Nitrogen Position Research Articles

Self‐Assembled Bent Perylenediimides

The properties of π‐functional materials are predominantly influenced by both their molecular structures and interactions between π‐systems. Recent advancements have focused on modifying the geometry or topology of π‐molecules from planar to nonplanar conformations to tailor molecular properties. However, the interactions among nonplanar π‐molecules remain largely unexplored, likely due to the significant reduction in contact surfaces arising from their curved structures. Herein, we investigated the electro‐optical properties and π‐stacking behaviors of a series of bent perylenediimides (B‐PDIs) with gradual changes in bending angles, achieved by altering the lengths of linear alkyl chains connecting the two nitrogen positions of each PDI. Curvature‐dependent self‐assembly of these bent PDIs is observed, which is primarily driven by dipole‐dipole interactions rather than dispersion forces. More importantly, fine‐tuning intermolecular coupling through bending enables excited‐state symmetry‐breaking charge separation in [n]B‐PDIs (n = 16, 12) in the crystalline solid state.

Self-Assembled Bent Perylenediimides.

The properties of π-functional materials are predominantly influenced by both their molecular structures and interactions between π-systems. Recent advancements have focused on modifying the geometry or topology of π-molecules from planar to nonplanar conformations to tailor molecular properties. However, the interactions among nonplanar π-molecules remain largely unexplored, likely due to the significant reduction in contact surfaces arising from their curved structures. Herein, we investigated the electro-optical properties and π-stacking behaviors of a series of bent perylenediimides (B-PDIs) with gradual changes in bending angles, achieved by altering the lengths of linear alkyl chains connecting the two nitrogen positions of each PDI. Curvature-dependent self-assembly of these bent PDIs is observed, which is primarily driven by dipole-dipole interactions rather than dispersion forces. More importantly, fine-tuning intermolecular coupling through bending enables excited-state symmetry-breaking charge separation in [n]B-PDIs (n = 16, 12) in the crystalline solid state.

Exploring the Electronic Interactions of Adenine, Cytosine, and Guanine with Graphene: A DFT Study.

This study has provided new insights into the interaction between graphene and DNA nucleobases (adenine, cytosine, and guanine). It compares how each nucleobase interacts with graphene, examining their selectivity and binding energy. The research also explores how these interactions impact the electronic properties of graphene, showing potential applications in graphene-based biosensors and DNA sequencing technologies. Additionally, the findings suggest potential uses in DNA sensing and the functionalization of graphene for various biomedical applications. This study employs density functional theory (DFT) methods, utilizing the B3LYP functional with the 6-311G basis set, to explore the electronic interactions between DNA nucleobases (adenine, cytosine, and guanine) with pure graphene (Gr). We investigate various properties, including adsorption energy, HOMO-LUMO energy levels, charge transfer mechanisms, dipole moments, energy gaps, and density of states (DOS). Our findings indicate that cytosine interacts most favorably with graphene through its oxygen site (Gr-Cyt-O), exhibiting the strongest adsorption. Additionally, adenine's interaction significantly enhances its electronegativity and chemical potential, particularly at the nitrogen position, while decreasing its electrophilicity. Guanine, characterized by the smallest energy gap, demonstrates the highest conductivity among the nucleobases. These results suggest that graphene possesses advantageous properties as an adsorbent for guanine, highlighting its potential applications in biosensor technology.

Quinoline Substituted Anthracene Isomers: A Case Study for Simultaneously Optimizing High Mobility and Strong Luminescence in Herringbone-Packed Organic Semiconductors.

The development of high mobility emissive organic semiconductors is significant for advancing optoelectronic devices with simplified architecture and enhanced performance. The herringbone-packed structure is regarded as the ideal arrangement for simultaneously achieving high mobility and strong emission in organic semiconductors. However, it remains a great challenge that the relationship between molecular structure and optoelectronic property is still elusive. Herein, four quinoline-substituted anthracene isomers were designed and synthesized by introducing quinoline groups to anthracene core. Their intermolecular interactions and packing mode in the herringbone-packed structures were regularly tuning by subtle changing the nitrogen position on quinoline group, resulting in the superior integration of optoelectronic properties. Through a comprehensive analysis of aggregation states and optoelectronic properties, we revealed that in herringbone-packed aggregates, a centroid distance of approximately 7-7.5 Å along CH-π direction and 6-6.5 Å along π-π direction is beneficial for simultaneously achieving high mobility and strong emission. These properties are closely related to the molecular twist angles, which are influenced by intramolecular interactions. This structure-property relationship has been further validated in other herringbone-packed high mobility emissive organic semiconductors, demonstrating its broad applicability and universal potential. This work figures out the practical molecular design principle for high mobility emissive organic semiconductors.

Role of Pyridine Nitrogen Position on the Moisture Sensitivity of Organic Emitters.

Moisture-sensitive fluorescent emitters are a class of smart materials that can change their emission behavior upon exposure to water. In this study, we have synthesized two highly fluorescent organic emitters, 4BPy-PTA and 2BPy-PTA, and showed how moisture sensitivity can be enhanced by molecular design modification. Owing to the different nitrogen atom positions in the acceptor units, the emitters show different degrees of moisture sensitivity. Upon moisture exposure, both emitters change their emission color from greenish-yellow to blue, but a larger shift was witnessed in 4BPy-PTA (81 nm) than in 2BPy-PTA (68 nm). Moisture exposure enhances the photoluminescence quantum yield (PLQY) of 4BPy-PTA from 37 to 48%, whereas it suppresses the PLQY of 2BPy-PTA from 59 to 15%. A shorter moisture sensing time, large emission color shift, and enhanced PLQY make 4BPy-PTA a better moisture-sensitive material than 2BPy-PTA. Interestingly, the emission colors of the emitters can be completely regained by heating and partially by applying mechanical force to the moisture-exposed solids. In addition, these emitters also show mechanochromic luminescence behavior with a completely reversible emission color switch between blue and green.

Analogous Chelation to Boost Utilization of Sb in Sb Nanoparticles and N-doped Carbon Composites for Enhancing Potassium Storage.

Antimony (Sb) is an attractive anode material for potassium-ion batteries (PIBs), but it suffers from aggregation during the charging-discharging process, thus causing embedded active sites and collapsed structure. The analogous chelation refers to the reaction in which the central nanoparticle is linked to the matrix through multiple coordination bonds to form a stable composite. This strategy can inhibit aggregation and maintain the nanosized structure of Sb, thus activating the utilization of Sb active sites and structural stability. Given the special position of nitrogen (N) in the periodic table of elements and the strong bond energy of Sb-N, the N element can serve as an intermediate to connect Sb nanoparticles and an intrinsic N-doped carbon network via strong Sb-N-C/Sb-N═C covalent bonds using analogous chelation. Herein, a hybrid material of Sb@CTF-NC is fabricated via analogous chelation. The Sb atoms exposed on the surface of Sb nanoparticles are used to chelate with the N-doped carbon for high-performance PIBs. The mechanism underwent ex situ characterizations. The calculation of density functional theory reveals that the increase of adsorption energy and reduction of the K+ diffusion barrier accelerate the electrochemical reaction kinetics.

Controlling the asphaltene precipitation behaviors by changing the position and number of nitrogen in the aromatic heterocyclic pendant of polymers with the assistance of DFT calculations

AbstractAs the largest component in crude oil, asphaltenes are apt to settle out and result in the blockage of pipeline during production and transportation, which largely reduces the safety and economic benefits. In this study, a series of poly(maleic anhydride‐octadecene)s (PMO) amidated by pyrimidine (MD), pyrazine (BQ), pyrazole (BZ), triazole (3DZ), triazine (6J3Q), phenyl triazine (6B3Q) and pyrazolo pyridine (ZBD) were synthesized. The interaction energies between the different polymers and asphaltene were calculated by using density functional theory (DFT). It shows that the greater the number of nitrogen‐containing groups and rings, the higher the interaction energy. Moreover, the position of the nitrogen on the aromatic ring also impacts the interaction energy. The interaction energy between asphaltene and polymer with adjacent N (PMO‐BZ) is larger than that with para‐N (PMO‐BQ) and interstitial N (PMO‐MD). In addition, the performance of polymers on asphaltene precipitation from model oil and crude oil is explored by UV–Vis spectroscopy, turbidity, dynamic light scattering (DLS) and rheological methods. The performance of polymers follows the sequence of PMO‐BZ > PMO‐6J3Q > PMO‐BQ > PMO‐MD > PMO‐6B3Q > PMO‐ZBD, which is not consistent with the change of interaction energy. Apparently, the efficiency of the polymer increases and then declines with the increase of interaction energy. Notably, the polymer (PMO‐BZ) containing monocyclic ring with adjacent N increased the IPP of asphaltenes from 0.363 to 0.800 and reduced the particle size from 1527.2 to 99.7 nm. The interaction energies of PMO‐BZ and PMO‐6J3Q with asphaltene are in the range of 15.87–17.04 KJ/mol, and the polymers with interaction energies in this range are more effective on asphaltene inhibition than the others. Consequently, the interaction energies obtained from DFT calculations can be used to guide the design and synthesis of polymers with nitrogen‐containing heterocyclic pendant for asphaltene inhibition.

N‐methylation of histidine to tune tautomeric preferences in histidine‐heme coordination and enzyme‐mimetic catalysis

AbstractEnzymes with active sites involving histidine selectively utilize either the δ‐ or ε‐nitrogen atom (Nδ or Nε) of the histidine imidazole for catalysis. However, evaluating the impact of Nδ and Nε is difficult, and directly integrating noncanonical N‐methylated histidine within enzymes poses risks due to laborious procedures. In this study, we present the self‐assembly of Fmoc‐Histidine (Fmoc‐His) with hemin to create a peroxidase‐mimetic catalyst, in which either the Nε or Nδ of histidine is methylated to modify the tautomeric preferences, thereby tuning hemin catalysis. UV‐vis spectra, 1H‐NMR, and fluorescence experiments elucidate that the N‐methylation of histidine alters the self‐assembly propensity of Fmoc‐His, and affects the binding affinity of histidine to hemin iron, with Fmoc‐δmHis/hemin exhibiting stronger binding than Fmoc‐εmHis/hemin. Theoretical simulation results suggest that εmHis and δmHis ligation produce a saddled structure and planar structure of hemin, respectively, stemming from the disparity of steric hindrance at the Nε and Nδ positions. The significant inhibition of hemin's oxidative activity by Fmoc‐δmHis is observed, likely due to the strong binding of Fmoc‐δmHis, potentially hindering access of the substrate, H2O2, to the hemin iron. Conversely, Fmoc‐εmHis enhances hemin catalysis, surpassing even Fmoc‐His alone. This differential impact of Fmoc‐εmHis and Fmoc‐δmHis on hemin activity is further corroborated by apparent activation energy and kinetic parameters (kcat, kcat/Km). This study sheds light on the heterogeneous biological effects at the nitrogen positions of histidine imidazole and offers insights into designing supramolecular metalloenzymes.

Dual responsive behaviors in fluorescence of molecular crystals based on naphthalene pyridyl derivatives

Three compounds based on naphthalene and pyridine structures with different nitrogen positions (NP-2, NP-3, and NP-4) were synthesized. Except for displaying aggregation-induced emission (AIE) properties, the solution and crystals of these compounds show reversible fluorescence changes under alternative acid and base treatments. Experimental results, including X-ray diffraction, optical spectroscopy measurements, and cross-polarized microscope characterization, suggested that compounds might undergo reversible crystal-to-crystal transition upon external acid and base stimuli. It also revealed that the position of the heteroatom nitrogen in the pyridine unit significantly affected the intra- and intermolecular interactions, leading to restricted-intermolecular motions (RIMs) that caused the AIE effect. Besides, computational calculations indicated significant changes in molecular geometries and electronic interactions between the initial states and the protonated states. An information encryption system involving activation and operation codes was established based on the multiple stimuli-responsive properties. Our work not only presents a facile way to develop multiple responsive properties in molecular crystal systems but also explores their potential as highly emissive functional dyes for future applications.

Influence of Nitrogen Position on the Electrocatalytic Performance of B,N-Codoped Carbon Quantum Dots for the Oxygen Reduction Reaction

Nanocomposites containing B,N-codoped carbon quantum dots (CQDs) and an anion exchange ionomer based on poly(2,6-dimethylpolyphenyleneoxide) with trimethylammonium groups on long side chains (PPO-LC) were studied as catalytic electrodes for the oxygen reduction reaction (ORR). The objective was to reveal the impact of graphitic vs pyridinic/pyrrolic nitrogen on the ORR electrocatalysis. The CQDs were prepared by hydrothermal synthesis and analyzed by X-ray photoelectron spectroscpy to ascertain the B and N content and their position. The electrodes were prepared by drop-casting an ink of CQDs and PPO-LC on acid-treated carbon paper support. Characterizations of the electrodes included water contact angle, capacitance measurements, Fourier transform infrared spectra as well as scanning electron microscopy and optical microscopy. The onset and half-wave potentials, limiting current densities, Koutecky-Levich and Tafel plots revealed that the sample with only pyridinic/pyrrolic nitrogen showed the lowest electrocatalytic performance, underlining the importance of graphitic nitrogen for good ORR activity. Four-electron reduction was observed for the samples containing graphitic nitrogen. The onset potential (0.92 V/RHE) was among the best in the literature for carbonaceous materials. Finally, durability tests were performed indicating a good long-time stability of the electrodes; the electrode degradation was analyzed by impedance spectroscopy.

Air-Stable and Eco-Friendly Symmetrical Imine with Thiadiazole Moieties in Neutral and Protonated form for Perovskite Photovoltaics.

This paper proposes molecular and supramolecular concepts for potential application in perovskite solar cells. New air-stable symmetrical imine, with thiadiazole moieties PPL2: (5E,6E)-N2,N5-bis(4-(diphenylamino)benzylidene)-1,3,4-thiadiazole-2,5-diamine), as a hole-transporting material was synthesised in a single-step reaction, starting with commercially available and relatively inexpensive reagents, resulting in a reduction in the cost of the final product compared to Spiro-OMeTAD. Moreover, camphorsulfonic acid (CSA) in both enantiomeric forms was used to change the HOMO-LUMO levels and electric properties of the investigated imine-forming complexes. Electric, optical, thermal, and structural studies of the imine and its complexes with CSA were carried out to characterise the new material. Imine and imine/CSA complexes were also characterised in depth by the proton Nuclear Magnetic Resonance 1H NMR method. The position of nitrogen in the thidiazole ring influences the basicity of donor centres, which results in protonation in the imine bond. Simple devices of ITO/imine (with or without CSA(-) or CSA(+))/Ag/ITO architecture were constructed, and a thermographic camera was used to find the defects in the created devices. Electric behaviour was also studied to demonstrate conductivity properties under the forward current. Finally, the electrical properties of imine and its protonated form with CSA were compared with Spiro-OMeTAD. In general, the analysis of thermal images showed a very similar response of the samples to the applied potential in terms of the homogeneity of the formed organic layer. The TGA analysis showed that the investigated imine exhibits good thermal stability in air and argon atmospheres.

Macrocycle-based covalent-organic-polymer as efficient oxygen electrocatalysts for zinc-air flow batteries

Covalent organic polymers (COPs), as emerging porous materials with well-defined architectures and high hydrothermal stability, have attracted extensive attention in the field of electrocatalysis. Herein, we report a rational design method for preparing oxygen reduction reaction electrocatalysts with the assistance of a predesigned macrocyclic COP model molecular. With the predesigned nitrogen position and structural features in macrocyclic chain-like COP-based materials, the obtained COPMCT-Co-900 catalyst provided excellent oxygen reduction performance, where the half-wave potential (E1/2) reaches 0.85 V (vs . RHE), comparable to commercial Pt/C. We also extended the strategy to similar macrocycle COPs and Fe-based and Ni-based metal sources and studied the oxygen reduction reaction performance of corresponding catalysts, proving the universality of the method. Interestingly, we assemble COPMCT-Co-900 catalyst as air electrode catalyst of the self-made rechargeable zinc-air flow batteries, which exhibit outstanding power density (155.6 mW·cm-2) and long cycle life (90 h, 270 cycles at 10 mA·cm-2). Our studies provide a new method for the development of high-performance oxygen electrodes applied in zinc-air flow battery devices.

Influence of low-density polyethylene addition on nitrogen transformation during sludge protein pyrolysis

Co-pyrolysis of sludge and waste plastics is a long-term strategic approach for producing valuable fuels. However, sludge is characterized by a high protein content, which serves as a significant source of nitrogenous components in bio-oil. To improve the quality of pyrolysis products, the present study investigated the effect of low-density polyethylene (LDPE) on nitrogen transformation during the pyrolysis of sludge protein (SP). The study findings indicated that LDPE addition reduced the amount of solid residue owing to the interaction between SP and H radicals generated by LDPE pyrolysis. The thermal weight loss difference consistently remained below 0 when the SP-to-LDPE mixing ratio was 7:3, indicating that LDPE promotes the pyrolysis of SP. For the analysis of nitrogen-containing products during pyrolysis, LDPE addition significantly reduced the levels of nitrogen-containing compounds in the bio-oils of glutamate (Glu), histidine (His), and tyrosine (Tyr). Specifically, at 600°C, Glu, His, and Tyr in the bio-oils decreased by 31.4%, 33.3%, and 34.38%, respectively. No significant changes were observed in the nitrogen content within the pyrolysis char of Glu and His. However, all three amino acids exhibited a significant increase in the formation of NOx precursors due to the attack on the nitrogen positions of the heterocyclic nitrogen species by the H radicals generated by LDPE. This study contributes to research on the impact of LDPE on nitrogen migration and conversion during the pyrolysis of SP, laying the foundation for subsequent studies on pollutant removal reactions.

Photodynamics of azaindoles in polar media: the influence of the environment.

We have studied the relaxation dynamics of a family of azaindole (AI) structural isomers, 4-, 5-, 6- and 7-AI, by steady-state and time-resolved methods (fs-transient absorption and fluorescence up-conversion), in solvents of different polarity. The measurements in aprotic solvents show distinctive fluorescence yields and excited state lifetimes among the isomers, which are tuned by the polarity of the medium. Guided by simple TD-DFT calculations and based on the behavior observed in the isolated species, it has been possible to address the influence of the environment polarity on the relaxation route. According to the obtained picture, the energy of the nπ* state, which is strongly dependent on the position of the pyridinic nitrogen, controls the rate of the internal conversion channel that accounts for the distinctive photophysical behavior of the isomers. On the other hand, preliminary measurements in protic media (methanol) show a very different photodynamical behavior, in which the anomalous measured fluorescent patterns are very likely the result of reactive channels (proton transfer) triggered by the electronic excitation.

An alternating copolymer of phenothiazine and ethylenedioxythiophene for perovskite solar cells: effects of flexible and rigid substituent alternation.

Developing p-type polymeric semiconductors with exceptional electrical performance, heat tolerance, and cost-effectiveness is pivotal for advancing the practical application of n-i-p perovskite solar cells. Here, we employed direct arylation polycondensation to synthesize an alternating copolymer of phenothiazine and 3,4-ethylenedioxythiophene, featuring a high glass transition temperature (175 °C). In addition to the alternation of conjugated units within the main chain, the copolymer features alternating flexible (2-octyldodecyl) and rigid (trimethylphenyl) substituents at the nitrogen positions of the phenothiazine moiety. Compared to reference polymers with solely flexible or rigid substituents, the alternating use of these moieties resulted in the polymeric semiconductor composite film with smoother morphology and enhanced hole mobility. By employing this polymer with a distinct distribution of substituents and an innovative main chain structure as a hole transport material, we fabricated perovskite solar cells achieving an average efficiency of 25.1%. These cells also exhibited excellent stabilities under conditions of 85 °C thermal storage and 45 °C operation.

2‐Aryl Imidazolium Salts as Potential Bladder Cancer Chemotherapeutic Candidates

AbstractAs potential intravesical exfoliants for the treatment of bladder cancer, four new imdiazolium salts have been prepared. These compounds are modified on the nitrogen positions of the 4,5‐diphenyl‐1H‐imidazole or benzimidazole rings with naphthalen‐2‐ylmethyl groups, and the 2 positions on the azolium cations are occupied by arene rings. The 4,5‐diphenyl‐1H‐imidazole and benzimidazole precursors are produced from 1,2‐phenylenediamine and benzil respectively, and the imidazolium cations are generated from sequential alkylation of the nitrogen positions using 2‐bromomethyl naphthalene. The four imidazolium salts were screened for their chemotherapuetic activity using the NCI‐60 Human Tumour Cell Line Screen, and we observed that the cytotoxicity was more dependent on the identity of the imidazolium group (benzimidazolium versus diphenylimidazolium) rather than on the 2‐aryl position structure.

Ensemble and single-particle level fluorescent fine-tuning of carbon dots via positional changes of amines toward "supervised" oral microbiome sensing.

Carbon dots (CDs) have attracted a host of research interest in recent years mainly due to their unique photoluminescence (PL) properties that make them applicable in various biomedical areas, such as imaging and image-guided therapy. However, the real mechanism underneath the PL is a subject of wide controversy and can be investigated from various angles. Our work investigates the effect of the isomeric nitrogen position as the precursor in the synthesis of CDs by shedding light on their photophysical properties on the single particles and ensemble level. To this end, we adopted five isomers of diaminopyridine (DAP) and urea as the precursors and obtained CDs during a hydrothermal process. The various photophysical properties were further investigated in depth by mass spectroscopy. CD molecular frontier orbital analyses aided us in justifying the fluorescence emission profile on the bulk level as well as the charge transfer processes. As a result of the varying fluorescent responses, we indicate that these particles can be utilized for machine learning (ML)-driven sensitive detection of oral microbiota. The sensing results were further supported by density functional theoretical calculations and docking studies. The generating isomers have a significant effect on the overall photophysical properties at the bulk/ensembled level. On the single-particle level, although some of the photophysical properties such as average intensity remained the same, the overall differences in brightness, photo-blinking frequency, and bleaching time between the five samples were conceived. The various photophysical properties could be explained based on the different chromophores formed during the synthesis. Overall, an array of CDs was demonstrated herein to achieve separation efficacy in segregating a mixed oral microbiome culture in a rapid (), high-throughput manner with superior accuracy. We have indicated that the PL properties of CDs can be regulated by the precursors' isomeric position of nitrogen. We emancipated this difference in a rapid method relying on ML algorithms to segregate the dental bacterial species as biosensors.

Mesomorphism and luminescence in coordination compounds and ionic salts based on pyridine-functionalized β-diketones. Influence of the pyridine nitrogen position

Pyridine-functionalized β-diketones with the pyridine nitrogen atom at 3 or 4 position (L3N and L4N, respectively) have been used as building blocks to obtain two new families of compounds with mesomorphic and luminescent behaviors. The N-pyridine coordination of the β-diketones to zinc(II), palladium(II) and platinum(II) metal centers has allowed to synthesize neutral coordination compounds of the type [MCl2(LZN)2] (M = Zn(II), Pd(II), Pt(II); Z = 3, 4). Particularly, coordination of L4N towards Pt(II) gives rise to the cationic species [Pt(NH3)2(L4N)2]2+. Otherwise, protonation of the pyridine moiety was strategically used to obtain a novel series of pyridinium ionic salts of the type (HLZN)nA (n = 1, A = Cl; n = 2, A = MCl4, M = Zn(II), Pd(II), Pt(II); Z = 3, 4). The neutral or ionic nature of the complexes, as well as the β-diketone ligands and the metal center in both the neutral and anionic complexes, has a great influence on the mesomorphic behavior. Thus, columnar or smectic mesophases can be selectively formed. Single-crystal and temperature-dependent powder X-ray diffraction studies have been performed to analyze the molecular packing in the crystal and the supramolecular ordering in the mesophase. All the aforementioned factors also play a key role on the luminescence properties, the Zn(II) coordination compounds and ionic salts being the best candidates as bifunctional materials.

Oxygen activity excited thiophene-diketopyrrolopyrrole-based organic molecules as anode for lithium-ion batteries with enhanced interfacial storage capacity and long cycling capability

In this work, we synthesized various thiophene-diketopyrrolopyrrole-based (DPP-2T-based) molecules by Knoevenagel condensation and halogenation reaction, which applied DPP-2T-based small molecules as anode for lithium-ion batteries (LIBs) for the first time. We studied the different substituents on battery performance and explored the charge–discharge mechanism for DPP-2T-based molecules. DPP-2T-based molecules exhibit different electrochemical properties by substituting various groups at nitrogen positions, where DPP-2T-TA (tert-butyl acetate) electrode possesses better capacity and long-term cycle performance than that of DPP-2T-H (no substitution) and DPP-2T-C6 (hexane) electrode. DPP-2T-TA electrode present an unusual upward tendency for its discharge specific capacity during cycling, which displays that of 530 mAh/g (1000 mA g−1) after 2000 cycles and the capacity retention reaches up to 142.5 %. It is better than those of DPP-2T-H (439 mAh/g, 108.1 %) and DPP-2T-C6 (423 mAh/g, 113.1 %) electrode, which is ascribed to oxygen activity excitation in tert-butyl acetate. This moment, the energy density and power density of DPP-2T-TA electrode are 346 Wh kg−1 and 699 W kg−1, respectively. To further explain this phenomenon, we used many ex-situ measurgin methods such as differential specific capacity (dQ/dV) curves, scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectrometer, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and natural bond orbital (NBO) analysis to characterize the detailed lithiation/delithiation process of DPP-2T-TA electrode. The results suggest that the unusual capacity amplification for DPP-2T-TA electrode attributed to lithium-ions inserted into unsaturated carbons and increases its interfacial storage capacity. We believe that the synthesis of DPP-2T-based organic molecules can provide a novel strategy for the development of organic electrode materials for LIBs.

The three pyridazines, three naphthyridines and two azoles: effect of the position of the second heteroatom on pK aH of their eight conjugate acids

Abstract In the present work, how the position of the second nitrogen in the conjugate acids of the three pyridazines viz., 1,2-pyridazine, 1,3-pyridazine (the pyrimidine) and 1,4-pyridazine (the pyrazine) and three naphthyridines viz., cinnoline, quinazoline and quinoxaline changes the pK aH systematically is taken up. They decrease nearly by a factor of half each time in the class of their own. In contrast there is an increase in the pK aH when we move from pyrazole to imidazole. The pK aH of pyrazole is less than imidazole by −4.45 units. Suitable explanations are given.