Theoretical investigation of nitric oxide interaction with aluminum phthalocyanine

Recent Advances in Phthalocyanine and Porphyrin-Based Materials as Active Layers for Nitric Oxide Chemical Sensors

Nitric oxide (NO) is a highly reactive toxic gas that forms as an intermediate compound during the oxidation of ammonia and is used for the manufacture of hydroxylamine in the chemical industry. Moreover, NO is a signaling molecule in many physiological and pathological processes in mammals, as well as a biomarker indicating the course of inflammatory processes in the respiratory tract. For this reason, the detection of NO both in the gas phase and in the aqueous media is an important task. This review analyzes the state of research over the past ten years in the field of applications of phthalocyanines, porphyrins and their hybrid materials as active layers of chemical sensors for the detection of NO, with a primary focus on chemiresistive and electrochemical ones. The first part of the review is devoted to the study of phthalocyanines and porphyrins, as well as their hybrids for the NO detection in aqueous solutions and biological media. The second part presents an analysis of works describing the latest achievements in the field of studied materials as active layers of sensors for the determination of gaseous NO. It is expected that this review will further increase the interest of researchers who are engaged in the current level of evaluation and selection of modern materials for use in the chemical sensing of nitric oxide.

Efficiency of water treatment with crushed shell of jatobá-do-cerrado (Hymenaea stigonocarpa) fruit to adsorb Cu(II) and Ni(II) ions: experimental and quantum chemical assessment of the complexation process

The shell surrounding fruits of the jatobá-do-cerrado tree, in its natural state, was modified by the addition of HNO₃ and NaOH and used as an adsorbent in the removal of Cu(II) and Ni(II) from aqueous solutions. The untreated (JIN) and chemically modified (JCT) fruit shell samples were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray diffraction. Their efficiency as adsorbents in the removal of Cu(II) and Ni(II) ions from aqueous solutions was studied under different conditions of pH (2-9) and it was observed that the optimal pH for Cu (II) adsorption was 5.5 and for Ni (II) it was 6.0. The adsorption isotherms were obtained at different temperatures (298, 308, 318 K) and the q_max values ranged from 33.96 to 41.00 mg g^-1. The adsorbents presented higher selectivity toward Cu ions (II). The thermodynamic analysis results suggest that the adsorption process studied is of a physical nature. Supported by quantum mechanical calculations, the interaction sites of the ion-cellulose and ion-lignin complexes were identified, evidencing the central role of water molecules in stabilization of the complexes. The experimental and theorical results indicate that JIN and JCT have good potential for the adsorption of Cu(II) and Ni(II) ions and are thus promising materials for the removal of other metal ions in aqueous systems.

A simple and facile bioinspired catalytic strategy to decolorize dye wastewater by using metal octacarboxyphthalocyanine particles

To explore the simple, facile, environmental friendly and low cost catalytic technique to decolorize harmful dye contaminants in solution and understand the mechanism is an interesting and practical research. In this paper, we provide a highly efficient and convenient method for fast decolorization of dyes (methylene blue and rhodamine B) in aqueous solution catalyzed by iron octacarboxyphthalocyanine (FeOCPc) or cobalt octacarboxyphthalocyanine (CoOCPc). Compared to the traditional methods, our method is very simple. The 30 mg/L methylene blue could be decolorized almost absolutely less than 30 min just by dispersing FeOCPc powders into the dye solution. The decolorization of rhodamine B at high concentration (30 mg/L) could be achieved to 100% decolorization degree less than 20 min in the presence of FeOCPc and tert-butyl hydroperoxide (BuOOH). Moreover, the ESR and HPLC-MS measurement were performed to determine the active radicals and various intermediates in decolorization processes and the possible catalytic mechanism was proposed. It is noted that both FeOCPc and CoOCPc catalysts show the different catalytic oxidation behaviors depending on the oxidant (O₂ or BuOOH). Our investigation provides a novel, low cost and convenient strategy to purify the environmental pollutions.

Rovibrational spectroscopic constants of the interaction between ammonia and metallo-phthalocyanines: a theoretical protocol for ammonia sensor design

We developed an adapted theoretical approach based on DFT calculations (B3LYP) and the nuclear Schrödinger equation using the Discrete Variable Representation method to model the interaction of ammonia with metallo-phthalocyanines.

Critical role of gap junction communication, calcium and nitric oxide signaling in bystander responses to focal photodynamic injury

Ionizing and nonionizing radiation affect not only directly targeted cells but also surrounding “bystander” cells. The underlying mechanisms and therapeutic role of bystander responses remain incompletely defined. Here we show that photosentizer activation in a single cell triggers apoptosis in bystander cancer cells, which are electrically coupled by gap junction channels and support the propagation of a Ca²⁺ wave initiated in the irradiated cell. The latter also acts as source of nitric oxide (NO) that diffuses to bystander cells, in which NO levels are further increased by a mechanism compatible with Ca²⁺-dependent enzymatic production. We detected similar signals in tumors grown in dorsal skinfold chambers applied to live mice. Pharmacological blockade of connexin channels significantly reduced the extent of apoptosis in bystander cells, consistent with a critical role played by intercellular communication, Ca²⁺ and NO in the bystander effects triggered by photodynamic therapy.

Reactive oxygen and nitrogen species disturb Ca(2+) oscillations in insulin-secreting MIN6 β-cells

Disturbances in pulsatile insulin secretion and Ca(2+) oscillations in pancreatic β-cells are early markers of diabetes, but the underlying mechanisms are still incompletely understood. Reactive oxygen/nitrogen species (ROS/RNS) are implicated in reduced β-cell function, and ROS/RNS target several Ca(2+) pumps and channels. Thus, we hypothesized that ROS/RNS could disturb Ca(2+) oscillations and downstream insulin pulsatility. We show that ROS/RNS production by photoactivation of aluminum phthalocyanine chloride (AlClPc) abolish or accelerate Ca(2+) oscillations in the MIN6 β-cell line, depending on the amount of ROS/RNS. Application of the sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) inhibitor thapsigargin modifies the Ca(2+) response to high concentrations of ROS/RNS. Further, thapsigargin produces effects that resemble those elicited by moderate ROS/RNS production. These results indicate that ROS/RNS interfere with endoplasmic reticulum Ca(2+) handling. This idea is supported by theoretical studies using a mathematical model of Ca(2+) handling adapted to MIN6 cells. Our results suggest a putative link between ROS/RNS and disturbed pulsatile insulin secretion.