Photochemical behaviour and toxicity evolution of phenylbenzoate liquid crystal monomers in water.

Liquid crystal monomers (LCMs) are a group of emerging pollutants that pose potential environmental risks because of their ubiquitous occurrence and toxicity. Understanding their environmental transformation is essential for assessing the ecological risk. In this study, we investigated the photochemical transformation kinetics, mechanism, and photo-induced toxicity of three phenylbenzoate LCMs in water. Their apparent photolytic rate constants were within (0.023 - 0.058) min-1, and the half-lives were < 30.0 min, showing lower persistence in water. Dissolved organic matter significantly inhibited their photolysis because of light-shielding effect and quenching of excited triplet states of LCMs. Their photolysis mainly occurred through excited triplet states, and the reactive oxygen species (i.e., ⋅OH, 1O2 and ⋅O2-) contributed to their degradation. The main photolysis pathways were ester bond cleavage, ⋅OH substitution/addition, and defluorination. Experiments and computational simulation revealed that some ·OH addition/substitution products have similar toxicity with LCMs. Additionally, the ∙OH reaction rate constants (kOH) of LCMs were determined to be > 1 × 109 M-1 s-1, evidence for their high reactivity toward ⋅OH. We have further developed reliable methods to estimate kOH of other phenylbenzoate-like LCMs with quantum chemical calculations. These results are useful for understanding the transformation and fate of LCMs in aquatic environments.

Design, synthesis and insecticidal activity of novel Isoxazoline Acylhydrazone compounds.

BACKGROUND: Nowadays, the diamondback moth has ascended to become one of the most formidable pests plaguing cruciferous vegetables. Consequently, the exigency for the development of efficacious pesticide candidates for crop protection has never been more paramount. In response to this pressing need, this study presents a compendium of novel isoxazoline derivatives, incorporating acylhydrazone moieties, synthesized with the express purpose of serving as potential insecticides. RESULTS: The structures of these derivatives were confirmed using Proton nuclear magnetic resonance (1 H NMR), Carbon-13 nuclear magnetic resonance (13 C NMR), and high-resolution mass spectrometry (HR-MS). Most of these derivatives demonstrated effective insecticidal activities against Plutella xylostella. Notably, compound E3 exhibited exceptional insecticidal activity against Plutella xylostella (LC50 = 0.19 mg L-1 ), surpassing the effectiveness of ethiprole (LC50 = 3.28 mg L-1 ), and comparable to that of fluxametamide (LC50 = 0.22 mg L-1 ). Interestingly, compound E3 also displayed potent insecticidal activity against Pyrausta nubilalis (LC50 = 0.182 mg L-1 ) and Chilo suppressalis (LC50 = 0.64 mg L-1 ), and the LC50 values of fluxametamide were 0.23 mg L-1 (P. nubilalis) and 2.26 mg L-1 (C. suppressalis), respectively. The molecular docking results revealed that the compound E3 can form a hydrogen bond and two Pi-Pi bonds with the active sites of GABA receptors. In addition, the DFT calculations were also performed to study the relationship between insecticidal activities. The structure-activity relationships suggested that the identity of the R substituent was crucial for their pesticidal activities. CONCLUSION: The results of the present study suggest that isoxazoline acylhydrazone derivatives could be promising candidates against P. xylostella and other Lepidopteran pests. © 2023 Society of Chemical Industry.

Photochemical behavior and photo-induced toxicity of chiral pesticides and their chiral monomers in aqueous environment.

The photochemical behaviors of chiral pollutants in aqueous solutions are rarely studied using chiral monomers, which may hamper their precise risk assessment and lead to suspicious conclusions. In this study, we systematically investigated the phototransformation behavior and toxicity evolution of two widely used chiral pesticides (triadimefon (TF) and triadimenol (TN)) at enantiomer and diastereomer levels, and proposed a calculation method of total photolysis rate constants of chiral mixture. Results show that TF and TN could be photodegraded faster in pure water than in natural waters, and the observed photolysis rate constants (kobs) of TN with two chiral centers exhibit enantioselectivity, i.e., kobs(TN-RS) = kobs(TN-SR) > kobs(TN-RR) = kobs(TN-SS). The photolysis of TF and TN mainly occurs through their excited singlet and triplet states, respectively. Their photodegradation pathways mainly include dechlorination and elimination of triazole ring. TF could also undergo ether bond cleavage. It is also found that, both TF and TN exhibit photo-induced toxicity to V. fischeri, due to the generation of more toxic products than parent compounds. Furthermore, TN exhibits enantioselective photo-induced toxicity after 240-min irradiation, which could be ascribed to the formation of chiral products. These results could benefit the understanding of enantioselective environmental behavior of chiral pollutants.

Expedient discovery of novel oxime ester derivatives of piperine/piperine analogs as potent pesticide candidates and their mode of action against Tetranychus cinnabarinus Boisduval.

BACKGROUND: Nowadays, pest infestation and resistance have appeared as a consequence of repeated and extensive use of pesticides. Thus, development of new effective pesticide candidates in crop protection is highly desirable. Herein, a series of new piperine derivatives containing oxime ester scaffolds were regioselectively and stereoselectively prepared as pesticidal agents. RESULTS: Steric configurations of compounds 2, 5z and 13e were definitively determined by single-crystal X-ray diffraction. Against Tetranychus cinnabarinus, notably, compounds 5f [median lethal concentration (LC50 ) = 0.14 mg mL-1 ] and 5v (LC50 = 0.13 mg mL-1 ) showed >107-fold greater acaricidal activity than piperine (LC50 = 15.02 mg mL-1 ), which were comparable to the commercial acaricide spirodiclofen. Against Aphis citricola, compound 5d (LD50 = 19.12 ng aphid-1 ) exhibited 6.1-fold more potent aphicidal activity than piperine (LD50 = 116.06 ng aphid-1 ). Additionally, through scanning electron microscopy, the toxicology study suggested that the acaricidal activity of piperine derivatives may be related to damage of the cuticle layer crest of T. cinnabarinus. CONCLUSION: The structure-activity relationships suggested that 3,4-dioxymethylene of piperine was crucial for its acaricidal activity; and introduction of a certain length of aliphatic chain at the C-2 position was beneficial to the aphicidal and acaricidal activities. Compounds 5f and 5v are potential leads for further structural modification as acaricidal agents. © 2023 Society of Chemical Industry.

Field-measured canopy height may not be as accurate and heritable as believed: evidence from advanced 3D sensing.

Canopy height (CH) is an important trait for crop breeding and production. The rapid development of 3D sensing technologies shed new light on high-throughput height measurement. However, a systematic comparison of the accuracy and heritability of different 3D sensing technologies is seriously lacking. Moreover, it is questionable whether the field-measured height is as reliable as believed. This study uncovered these issues by comparing traditional height measurement with four advanced 3D sensing technologies, including terrestrial laser scanning (TLS), backpack laser scanning (BLS), gantry laser scanning (GLS), and digital aerial photogrammetry (DAP). A total of 1920 plots covering 120 varieties were selected for comparison. Cross-comparisons of different data sources were performed to evaluate their performances in CH estimation concerning different CH, leaf area index (LAI), and growth stage (GS) groups. Results showed that 1) All 3D sensing data sources had high correlations with field measurement (r > 0.82), while the correlations between different 3D sensing data sources were even better (r > 0.87). 2) The prediction accuracy between different data sources decreased in subgroups of CH, LAI, and GS. 3) Canopy height showed high heritability from all datasets, and 3D sensing datasets had even higher heritability (H2 = 0.79-0.89) than FM (field measurement) (H2 = 0.77). Finally, outliers of different datasets are analyzed. The results provide novel insights into different methods for canopy height measurement that may ensure the high-quality application of this important trait.

Relationship between photolysis mechanism and photo-enhanced toxicity to Vibrio Fischeri for neonicotinoids with cyano-amidine and nitroguanidine structures.

Neonicotinoids are widely used pesticides that contaminate aquatic environments. Although these chemicals can be photolyzed under sunlight radiation, it is unclear for the relationship between photolysis mechanism and toxicity change in aquatic organisms. This study aims to determine the photo-enhanced toxicity of four neonicotinoids with different main structures (acetamiprid, and thiacloprid for cyano-amidine structure, imidacloprid and imidaclothiz for nitroguanidine). To Achieve the goal, photolysis kinetics, effect of dissolved organic matter (DOM) and reactive oxygen species (ROSs) scavengers on photolysis rates, photoproducts, and photo-enhanced toxicity to Vibrio fischeri were investigated for four neonicotinoids. The results showed direct photolysis plays a key role in the photo-degradation of imidacloprid and imidaclothiz (photolysis rate constants are 7.85 × 10-3 and 6.48 × 10-3 min-1, respectively), while the photosensitization process of acetamiprid and thiacloprid was dominated by ·OH reactions and transformation (photolysis rate constants are 1.16 × 10-4 and 1.21 × 10-4 min-1, respectively). All four neonicotinoid insecticides exerted photo-enhanced toxicity to Vibrio fischeri, indicating photolytic product(s) posed greater toxicity than their parent compounds. The addition of DOM and ROS scavengers influenced photo-chemical transformation rates of parent compounds and their intermediates, leading to diverse effects on photolysis rates and photo-enhanced toxicity for the four insecticides as a result of different photo-chemical transformation processes. Based upon the detection of chemical structures of intermediates and Gaussian calculations, we observed different photo-enhanced toxicity mechanisms for the four neonicotinoid insecticides. Molecular docking was used to analyze the toxicity mechanism of parent compounds and photolytic products. A theoretical model was subsequently employed to describe the variability of toxicity response to each of the four neonicotinoids.

Overview of Piperine: Bioactivities, Total Synthesis, Structural Modification, and Structure-Activity Relationships.

Natural products are an invaluable source for the discovery of drug and pesticide candidates. Piperine, a simple and pungent alkaloid, is isolated from several plants of Piperaceae. Piperine and its derivatives displayed a wide range of biological properties, such as antitumor activity, anti-inflammatory activity, antioxidant activity, neuroprotective activity, insecticidal activity, etc. In recent years, lots of works focused on the biological activities, mechanisms of action, total synthesis, and structural modifications of piperine and its derivatives have been conducted. To the best of our knowledge, however, few review articles related to the biological activities, mechanisms of action, total synthesis, and structural modifications of piperine and its derivatives have been reported to date. Therefore, this review summarizes the research advances (from 2014 to 2020) of piperine and its derivatives regarding bioactivity, mechanisms of action, total synthesis, and structural modifications. Meanwhile, the structure-activity relationships of piperine and its derivatives are also discussed.

A CNN-based misleading video detection model.

Videos, especially short videos, have become an increasingly important source of information in these years. However, many videos spread on video sharing platforms are misleading, which have negative social impacts. Therefore, it is necessary to find methods to automatically identify misleading videos. In this paper, three categories of features (content features, uploader features and environment features) are proposed to construct a convolutional neural network (CNN) for misleading video detection. The experiment showed that all the three proposed categories of features play a vital role in detecting misleading videos. Our proposed approach that combines three categories of features achieved the best performance with the accuracy of 0.90 and the F1 score of 0.89. It also outperformed other baselines such as SVM, k-NN, decision tree and random forest models by more than 22%.

Predicting reaction rate constants of ozone with ionic/non-ionic compounds in water.

Ozonation is a significant technology for the mitigation of pollutants in water. The second-order reaction rate constant (kO3) of ozone (O3) with compounds is essential for measuring their reactivity toward O3 and understanding their fate during ozonation. However, there is a huge gap between the number of existing chemicals and the available experimental kO3 values. Moreover, the reactivity of ionizable compounds with different ionization forms toward O3 may differ greatly. In this study, two quantitative structure activity relationship (QSAR) models for non-ionic and ionic species, are respectively established with partial least squares (PLS) and support vector machine (SVM) methods based on the large datasets (324 non-ionic states and 188 ionic states). These models exhibit good fitting ability (non-ionic model: R2tr > 0.760; ionic model: R2tr > 0.780), robustness (Q2CUM > 0.700), predictive performance (non-ionic model: R2ext > 0.760; ionic model: R2ext > 0.810) and wide applicability domain. The molecular parameters in two models are revealed to be significantly different, which may be attributed to the significant difference in molecular structures in two datasets and different reactivities of uncharged and charged states toward O3. Additionally, the overall kO3 for compounds at certain pH can be estimated by combining the two single QSAR models. These models and methods can become the effective tools for predicting the conversion rate of pollutants by O3 in the urban sewage and drinking water treatment.

Efficacy and safety between early use and late use of celecoxib in hip osteoarthritis patients who receive total hip arthroplasty: a randomized, controlled study.

Celecoxib is commonly used for pain management after total hip arthroplasty (THA), while the optimal timing of analgesic celecoxib remains unclear. This randomized, controlled study aimed to investigate the pain control efficacy and safety of preoperative celecoxib versus postoperative celecoxib in osteoarthritis (OA) patients undergoing THA. Totally, 192 hip OA patients about to undergo THA were randomized into pre-treatment group (N = 96) and post-treatment group (N = 96). The former was given 400 mg celecoxib at 4 h before THA, 200 mg at 4 h after THA, and then 200 mg every 12 h until 72 h post-operation. The latter was given 400 mg celecoxib at 4 h after THA, and then 200 mg every 12 h until 72 h post-operation. Pain at rest visual analog scale (VAS) score at 6 h, and pain at flexion VAS scores at 6 h, 12 h, and on D1, D2 were decreased in pre-treatment group compared to post-treatment group (all P < 0.05). Furthermore, additional consumption of patient-controlled analgesia (PCA) (P = 0.006) and total consumption of PCA (P = 0.006) were both reduced in pre-treatment group compared to post-treatment group. Meanwhile, compared to post-treatment group, patient satisfaction in pre-treatment group was higher on D1 (P = 0.010) and D2 (P = 0.039). While, Harris hip score showed no difference between pre-treatment group and post-treatment group on M1 or M3 (both P > 0.05). In conclusion, preoperative celecoxib exhibits better analgesic efficacy and patients' satisfaction management with similar tolerance compared to postoperative celecoxib in hip OA patients undergoing THA.

Detection of fake-video uploaders on social media using Naive Bayesian model with social cues.

With the rapid development of the Internet, the wide circulation of disinformation has considerably disrupted the search and recognition of information. Despite intensive research devoted to fake text detection, studies on fake short videos that inundate the Internet are rare. Fake videos, because of their quick transmission and broad reach, can increase misunderstanding, impact decision-making, and lead to irrevocable losses. Therefore, it is important to detect fake videos that mislead users on the Internet. Since it is difficult to detect fake videos directly, we probed the detection of fake video uploaders in this study with a vision to provide a basis for the detection of fake videos. Specifically, a dataset consisting of 450 uploaders of videos on diabetes and traditional Chinese medicine was constructed, five features of the fake video uploaders were proposed, and a Naive Bayesian model was built. Through experiments, the optimal feature combination was identified, and the proposed model reached a maximum accuracy of 70.7%.

Optimization of Osthole in the Lactone Ring: Structural Elucidation, Pesticidal Activities, and Control Efficiency of Osthole Ester Derivatives.

Here, we prepared a series of novel osthole-type ester derivatives modified in the lactone ring of osthole, which is isolated from Cnidium monnieri. The positions of H-3 and H-4 of the representative compound 4z were determined by a 1H-1H COSY spectrum. By opening the lactone ring of osthole, the double bonds at the C-3 and C-4 positions of diol 3 and esters 4a-4z, 4a', and 4b' were still retained as a Z configuration. That is, H-3 and H-4 of compounds 3 and 4a-4z, 4a', and 4b' were all in the cis relationship. The steric configurations of 4k, 4v, and 4z were further undoubtedly determined by single-crystal X-ray diffraction. Against Tetranychus cinnabarinus Boisduval, four aliphatic esters 4c (R = n-C3H7; LC50: 0.31 mg/mL), 4d (R = CH3(CH2)10; LC50: 0.24 mg/mL), 4a' (R = CH3(CH2)9; LC50: 0.28 mg/mL), and 4b' (R = CH3(CH2)12; LC50: 0.32 mg/mL) showed the most promising acaricidal activity, and compounds 4c, 4d, and 4a' also exhibited a potent control efficiency. Especially, compound 4d exhibited greater than fivefold acaricidal activity of the precursor osthole (LC50: 1.22 mg/mL). Against Mythimna separata Walker, compounds 4g, 4l, and 4m displayed 1.6-1.8-fold potent insecticidal activity of osthole. It demonstrated that the lactone ring of osthole is not necessary for the agricultural activities, thiocarbonylation of osthole was not beneficial for the agricultural activities, introduction of R as an aliphatic chain is vital for the acaricidal activity, notably, the length of the aliphatic chain is related to the acaricidal activity, 4d could be further studied as a lead acaricidal agent, and to the aromatic series, R containing the fluorine atom(s) is important for the insecticidal activity.

Advances on Monosaccharides and Oligosaccharides: Structural Modifications and Bioactivities.

Derivatives of monosaccharides and oligosaccharides play important roles in biological processes. Monosaccharides are the single carbohydrate building blocks, such as glucose, xylose, and fructose. Oligosaccharides are composed of 2-10 monosaccharides, including disaccharides and trisaccharides. Moreover, monosaccharides, oligosaccharides and their derivatives are vital molecules with various biological properties, including anticancer activity, antiviral activity, insecticidal activity, antimicrobial activity, and antioxidant activity. This review covers a survey of structural modifications, biological activities, and mechanisms of action of monosaccharides, oligosaccharides and their derivatives. Additionally, their structure-activity relationships are also concluded.

Spirodiclofen ether derivatives: semisynthesis, structural elucidation, and pesticidal activities against Tetranychus cinnabarinus Boisduval, Aphis citricola Van der Goot and Mythimna separata Walker.

BACKGROUND: Spirodiclofen is a spirocyclic tetronic acid-type acaricidal agent. Nowadays, serious pests resistance to spirodiclofen and cross-resistance to other acaricides has appeared. To overcome pests resistance and discover new potential agrochemicals, a series of ether derivatives were prepared based on spirodiclofen as a lead compound. Their pesticidal activities were investigated against three typically agricultural pests, Mythimna separata Walker, Aphis citricola Van der Goot and Tetranychus cinnabarinus Boisduval. RESULTS: Four steric structures of compounds 5e, 5f, 5i and 5j were determined by single-crystal X-ray diffraction. Against T. cinnabarinus, compounds 5b, 5f and 5l exhibited potent acaricidal activity, and their good control effects in the glasshouse were observed when compared with spirodiclofen, especially the control efficiency of compound 5b was comparable to that of spirodiclofen; against M. separata, compound 5j showed > 1.8-fold potent insecticidal activity of spirodiclofen; against A. citricola, compounds 5d and 5j displayed > 2.0-fold potent aphicidal activity of spirodiclofen. The relationships between their structures and agricultural activities were also discussed. CONCLUSION: Compounds 5b and 5d could be further studied as acaricidal and aphicidal agents, respectively; compound 5j can be considered as a lead compound for the insecticidal and aphicidal activities. This will pave the way for future application of these derivatives as pesticide substitutes for spirodiclofen. © 2021 Society of Chemical Industry.

Construction of oxime ester derivatives of osthole from Cnidium monnieri, and evaluation of their agricultural activities and control efficiency.

BACKGROUND: In order to discover natural-product-based pesticidal candidates, a series of coumarin-like derivatives containing oxime ester fragments at the C-8 position were prepared by structural modification of osthole, a natural plant product isolated from Cnidium monnieri. Their pesticidal activities were evaluated against two typically fruit trees/crop-threatening agricultural pests, Mythimna separata Walker and Tetranychus cinnabarinus Boisduval. RESULTS: Osthole was regioselectively oxidized by selenium dioxide to give the E-isomer, (2'E)-3'-formaldehydylosthole (2). Four key steric structures of 2, (2'E, 4'E)-(o-chloropyrid-3-ylcarbonyl)oximinylosthole (4o), (2'E, 4'E)-(styrylcarbonyl)oximinylosthole (4t), and (2'E, 4'E)-(acetyl)oximinylosthole (4w) were undoubtedly confirmed by X-ray crystallography. Against T. cinnabarinus, it is noteworthy that (2'E, 4'E)-(p-chlorophenylcarbonyl)oximinylosthole (4c) exhibited over three-fold more potent acaricidal activity of the precursor osthole, with especially good control efficiency observed in the glasshouse. Against M. separata, compounds 4c and (2'E, 4'E)-(p-nitrophenylcarbonyl)oximinylosthole (4f) showed the most pronounced growth inhibitory activity. The relationships between their structures and agricultural activities also were studied. CONCLUSION: These results demonstrate that compound 4c could be further structurally modified as pesticidal agents. It will lay the foundation for future application of osthole derivatives as pesticides. © 2020 Society of Chemical Industry.

Non-food bioactive products for insecticides (II): Investigation on stress responses of Tetranychus cinnabarinus Boisduval against a derivative of the alkaloid matrine.

Besides structural modification of natural bioactive products to afford promising agrochemical candidates, investigation of their mechanisms of action against pests is also an important strategy to obtain novel potentially botanical pesticides. N-(p-Ethyl)phenylsulfonylmatrinic acid (2), derived from an natural alkaloid matrine (1), exhibited about 5.9-fold more pronounced acaricidal activity than 1 against the adult females of Tetranychus cinnabarinus Boisduval, and good control efficiency in the greenhouse. By comparison of nAChR, AChE and VGSC of treated and untreated T. cinnabarinus via RT-PCR and qRT-PCR analysis, it was found that compound 2 could activate nAChR and VGSC via up-regulation of nAChR α1, α4 and α5 subunits and VGSC expressions; compound 2 may be the AChE and AChE enzyme inhibitor. Importantly, a scheme of compound 2 interaction with nAChR, AChE and VGSC of T. cinnabarinus was proposed. It will lay the foundation for future optimization and application of matrine derivatives as agrochemicals.

Preparation of Matrinic/Oxymatrinic Amide Derivatives as Insecticidal/Acaricidal Agents and Study on the Mechanisms of Action against Tetranychus cinnabarinus.

In continuation of our program to develop natural-product-based pesticidal candidates, matrinic/oxymatrinic amides were obtained through structural optimization of matrine. N'-(4-Fluoro)phenyl-N-(4-bromo)phenylsulfonyloxymatrinic amide (IIm) showed potent insecticidal activity against Mythimna separata. N-(Un)substituted phenylsulfonylmatrinic acids (3a-c) exhibited promising acaricidal activity against Tetranychus cinnabarinus. By qRT-PCR analysis of nAChR subunits and AChE genes and determination of AChE activity of (un)treated T. cinnabarinus, it suggested that the open lactam ring of matrine and carboxyl group and (4-methyl)phenylsulfonyl of N-(4-methyl)phenylsulfonylmatrinic acid (3b) were necessary for action with α2, α4, α5, and ß3 nAChR subunits; compound 3b was an inhibitor of AChE in T. cinnabarinus, and AChE was one possible target of action in T. cinnabarinus against 3b; and compound 3b may be an antagonist of nAChR and AChE in T. cinnabarinus.

Synthesis of some ester derivatives of 4'-demethoxyepipodophyllotoxin/2'-chloro-4'-demethoxyepipodophyllotoxin as insecticidal agents against oriental armyworm, Mythimna separata Walker.

Podophyllotoxin is a naturally occurring non-alkaloid toxin isolated from the roots and rhizomes of Podophyllum peltatum and P. hexandrum. In continuation of our program aimed at the discovery and development of natural product-based insecticides, two series of ester derivatives of 4'-demethoxyepipodophyllotoxin/2'-chloro-4'-demethoxyepipodophyllotoxin were prepared. The structures of the target compounds were well characterized by 1H NMR, IR, optical rotation and mp. The precise three-dimensional structural information of 8j was further determined by single-crystal X-ray diffraction. Their insecticidal activity was tested against Mythimna separata Walker. These compounds showed delayed insecticidal activity. Among all derivatives, some compounds showed more potent insecticidal activity than toosendanin against M. separata; especially compounds 8k and 9k exhibited the most potent activity with the final mortality rates of 71.4%. Their structure-activity relationships were discussed.

Semisynthesis of Esters of Fraxinellone C4/10-Oxime and Their Pesticidal Activities.

A total of 20 esters of fraxinellone C4/10-oxime were synthesized and determined by melting points, optical rotation, infrared spectra, proton nuclear magnetic resonance spectra, and high-resolution mass spectrometry spectra. Two steric configurations of compounds 7i and 8i were unambiguously confirmed by X-ray crystallography. Additionally, their pesticidal activities were assessed on two typical lepidopteran pests, Mythimna separata Walker and Plutella xylostella Linnaeus. Generally, all compounds exhibited less potent oral toxicity than toosendanin against third-instar larvae of P. xylostella. However, all compounds showed the growth inhibitory property against early third-instar larvae of M. separata. Notably, compounds 7m, 8b, 8k, 9, and 11 displayed more potent pesticidal activity than toosendanin. This demonstrated that introducing the C-4 carbonyl or oxime group on fraxinellone resulted in more promising derivatives than those bearing a C-10 carbonyl or oxime substituent.

Constructing (super)alkali-boron-heterofullerene dyads: an effective approach to achieve large first hyperpolarizabilities and high stabilities in M3O-BC59 (M = Li, Na and K) and K@n-BC59 (n = 5 and 6).

Using DFT methods, the electronic properties and the first hyperpolarizabilities of boron-heterofullerene-(super)alkali dyads: M3O-BC59 (M = Li, Na and K) and K@n-BC59 (n = 5 and 6) were systematically investigated. It is found that both M3O and K can effectively bind to BC59 with high binding energies (2.50-2.69 eV for K and 4.24-5.14 eV for M3O). The interaction between K and BC59 in K@n-BC59 is identified as primarily ionic in nature, whereas that between the superalkali M3O unit and BC59 becomes much stronger owing to the formation of a strong chemical bond (B-O bond). Moreover, compared with the sole parent cluster BC59 (619 au), both K@n-BC59 (n = 5 and 6) and M3O-BC59 (M = Li, Na and K), possess large first hyperpolarizabilities (ß0), which are 3352, 2621 and 4921, 5440 and 7800 au, respectively, where the superalkali doped dyads (M3O-BC59) are much superior to the simple alkali exo-hedral species (K@n-BC59), and heavier superalkali can be more powerful in enhancing the ß0 values of M3O-BC59. Clearly, these superalkali doped dyads M3O-BC59, formal donor-acceptor (DA) chromophores, exhibit not only excellent stability but also large first hyperpolarizability; therefore, they are expected to be potential candidates for excellent second-order NLO materials.