ABSTRACT
Purpose: Mitochondrial damage may lead to uncontrolled oxidative stress and massive apoptosis, and thus plays a pivotal role in the pathological processes of myocardial ischemia-reperfusion (I/R) injury. However, it is difficult for the drugs such as puerarin (PUE) to reach the mitochondrial lesion due to lack of targeting ability, which seriously affects the expected efficacy of drug therapy for myocardial I/R injury. Methods: We prepared triphenylphosphonium (TPP) cations and ischemic myocardium-targeting peptide (IMTP) co-modified puerarin-loaded liposomes (PUE@T/I-L), which effectively deliver the drug to mitochondria and improve the effectiveness of PUE in reducing myocardial I/R injury. Results: In vitro test results showed that PUE@T/I-L had sustained release and excellent hemocompatibility. Fluorescence test results showed that TPP cations and IMTP double-modified liposomes (T/I-L) enhanced the intracellular uptake, escaped lysosomal capture and promoted drug targeting into the mitochondria. Notably, PUE@T/I-L inhibited the opening of the mitochondrial permeability transition pore, reduced intracellular reactive oxygen species (ROS) levels and increased superoxide dismutase (SOD) levels, thereby decreasing the percentage of Hoechst-positive cells and improving the survival of hypoxia-reoxygenated (H/R)-injured H9c2 cells. In a mouse myocardial I/R injury model, PUE@T/I-L showed a significant myocardial protective effect against myocardial I/R injury by protecting mitochondrial integrity, reducing myocardial apoptosis and decreasing infarct size. Conclusion: This drug delivery system exhibited excellent mitochondrial targeting and reduction of myocardial apoptosis, which endowed it with good potential extension value in the precise treatment of myocardial I/R injury.
Subject(s)
Isoflavones , Liposomes , Myocardial Reperfusion Injury , Organophosphorus Compounds , Animals , Liposomes/chemistry , Myocardial Reperfusion Injury/drug therapy , Isoflavones/chemistry , Isoflavones/pharmacology , Isoflavones/administration & dosage , Isoflavones/pharmacokinetics , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacology , Organophosphorus Compounds/administration & dosage , Organophosphorus Compounds/pharmacokinetics , Male , Mice , Apoptosis/drug effects , Reactive Oxygen Species/metabolism , Cations/chemistry , Myocardium/pathology , Myocardium/metabolism , Oxidative Stress/drug effects , Peptides/chemistry , Peptides/pharmacology , Peptides/administration & dosage , Drug Delivery Systems/methodsABSTRACT
Radiotherapy leverages ionizing radiation to kill cancer cells through direct and indirect effects, and direct effects are considered to play an equal or greater role. Several photosensitizers have been developed to mimic the direct effects of radiotherapy, generating radical cations in DNA models, but none has been applied in cellular studies. Here, we design a radiomimetic photosensitizer, producing DNA radical cations in cells for the first time. To reduce adverse effects, several redox-inducible precursors are prepared as cancer cells have elevated levels of GSH and H2O2. These precursors respond to GSH or H2O2, releasing the active photosensitizer that captures DNA abasic (AP) sites and generates DNA radical cations upon photolysis, without disrupting the redox state of cells. DNA radical cations migrate freely and are eventually trapped by H2O and O2 to yield DNA lesions, thus triggering DNA damage response. Our study suggests that direct effects of radiotherapy suppress cancer cell proliferation mainly by inducing G2/M phase cell cycle arrest, rather than promoting apoptosis. Synergistic effects of the precursor and chemotherapeutic agents are also observed in combination phototherapy. Beyond highlighting an alternative strategy for phototherapy, this proof-of-concept study affords a facile cellular platform to study the direct effects of radiotherapy.
ABSTRACT
The objective of this research was to develop and assess chitosan-grafted copolymer/HZSM5 zeolite Schiff base nanofibers for Cu2+ and Zn2+ adsorption from aqueous media. Nanofibers were prepared via electrospinning and characterized using XRD, FTIR, 1H NMR, FESEM, TGA, BET, and XPS. The study evaluated the effect of unmodified HZSM5 and Schiff base functionalization on adsorption capacities. Incorporating 10.0 wt% zeolite Schiff base as the optimum content into the chitosan-grafted copolymer significantly enhanced adsorption, achieving increases of 98.2 % for Zn2+ and 42.2 % for Cu2+. Specifically, Zn2+ adsorption increased from 27.6 to 54.7 mg/g, and Cu2+ from 67.1 to 95.4 mg/g. Factors such as temperature, pH, adsorption time, and initial cation concentration were analyzed. Kinetic studies revealed a double-exponential model, and isotherm analysis indicated a good fit with the Redlich-Peterson model, showing maximum monolayer capacities of 310.1 mg/g for Cu2+ and 97.8 mg/g for Zn2+ (pH 6.0, 240 min, 45 °C). The adsorption thermodynamics indicated a spontaneous and endothermic adsorption. Reusability tests showed minimal capacity loss (4.91 % for Cu2+ and 5.59 % for Zn2+) after five cycles. The nanofiber displayed greater selectivity for Cu2+ over Zn2+ in multi-ion systems and real electroplating wastewater, highlighting its potential for targeted heavy metal removal.
ABSTRACT
The title compound, bis-[di-thio-bis-(formamidinium)] hexa-bromido-ruthenium dibromide trihydrate, [(NH2)2CSSC(NH2)2]2[RuBr6]Br2·3H2O, crystallizes in the ortho-rhom-bic system, space group Cmcm, Z = 4. The [RuBr6]2- anionic complex has an octa-hedral structure. The Ru-Br distances fall in the range 2.4779â (4)-2.4890â (4)â Å. The S-S and C-S distances are 2.0282â (12) and 1.783â (2)â Å, respectively. The H2O mol-ecules, Br- ions, and NH2 groups of the cation are linked by hydrogen bonds. The conformation of the cation is consolidated by intra-molecular O-Hâ¯Br, O-Hâ¯O, N-Hâ¯Br and N-Hâ¯O hydrogen bonds. The [(NH2)2CSSC(NH2)2]2+ cations form a hydrogen-bonded system involving the Br - ions and the water mol-ecules. Two Br - anions form four hydrogen bonds, each with the NH2 groups of two cations, thus linking the cations into a ring. The rings are connected by water mol-ecules, forming N-Hâ¯O-Hâ¯Br hydrogen bonds.
ABSTRACT
In organic-inorganic hybrid perovskite solar cells (PSCs), hydrogen defects introduce deep-level trap states, significantly influencing non-radiative recombination processes. Those defects are primarily observed in MA-PSCs rather than FA-PSCs. As a result, MA-PSCs demonstrated a lower efficiency of 23.6% compared to 26.1% of FA-PSCs. In this work, both hydrogen vacancy (VH -) and hydrogen interstitial (Hi -) defects in MAPbI3 bulk and on surfaces, respectively are investigated. i) Bulk VH - defects have dramatic impact on non-radiative recombination, with lifetime varying from 67 to 8 ns, depending on whether deprotonated MA0 are ion-bonded or not. ii) Surface H-defects exhibited an inherent self-healing mechanism through a chemical bond between MA0 and Pb2+, indicating a self-passivation effect. iii) Both VH - and Hi - defects can be mitigated by alkali cation passivation; while large cations are preferable for VH - passivation, given strong binding energy of cation/perovskite, as well as, weak band edge non-adiabatic couplings; and small cations are suited for Hi - passivation, considering the steric hindrance effect. The dual passivation strategy addressed diverse experimental outcomes, particularly in enhancing performance associated with cation selections. The dynamic connection between hydrogen defects and non-radiative recombination is elucidated, providing insights into hydrogen defect passivation essential for high-performance PSCs fabrication.
ABSTRACT
Heparin-induced thrombocytopenia (HIT) is an antibody-mediated immune response against complexes of heparin and platelet factor 4 (PF4). The electrostatic interaction between heparin and PF4 is critical for the anti-PF4/heparin antibody response seen in HIT. The binding of metal cations to heparin induces conformational changes and charge neutralization of the heparin molecule, and cation-heparin binding can modulate the specificity and affinity for heparin-binding partners. However, the effects of metal cation binding to heparin in the context of anti-PF4/heparin antibody response have not been determined. Here, we utilized inductively coupled plasma mass spectrometry (ICP-MS) to quantify 16 metal cations in patient plasma and tested for correlation with anti-PF4/heparin IgG levels and platelet count after clinical suspicion of HIT in a cohort of heparin-treated patients. The average age of the cohort (n = 32) was 60.53 (SD = 14.31) years old, had a mean anti-PF4/heparin antibody optical density [OD405] of 0.93 (SD = 1.21) units, and was primarily female (n = 23). Patients with positive anti-PF4/heparin antibody test results (OD405 ≥ 0.5 units) were younger, had increased weight and BMI, and were more likely to have a positive serotonin release assay (SRA) result compared to antibody-negative patients. We observed statistical differences between antibody-positive and -negative groups for sodium and aluminum and significant correlations of anti-PF4/heparin antibody levels with sodium and silver. While differences in sodium concentrations were associated with antibody-positive status and correlated with antibody levels, no replication was performed. Additional studies are warranted to confirm our observed association, including in vitro binding studies and larger observational cohorts.
Subject(s)
Anticoagulants , Heparin , Platelet Factor 4 , Thrombocytopenia , Humans , Platelet Factor 4/immunology , Thrombocytopenia/chemically induced , Thrombocytopenia/immunology , Thrombocytopenia/blood , Thrombocytopenia/diagnosis , Female , Heparin/adverse effects , Heparin/immunology , Middle Aged , Male , Aged , Anticoagulants/adverse effects , Anticoagulants/immunology , Immunoglobulin G/blood , Immunoglobulin G/immunology , Platelet Count , Autoantibodies/blood , Adult , Metals , Biomarkers/bloodABSTRACT
This review article is aimed at providing updated information on the contribution of immediate and delayed oxidative reactions to the photo-induced damage to cellular DNA/skin under exposure to UVB/UVA radiations and visible light. Low-intensity UVC and UVB radiations that operate predominantly through direct excitation of the nucleobases are very poor oxidizing agents giving rise to very low amounts of 8-oxo-7,8-dihydroguanine and DNA strand breaks with respect to the overwhelming bipyrimidine dimeric photoproducts. The importance of these two classes of oxidatively generated damage to DNA significantly increases together with a smaller contribution of oxidized pyrimidine bases upon UVA irradiation. This is rationalized in terms of sensitized photooxidation reactions predominantly mediated by singlet oxygen together with a small contribution of hydroxyl radical that appear to also be implicated in the photodynamic effects of the blue light component of visible light. Chemiexcitation-mediated formation of "dark" cyclobutane pyrimidine dimers in UVA-irradiated melanocytes is a recent major discovery that implicates in the initial stage, a delayed generation of reactive oxygen and nitrogen species giving rise to triplet excited carbonyl intermediate and possibly singlet oxygen. High-intensity UVC nanosecond laser radiation constitutes a suitable source of light to generate pyrimidine and purine radical cations in cellular DNA via efficient biphotonic ionization.
ABSTRACT
2D-3D tin-based perovskites are considered as promising candidates for achieving efficient lead-free perovskite solar cells (PSCs). However, the existence of multiple low-dimensional phases formed during the film preparation hinders the efficient transport of charge carriers. In addition, the non-homogeneous distribution of low-dimensional phases leads to lattice distortion and increases the defect density, which are undesirable for the stability of tin-based PSCs. Here, mixed spacer cations [diethylamine (DEA+) and phenethylamine (PEA+)] are introduced into tin perovskite films to modulate the distribution of the 2D phases. It is found that compared to the film with only PEA+, the combination of DEA+ and PEA+ favors the formation of homogeneous low-dimensional perovskite phases with three octahedral monolayers (n = 3), especially near the bottom interface between perovskite and hole transport layer. The homogenization of 2D phases help improve the film quality with reduced lattice distortion and released strain. With these merits, the tin PSC shows significantly improved stability with 94% of its initial efficiency retained after storing in a nitrogen atmosphere for over 4600 h, and over 80% efficiency maintained after continuous illumination for 400 h.
ABSTRACT
Microbial strain improvement through adaptive laboratory evolution (ALE) has been a key strategy in biotechnology for enhancing desired phenotypic traits. In this Biotech Method paper, we present an accelerated ALE (aALE) workflow and its successful implementation in evolving Cupriavidus necator H16 for enhanced tolerance toward elevated glycerol concentrations. The method involves the deliberate induction of genetic diversity through controlled exposure to divalent metal cations, enabling the rapid identification of improved variants. Through this approach, we observed the emergence of robust variants capable of growing in high glycerol concentration environments, demonstrating the efficacy of our aALE workflow. When cultivated in 10% v/v glycerol, the adapted variant Mn-C2-B11, selected through aALE, achieved a final OD600 value of 56.0 and a dry cell weight of 15.2 g L-1, compared to the wild type (WT) strain's final OD600 of 39.1 and dry cell weight of 8.4 g L-1. At an even higher glycerol concentration of 15% v/v, Mn-C2-B11 reached a final OD600 of 48.9 and a dry cell weight of 12.7 g L-1, in contrast to the WT strain's final OD600 of 9.0 and dry cell weight of 3.1 g L-1. Higher glycerol consumption by Mn-C2-B11 was also confirmed by high-performance liquid chromatography (HPLC) analysis. This adapted variant consumed 34.5 times more glycerol compared to the WT strain at 10% v/v glycerol. Our method offers several advantages over other reported ALE approaches, including its independence from genetically modified strains, specialized genetic tools, and potentially carcinogenic DNA-modifying agents. By utilizing divalent metal cations as mutagens, we offer a safer, more efficient, and cost-effective alternative for expansion of genetic diversity. With its ability to foster rapid microbial evolution, aALE serves as a valuable addition to the ALE toolbox, holding significant promise for the advancement of microbial strain engineering and bioprocess optimization.
Subject(s)
Cupriavidus necator , Glycerol , Cupriavidus necator/genetics , Cupriavidus necator/metabolism , Glycerol/metabolism , Glycerol/chemistry , Cations, Divalent , Directed Molecular Evolution/methodsABSTRACT
Establishing unprecedented types of bonding interactions is one of the fundamental challenges in synthetic chemistry, paving the way to new (electronic) structures, physicochemical properties, and reactivity. In this context, unsupported element-element interactions are particularly noteworthy since they offer pristine scientific information about the newly identified structural motif. Here we report the synthesis, isolation, and full characterization of the heterobimetallic Bi / Pt compound [Pt(PCy3)2(BiMe2)(SbF6)] (1), bearing the first unsupported transition metalâbismuth donor/acceptor interaction as its key structural motif. 1 is surprisingly robust, its electronic spectra are interpreted in a fully relativistic approach, and it reveals an unprecedented reactivity towards H2.
ABSTRACT
BACKGROUND: Transfusion-dependent thalassemia (TDT) is a severe form of beta-thalassemia, characterized by defective-globin production, resulting in a buildup of unpaired alpha globin chains. Patients with TDT can only survive if they receive safe blood transfusions regularly, which causes iron overload in their blood, which causes a variety of disorders. Cations and trace elements in TDT patients as a drug target deserve more studies. OBJECTIVES: In the present study, the cations and some trace elements were studied in TDT patients as a tool to adjust their level in the case of any disturbances. METHODS: Serum calcium, magnesium, zinc, copper, and iron were measured spectrophotometrically while manganese and cobalt were measured by flameless atomic absorption spectroscopy in 100 TDT patients and compared with 35 healthy control children. RESULTS: Patients with TDT exhibit a notable elevation in blood levels of iron, copper, copper/zinc ratio, and manganese, with a substantial reduction in serum levels of zinc, magnesium, calcium, and cobalt, as compared to the control group. These minerals have diverse associations with clinical data and transfusion frequencies. The receiver operating characteristic (ROC) analysis revealed that the elevated levels of iron, manganese, and calcium exhibit the greatest diagnostic capability, with a sensitivity and specificity of over 80 %, and a Youdin's J value of more than 0.6. CONCLUSION: The levels of cations and trace elements are disturbed in TDT patients. Hence, the monitoring and adjustment of the level of these minerals are important to prevent further consequences.
Subject(s)
Thalassemia , Trace Elements , Humans , Female , Male , Trace Elements/blood , Child , Thalassemia/blood , Thalassemia/therapy , Blood Transfusion/methods , Adolescent , Child, Preschool , Cations/bloodABSTRACT
Background: Phosphorus in the soil is mostly too insoluble for plants to utilize, resulting in inhibited aboveground biomass, while Carex can maintain their aboveground biomass through the presence of dauciform roots. However, dauciform roots lead to both morphological and physiological changes in the root system, making their primary mechanism unclear. Methods: A greenhouse experiment was conducted on three Carex species, in which Al-P, Ca-P, Fe-P, and K-P were employed as sole phosphorus sources. The plants were harvested and assessed after 30, 60 and 90 days. Results: (1) The density of dauciform roots was positively correlated with root length and specific root length, positively influencing aboveground biomass at all three stages. (2) The aboveground phosphorus concentration showed a negative correlation with both dauciform root density and aboveground biomass in the first two stages, which became positive in the third stage. (3) Aboveground biomass correlated negatively with the aboveground Al concentration, and positively with Ca and Fe concentration (except Al-P). (4) Root morphological traits emerged as critical factors in dauciform roots' promotion of aboveground biomass accumulation. Conclusion: Despite the difference among insoluble phosphorus, dauciform roots have a contributing effect on aboveground growth status over time, mainly by regulating root morphological traits. This study contributes to our understanding of short-term variation in dauciform roots and their regulatory mechanisms that enhance Carex aboveground biomass under low available phosphorus conditions.
ABSTRACT
Only few excipients are known to be suitable as pelletization aids. In this study, the potential use of croscarmellose sodium (CCS) as pelletization aid was investigated. Furthermore, the impact of cations on extrusion-spheronization (ES) of CCS was studied and different grades of CCS were tested. The influence of different cations on the swelling of CCS was investigated by laser diffraction. Mixtures of CCS with lactose monohydrate as filler with or without the inclusion of different cations were produced. The mixtures were investigated by mixer torque rheometry and consequently extruded and spheronized. Resulting pellets were analyzed by dynamic image analysis. In addition, mixtures of different CCS grades with dibasic calcium phosphate anhydrous (DP) and a mixture with praziquantel (PZQ) as filler were investigated. Calcium and magnesium cations caused a decrease of the swelling of CCS and influenced the use of CCS as pelletization aid since they needed to be included for successful ES. Aluminum, however, led to an aggregation of the CCS particles and to failure of extrusion. The inclusion of cations decreased the uptake of water by the mixtures which also reduced the liquid-to-solid-ratio (L/S) for successful ES. This was shown to be dependent on the amount of divalent cations in the mixture. With DP or PZQ as filler, no addition of cations was necessary for a successful production of pellets, however the optimal L/S for ES was dependent on the CCS grade used. In conclusion, CCS can be used as a pelletization aid.
Subject(s)
Excipients , Particle Size , Excipients/chemistry , Drug Compounding/methods , Calcium Phosphates/chemistry , Lactose/chemistry , Chemistry, Pharmaceutical/methods , Cations/chemistry , Praziquantel/chemistry , Magnesium/chemistryABSTRACT
The stable operation of the CO2 reduction reaction (CO2RR) in membrane electrode assembly (MEA) electrolyzers is known to be hindered by the accumulation of bicarbonate salt, which are derived from alkali metal cations in anolytes, on the cathode side. In this study, we conducted a quantitative evaluation of the correlation between the CO2RR activity and the transported alkali metal cations in MEA electrolyzers. As a result, although the presence of transported alkali metal cations on the cathode surface significantly contributes to the generation of C2+ compounds, the rate of K+ ion transport did not match the selectivity of C2+, suggesting that a continuous supply of high amount of K+ to the cathode surface is not required for C2+ formation. Based on these findings, we achieved a faradaic efficiency (FE) and a partial current density for C2+ of 77 % and 230â mA cm-2, respectively, even after switching the anode solution from 0.1â M KHCO3 to a dilute K+ solution (<7â mM). These values were almost identical to those when 0.1â M KHCO3 was continuously supplied. Based on this insight, we successfully improved the durability of the system against salt precipitation by intermittently supplying concentrated KHCO3, compared with the continuous supply.
ABSTRACT
A selective deelectronation reagent with very high potential of +2.00 (solution)/+2.41â V (solid-state) vs. Fc+/0 and based on a room temperature stable perfluoronaphthalene (naphthaleneF) radical cation salt was developed and applied. The solid-state deelectronation of commercial naphthaleneF with [NO]+[F{Al(ORF)3}2]- generates [naphthaleneF]+â [F{Al(ORF)3}2]- (ORF=OC(CF3)3) in gram scale. Thermochemical analysis unravels the solid-state deelectronation potential of the starting [NO]+-reagent to be +2.34â V vs. Fc+/0 with [F{Al(ORF)3}2]- counterion, but only +1.14â V vs. Fc+/0 with the small [SbF6]- ion. Selective reactions demonstrate the selectivity of [naphthaleneF]+â for deelectronation of a multitude of organ(ometall)ic molecules and elements in solution: providing the molecular structures of the acene dications [tetracene]2+, [pentacene]2+ or spectroscopic evidence for the carbonyl complex of the ferrocene dication [Fc(CO)]2+, the [P9]+ cation from white phosphorus, the solvent-free copper(I) salt starting from copper metal and the dicationic Fe(IV)-scorpionate complex [Fe(sc)2]2+.
ABSTRACT
Transporters for organic cations (OCs) facilitate exchange of positively charged molecules through the plasma membrane. Substrates for these transporters encompass neurotransmitters, metabolic byproducts, drugs, and xenobiotics. Consequently, these transporters actively contribute to the regulation of neurotransmission, cellular penetration and elimination process for metabolic products, drugs, and xenobiotics. Therefore, these transporters have significant physiological, pharmacological, and toxicological implications. In cells of renal proximal tubules, the vectorial secretion pathways for OCs involve expression of organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs) on basolateral and apical membrane domains, respectively. This review provides an overview of documented regulatory mechanisms governing OCTs and MATEs. Additionally, regulation of these transporters under various pathological conditions is summarized. The expression and functionality of OCTs and MATEs are subject to diverse pre- and post-translational modifications, providing insights into their regulation in various pathological conditions. Typically, in diseases, downregulation of transporter expression is observed, probably as a protective mechanism to prevent additional damage to kidney tissue. This regulation may be attributed to the intricate network of modifications these transporters undergo, shedding light on their dynamic responses in pathological contexts.
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In this paper we revisit earlier work relating to monoatomic atoms and ions published by pioneers in the area of electrostatic potentials. We include plots of the radial distributions of the electrostatic potentials for spherically symmetric atoms and cations, and for singly, doubly and triply negative anions. For atoms with anisotropy in their densities and electrostatic potentials, such as the halonium cations, it is shown how the molecular surface approach for plotting electrostatic potentials complements that achieved by directional radial distributions.
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The ongoing advancements in lithium-ion battery technology are pivotal in propelling the performance of modern electronic devices and electric vehicles. Amongst various components, the cathode material significantly influences the battery performance, such as the specific capacity, capacity retention and the rate performance. Ternary cathode materials, composed of nickel, manganese, and cobalt (NCM), offer a balanced combination of these traits. Recent developments focus on elemental doping, which involves substituting a fraction of NCM constituent ions with alternative cations such as aluminum, titanium, or magnesium. This strategic substitution aims to enhance structural stability, increase capacity retention, and improve resistance to thermal runaway. Doped ternary materials have shown promising results, with improvements in cycle life and operational safety. However, the quest for optimal doping elements and concentrations persists to maximize performance while minimizing cost and environmental impact, ensuring the progression towards high-energy-density, durable, and safe battery technologies.
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Infrared (IR) emission bands by interstellar polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic nitrogen heterocycles (PANHs) are observed towards a large variety of interstellar objects and offer detailed insights into the chemistry and physics of the interstellar medium. The analysis of the emission bands, and thus the interpretation of the molecular characteristics of the carriers, heavily relies on the use of density functional theory (DFT) calculated IR spectra. However, there are significant challenges in accurately predicting the experimental IR band positions, particularly for PANH emission vibrational modes around 6â µm. In this work, we present gas-phase mid-infrared (mid-IR) spectra of cationic 3-azafluoranthene (3AFâ +) and protonated 3-azafluoranthene (3AFH+) to investigate their experimental IR band positions in relation to DFT calculated bands. The experimental spectra are compared to DFT simulated spectra, where different approaches were followed to correct for anharmonicities. The best agreement is achieved by scaling frequencies of modes with large nitrogen displacements with a different factor. Even though our findings might be limited to a small number of PANH structures, they indicate, that nitrogen atom incorporation needs to be accounted for by carefully adjusting the corresponding scaling factors while computing IR spectra of PANHs on DFT level.
ABSTRACT
Cyclophane-type dications with two units of xanthylium were designed, with the expectation that intramolecular interaction between cation units could induce changes in absorption and redox behavior. The desired dications were synthesized via the macrocyclic diketone as a key intermediate, which was efficiently obtained by a stepwise etherification. X-ray and UV/Vis measurements revealed that the cyclophane-type dications adopt a stacking structure in both the crystal and solution. Due to the intramolecular interaction caused by π-π stacking of the xanthylium units, a considerable blue shift compared to the corresponding monocations and a two-stage one-electron reduction process were observed in the dications. Furthermore, upon electrochemical reduction of dications, the formation of biradicals via radical cation species was demonstrated by UV/Vis spectroscopy with several isosbestic points at both stages. Therefore, the cation-stacking approach is a promising way to provide novel properties due to perturbation of their molecular orbitals and to stabilize the reduced species even though they have open-shell characters.