Value of a nomogram model in early recurrence of pancreatic ductal adenocarcinoma after laparoscopic pancreaticoduodenectomy / 临床肝胆病杂志

ObjectiveTo investigate the risk factors for early tumor recurrence after laparoscopic pancreaticoduodenectomy （LPD） in patients with pancreatic ductal adenocarcinoma （PDAC）， and to establish a predictive model. MethodsA retrospective analysis was performed for the clinical data of 240 PDAC patients who underwent LPD in The First Hospital of Jilin University from April 2016 to July 2022， with early postoperative tumor recurrence （time to recurrence ≤12 months） as the study outcome. The patients were randomly divided into training group with 168 patients and validation group with 72 patients at a ratio of 7∶3. In the training group， there were 70 patients （41.67%） with early postoperative recurrence and 98 （58.33%） without early recurrence， and in the validation group， there were 32 （44.44%） with early postoperative recurrence and 40 （55.56%） without early recurrence. The chi-square test or the Fisher’s exact test was used for comparison of categorical data between groups； a logistic regression analysis was used to investigate the risk factors for early postoperative recurrence； the receiver operating characteristic （ROC） curve and the area under the ROC curve （AUC） were used to evaluate the discriminatory ability of the model， with AUC>0.75 indicating that the model had adequate discriminatory ability. The Bootstrap resampling method was used for validation after 1 000 times of random sampling， and the model was validated again in the validation group. The calibration curve and the Hosmer-Lemeshow goodness-of-fit test were used to evaluate the degree of calibration， and the decision curve analysis was used to evaluate clinical practicability. ResultsThe univariate and multivariate analyses showed that preoperative CA19-9 level≥37 U/mL （odds ratio ［OR］=6.265， 95% confidence interval ［CI］： 1.938‍ ‍—‍ ‍20.249， P<0.05）， maximum tumor diameter >3 cm （OR=10.878， 95%CI： 4.090‍ ‍—‍ ‍28.932， P<0.05）， poor tumor differentiation （OR=3.679， 95%CI： 1.435‍ ‍—‍ ‍9.433， P<0.05）， lymph node metastasis （OR=0.209， 95%CI： 0.080‍ ‍—‍ ‍0.551， P<0.05）， and absence of adjuvant chemotherapy after surgery （OR=0.167， 95%CI： 0.058‍ ‍—‍ ‍0.480， P<0.05）. A nomogram model was constructed based on these factors； the ROC curve analysis showed that the model had an AUC of 0.895 （95%CI： 0.846‍ ‍—‍ ‍0.943， P<0.001）， and the calibration curve and the Hosmer-Lemeshow test showed that the model had a good degree of calibration （P=0.173）. The decision curve analysis showed that the nomogram had a good clinical application value. ConclusionPreoperative CA19-9 level ≥37 U/mL， maximum tumor diameter >3 cm， poor tumor differentiation， lymph node metastasis， and absence of adjuvant chemotherapy after surgery are independent risk factors for the early recurrence of PDAC after LPD， and the nomogram model established based on these factors can effectively predict early postoperative recurrence.

Two Metastable Endohedral Metallofullerenes Sc2C2@C1(39656)-C82 and Sc2C2@C1(51383)-C84: Direct-C2-Insertion Products from Their Most Stable Precursors.

Endohedral metallofullerenes (EMFs) are sub-nano carbon materials with diverse applications, yet their formation mechanism, particularly for metastable isomers, remains ambiguous. The current theoretical methods focus mainly on the most stable isomers, leading to limited predictability of metastable ones due to their low stabilities and yields. Herein, we report the successful isolation and characterization of two metastable EMFs, Sc2C2@C1(39656)-C82 and Sc2C2@C1(51383)-C84, which violate the isolated pentagon rule (IPR). These two non-IPR EMFs exhibit a rare case of planar and pennant-like Sc2C2 clusters, which can be considered hybrids of the common butterfly-shaped and linear configurations. More importantly, the theoretical results reveal that despite being metastable, these two non-IPR EMFs survived as the products from their most stable precursors, Sc2C2@C2v(5)-C80 and Sc2C2@Cs(6)-C82, via a C2 insertion during the post-formation annealing stages. We propose a systematic theoretical method for predicting metastable EMFs during the post-formation stages. The unambiguous molecular-level structural evidence, combined with the theoretical calculation results, provides valuable insights into the formation mechanisms of EMFs, shedding light on the potential of post-formation mechanisms as a promising approach for EMF synthesis.

Functional dyspepsia treated with acupuncture of different frequencies: a randomized controlled trial / 中国针灸

OBJECTIVE@#To compare the clinical efficacy of acupuncture with different frequencies in the treatment of patients with functional dyspepsia (FD).@*METHODS@#A total of 90 patients with FD were randomly divided into a 3-time acupuncture treatment per week group (3-A group, 31 cases, 2 cases dropped off), a 1-time acupuncture treatment per week group (1-A group, 30 cases, 2 cases dropped off) and a control group (29 cases, 2 cases dropped off). In the two acupuncture groups, the acupoints were Zhongwan (CV 12) and bilateral Tianshu (ST 25), Neiguan (PC 6), Liangqiu (ST 34), Yanglingquan (GB 34), Zusanli (ST 36) and Taichong (LR 3), stimulated 3 times a week and once a week, respectively; and the treatment was given consecutively for 4 weeks. In the control group, no intervention was adopted, but the compensatory therapy was provided after the end of follow-up. The scores of the symptom index of dyspepsia (SID), self-rating anxiety scale (SAS) and self-rating depression scale (SDS) were compared among the 3 groups before treatment, after 4 weeks of treatment and in 4 and 8 weeks after treatment completion separately. The score of Nepean dyspepsia life quality index (NDLQI) was evaluated before treatment, after 2 and 4 weeks of treatment and in 4 and 8 weeks after treatment completion.@*RESULTS@#After 4 weeks of treatment and in 4 and 8 weeks after treatment completion, the scores of SID, SAS and SDS were all reduced in the 3-A group and the 1-A group when compared with the scores before treatment (P<0.000 1, P<0.05). After 4 weeks of treatment, the scores of SID, SAS and SDS in the two acupuncture groups were lower than those in the control group (P<0.000 1). After 2 and 4 weeks of treatment, the increased values of NDLQI score in the two acupuncture groups were all higher than those in the control group (P<0.05). In 4 and 8 weeks after treatment completion, the scores of SID, SAS and SDS in the 3-A group were lower than those in the 1-A group (P<0.001, P<0.05), and the increased values of NDLQI score in the 3-A group were higher than those in the 1-A group (P<0.000 1).@*CONCLUSION@#Acupuncture given 3 times per week is superior to the treatment given once per week in the aspects of relieving the clinical symptoms, improving the quality of life and regulating the emotional state in patients with FD. This efficacy is persistent for 8 weeks after treatment completion.

Improvement effects of Shangke xiaoyan hydrogel plaster on osteoarthritis model rats / 中国药房

OBJECTIVE To study the improvement effects of Shangke xiaoyan hydrogel plaster on osteoarthritis （OA） model rats. METHODS Rats were randomly divided into blank group， model group， voltaren group （200 mg/rat）， Shangke xiaoyan ointment group （500 mg/rat， containing Shangke xiaoyan fluid extract 50 mg） and Shangke xiaoyan hydrogel plaster group （200 mg/rat， containing Shangke xiaoyan fluid extract 50 mg）， with 8 rats in each group. Except for blank group， OA model was established in the other groups by injecting papain and L-cysteine into the right knee joint cavity of the rats； they applied the corresponding drugs， and changed the dressing once a day， for 14 consecutive days. The degree of knee joint swelling in rats was detected， and the magnetic resonance imaging characteristics of the knee joint in rats were observed； the levels of interleukin 1β （IL-1β）， IL-6， IL-18 and tumor necrosis factor （TNF- α） in rat serum were detected； the pathological and morphological characteristics of knee joint tissue were observed， and the histopathological and cartilage Mankin scores were performed； the protein expressions of IL-1β， IL-6 and TNF-α in knee joint tissue were all detected. RESULTS Compared with blank group， severe joint swelling， obvious joint effusion and patchy wear of the anterior horn of the lateral meniscus were observed in model group； the serum levels of IL-1β， IL-6， IL-18 and TNF- α and histopathological score and Mankin score were significantly increased （P＜0.05）； protein expressions of IL-1β， IL-6 and TNF-α in knee joint tissue were increased. Compared with model group， the knee swelling degree of the rats in Shangke xiaoyan hydrogel plaster group was reduced， a small amount 　　 of joint cavity effusion could be seen， and the shape of the meniscus was completely normal； the histopathological score E-mail：frankyan@cpu.edu.cn and Mankin score were significantly reduced （P＜0.05）levels of inflammatory factors in serum were reduced （P＜0.05） and those of knee tissue were decreased. CONCLUSIONS Shangke xiaoyan hydrogel plaster can improve OA of rats， the mechanism of which may be associated with reducing the levels of inflammatory factors in joint and serum.

Excretion of three alkaloids from Simiao Pills in urine, feces, and bile between normal and type 2 diabetic rats / 中国中药杂志

This study investigated the differences in excretion kinetics of three alkaloids and their four metabolites from Simiao Pills in normal and type 2 diabetic rats. The diabetes model was established in rats by injection of streptozotocin, and the alkaloids in urine, feces, and bile of normal and diabetic rats were detected by LC-MS/MS to explore the effect of diabetes on alkaloid excretion of Simiao Pills. The results showed that 72 h after intragastric administration of the extract of Simiao Pills, feces were the main excretion route of alkaloids from Simiao Pills. The total excretion rates of magnoflorine and berberine in normal rats were 4.87% and 56.54%, which decreased to 2.35% and 35.53% in diabetic rats, which had statistical significance(P<0.05). The total excretion rates of phellodendrine, magnoflorine, and berberine in the urine of diabetic rats decreased significantly, which were 53.57%, 60.84%, and 52.78% of those in normal rats, respectively. After 12 h of intragastric administration, the excretion rate of berberine in the bile of diabetic rats increased significantly, which was 253.33% of that of normal rats. In the condition of diabetes, the excretion rate of berberine metabolite, thalifendine significantly decreased in urine and feces, but significantly increased in bile. The total excretion rates of jateorrhizine and palmatine in the urine increased significantly, and t_(1/2) and K_e changed significantly. The results showed that diabetes affected the in vivo process of alkaloids from Simiao Pills, reducing their excretion in the form of prototype drug, affecting the biotransformation of berberine, and ultimately increasing the exposure of alkaloids in vivo, which would be conducive to the hypoglycemic effect of alkaloids. This study provides references for the clinical application and drug development of Simiao Pills in diabetes.

Carbene Addition Isomers of C70 formed in the Flame of Low-Pressure Combustion.

In the flames during low-pressure combustion, not only a rich variety of fullerenes but also many reactive intermediates can be produced (e.g., carbene, CH2) that are short-lived and cannot be stabilized directly under normal circumstances. These intermediates can be captured by fullerene carbon cages for stabilization. In this paper, three C71H2 isomers were synthesized in situ in low-pressure benzene-acetylene-oxygen diffusion flame combustion. The results, which were unambiguously characterized by single-crystal X-ray diffraction, show that the three isomers are carbene addition products of D5h-C70 on different sites. The relative energies and stability of different C71H2 isomers are revealed by Ultraviolet-Visible (UV-Vis) absorption spectroscopy, in combination with theoretical calculations, in this work. Both the in situ capture and theoretical study of these C71H2 isomers in low-pressure combustion will provide more information regarding carbene additions to other fullerenes or other carbon clusters at high temperatures.

Capturing nonclassical C70 with double heptagons in low-pressure combustion.

A double-heptagon-containing C70H6 (dihept-C70H6) was isolated and unambiguously characterized in the soot of low-pressure combustion, which shares the identical heptagonal cage as dihept-C70Cl6 previously identified in the products of carbon arc, and thus represents the first nonclassical fullerene isolable in both carbon arc and combustion.

Sulfur-Doped Quintuple [9]Helicene with Azacorannulene as Core.

Herein, a hetero(S,N)-quintuple [9]helicene (SNQ9H) molecule with an azacorannulene core was synthesized, currently representing the highest hetero-helicene reported in the field of multiple [n]helicenes. X-ray crystallography indicated that SNQ9H includes not only a propeller-shaped conformer SNQ9H-1, but also an unforeseen quasi-propeller-shaped conformer SNQ9H-2. Different conformers were observed for the first time in multiple [n≥9]helicenes, likely owing to the doping of heteroatomic sulfurs in the helical skeletons. Remarkably, the ratio of SNQ9H-1 to SNQ9H-2 can be regulated in situ by the reaction temperature. Experimental studies on the photophysical and redox properties of SNQ9H and theoretical calculations clearly demonstrated that the electronic structures of SNQ9H depend on their molecular conformations. The strategy of introducing heteroatomic sulfurs into the helical skeleton may be useful in constructing various conformers of higher multiple [n]helicenes in the future.

Acupuncture as adjuvant therapy for 32 cases of coronavirus disease 2019 / 中国针灸

OBJECTIVE@#To observe the clinical effect of acupuncture on coronavirus disease 2019 (COVID-19) based on the conventional treatment.@*METHODS@#A total of 35 patients with COVID-19 of mild or ordinary type were involved (3 cases dropped off). Acupuncture was applied on the basis of western medicine and Chinese materia medica treatment. Dazhui (GV 14), Fengchi (GB 20), Kongzui (LU 6), Hegu (LI 4), etc. were selected as the main acupoints, the supplementary acupoints and the reinforcing and reducing manipulations were selected according to syndrome differentiation. Acupuncture treatment was given once a day, 5 times a week. On day 3 and day 7 of acupuncture, relief condition of the main symptoms was observed. Before acupuncture and on day 3 and day 7 of acupuncture, efficacy evaluation scale of TCM on COVID-19 (efficacy evaluation scale) score was recorded. The effects of different intervention time of acupuncture on patients' hospitalization time were compared, the understanding of acupuncture treatment of patients discharged from hospital was recorded, the clinical efficacy and safety of acupuncture treatment were evaluated.@*RESULTS@#On day 3 and day 7 of acupuncture, the symptoms of lung system and non lung system were both relieved; the scores of efficacy evaluation scale were both decreased compared before acupuncture (P<0.05), and the efficacy evaluation scale score of day 7 of acupuncture were lower than day 3 of acupuncture (P<0.05). The average hospitalization time of patients received early acupuncture was shorter than late acupuncture (P<0.05). The total effective rate was 84.4% (27/32) on day 7 of acupuncture, which was higher than 34.4% (11/32) on day 3 of acupuncture (P<0.05). During the acupuncture treatment, there were neither adverse reactions in patients nor occupational exposures in doctors. The patients generally believed that acupuncture could promote the recovery of COVID-19 and recommended acupuncture treatment.@*CONCLUSION@#On the basis of the conventional treatment, acupuncture can effectively relieve the clinical symptoms in patients with COVID-19, early intervention of acupuncture can accelerate the recovery process. Acupuncture has good safety, clinical compliance and recognition of patients.

Brief analysis on main indications and compatibility rules of Ciliao (BL 32) based on data mining / 中国针灸

Based on the data mining technology, the main indications and compatibility rules of Ciliao (BL 32) were analyzed and summarized. The relevant literature was retrieved from the databases of CNKI, Wanfang, VIP, Cochrane Library, SinoMed, Scopus, Web of Science, EMbase and PubMed, from the date of establishment to September 8, 2021. Using the software of SPSS Modeler 18.0 and Gephi0.9.2, the included literature was analyzed by data mining. A total of 218 articles were included, of them, there were 36 articles using single-acupoint prescriptions and 182 articles using compound prescriptions. Acupuncture was the most frequently used intervention of Ciliao (BL 32), followed by electroacupuncture. Dysmenorrhea and labor analgesia were the dominant indications of single-acupoint prescriptions of Ciliao (BL 32), and 9 diseases i.e. dysmenorrhea, urinary incontinence, urinary retention, chronic pelvic inflammatory disease, chronic prostatitis and lumbar disc herniation were the dominant indications of compound prescriptions. The main indications of Ciliao (BL 32) involved diseases of reproductive system, urinary system and waist. There were 92 acupoints in compatibility with Ciliao (BL 32), which were main belonged to the bladder meridian, the conception vessel and the spleen meridian, the most frequently used acupoints were Sanyinjiao (SP 6), Guanyuan (CV 4), Shenshu (BL 23) and Zhongji (CV 3).

LIU Zhi-shun's experience in treatment of infertility with decreasing ovarian reserve with electroacupuncture / 中国针灸

To summarize LIU Zhi-shun's clinical experience in treatment of infertility with decreasing ovarian reserve (DOR) with electroacupuncture. LIU Zhi-shun believes that the location of infertility with DOR is the uterus, mainly involving the kidney, thoroughfare and conception vessels. He advocates to select acupoints by combining "disease-symptom-position" with prescription, and selects acupoint prescription of Bushen Tiaochong Zhuyun included Guanyuan (CV 4), Zigong (EX-CA 1), Tianshu (ST 25), Sanyinjiao (SP 6), Ciliao (BL 32) and Zhongliao (BL 33) for electroacupuncture treatment. The key points of operation are accurate positioning and deep acupuncture, focusing on regulating mind and getting qi, adopting electroacupuncture treatment and low frequency stimulation and treating slowly for long-term disease.

Simultaneous determination of seven effective components in Shenkui Tongmai granules based on UHPLC-MS/MS.

OBJECTIVES: The objective of the study was to establish the quality standard of the formulation of Shenkui Tongmai granules (SKTM) from the perspective of safety and effectiveness. METHODS: A sensitive and specific method to simultaneously detect seven effective components by ultra-high performance liquid chromatography-tandem-mass spectrometry (UHPLC-MS/MS) in SKTM, including calycosin 7-O-ß-d-glucopyranoside, icariin, sodium danshensu, hyperoside, astragaloside IV, hesperidin, and salvianolic acid, was developed and validated. A Kromasil 100-3.5 C18 column with a mobile phase of 6.5 mmol/l ammonium acetate in acetonitrile was used to separate these above-listed components. Gradient programming was used with a flow rate of 0.2 ml/min, and the components were achieved in 13 min. Multiple reaction monitoring (MRM) in positive/negative mode was applied for the MS/MS detection. KEY FINDINGS: The analytical method was satisfactorily validated for linearity, accuracy and precision, repeatability and stability. The developed UHPLC-MS/MS method had high repeatability and accuracy and it was in a good linear relationship within their respective ranges (r = 0.9999) with the RSD value of the sample recovery of less than 5%. CONCLUSIONS: The current method established here is suitable for use in determining seven effective components in SKTM simultaneously, which may provide a new reliable method for overall quality control of SKTM.

Comparative analysis of pharmacokinetics and intestinal absorption of six alkaloids between Sanmiao Pills and Simiao Pills in rats / 中国中药杂志

The present study investigated the differences in pharmacokinetics and intestinal absorption of six alkaloids in Sanmiao Pills and Simiao Pills in rats and explored the different efficacies of the two formulae. After oral administration of Sanmiao Pills and Simiao Pills in rats, blood samples were collected at different time points. Samples were prepared for the determination of six alkaloids in plasma by UPLC-MS/MS. The chromatography was performed on an ACE Excel 3 C_(18 )column with acetonitrile-0.1% formic acid in water as the mobile phase for gradient elution. Analytes were detected in the positive ion mode. Plasma concentrations and pharmacokinetic parameters were calculated. Intestinal absorption of alkaloids was investigated by single-pass intestinal perfusion and absorption parameters of ingredients were calculated. The results showed that the UPLC-MS/MS method for simultaneous determination of concentrations of six alkaloids in plasma was developed and validated by methodological investigations, such as specificity, calibration curves, precision, accuracy, recovery, matrix effect, and stability. The results of the pharmacokinetic assay revealed that C_(max) and AUC values of phellodendrine, berberine, magnoflorine, berberrubine, and jatrorrhizine in Simiao Pills were significantly increased, and CL/F values were reduced as compared with those in Sanmiao Pills, which indicated the increase in plasma concentrations of alkaloids. The intestinal absorption parameters K_(a )and P_(eff) values of phellodendrine, berberine, and jatrorrhizine in Simiao Pills were higher than those in Sanmiao Pills. The intestinal absorption and plasma concentrations of alkaloids in Simiao Pills were significantly higher than those in Sanmiao Pills, suggesting that the composition of Simiao Pills was more conducive to the alkaloids into the blood to resist inflammation and lower uric acid.

Clinical features and risk factors associated with severe COVID-19 patients in China / 中华医学杂志(英文版)

BACKGROUND@#Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly spread throughout the world. In this study, we aimed to identify the risk factors for severe COVID-19 to improve treatment guidelines.@*METHODS@#A multicenter, cross-sectional study was conducted on 313 patients hospitalized with COVID-19. Patients were classified into two groups based on disease severity (nonsevere and severe) according to initial clinical presentation. Laboratory test results and epidemiological and clinical characteristics were analyzed using descriptive statistics. Univariate and multivariate logistic regression models were used to detect potential risk factors associated with severe COVID-19.@*RESULTS@#A total of 289 patients (197 nonsevere and 92 severe cases) with a median age of 45.0 (33.0, 61.0) years were included in this study, and 53.3% (154/289) were male. Fever (192/286, 67.1%) and cough (170/289, 58.8%) were commonly observed, followed by sore throat (49/289, 17.0%). Multivariate logistic regression analysis suggested that patients who were aged ≥ 65 years (OR: 2.725, 95% confidence interval [CI]: 1.317-5.636; P = 0.007), were male (OR: 1.878, 95% CI: 1.002-3.520, P = 0.049), had comorbid diabetes (OR: 3.314, 95% CI: 1.126-9.758, P = 0.030), cough (OR: 3.427, 95% CI: 1.752-6.706, P < 0.001), and/or diarrhea (OR: 2.629, 95% CI: 1.109-6.231, P = 0.028) on admission had a higher risk of severe disease. Moreover, stratification analysis indicated that male patients with diabetes were more likely to have severe COVID-19 (71.4% vs. 28.6%, χ2 = 8.183, P = 0.004).@*CONCLUSIONS@#The clinical characteristics of those with severe and nonsevere COVID-19 were significantly different. The elderly, male patients with COVID-19, diabetes, and presenting with cough and/or diarrhea on admission may require close monitoring to prevent deterioration.

Interpretation of updated version 2020 of expert consensus decision pathway on the management of mitral regurgitation / 中国胸心血管外科临床杂志

@#American College of Cardiology (ACC) issued the updated expert consensus decision pathway on the management of mitral regurgitation in April 2020. The whole process in caring patients with mitral valve regurgitation from patient evaluation to treatment choice was discussed in the consensus. The main change from the 2017 version is the confirmation of the effect of transcatheter mitral valve repair on secondary mitral regurgitation. It standardized the process in this field. In this paper, we aimed to introduce the focus update of this consensus.

Rational synthesis of an atomically precise carboncone under mild conditions.

Carboncones, a special family of all-carbon allotropes, are predicted to have unique properties that distinguish them from fullerenes, carbon nanotubes, and graphenes. Owing to the absence of methods to synthesize atomically well-defined carboncones, however, experimental insight into the nature of pure carboncones has been inaccessible. Herein, we describe a facile synthesis of an atomically well-defined carboncone[1,2] (C70H20) and its soluble penta-mesityl derivative. Identified by x-ray crystallography, the carbon skeleton is a carboncone with the largest possible apex angle. Much of the structural strain is overcome in the final step of converting the bowl-shaped precursor into the rigid carboncone under mild reaction conditions. This work provides a research opportunity for investigations of atomically precise single-layered carboncones having even higher cone walls and/or smaller apex angles.

General One-step Synthesis of Symmetrical or Unsymmetrical 1,4-Di(organo)fullerenes from Organo(hydro)fullerenes through Direct Oxidative Arylation.

A general one-step synthesis of symmetrical or unsymmetrical 1,4-di(organo)fullerenes from organo(hydro)fullerenes (RC60H) is realized by direct oxidative arylation. The new combination of catalytic trifluoromethanesulfonic acid (TfOH) and stoichiometric o-chloranil is the first to be used to directly generate an R-C60+ intermediate from common RC60H. Unexpectedly, the in situ generated R-C60+ intermediate is shown to be quite stable in whole 13C NMR spectroscopy characterization in the absence of cation quenching reagents. Because the direct oxidation of common RC60H to form the corresponding R-C60+ has never been realized, the present combination of TfOH and o-chloranil solves the challenges associated with the formation of stable RC60+ cations from common RC60H without any coordination of an R group.

Double Negatively Curved C70 Growth through a Heptagon-Involving Pathway.

All previously reported C70 isomers have positive curvature and contain 12 pentagons in addition to hexagons. Herein, we report a new C70 species with two negatively curved heptagon moieties and 14 pentagons. This unconventional heptafullerene[70] containing two symmetric heptagons, referred to as dihept-C70 , grows in the carbon arc by a theoretically supported pathway in which the carbon cluster of a previously reported C66 species undergoes successive C2 insertion via a known heptafullerene[68] intermediate with low energy barriers. As identified by X-ray crystallography, the occurrence of heptagons facilitates a reduction in the angle of the π-orbital axis vector in the fused pentagons to stabilize dihept-C70 . Chlorination at the intersection of a heptagon and two adjacent pentagons can greatly enlarge the HOMO-LUMO gap, which makes dihept-C70 Cl6 isolable by chromatography. The synthesis of dihept-C70 Cl6 offers precious clues with respect to the fullerene formation mechanism in the carbon-clustering process.

An Unconventional Hydrofullerene C66H4 with Symmetric Heptagons Retrieved in Low-Pressure Combustion.

The combustion has long been applied for industrial synthesis of carbon materials such as fullerenes as well as carbon particles (known as carbon black), but the components and structures of the carbon soot are far from being clarified. Herein, we retrieve an unprecedented hydrofullerene C66H4 from a soot of a low-pressure combustion of benzene-acetylene-oxygen. Unambiguously characterized by single-crystal X-ray diffraction, the C66H4 renders a nonclassical geometry incorporating two heptagons and two pairs of fused pentagons in a C2 v symmetry. The common vertexes of the fused pentagons are bonded with four hydrogen atoms to convert the hydrogen-linking carbon atoms from sp2 to sp3 hybridization, which together with the adjacent heptagons essentially releases the sp2-bond strains on the abutting-pentagon sites of the diheptagonal fused pentagon C66 (dihept-C66). DFT computations suggest the possibility for an in situ hydrogenation process leading to stabilization of the dihept-C66. In addition, the experiments have been carried out to study heptagon-dependent properties of dihept-C66H4, indicating the key responsibility of the heptagon for changing hydrocarbon activity and electronic properties. The present work with the unprecedented double-heptagon-containing hydrofullerene successfully isolated and identified as one of the low-pressure combustion products shows that the heptagon is a new building block for constructing fullerene products in addition to pentagons and hexagons in low-pressure combustion systems.

Flexible decapyrrylcorannulene hosts.

The assembly of spherical fullerenes, or buckyballs, into single crystals for crystallographic identification often suffers from disordered arrangement. Here we show a chiral configuration of decapyrrylcorannulene that has a concave 'palm' of corannulene and ten flexible electron-rich pyrryl group 'fingers' to mimic the smart molecular 'hands' for self-adaptably cradling various buckyballs in a (+)hand-ball-hand(-) mode. As exemplified by crystallographic identification of 15 buckyball structures representing pristine, exohedral, endohedral, dimeric and hetero-derivatization, the pyrryl groups twist with varying dihedral angles to adjust the interaction between decapyrrylcorannulene and fullerene. The self-adaptable electron-rich pyrryl groups, susceptible to methylation, are theoretically revealed to contribute more than the bowl-shaped palm of the corannulene in holding buckyball structures. The generality of the present decapyrrylcorannulene host with flexible pyrryl groups facilitates the visualization of numerous unknown/unsolved fullerenes by crystallography and the assembly of the otherwise close-packed spherical fullerenes into two-dimensional layered structures by intercalation.