in trans, and closely similar pattern Co > Ni > Mn in cis with higher values in trans configuration. This reflects the correlation between the spin-dependent transport properties with the transition metal-centre type and the molecular structure. Further, thermoelectrical properties such as thermal conductance (k), Seebeck coefficient (S) and figure of merit (ZT) are investigated. It was found that (k), (S) and (ZT) have higher values in case of trans configuration for Co-Pc, Ni-Pc and Zn-Pc structures. Thus, by varying the transition metal-centre type and the molecular configuration of (Pc) molecule, transport properties can be tuned to produce a good value of the transmission and electrical conductance, thermal conductance, Seebeck coefficient, and figure of merit of the (Pc) molecular junction for potential high conductance and efficient thermoelectric applications.

Strategy for improving the activity and selectivity of CO2 electroreduction on flexible carbon materials for carbon neutral

Selective electrochemical reduction of CO2 is of interest in relieving the accumulation of CO2 in the atmosphere and the global energy crisis. This study investigates active sites and reaction mechanisms for CO2 electroreduction over metal N-doped flexible carbon materials using Phthalocyanine (Pc) and Iron Phthalocyanine (FePc) molecules as model catalysts. Both the FePc molecule and Pc molecule show catalytic activity for CO production and H2 evolution based on experimental results and DFT calculations. The presence of Fe atom results in a significantly higher activity for CO production and a little lower activity for H2 evolution. Calculated pKa and redox potentials (Ure) are introduced for the multi-step proton-coupled electron transfer (PCET) steps of two competitive reactions. Specifically, a comparison between them is conducted to explain the competition between CO2 electroreduction and H2 evolution reaction with the support of energy diagram. The rate-determining steps for CO2 reduction and H2 evolution are also investigated. Both the CO and H2 formation on Pc molecule depend on electron transfer process. Besides, the Ure of two rate-determining steps are close, which is related to the closed Eonset for CO and H2 formation in the experiment. This study demonstrates that the mechanism for CO2 reduction from DFT calculation is in agreement with the experimental results. The technological approach and reaction mechanism can be applied to other types of CO2 electroreduction on carbon materials. Thus, this work provides a guidance in the rational design of the green catalyst and the implementation of carbon neutral.

Phthalocyanine pendented polyaniline via amide linkage for an electrochemical sensing of H2O2

Cobalt phthalocyanines are known to be the better electrocatalyst for a wide range of organic, inorganic, and biomolecular analytes. The synthesis of electrocatalysts through phthalocyanine (Pc) functionalization involves a single-step reaction to a multi-step reaction. The functionalization of Pc catalyst with the conducting polymer involves either simple electronic interactions or direct covalent bonding. Here we are reporting covalently connected tetra carboxy cobalt phthalocyanine (TCCoPc) pendent via amide linking to the conducting polyaniline (PANI) backbone. The synthesized electrocatalyst is extensively utilized for the sensing of biologically active H2O2 on the surface of the catalyst modified glassy carbon electrode (GCE). The synthesized molecule was characterized by various spectroscopic techniques and the detailed electrochemical activity of the synthesized molecule for the sensing of H2O2 was investigated using linear sweep voltammetry and chronoamperometry techniques, by fabricating on the GCE. The superlative catalytic activity of the synthesized molecule is might be due to the synergetic effect of pendanted macrocyclic Pc molecule with the redox-active demeanor of central cobalt metal atom and anchoring of the metal-centered Pc through amide linking with the conducting PANI.

Preparation of phosphatidylcholine containing capric acid at the sn-1 position via Novozym® 435-catalyzed acidolysis

Abstract PC from soybean and C10:0 were subjected to lipase-mediated acidolysis/interesterification for the preparation of PC containing C10:0 (C10:0-PC). Free fatty acid form of C10:0 was selected as the best acyl donor in comparison to triacylglycerol from of C10:0 and ethyl ester from of C10:0 because higher C10:0-PC yield (46.2 ± 1.8 mol%) was obtained when free fatty acid form of C10:0 was used as acyl donor while that of triacylglycerol and ethyl ester were 24.9 ± 3.1 mol% and N.D., respectively in a preliminary reaction condition. In addition, Novozym® 435 was selected as the best catalyst compared to the commercial lipases Lipozyme® TL IM, Lipozyme® RM IM and Lipase OF® because the highest C10:0-PC yield (46.2 ± 1.8 mol%) was obtained when Novozym® 435 was used as a catalyst in a preliminary reaction condition. The reaction was then optimized based on the evaluation of acyl ratio (C10:0/PC), solvents, and reaction time, with mainly pursing C10:0-PC yield. It was demonstrated that high levels of acyl ratio decrease C10:0-incorporation, that solvents having low polarity are more effective in this reaction, and that the hydrolysis reaction was superior to the acidolysis reaction at the early stage of the process. Finally, C10:0-PC yield of 61.8 ± 3.0 mol% was obtained in the optimum reaction conditions, In this reaction system, Novozym® 435 showed regiospecificity at the sn-1 position of the PC molecule.

Structural, Electronic, and Magnetic Properties of Cobalt Tetrakis (Thiadiazole) Porphyrazine Molecule Films on Au(111).

We investigated the structural and electronic/spin configurations of a film of the Co tetrakis(1,2,5-thiadiazole) porphyrazine (CoTTDPz) molecule adsorbed on the Au(111) surface by a scanning tunneling microscope (STM). CoTTDPz has a structure similar to that of the Co phthalocyanine molecule, but the benzene ring of the isoindole of the phthalocyanine molecule is replaced by the pentagon moiety of 1,2,5-thiadiazoles that has an S atom at the apex. We find an ordered molecular lattice with a threefold symmetry where a nearest-neighbor distance of 1.30 nm was measured, which is significantly smaller than that observed for the metal Pc molecule. The unit cell of the lattice contains two molecules that are rotated by 60° relative to each other. With the configuration achieved by this rotation, the neighboring molecules can form a stronger interaction through bonding between the S atom at the apex of one molecule and the N atom of the other (the N atom that is bridging the thiadiazoles). The strong interaction between the molecule and the substrate appears in the spin state examined by the detection of the Kondo resonance, which is formed by the screening of an isolated spin by the conduction electron. Even though the existence of the spin was confirmed for the bulk and thick films of this molecule, no Kondo features are detected for the molecules in the first, second, and third layers of the films. However, the isolated molecule in the third layer showed an intriguing combination of the Kondo feature and an inelastic excitation feature caused by a spin-flip process.

Mini-Review: “Ball-Type Phthalocyanines”: Similarities and Differences from Mono Phthalocyanines

Ball-type phthalocyanines are recently synthesized binuclear derivatives of the widely known phthalocyanine molecule. In the ball-type Pc molecule, two cofacially arranged Pc rings have four bridged substituents on the peripheral positions of benzenes. Due to their cofacially arranged phthalocyanine rings and, strong intramolecular and intermolecular interactions, ball-type phthalocyanines have different properties than their parent molecule and these structures have many potential application areas. This review describes three different synthesis methods of ball-type phthalocyanines; synthesis in the solvent, synthesis in solid, and synthesis under microwave irradiation. The synthesis that occurs in the shortest time with the highest yield is the synthesis in the solid phase. General differences between a ball-type phthalocyanine and a monophthalocyanine, such as differences in electronic spectra and effects of cofacial arrangement and central metal atoms, are also discussed. The shape of the Q-bands indicates the differences in electronic spectra. In ball-type Pcs, the Q-bands are broad and have poor resolution. Some potential applications, such as gas sensors, NLO devices, potential usage in photodynamic therapy and artificial photosynthesis of ball-type phthalocyanines are also mentioned. Ball-type Pcs can be used as a sensor for gases such as; CO2, CO, SO2, VOC. A novel water-soluble ball-type Pc may have potential application in PDT. Finally, we consider future prospects of these molecules.

Interaction of Copper Phthalocyanine with Nitrogen Dioxide and Ammonia Investigation Using X-ray Absorption Spectroscopy and Chemiresistive Gas Measurements.

The interaction site of phthalocyanine (Pc) with nitrogen dioxide (NO2) has been characterized using different methods and found to be conflicting. By knowing the interaction site, the Pc molecule can be better customized to improve the gas sensitivity. In this article, the interaction sites of copper phthalocyanine (CuPc) with oxidizing NO2 or with reducing gas (ammonia, NH3) were identified using in situ X-ray absorption spectroscopy (XAS). The sensitivity of CuPc to sub-ppm levels of the tested gases was established in the CuPc chemoresistive gas sensors. The analyte–sensor interaction sites were identified and validated by monitoring the Cu K-edge XAS before and during gas exposure. From the X-ray absorption near-edge structure and its first derivative, a low or lack of axial coordination on the Cu metal center of CuPc is evident. Using the extended X-ray absorption fine structure with molecular orbital information of the involved molecules, the macrocycle interaction between CuPc and NO2 or NH3 was proposed to be the dominant sensing mechanism on CuPc sensors.

Exceptionally effective generation of singlet oxygen in aqueous media via iodinated zinc-phthalocyanine

Asymmetrically substituted zinc phthalocyanine (Pc) derivatives bearing quaternized triazolyl moieties for water solubility and iodine as a heavy metal atom have been investigated as singlet oxygen generators in aqueous media. In addition to the heavy atom effect exerted by iodine covalently bonded to the Pc molecule, a second dimensional effect induced by aggregation which brings the iodine anions of triazolyl units into closer proximity to the Pc core leading to the highest reported singlet oxygen generation for a Pc derivative in water (ΦΔ = 0.87).

Effect of pressure on structure and fluorescence of phthalocyanine

Phthalocyanine (Pc) is a kind of important photoelectric material, but a lot of questions remain to be clarified, like the relationship between the structure of Pc and its photoelectric property. High pressure is a powerful tool to study the structure transformation. High pressure study on piezochromic materials, which shows color change under high pressure due to structure changing, serves as an effectively way of studying the relationship between materials’ structure and photoelectric property. In this work Raman spectrum is employed to study the phase change of α phase metal-free Pc (α-H<sub>2</sub>Pc) under high pressure, meanwhile the effect of pressure on fluorescence (FL) is also studied to show how the Pc’s structure affects the photoelectric property. The diamond anvil cell is employed to achieve the high pressure condition, by using NaCl as a pressure transmitting medium. And Raman and FL measurements are performed by using a LabRam HR Evolution spectrometer equipped with a 473 nm laser. The Raman spectra of α-H<sub>2</sub>Pc show to slightly change during compression to 12.0 GPa. The main Raman peaks remain at highest pressure, including the Raman peak from macrocyclic of Pc molecules, which shows the stability of Pc molecules. Note that an enhancement of Raman peak at 623 cm<sup>–1</sup> can be found with the pressure increasing, which appears only in the Raman spectrum of χ phase metal-free Pc (χ-H<sub>2</sub>Pc), showing that α-H<sub>2</sub>Pc is converted into χ-H<sub>2</sub>Pc under pressure. The curve for Raman frequency as a function of pressure shows that no obvious evidence related to bonding or structure transition can be observed, which means that α-H<sub>2</sub>Pc is transformed into χ-H<sub>2</sub>Pc gradually. For FL spectrum, only the FL of excimer can be found in α-H<sub>2</sub>Pc at atmosphere pressure. When the solid α-H<sub>2</sub>Pc is compressed, the FL intensity is found to decrease as pressure increases, and it is quenched at 3.0 GPa. The FL of Pc molecule, which is not found in α-H<sub>2</sub>Pc at ambient pressure, appears at 0.7 GPa. As the pressure increases, the FL intensity ratio between Pc molecule and excimer is enhanced. Considering the pressure induced phase transition from α-H<sub>2</sub>Pc to χ-H<sub>2</sub>Pc gradually, the change in FL spectrum should be due to the structure transformation. It is proved that the degree of overlapping between Pc molecules in α-H<sub>2</sub>Pc is larger than that in χ-H<sub>2</sub>Pc. We think, the degree of overlapping decreases under high pressure, which hinders the formation of excimer. It makes the excimer emission decrease and the FL of Pc molecules appear under high pressure. Our work can explain the relationship between Pc crystal structure and its fluorescence, reveals the kinetic behavior of macromolecules similar to Pc system under high pressure, and provides a new possibility of designing the photoelectric materials with excellent performances.

Superior Sensor for Be2+ Ion Recognition via the Unprecedented Octahedral Crystal Structure of a One-Dimensional Coordination Polymer of Crown Fused Zinc Phthalocyanine.

The unprecedented one-dimensional (1-D) coordination polymer of crown fused zinc phthalocyanine (P-CfZnPc) with an octahedral crystal structure and with intermolecular packing that has superior multichannel sensor ability for Be2+ ion recognition was prepared and characterized by single-crystal X-ray diffraction analysis (XRD) and a wide range of spectroscopic and voltammetric methods. An exceptional feature of the crystal structure of P-CfZnPc is that each zinc ion in the phthalocyanine (Pc) polymer is coordinated by the four isoindole nitrogen atoms and an outer oxygen atom of the Pc molecule. This structure is the first example of an octahedral arrangement in a 1-D polymeric chain for zinc phthalocyanines (ZnPcs) and zinc porphyrins (ZnPs) reached without the presence of a coordinating solvent, which was confirmed by XRD analysis. Interestingly, this (1-D) coordination polymer preserves its conformation in THF (tetrahydrofuran) solution, thereby effectively preventing aggregation. This result was confirmed by the particle size of the molecule (125 nm) using dynamic light scattering (DLS) and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectra as well as UV-vis spectroscopy. The sensor has long-term stability (more than 3 months in solution), a very low response time (less than 1 s), and nonaggregating ability, facilitating the accurate determination of ultra-trace amounts of Be2+ (lower than 1 ppb), which is extremely important in terms of human health and environmental protection. The sensor can highly selectively and sensitively bind Be2+ among Li+, Na+, K+, Cs+, Mg2+, Ca2+, Ba2+, Al3+, Co2+, Hg2+, Ni2+, Pb2+, and Zn2+ ions via Be2+-induced J aggregation of Pc molecules. Such a binding leads to not only a significant decrease in Pc absorption (677 nm) as well as the creation of new absorption (720 nm) but also fluorescence emission quenching (690 nm). Furthermore, the sensor displayed highly selective voltammetric recognition for Be2+ following J aggregation/disaggregation in the second reduction process. The binding mechanism of the sensor and Be2+ ion was also explained on the basis of TD-DFT calculations.

Substitute ftalosiyanin yüzeyinde amonyak adsorpsiyon kinetiği

The sensing performance of 2(3),9(10),16(17),23(24)- tetrakis-[4-nitro-2-(octyloxy)phenoxy]phthalocyaninato zinc(II) thin film towards ammonia and the influence of relative humidity on it were studied. The results show that the exposure to ammonia gas leads to an increase in sensor current, which is unexpected because of the strong electron donating character of ammonia and p-type semiconductivity of phthalocyanine. This unexpected behavior is related to the change in electronic band structure of the Pc molecule. It was observed that relative humidity enhances the ammonia adsorption. Several adsorption kinetics model were employed to represent the ammonia adsorption on the sensor surface. Analysis of the experimental data indicated that a simple adsorption model can be used to represent our adsorption system.

Noncovalent complexes of Ih−C80 fullerene with phthalocyanines

ABSTRACTThe noncovalent interactions of Ih−C80 fullerene with free-base and 3d transition M(II) phthalocyanines (where M = Mn, Fe, Co, Ni, Cu, Zn) were studied at the PBE-D/DNP level of density functional theory. The optimized complex geometries, formation energies and electronic parameters were analyzed and compared to those reported previously for similar dyads with C60. In the complexes with Ih−C80, the central metal atom (as well as one H atom of H2Pc) is always coordinated to a C6:6:6 atom of C80 cage, exhibiting only one general interaction pattern. The shortest M…CC80 and N…CC80 distances are notably longer than in dyads with C60, and the distortion of Pc macrocycle is less significant. In none of C80-based dyads the formation of new coordination bonds by metal atoms was observed. The bonding strength for Pc–C80 dyads varies approximately to the same degree of 20 kcal/mol as for their Pc–C60 analogues, however negative formation energies for Pc–C80 dyads are on average by 5–6 kcal/mol lower than for their C60 analogues. While in closed-shell Pc–fullerene systems HOMO is usually found totally on Pc molecule, in the case of C80-based dyads only a minor HOMO fraction can be detected for some dyads on Pc, with the major one always distributed over fullerene cage. As a result, the calculated HOMO-LUMO gap energies turn to be very low, around 0.1 eV. Analysis of spin density plots revealed that H2Pc+C80, NiPc+C80 and ZnPc+C80 dyads behave as closed-shell systems, like similar noncovalent complexes of Pcs with C60.