[Changes in Ozone Pollution Trend Characteristics and Sensitivity in Jinan from 2015 to 2020].

The surface ozone (O3) spatiotemporal distribution, variations, and its causes in Ji'nan from 2015 to 2020 were revealed based on the air quality monitoring network data and satellite retrievals from the Ozone Monitoring Instrument (OMI). The results showed that the ozone concentration in Ji'nan gradually increased from 2015 to 2020. The annual 90th percentile of the daily maximum 8-h average (MDA8) O3(namely the annual evaluation value) and the MDA8 O3(April-September) increased by 4.8 µg·(m3·a)-1 and 3.8 µg·(m3·a)-1, respectively. The trend of the ozone levels in the high-concentration range increased faster than that in the low-concentration range. The MDA8 in June increased by 7.4 µg·(m3·a)-1, and the rate range of increases was 2.6-3.9 µg·(m3·a)-1 in the cool seasons (December-February); thus, the O3 control in winter cannot be ignored. It is apparent from the diurnal variations in ozone from 2015 to 2020 in April-September that the average ozone levels have risen in recent years. The growth rate in the daytime was higher than that at night. The capacity of photochemical production has been increasing, especially in recent years. Additionally, it is noteworthy that the peak time for ozone levels occurred approximately 1-2 h earlier. The disparity of ozone concentrations among different stations gradually decreased in recent years. Compared with that in 2015, the range of areas with high O3 concentrations in 2019-2020 was further expanded. The significant positive trends in MDA8-90th and MDA8 (April-September) were observed in 16.1% and 22.6% of the monitoring sites in Ji'nan (P<0.05), most of which were located in urban areas and the suburbs close to urban areas. The temporal and spatial changes in ozone in Jinan had been affected by the changes in VOCs and NOx emissions since 2015. Satellite remote sensing data from 2015 to 2020 revealed that the NO2 tropospheric columns (April-September) showed reductions of 20.6%, with a decreasing rate of 0.3×1015 mole·(cm2·a)-1, especially in the urban areas and suburbs. The detected variation trends of tropospheric HCHO were weak and insignificant, which suggested that the decrease in NOx emissions was much greater than the decrease in VOCs emissions, and the gap had become more obvious in the urban areas. With responses to precursor emissions, the chemical sensitivity of O3 formation had been changing. The VOCs-limited regimes continuously decreased, and the mixed NOx/VOCs-sensitive regimes and NOx-limited regimes increased. In general, such an extremely inappropriate control ratio of ozone precursor NOx/VOCs led to an overall trend of slow increasing fluctuations of O3 in Ji'nan. The findings clearly indicate that the reduction of VOCs in Ji'nan was far from sufficient, and strengthening the current control of VOCs emissions is an effective measure to control the growth trend of O3 pollution in Ji'nan in the near future, especially in urban and surrounding suburban areas.

Combined effects of prenatal phthalate exposure on cardiometabolic risk score among 4- to 7-year-old children: MABC study.

There is currently no consensus about the impact of prenatal phthalate exposure on blood pressure and glycolipids in children. Few studies consider the health effects as an integrated indicator. The combined effect of multiple phthalate exposures is often ignored. Based on the Ma'anshan Birth Cohort, 2298 woman-child pairs were included in this study. Maternal urine was collected in each trimester to analyze 6 phthalate metabolites. The overall cardiometabolic risk (CMR) score was calculated based on serum glycolipids and blood pressure for children aged 4-7 years. A higher score represents a less favorable CMR profile. The restricted cubic spline model was used to explore the relationship between prenatal phthalate exposure and childhood CMR score. In addition, the quantile g-computation and the Bayesian kernel machine regression were used to evaluate the combined effect. The MBP exposure in the 1st trimester (MBP-1st) and the MEP-2nd were non-linearly associated with the CMR score (Fnonlinear = 3.28 and 5.60, Pnonlinear = 0.0378 and 0.0038, respectively). The MBP-3rd (Flinear = 5.31, Plinear = 0.0012) and the ∑LMWP-3rd (Flinear = 4.37, Plinear = 0.0045) were negatively associated with the score in a linear manner. The phthalate mixture in the 2nd trimester increased the score (psil = 0.1747, 95% CI = 0.0077-0.3416), with the MEP being the most common [weights = 0.5290; posterior inclusion probability (PIP) = 0.40]. The phthalate mixture in the 3rd trimester decreased the score (psil = -0.2024, 95% CI = -0.4097－0.0048), with the MEHP (weights = -0.5101; PIP = 0.14) and the MBP (weights = -0.3993, PIP = 1.00) being the greatest contributors. In conclusion, the MBP-1st and the MEP-2nd are non-linearly associated with the cardiometabolic risk in children. The MBP-3rd and the ∑LMWP-3rd decrease the childhood risk. The combined exposure to phthalate mixture in the second and third trimester elevates and decreases the risk of childhood cardiometabolism, respectively.

Evaluation of high-risk factors and the diagnostic value of alpha-fetoprotein in the stratification of primary liver cancer.

BACKGROUND: Alpha-fetoprotein (AFP) is one of the diagnostic standards for primary liver cancer (PLC); however, AFP exhibits insufficient sensitivity and specificity for diagnosing PLC. AIM: To evaluate the effects of high-risk factors and the diagnostic value of AFP in stratified PLC. METHODS: In total, 289 PLC cases from 2013 to 2019 were selected for analysis. First, the contributions of high-risk factors in stratifying PLC were compared according to the following criteria: Child-Pugh score, clinical stage of liver cirrhosis, tumor size, and Barcelona Clinic Liver Cancer (BCLC) stage. Then, the diagnostic value of AFP was evaluated in different stratifications of PLC by receiver operating characteristic curves. For PLC cases in which AFP played little role, the diagnostic values of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9), gamma-glutamyl transferase (GGT), and AFP were analyzed. RESULTS: The roles of high-risk factors differed in stratified PLC. The incidence of smoking and drinking history was higher in PLC with Child-Pugh scores of C (P < 0.0167). The hepatitis B virus (HBV) infection rate in PLC with cirrhosis was more than in PLC without cirrhosis (P < 0.0167). Small tumors were more prone to cirrhosis than large tumors (P < 0.005). BCLC stage D PLC was more likely to be associated with HBV infection and cirrhosis (P < 0.0083). AFP levels were higher in PLC with cirrhosis, diffuse tumors, and BCLC stage D disease. In diagnosing PLC defined as Child-Pugh A, B, and C, massive hepatoma, diffuse hepatoma, BCLC stage B, C, and D, and AFP showed significant diagnostic value [all area under the curve (AUC) > 0.700]. However, these measures were meaningless (AUC < 0.600) in small hepatomas and BCLC A stage PLC, but could be replaced by the combined detection of CEA, CA 19-9, GGT, and AFP (AUC = 0.810 and 0.846, respectively). CONCLUSION: Stratification of PLC was essential for precise diagnoses and benefited from evaluating AFP levels.

Impacts of Mercury Exposure Levels and Sources on the Demethylation of Methylmercury Through Human Gut Microbiota.

This study aims to investigate methylmercury (MeHg) demethylation processes in human gut. Here, we determined the compositions and MeHg demethylation rates of gut microbiota in residents from different Hg exposure levels (Wanshan (WS) town and Yangtou (YT) town) and different Hg exposure sources (Zhuchang (ZC) town and YT town) regions. MeHg and inorganic Hg exposure levels in residents of WS town were significantly higher than those of YT and ZC town. Desulfovibrio and Methanogens, which related to Hg methylation/demethylation, showed significantly higher abundance in WS and ZC, comparing with YT. In vitro experiments demonstrated that human intestinal microbiota could degrade MeHg directly. Besides, gut microbiota in WS and ZC exhibited significantly higher demethylation rates than YT, suggesting Desulfovibrio and Methanogens may play important roles in intestinal MeHg demethylation. This study highlights Hg exposure levels and sources may affect demethylation efficiency of gut microbiota, which provides new insights for MeHg demethylation processes in human body.

Laparoscopic Glissonian pedicle versus hilar dissection approach hemihepatectomy: A prospective, randomized controlled trial.

BACKGROUND/PURPOSE: This over 7-year case study is the first to compare the results of laparoscopic Glissonian pedicle approach hemihepatectomy (LGAH) and laparoscopic hilar dissection approach hemihepatectomy (LHAH) in a randomized controlled trial (RCT). METHODS: Patients who had undergone laparoscopic hemihepatectomy, either LGAH or LHAH, between March 2012 and December 2019 at our center were prospectively enrolled and assigned to the LGAH or LHAH group. Both groups were stratified and compared, and the preoperative and follow-up outcomes were analyzed. The primary endpoint was total operative time. RESULTS: The groups were equally matched for age, sex, HBsAg, Child-Pugh class, benign disease, malignancy, liver cirrhosis, tumor diameter and type of resection. Ninety-six patients had undergone LGAH and 94 had undergone LHAH. No preoperative death occurred in the two groups. LGAH did not enhance the postoperative overall complication rates (P = .465) or intraoperative blood loss (P = .535) compared with LHAH. However, the overall operative time (P = .014) and hilar dissection time (P = .000) were significantly shorter in the LGAH group than in the LHAH group. No significant differences were found between the groups regarding the 1-year (P = .384), 3-year (P = .332), and 5-year overall survival rates (P = .662) or 1-year (P = .856), 3-year (P = .348), and 5-year disease-free survival rates (P = .573). CONCLUSIONS: LGAH and LHAH are both effective procedures for treating the hilar structures in selected patients. LGAH has advantages over LHAH in reducing total operation time under the condition where both procedures can be used. LGAH for selected patients is worthy of promotion owing to its simplicity and convenience. REGISTRATION NUMBER: NCT01567631 (http://www. CLINICALTRIALS: gov).

RCN1 induces sorafenib resistance and malignancy in hepatocellular carcinoma by activating c-MYC signaling via the IRE1α-XBP1s pathway.

The increasing incidence of hepatocellular carcinoma (HCC) is of great concern globally, but the molecular pathogenesis of these tumors remains unclear. Sorafenib is a first-line drug for the treatment of advanced HCC. However, the efficacy of sorafenib in improving patient survival is limited, and most patients inevitably develop resistance to this drug. Recent studies have demonstrated that the activation of the IRE1α-XBP1s pathway might play a protective role in the response to sorafenib and contribute to malignancy in HCC. Here, we found that RCN1, an endoplasmic reticulum resident protein, is significantly upregulated in sorafenib-resistant HCC cells and promotes tumor progression. Our analysis showed that RCN1 may be an independent predictor of tumor recurrence and overall survival. Mechanistically, RCN1 promotes the dissociation of GRP78 from IRE1α in sorafenib-resistant cells by interacting with GRP78 through its EFh1/2 domain. Subsequently, the IRE1α-XBP1s pathway, a branch of the unfolded protein response, is sustainably activated. Interestingly, IRE1α-XBP1s pathway activity is required for c-MYC signaling, one of the most highly activated oncogenic pathways in HCC. These results suggest that RCN1-targeted therapy might be a feasible strategy for the treatment of HCC.

Synthesis and Biological Evaluation of Celastrol Derivatives with Improved Cytotoxic Selectivity and Antitumor Activities.

Cdc37 associates kinase clients to Hsp90 and promotes the development of cancers. Celastrol, a natural friedelane triterpenoid, can disrupt the Hsp90-Cdc37 interaction to provide antitumor effects. In this study, 31 new celastrol derivatives, 2a-2d, 3a-3g, and 4a-4t, were designed and synthesized, and their Hsp90-Cdc37 disruption activities and antiproliferative activities against cancer cells were evaluated. Among these compounds, 4f, with the highest tumor cell selectivity (15.4-fold), potent Hsp90-Cdc37 disruption activity (IC50 = 1.9 µM), and antiproliferative activity against MDA-MB-231 cells (IC50 = 0.2 µM), was selected as the lead compound. Further studies demonstrated 4f has strong antitumor activities both in vitro and in vivo through disrupting the Hsp90-Cdc37 interaction and inhibiting angiogenesis. In addition, 4f exhibited less toxicity than celastrol and showed a good pharmacokinetics profile in vivo. These findings suggest that 4f may be a promising candidate for development of new cancer therapies.

Optimization of N-Phenylpropenoyl-l-amino Acids as Potent and Selective Inducible Nitric Oxide Synthase Inhibitors for Parkinson's Disease.

N-Phenylpropenoyl-l-amino acids (NPAs) are inducible nitric oxide synthase (iNOS) inhibitors possessing preventive effects for Parkinson's disease (PD). Here, structural modifications for improving the iNOS inhibitory activity and blood-brain barrier (BBB) permeability of NPAs were conducted, leading to 20 optimized NPA derivatives (1-20). Compound 18, with the most potent activity (IC50 = 74 nM), high BBB permeability (Pe = 19.1 × 10-6 cm/s), and high selectivity over other NOS isoforms, was selected as the lead compound. Further studies demonstrated that 18 directly binds to iNOS. In the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced acute PD model, the oral administration of 18 (1 and 2 mg/kg) exerted preventive effects by alleviating the loss of dopaminergic (DAergic) neurons. Notably, in the MPTP-/probenecid-induced chronic PD model, the same dose of 18 also displayed a therapeutic effect by repairing the damaged DAergic neurons. Finally, good pharmacokinetic properties and low toxicity made 18 a promising candidate for the treatment of PD.

Origin of Magnetic Relaxation Barriers in a Family of Cobalt(II)-Radical Single-Chain Magnets: Density Functional Theory and Ab Initio Calculations.

Density functional theory (DFT) and ab initio calculations were performed to probe the origin of the magnetic relaxation barriers for two finite single-chain magnets (SCMs) featuring a one-dimension chain, Co(hfac)2(R-NapNIT) (R-NapNIT = 2-(2'-(R-)naphthyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, R = MeO (1) or EtO (2)). Our calculations show that the strong intrachain CoII-CoII exchange coupling interactions transmitted by radicals can contribute much more than ionic anisotropy to the height of the reversal barrier of magnetization for the single-chain magnets (SCMs) with |2E| < |4J/3|. In addition, the anisotropic energy barrier ΔA decreases with the decrease of |2E/J| ratio and finally vanishes in the limit of broad domain walls (|2E| < < |4 J/3|). Therefore, the total magnetic relaxation energy barriers of two SCMs mostly originate from the correlation energy barrier Δξ deriving from the indirect ferromagnetic interaction between CoII-CoII transmitted by the strong CoII-radical antiferromagnetic interactions.

Comparison of long-term oncologic outcomes laparoscopy-assisted gastrectomy and open gastrectomy for gastric cancer.

PURPOSE: Laparoscopy-assisted gastrectomy (LAG) is proven by considerable studies as a safe procedure for early gastric cancer (EGC), but its long-term oncologic outcomes in advanced gastric cancer (AGC) have not been well-described. This study aimed at verifying the non-inferiority of LAG in the treatment of EGC and comparing the oncological feasibility of LAG and open gastrectomy (OG) for AGC. METHODS: A total of 209 consecutive patients who underwent LAG or OG with D2 lymph node dissection between December 2008 and November 2012 were included. The survival rate was estimated with the Kaplan-Meier method and the risk factors affecting the survival and recurrence were evaluated with Cox regression models. Subgroup analysis was performed in AGC patients receiving both distal and total gastrectomy. RESULTS: Of 209 patients, 194 (92.8%; mean age, 62.7 years; 56 [28.9%] women) eligible patients were finally enrolled in this study. No significant differences in the number of lymph nodes retrieved and postoperative complications were observed between patients receiving LAG and OG. During a mean follow-up of 58.3 ± 38.1 months (range 0-121 months), the 5-year overall survival and disease-free survival rates were 56.1% and 53.0% for LAG, and 57.7% and 50.9% for OG. In the subgroup analysis for AGC, laparoscopy-assisted distal gastrectomy and total gastrectomy did not result in inferior long-term outcomes, and recurrence was found in 49 patients (31.2%). Age more than 65 years and the advanced tumor stage were independent risk factors of survival. CONCLUSION: LAG is a feasible and safe treatment for gastric cancer, with good oncologic results.

Why lanthanide ErIII SIMs cannot possess huge energy barriers: a theoretical investigation.

Complete active space self-consistent field (CASSCF) combined with restricted active space spin interaction with spin-orbit coupling (RASSI-SO) was used to probe why single-ion magnets (SIMs) composed of the "prolate" lanthanide ion ErIII cannot possess huge energy barriers. According to the proposal by Long et al., equatorially coordinated ligand environments are preferable for "prolate" lanthanide ions to have large energy barriers. However, our calculations show that the larger gx,y values in the first excited Kramers' doublets (KDs) induced by the surrounding equatorially coordinated ligands lead to their larger transversal magnetic moments which result in fast quantum tunneling of magnetizations (QTMs) in their first excited states. Therefore, the spin-phonon transitions can only proceed from the ground to the first excited KDs for our studied three compounds and all models. However, the effective energy barriers Ueff of the three compounds are smaller than the calculated energy gaps between the lowest two KDs due to their more flexible molecular structures. For the above reason, the energy barriers did not increase continuously as we expected when we decreased the Er-L bond lengths. We deduced that mononuclear ErIII compounds cannot easily possess huge energy barriers through enhancing the surrounding equatorially coordinated ligand field.

A family of lanthanide complexes with a bis-tridentate nitronyl nitroxide radical: syntheses, structures and magnetic properties.

Eleven new lanthanide complexes based on a bis-tridentate nitronyl nitroxide radical NIT-Pm2Py (2-(4,6-di(pyridin-2-yl)pyrimidin-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy-3-oxide), namely (NIT-Pm2Py)Ln(hfac)3 (Ln = Gd (1Gd), Tb (2Tb), Dy (3Dy), Ho (4Ho), Er (5Er), Yb (6Yb)), [(NIT-Pm2Py)Ln2(hfac)6]·xH2O (Ln = Gd (7Gd), Tb (8Tb), Ho (10Ho), x = 0.5 for 7Gd and 1 for 8Tb and 10Ho) and (NIT-Pm2Py)Ln2(hfac)6 (Ln = Dy (9Dy), Er (11Er)) were prepared and characterized. These complexes can be selectively prepared by controlling the reaction ratio of Ln(hfac)3·2H2O to the radical ligand NIT-Pm2Py. Single crystal X-ray crystallographic analyses confirmed that 1Gd-6Yb are isostructural 2p-4f LnIII-radical complexes, in which the NIT-Pm2Py radical acts as a terminal tridentate ligand chelating to one LnIII ion. On the other hand, 7Gd-11Er are isostructural 4f-2p-4f LnIII-radical-LnIII complexes with the NIT-Pm2Py acting as a bridging ligand between two LnIII ions. 7Gd-11Er represent a rare family of complexes showing the NIT bridged 4f-2p-4f three-spin motif. Alternating-current (ac) magnetic susceptibility investigations revealed that complex 6Yb exhibits field-induced frequency dependence, suggesting a possible field-induced single-molecule magnet behavior. Ab initio calculations were performed on all these complexes. The fitting of the magnetic susceptibilities of these complexes indicates weak antiferromagnetic coupling between the LnIII and NIT radical.

Single-Molecule Magnetism in Three Dy2 Complexes from the Use of a Pentadentate Schiff Base Ligand and Different Benzoates.

Three dinuclear dysprosium(III) complexes, [Dy2 L2 (O2 CPh)2 ]⋅2 MeOH (1), [Dy2 L2 {(2-NO2 )O2 CPh}2 ] (2), and [Dy2 L2 {(2-OH)O2 CPh}2 ]⋅MeOH⋅MeCN (3) (H2 L=N1 ,N3 -bis(4-chlorosalicyladehyde)diethylenetriamine), have been synthesized and structurally characterized. Complexes 1-3 possess similar Ln2 cores and differ in substituents at the benzyl rings of benzoates. Direct current (dc) magnetic susceptibility studies in the 2-300 K range showed weak antiferromagnetic interactions between two dysprosium(III) ions in 1-3. The alternating current (ac) magnetic susceptibility measurements indicated that they all exhibited SMM behavior. The strategic attachment of the -NO2 group (in 2) and the -OH functionality (in 3) on the skeleton of the benzoic acid led to subtle variations of the bond lengths and bond angles in the coordination environments of the central dysprosium(III) ions, consequently resulting in the enhancement of the energy barriers for 2 and 3. Complete-active-space self-consistent field (CASSCF) calculations were employed to rationalize the experimental outcomes. Theoretical calculations confirm the existence of antiferromagnetic interactions in 1-3, and the calculated dc magnetic susceptibility data agree well with those obtained experimentally. The computational results reveal more axial g tensors, as well as higher first excited Kramers doublets in 2 and 3; thus resulting in higher energy barriers in compounds 2 and 3.

Field-Induced Single-Ion Magnetic Behavior in Two Mononuclear Cobalt(II) Complexes.

The employment of a new rigid N-tridentate ligand, bis(1-chloroimidazo[1,5-a]pyridin-3-yl)pyridine (bcpp), in the construction of cobalt(II) single-ion magnets is reported. Two cobalt(II) complexes, [Co(bcpp)Cl2 ] (1) and [Co(bcpp)Br2 ] (2), have been prepared and characterized. Single-crystal XRD analyses reveal that complexes 1 and 2 are isostructural. They are pentacoordinated mononuclear cobalt(II) compounds with expected trigonal bipyramidal geometry. Both analysis of the magnetic data and ab initio calculations reveal easy-plane magnetic anisotropy (D>0) for 1 and 2. Detailed alternating current magnetic susceptibility measurements reveal the occurrence of slow magnetic relaxation behavior for the cobalt(II) centers of 1 and 2; thus indicating that both complexes are field-induced single-ion magnets.

Synthesis, Structures, and Single-Molecule Magnetic Properties of Three Dy2 Complexes.

To explore the influences of the subtle structural variations in the ligand backbones on the single-molecule magnetic properties of dinuclear dysprosium(III) complexes, three ligands-H2 L1 (H2 L1 =N1 ,N3 -bis(salicylaldehyde)diethylenetriamine), H2 L2 (H2 L2 =N1 ,N3 -bis(3-methoxysalicylidene)diethylenetriamine), and H2 L3 (H2 L3 =N1 ,N3 -bis(5-chlorosalicyladehyde)diethylenetriamine)-were synthesized and employed to prepare the expected dinuclear dysprosium(III) complexes. The three ligands differ in terms of the substituents at the benzene rings of the salicylaldehyde moieties. The reactions of Dy(NO3 )3 ⋅6 H2 O, pivalic acid, and the ligands H2 L1 , H2 L2 , and H2 L3 generated complexes with the formulae [Dy2 (L1 )2 (piv)2 ] (1), [Dy2 (L2 )2 (piv)2 ] (2), and [Dy2 (L3 )2 (piv)2 ]⋅ 2 MeCN (3), respectively. The purposeful attachment of the functional groups with varied sizes at the benzene rings of the salicylaldehyde backbones resulted in slight differences in the Dy-O-Dy bond angles and the Dy⋅⋅⋅Dy bond lengths in 1-3; consequently, the three complexes exhibited distinct magnetic properties. They all showed slow magnetization relaxation with energy barriers of 40.32 (1), 31.67 (2), and 33.53 K (3). Complete active space self-consistent field (CASSCF) calculations were performed on complexes 1-3 to rationalize the slight discrepancy observed in the magnetic behavior. The calculated results satisfactorily explained the experimental outcomes.

Effect of Bridging Ligands on Magnetic Behavior in Dinuclear Dysprosium Cores Supported by Polyoxometalates.

A family of dinuclear dysprosium cores bridged by different ligands within a polyoxometalates (POMs) framework, (TBA)8.5H1.5[(PW11O39)2Dy2X2(H2O)2]·6H2O (X = OH (1), F (2), OAc (3); TBA = tetra- n-butylammonium), was successfully synthesized and structurally characterized. Magnetic studies indicate that the bridging ligands can significantly affect the magnetic behaviors, with 1 and 3 showing antiferromagnetic coupling and 2 bridged by fluoride ions showing ferromagnetic interaction. 1 and 2 behaved as single-molecule magnets (SMMs) with the thermally activated energy barrier of 98(5) and 74(6) cm-1 under zero dc filed, respectively, whereas no SMM behavior was observed for 3 bridged by two µ-η1:η2-acetato ligands. Notably, the low-temperature fluorescence spectra of 1-3 provide valuable information on the energy levels, which are consistent with the anisotropic barriers determined by magnetic measurements. These results offer an insight into the magneto-optical correlation. Furthermore, the effective energy barrier of 1 reaches a breakthrough among all POM-based SMMs.

Reversible on-off switching of both spin crossover and single-molecule magnet behaviours via a crystal-to-crystal transformation.

The on-off switching of spin-crossover (SCO) and single-molecule magnetism (SMM) remains highly attractive, especially if it involves dynamic crystal-to-crystal transformation. Herein we report the first molecule, a mononuclear cobalt(ii) complex, that exhibits on-off switching between SCO and SMM reversibly during crystal-to-crystal transformation. Subtle structural transformation triggered by a simple dehydration-rehydration process induces significant geometrical changes of the CoII center and modification of the supramolecular interactions and switches its colour and magnetic properties (dark red/SCO-on/SMM-off ↔ orange/SCO-off/SMM-on). This work suggests that modification of the weak supramolecular interactions could be very effective in achieving switchable materials involving both SCO and SMM properties.

Atropisomeric meroterpenoids with rare triketone-phloroglucinol-terpene hybrids from Baeckea frutescens.

Baefrutones A-F (1-6), six new meroterpenoids with rare triketone-phloroglucinol-monoterpene/sesquiterpene frameworks, together with their biosynthetically related intermediate (±)-baeckenon B (7), were isolated from the aerial part of Baeckea frutescens under the guidance of HPLC-Q/TOF-MS2 investigation. Compounds 1-4 represent the first examples of natural meroterpenoids existing as four pairs of inseparable diastereomeric atropisomers (2 : 1, 1H NMR integration) caused by the restricted rotation around the C-6-C-7-C-1' bonds arising from the intramolecular hydrogen bond between C-1 carbonyl and 2'-OH. The discovery of these architectures not only largely enriched the chemodiversity of the meroterpenoid and atropisomer library, but also might be exciting and challenging for asymmetric organic synthesis. Their structures and absolute configurations were established by extensive spectroscopic analysis, X-ray diffraction, and ECD calculations. Compounds 5 and 6 were biomimetically synthesized from 7 and ß-caryophyllene via a regioselective oxidative hetero-Diels-Alder reaction, thus providing access to the construction of the 6/6/9/4 tetracyclic ring system. The anti-inflammatory activities of these meroterpenoids were also discussed.

Consecutive one-/two-step relaxation transformations of single-molecule magnets via coupling dinuclear dysprosium compounds with chloride bridges.

The double chloride-bridged dimer of a dinuclear dysprosium(iii) single-molecule magnet (SMM) was successfully isolated by assembling centrosymmetric dinuclear Dy2 SMMs. Such structural transformation involves the generation and cleavage of chloride bridges and leads to consecutive transformations of one- and two-step slow relaxation of magnetization.