Donor-acceptor Interactions Research Articles

Fixed bed column experiments using cotton gin waste and walnut shells-derived biochar as low-cost solutions to removing pharmaceuticals from aqueous solutions

Acetaminophen (ACT), sulfapyridine (SPY), ibuprofen (IBP) and docusate (DCT) are pharmaceuticals with widespread usage that experience incomplete removal in wastewater treatment systems. While further removal of these pharmaceuticals from wastewater effluent is desired prior to beneficial reuse, additional treatment technologies are often expensive and energy intensive. This study evaluated the ability of biochar produced from cotton gin waste (CG700) and walnut shells (WS800) to remove four pharmaceuticals (ACT, SPY, IBP, and DCT) from aqueous solution. Physico-chemical properties of the biochars were characterized by Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and zeta potential. The increased pyrolysis temperature during the production of WS800 led to an increase in the specific surface area and increased dehydration of the biochar represented by the loss of the OH-group. Fixed-bed column experiments were performed to determine the difference in removal efficiency between the biochars and elucidate the effects of biochar properties on the adsorption capacity for the pharmaceuticals of interest. Results showed that CG700 had a greater affinity for removing DCT (99%) and IBP (50%), while WS800 removed 72% of SPY and 68% of ACT after 24 h. Adsorption was influenced by the solution pH, surface area, net charge, and functional groups of the biochars. The mechanisms for removal included pore filling and diffusion, hydrophobic interactions, hydrogen bonding, and π-π electron donor acceptor interactions. To conduct predictive modeling of the column breakthrough curves, the Thomas, Adams-Bohart, and Yoon-Nelson models were applied to the experimental data. Results demonstrated that these models generally provided a poor fit for the description of asymmetrical breakthrough curves. Overall, the results demonstrate that biochars from cotton gin waste and walnut shells could be used as cost-effective, environmentally friendly alternatives to activated carbon for the removal of pharmaceuticals from aqueous solutions.

Theoretical design of a new hydrogen storage based on the decorated phosphorene nanosheet by alkali metals

In this study, the ability of decorated phosphorene with Alkali metals to absorb H2 was investigated using density functional theory dispersion corrected calculations and ab initio molecular dynamics (AIMD) simulations. The results show that the Li-phosphorene complex shows greater stability than other decorated phosphorene nanosheets with alkali metals. Because of the significant dispersion interactions (−0.29 eV) with the phosphorene surface, Li-phosphorene is the most stable decorate, demonstrating the importance of dispersion interactions as the driving force in decorate formation. The analysis of non-covalent interactions revealed that van der Waals interactions between the surface and alkali metals play an important role in the stability of the phosphorene-metals decorated and confirmed the H2 physisorption on the phosphorene surface. Donor-acceptor (DA) interaction analysis confirmed that the origin of this sensitivity could be attributed to molecular orbital interactions between these metals and the phosphorene surface, so Li-phosphorene is the most stable decorated compound due to strong DA interaction (41.9 kcal mol−1). Overall, the results show that the decorated phosphorene with Li is a promising candidate for developing new nanomaterials for hydrogen storage. Moreover, AIMD results reveal that the capacity trend of the designed systems based on alkali metal-phosphorene for hydrogen adsorption is as follows: Li > Na > K > Rb > Cs. It is well worth mentioning that each Li atom can adsorb roughly three hydrogen molecules on the surface of the phosphorene nanosheet.

Dual-Response Photofunctional Covalent Organic Framework for Acid Detection in Various Solutions

The detection of acid in different solution environments plays a significant role in chemical, environmental and biological fields. However, reducing the constraints of detecting environment, such as aqueous, organic solvents and mixed phases of aqueous and organic phases, remains a challenge. Herein, by combining N, N, N′, N′-tetrakis(4-aminophenyl)-1,4-phenylenediamine (TPBD) and terephthalaldehyde (TA) via Shiff-base condensation, we constructed a covalent organic framework (COF) TPBD-TA COF. The COF exhibits color change from red to dark red as well as fluorescence quenching with the increase of acid contents in either aqueous or organic solvents, or a mixture of aqueous and organic solvents, due to the weak donor-acceptor interactions within the COF as well as the weak proton ionization ability of the solutions. Therefore, regardless of the detection environment, TPBD-TA COF can realize color and fluorescence dual-response to acid with the detection limit as low as 0.4 μmol/L and 58 nmol/L, respectively, due to the protonation of the nitrogen atoms on imine bonds of the COF.

Organocatalytic Assembly Based on Aromatic Donor–Acceptor Interactions for the Asymmetric Aldol Reaction on Water

AbstractAromatic donor modified prolinamide and aromatic acceptor modified thiourea were synthesized. They self‐assembled into a cooperative organocatalytic system through the aromatic donor‐acceptor interaction and catalyzed aldol reactions in high yields and stereoselectivity on water. The aromatic donor‐acceptor interaction was confirmed by mass spectrum, UV‐vis titraition and 1H‐NMR titration experiments.

CeO2-g-C3N4 S-scheme heterojunctions for enhanced photocatalytic performance: Effects of surface C/N ratio on photocatalytic and adsorption properties

In this work, novel CeO2–C-g-C3N4 S-scheme heterojunctions with significantly enhanced photocatalytic performance were prepared for the first time by a facile one-step molten KCl–LiCl method. The formation mechanism of CeO2–C-g-C3N4 was discussed, where g-C3N4 turned to C by carbonizing and the surface C content was adjusted by controlling the synthesis conditions. The photocatalytic property of the ternary composites first increased and then decreased with synthesis temperature and time. The 580 °C 4h CeO2–C-g-C3N4 exhibited the best performance towards MB (Methylene blue) and TC (Tetracyclines) degradation with a removal degree of 99.9% and 92.5%, respectively. The surface C/N ratio was a key index that influenced the photocatalytic performance, and was calculated to be 0.918–1.352 for various CeO2–C-g-C3N4 catalysts. The 580 °C 4h CeO2–C-g-C3N4 had an appropriate C/N ratio of 0.930 and a narrow band gap. The formed S-scheme 2D heterojunctions and generated C clearly promoted the separation of photo-excited e-/h+. Besides, it was indicated that e- and ·O2− were the main active species for TC photodegradation. The 580 °C 4h CeO2–C-g-C3N4 exhibited a large BET surface area, high negative zeta potential, strong π-π electron donor-acceptor interaction, and an excellent MB adsorption ability. It was evident that chemisorption on catalyst surface played an important role for adsorbing MB. The formation mechanism of CeO2–C-g-C3N4 and the effects of the surface C/N ratio on photocatalytic performance, determined in this work, offer new insights for preparing and structuring highly effective photocatalysts, which is expected to promote further photocatalytic and adsorption applications.

Enhanced adsorption of 3,4-methylenedioxymethamphetamine by magnetic graphene oxide-polydopamine nanohybrid modified zeolitic imidazolate framework-67 and its micro-mechanism: Experiments and calculations

Exploring the structure-dependent adsorption mechanism of contaminants in wastewater is beneficial to high-efficiency adsorbents design and environmental remediation. In this study, emerging porous material of zeolitic imidazolate framework-67 (ZIF-67) has been modified by the magnetic graphene oxide-polydopamine nanohybrid (mGOP) to obtain three-dimensional ZIF-67/mGOP through an in-situ growth strategy, which was applied to adsorb 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) in wastewater. A combination of characterizations, experiments (pH, humic acid and ion strength effect) and quantum chemical calculations revealed the microscopic adsorption mechanism involves each single component, of which the hydrogen bond (O/N…HO) and π–π electron donor acceptor (π–π EDA) interactions of mGOP endowed favourable adsorption of ZIF-67/mGOP, and mechanisms of the pore filling and Co-O chelation of ZIF-67 played synergistic effect. Such nanocomposite as a ZIFs-based adsorbent exhibited ultra-high porosity (total pore volume = 0.4033 cm3/g) and specific surface area (995.22 m2/g), revealed the heterogeneity and multilayer adsorption properties, and obtained a theoretical maximum adsorption capacity of 159.845 μg/g which higher than that of mZIF-67 alone. Overall, this work provided an effective strategy for rationally modulate ZIFs-based composites and exploration of adsorption mechanism.

Exploiting Modeling Studies for Evaluating the Potential Antiviral Activities of some Clinically Approved Drugs and Herbal Materials against SARS-CoV-2: Theoretical Studies toward Hindering the Virus and Blocking the Human Cellular Receptor

This research theoretically modeled the binding interaction of the Sars-Cov-2 (Spike protein) utilizing molecular docking with some potential repurposed antiviral medications and two botanical products (Curcumin and Quercetin). Molecular docking between the drugs and the Sars-Cov-2 proteins reflecting the pure electrostatic forces and H-bond formation is complemented with the DFT results that shed light on the electronic nature of the interactions. Moreover, DFT computations provide invaluable information about the drug reactivity indices calculated from the energies of the frontier orbitals. The DFT results indicate intermolecular electron donor-acceptor interaction besides the H-bond formation. Most of the considered medication molecules act as electron-sink candidates except EIDD-2801 (molnupiravir), the electron donor. The theoretical results show the high possibility of blocking the human cellular entry against Sare-Cov-2 via strong interaction of the drugs with its peptide sequence (β6) measured by the high binding energy of docking or weakening its activity due to the electronic donor-acceptor interactions indicated by reactivity indices computed from the frontier molecular orbitals.

Benchmarking biochar with activated carbon for immobilizing leachable PAH and heterocyclic PAH in contaminated soils

Remediation of residually contaminated soils remains a widespread problem. Biochar can immobilize polycyclic aromatic hydrocarbons (PAH). However, studies on its ability to immobilize PAH and N, S, and O substituted PAH (hetero-PAH) in real soils, and benchmarking with commercial activated carbon are missing. Here, we compared the ability of pristine biochar (BC), steam-activated biochar (SABC), and commercial activated carbon (AC) to immobilize PAH and hetero-PAH. The three carbons were tested on soils from four different contaminated sites in Austria. Different amendment rates (w/w) of the carbons were investigated (BC: 1.0, 2.5, and 5%; SABC: 0.5, 1.0, and 2.0%; AC: 1%) in batch experiments to cover meaningful ranges in relation to their performance. SABC performed better than AC, removing at least 80% PAH with the lowest application rate of 0.5%, and achieving a complete removal at an application rate of 1.0%. BC performed slightly worse but still acceptable in residually contaminated soils (40 and 100% removal at 1 and 5% amendment, respectively). The ability of BC and SABC to immobilize PAH decreased as the PAH-molar volume increased. PAH with three or more rings were preferentially removed by AC compared to SABC or BC. This can be explained by the difference in pore size distribution of the carbons which could limit the accessibility of PAH and hetero-PAH to reach sorption sites for π- π electron donor-acceptor interactions, which drive PAH and hetero-PAH sorption to carbons. Column percolation tests confirmed the results obtained in batch tests, indicating, that decisions for soil remediation can be derived from simpler batch experiments. In soil samples with 1% BC, a reduction of over 90% in the total concentration of PAH in the leached water was observed. Overall, BC and SABC were demonstrated to be valid substitutes for AC for stabilizing residually contaminated soils.

Molecular modeling, vibrational dynamics and NBO analysis of a synthetic bio‐relevant warfarin analog

We have performed the structural and spectroscopic analysis of a warfarin derivative (3-(1-(4-fluorophenyl)-3-(2-hydroxyphenyl)-3-oxopropyl)-4-hydroxy-2H-chromen-2-one). One-dimensional potential energy scanning (PES) of a warfarin derivative has been performed with the aim of finding low-lying energy conformations of this compound. During PES and other computations, we adopted DFT/B3LYP level along with the prevailing basis set 6-31++G(d,p). The conformational analysis through PES revealed five conformers and the global minima for conformer-4. The structures, IR and Raman spectra of conformers were deducted and the IR spectrum of the most stable conformer was correlated with the experimental FTIR spectrum of the target compound. The potential energy distributions (PEDs) for the most stable conformer was computed by employing the standard normal coordinate analysis (NCA) method in the input of Molvib program. Additionally, the HOMO/LUMO analysis and hyper-conjugative interaction energies of donor-acceptor interactions were calculated using NBO calculations. This conformational and vibrational spectroscopic investigation of the target molecule can be a crucial prerequisite for similar investigations on the target and its closely similar molecules.

Theoretical Insights into the Selectivity of Hydrophilic Sulfonated and Phosphorylated Ligands to Am(III) and Eu(III) Ions.

The separation of lanthanides and actinides has attracted great attention in spent nuclear fuel reprocessing up to date. In addition, liquid-liquid extraction is a feasible and useful way to separate An(III) from Ln(III) based on their relative solubilities in two different immiscible liquids. The hydrophilic bipyridine- and phenanthroline-based nitrogen-chelating ligands show excellent performance in separation of Am(III) and Eu(III) as reported previously. To profoundly explore the separation mechanism, herein, we first of all designed four hydrophilic sulfonated and phosphorylated ligands L1, L2, L3, and L4 based on the bipyridine and phenanthroline backbones. In addition, we studied the structures of these ligands and their neutral complexes [ML(NO3)3] (M = Am, Eu) as well as the thermodynamic properties of complexing reactions through the scalar relativistic density functional theory. According to the changes of the Gibbs free energy for the back-extraction reactions, the phenanthroline-based ligands L2 and L4 have stronger complexing capacity for both Am(III) and Eu(III) ions while the phosphorylated ligand L3 with the bipyridine framework has the highest Am(III)/Eu(III) selectivity. In addition, the charge decomposition analysis revealed a higher degree of charge transfer from the ligand to Am(III), suggesting stronger donor-acceptor interactions in the Am(III) complexes. This study can provide theoretical insights into the separation of actinide(III)/lanthanide(III) using hydrophilic sulfonated and phosphorylated N-donor ligands.

Efficient Narrowband Circularly Polarized Light Emitters Based on 1,4-B,N-embedded Rigid Donor-Acceptor Helicenes.

Narrow-band emission is essential for applicable circularly polarized luminescence (CPL) active materials in ultrahigh-definition CP-OLEDs. One of the most promising classes of CPL active molecules, helicenes, however, typically exhibit broad emission with a large Stokes shift. We present, herein, a design strategy capitalizing on intramolecular donor-acceptor interactions between nitrogen and boron atoms to address this issue. 1,4-B,N-embedded configurationally stable single- and double helicenes were synthesized straightforwardly. Both helicenes show unprecedentedly narrow fluorescence and CPL bands (full width at half maximum between 17-28 nm, 0.07-0.13 eV) along with high fluorescence quantum yields (72-85 %). Quantum chemical calculations revealed that the relative localization of the natural transition orbitals, mainly on the rigid core of the molecule, and small values of root-mean-square displacements between S0 and S1 state geometries, contribute to the narrower emission.

Chemical reactivity, solvent effects, spectroscopic (FTIR, Raman, SERS, UV–Visible), Hirshfeld analyses and antimalarial investigation of 3-Acetylbenzoic acid

The antimalarial compound 3-AcetylBenzoic acid (3ABA) was characterized by spectroscopic and UV–Visible spectral techniques. The most stable structure of 3ABA molecule was studied for PES analysis. The geometrical optimization, spectral investigations (Infrared and Raman were performed), electronic transitions and the energy gap between Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) and chemical nature of the title molecule were described (gas and solvation phase) for UV–Visible investigations. The adsorption energy is almost the same for Au and Ag, causing the nmCs to form stable clusters with Au and Ag. In all complexes with 3ABA, Raman spectra reveal an improvement. The donor acceptor's interaction and stabilization energy were analysed by Natural Bond Orbital (NBO) analyses. The chemical reactivity of the title molecule is illustrated using Molecular Electrostatic Potential (MEP), Electron Localized Function (ELF), Localized Orbital Locator (LOL), and Hirshfeld analyses. The antimalarial and antibacterial activities were investigated for Enogl acyl carrier proteins (1NHG, 4M89) using molecular docking analysis.

Enhanced Ultra‐Long Room Temperature Phosphorescence by Intermolecular Donor–Acceptor Interaction in Polymer Network

AbstractUltra‐long room temperature phosphorescence (URTP) is an attractive phenomenon in organic photonics. However, most of the reported strategies for enhancing URTP require complicated synthesis processes. Herein, a novel strategy is reported, two birds with one stone, for enhancing URTP by doping the ground‐state intermolecular donor–acceptor complexes into a dense polymer network: i) The dense network ensures the formation of intermolecular donor–acceptor complexes, which provide a smaller singlet‐triplet energy difference (ΔEST) and more intersystem crossing (ISC) channels than the individual donor or acceptor molecules; ii) The dense network adequately suppresses the non‐radiative relaxation caused by molecular vibrations and oxygen quenching. The URTP intensities of the intermolecular donor–acceptor complexes doped film are 20 times higher than that of the film only doped with acceptor molecules, and the phosphorescence lifetime is up to 200 ms. The theoretical calculation reveals the electronic interaction between donor and acceptor and the increased ISC channel, which elucidates the photophysical mechanism of the strategy and confirms its rationality. An advanced encryption application is developed based on enhanced URTP films. This work opens a new direction for URTP materials through the intermolecular donor–acceptor interaction.

Removal of chromium (VI) and bisphenol A from water using a novel spoilt milk-derived adsorbent: material characterisation and adsorption mechanisms

ABSTRACT This work aims to turn spoilt milk into a high specific surface area activated carbon exploitable in wastewater treatment. Spoilt milk was hydrothermally carbonised to generate hydrochar which was activated with potassium hydroxide at 800°C. The activated carbon displayed a high specific surface area of 1465 m2g−1, with a remarkable microporous character. The activated carbon exhibited excellent maximum monolayer adsorption of 472 mgg−1 and 640 mgg−1 for bisphenol A and chromium (VI), respectively. The adsorption equilibrium was achieved rapidly within 20 min for bisphenol A and 60 min for chromium (VI). Both adsorption processes were spontaneous (∆G° < 0). The adsorption was exothermic in the case of bisphenol A adsorption (∆H° = −56.28 kJmoL−1) and endothermic for potassium dichromate (∆H° = 25.14 kJmoL−1). The bisphenol A was adsorbed on the activated carbon via π-π donor-acceptor interactions, whereas the potassium dichromate was removed through chemical adsorption that included ion exchange, electrostatic interaction, complexation, and redox reaction. Overall, spoilt milk proved to be an excellent precursor of activated carbon for the removal of bisphenol A and dichromate from water.

Radical Pairing Interactions and Donor-Acceptor Interactions in Cyclobis(paraquat-p-phenylene) Inclusion Complexes.

Understanding molecular interactions in mechanically interlocked molecules (MIMs) is challenging because they can be either donor-acceptor interactions or radical pairing interactions, depending on the charge states and multiplicities in the different components of the MIMs. In this work, for the first time, the interactions between cyclobis(paraquat-p-phenylene) (abbreviated as CBPQTn+ (n = 0-4)) and a series of recognition units (RUs) were investigated using the energy decomposition analysis approach (EDA). These RUs include bipyridinium radical cation (BIPY•+), naphthalene-1,8:4,5-bis(dicarboximide) radical anion (NDI•-), their oxidized states (BIPY2+ and NDI), neutral electron-rich tetrathiafulvalene (TTF) and neutral bis-dithiazolyl radical (BTA•). The results of generalized Kohn-Sham energy decomposition analysis (GKS-EDA) reveal that for the CBPQTn+···RU interactions, correlation/dispersion terms always have large contributions, while electrostatic and desolvation terms are sensitive to the variation in charge states in CBPQTn+ and RU. For all the CBPQTn+···RU interactions, desolvation terms always tend to overcome the repulsive electrostatic interactions between the CBPQT cation and RU cation. Electrostatic interaction is important when RU has the negative charge. Moreover, the different physical origins of donor-acceptor interactions and radical pairing interactions are compared and discussed. Compared to donor-acceptor interactions, in radical pairing interactions, the polarization term is always small, while the correlation/dispersion term is important. With regard to donor-acceptor interactions, in some cases, polarization terms could be quite large due to the electron transfer between the CBPQT ring and RU, which responds to the large geometrical relaxation of the whole systems.

Investigation of linear and second-order nonlinear optical properties of donor-acceptor interaction derivatives based on acceptor DCPPr core

Red thermally activated delayed fluorescence (TADF) materials have attracted much attention from researchers due to their potential applications in display and lighting devices. Recently, DCPPr-TPA has displayed unique photophysical properties, such as high optical out-coupling factor and near infrared (NIR) emissions. However, its structure-property relationship has not been fully detected, which will further improve their performance. Herein, based on the reported DCPPr-TPA, four new derivatives are designed by inserting π-bridge ethylene units, introducing donor NO2 units or acceptor NH2 units, and replacing TPA unit with NI unit. Their linear and second-order nonlinear optical properties are investigated in detail using DFT and TD-DFT theories. It is concluded that the insertion of π-bridge ethylene units and the introduction of the donor NH2 units on TPA units are the most effective methods to reduce the energy gap, redshift the maximum absorption wavelength and increase the first hyperpolarizability. The four newly designed derivatives do not further enhance hole transport ability, but derivatives 1–3 do enhance electron transport ability, and derivatives 1–3 are all potential bipolar transport materials. In view of their large first hyperpolarizability, the studied derivatives may become second-order nonlinear optical (NLO) materials with excellent properties.

Preparation and characterization of glucose-based covalent organic polymer coated silica as stationary phase for high-performance liquid chromatography

Carbohydrate is a renewable, sustainable, hydrophilic, and biodegradable natural product, which is widely used in the field of adsorption. In this study, a glucose-based covalent organic polymer (COP) coated silica was fabricated by facile solvent knitting reaction between tetrabenzylglucose and silica-phenyl with anhydrous aluminum trichloride as catalyst, forming a core-shell stationary phase (donated as SiO2@COPBn-glu) for high performance liquid chromatography. The prepared SiO2@COPBn-glu was characterized by scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectrometry, solid-state 13C nuclear magnetic resonance spectrometry, X-ray photoelectron spectroscopy, and N2 adsorption-desorption experiments. Owing to the coexistence of benzene units and alkyl, hydroxyl and ether groups in the skeleton of COPBn-glu shell, the developed chromatographic packing exhibited reversed-phase/hydrophilic interaction mixed-mode with multiple retention mechanisms, such as hydrophobic, π-π, hydrogen bonding, and electron donor-acceptor interactions. The results revealed that the SiO2@COPBn-glu column demonstrated excellent selectivity and retention behavior for both hydrophilic and hydrophobic compounds with good repeatability and stability. Meanwhile, the chromatographic performance of the prepared SiO2@COPBn-glu column was compared with a C18 column to assess the role of the coating COPBn-glu shell. Therefore, the development of the SiO2@COPBn-glu stationary phase expands the potential application of COPs in separation field.

Adsorption of nitrophenol onto a novel Fe3O4-κ-carrageenan/MIL-125(Ti) composite: process optimization, isotherms, kinetics, and mechanism

Water pollution is a dreadful affair that has incessantly aggravated, exposing our planet to danger. In particular, the persistent nitro aromatic compound like nitrophenols causes anxiety to the researchers due to their hazardous impacts, excessive usage, and removal difficulty. For this purpose, a novel multi-featured composite was constructed based on κ-Carrageenan (κ-Carr), MOF (MIL-125(Ti)), and magnetic Fe3O4 for efficient adsorptive removal of o-nitrophenol (o-NP). Interestingly, BET measurements revealed the high surface area of Fe3O4-κ-Carr/MIL-125(Ti) of about 163.27 m2/g, while VSM showed its excellent magnetic property (20.34 emu/g). The comparison study pointed out the synergistic effect between Fe3O4, κ-Carr, and MIL-125(Ti), forming a composite with an excellent adsorption performance toward o-NP. The adsorption data obeyed pseudo-second-order kinetic model, and Freundlich isotherm model was better fitted than Langmuir and Temkin. Furthermore, Langmuir verified the supreme adsorption capacity of o-NP onto Fe3O4-κ-Carr/MIL-125(Ti) since the computed qmax reached 320.26 mg/g at pH 6 and 25 °C. Furthermore, the XPS results postulated that the adsorption mechanism pf o-NP proceeded via H-bonding, π-π interaction, and electron donor–acceptor interactions. Interestingly, Fe3O4-κ-Carr/MIL-125(Ti) composite retained good adsorption characteristics after reusing for five cycles, suggesting its viable applicability as an efficient, renewable, and easy-separable adsorbent for removing nitro aromatic pollutants.

Rational Design of Polymethine Dyes with NIR-II Emission and High Photothermal Conversion Efficiency for Multimodal-Imaging-Guided Photo-Immunotherapy.

Phototheranostics have emerged and flourished as a promising pattern for cancer theranostics owing to their precise photoinduced diagnosis and therapeutic to meet the demands of precision medicine. The diagnosis information and therapeutic effect are directly determined by the fluorescence imaging ability and photothermal conversion efficiency (PCE) of phototheranostic agents. Hence, how to balance the competitive radiative and nonradiative processes of phototheranostic agents is the key factor to evaluate the phototheranostic effect. Herein, molecules named ICRs with high photostaibility are rationally designed, exhibiting fluorescence emission in the second near-infrared window(NIR-II, 1000-1700 nm) and high PCE,which are related to the strong donor-acceptor (D-A) interaction and high reorganization energyNoteworthily, ICR-Qu with stronger D-A interaction and alarge-sized conjugated unit encapsulated in nanoparticles exhibits high PCE (81.1%). Inaddition, ICR-QuNPs are used for fluorescence imaging (FLI), photoacoustic imaging (PAI), and photothermal imaging (PTI) to guide deep-tissue photonic hyperthermia, achieving precise removal and inhibition of breast cancer. Furthermore, combined with α-PD-1, ICR-QuNPs show huge potential to be a facile and efficient tool for photo-immunotherapy. More importantly, this study not only reports an "all-in-one" polymethine-based phototheranostic agent, but also sheds light on the exploration of versatile organic molecules for future practical applications.

Inter-Alkali-Metal Dative Bond in the MMN3 - (M=Alkali Metal) Cluster.

Alkali metals are generally Lewis acids. On the contrary, Lewis basic character of alkali metals forming donor - acceptor complexes is a very rare phenomenon. In this contribution, I have theoretically designed an anionic cluster MMN3 - (M=alkali metals) on the basis of experimentally known reagent, alkali salt of azide ion MN3 , which shows unprecedented M:- →M donor-acceptor interaction. To the best of author's knowledge, the characterization of such donor-acceptor interaction among alkali metals is unprecedented. Formation of the 2c-2e donor-acceptor bonds have been confirmed by quantum theory of atoms in molecules and electron localization function analyses. The calculated bond dissociation energies are significant suggesting their possible spectroscopic identification.