Thermal Annealing Effects on Long-lived Fluorenol Room Temperature Phosphorescence for Styrene Detection.

Fluorene derivatives have been widely developed in OLEDs because of its efficient fluorescence quantum efficiency, but for which unique rigid biphenyl planar structure and large conjugated system, we hypothesize that they have a great potential for room temperature phosphorescence (RTP) applications, and confirmed this conjecture by subjecting polyvinyl alcohol (PVA) and phosphors to thermal annealing. The cross-linked structure formed during thermal annealing judiciously modulates the phosphorescence emission characteristics of the fluorenol with the synergistic interaction between PVA and fluorenol. Specifically, the lifetime exhibited a substantial increase from 1352.2 ms to 2874.1 ms, accompanied by a quantum yield augmentation from 4.8% to 11.3%, which substantiate that cross-linked induced by thermal annealing effectively amplifies the phosphorescent intensity and stability of the phosphors, facilitating ultralong phosphorescent emission at ambient conditions. Furthermore, an effective probe based on this film is developed for its highly sensitive, quantitative and immediate detection of volatile organic compounds. This investigation not only proffers a novel paradigm for the development of advanced RTP materials but also imparts insightful considerations for optimizing the performance of polymers in conjunction with functional materials, encompassing bioimaging, sensing, and optoelectronic devices.

Flexible Resistive Gas Sensor Based on Molybdenum Disulfide-Modified Polypyrrole for Trace NO2 Detection.

High sensitivity and selectivity and short response and recovery times are important for practical conductive polymer gas sensors. However, poor stability, poor selectivity, and long response times significantly limit the applicability of single-phase conducting polymers, such as polypyrrole (PPy). In this study, PPy/MoS2 composite films were prepared via chemical polymerization and mechanical blending, and flexible thin-film resistive NO2 sensors consisting of copper heating, fluorene polyester insulating, and PPy/MoS2 sensing layers with a silver fork finger electrode were fabricated on a flexible polyimide substrate using a flexible electronic printer. The PPy/MoS2 composite films were characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, and field-emission scanning electron microscopy. A home-built gas sensing test platform was built to determine the resistance changes in the composite thin-film sensor with temperature and gas concentration. The PPy/MoS2 sensor exhibited better sensitivity, selectivity, and stability than a pure PPy sensor. Its response to 50 ppm NO2 was 38% at 150 °C, i.e., 26% higher than that of the pure PPy sensor, and its selectivity and stability were also higher. The greater sensitivity was attributed to p-n heterojunction formation after MoS2 doping and more gas adsorption sites. Thus, PPy/MoS2 composite film sensors have good application prospects.

Toxic effect of fluorene on Perinereis aibuhitensis body wall and its corresponding defense mechanisms: A metabolomics perspective.

Fluorene is a coastal sediment pollutant with high ecological risk. Perinereis aibuhitensis is an ecotoxicological model used for polycyclic aromatic hydrocarbon bioremediation; however, the effects of fluorene on the physiological metabolism of P. aibuhitensis and its corresponding responses remain unclear. This study explored the tolerance and defense responses of P. aibuhitensis in sediments with different fluorene concentrations using histology, ecological biomarkers, and metabolic responses. Metabolomics analyses revealed that P. aibuhitensis has high tolerance to fluorene in sediments. Fluorene stress disrupted the normal metabolism of the P. aibuhitensis body wall, resulting in excessive glycosphospholipid and stearamide accumulation and elevated oxygen consumption rates. To mitigate this, P. aibuhitensis has adopted tail cutting, yellowing, and modulation of metabolite contents in the body wall. This study provides novel insights into the potential ecological risk of fluorene pollution in marine sediments and proposes the use of P. aibuhitensis in the bioremediation of fluorene-contaminated sediments.

Functionalization of a [2]Catenane with Donor-Acceptor Chromophores Using a Metal Template and Click Reactions.

Synthesizing molecules with significant topological features, such as catenanes, tailored with specific groups to confer desired functionality, is essential for investigating various properties arising from the entanglement due to mechanical bonds. This investigation can pave the way for uncovering novel functional materials employing mechanically interlocked molecules (MIMs). In this direction, we have synthesized a p-donor (D) and p-acceptor (A) functionalized [2]catenane using a non-labile Co(III) metal ion as a template with pyridine-diamide templating center and utilizing click reaction for ring-closing. The donor group is a fluorene derivative, and the acceptor is a benzophenazine derivative, commonly employed in synthesizing conjugated polymers for various optoelectronic devices. Synthetically, the acceptor group was introduced into a macrocycle with a pyridine diamide unit. It was then threaded with a ligand having alkyne terminals to obtain the desired [2]pseudorotaxane utilizing cobalt ion as a template. Ring-closing was then performed with a di-azide functionalized molecule with the donor chromophore. The desired D-A functionalized [2]catenane is obtained after demetalation. All the starting materials, macrocycle, and entangled structures have been characterized by 1H-NMR, 13C-NMR, and mass spectroscopy. Some of these materials are also characterized by single-crystal X-ray analysis. The photophysical properties are studied by UV-visible and fluorescence spectroscopy.

Effects of Planarization of the Triphenylamine Unit on the Electronic and Transport Properties of Triarylamine-Fluorene Copolymers in Both Doped and Undoped Forms.

Triarylamine-alt-fluorene (TAF) copolymers are widely used for hole injection and transport in organic electronics. Despite suggestions to planarize the triphenylamine moiety, little research has been conducted. Here, we report a comprehensive investigation of the effects of planarization on the electronic and transport properties of a model TAF polymer semiconductor core. We compared the conventional twisted-propeller N-4-methoxyphenyl-N,N-diphenylamine-4',4″-diyl (TA) unit and its planarized bridged analogue (bTA) where adjacent o,o'-positions are linked by 1,1-dimethylmethylene. We studied both polyelectrolyte and non-polyelectrolyte forms of this core in both doped and undoped states. We found that planarization leads to an unprecedented trap-free transport of holes, and a pronounced enhancement of their mobility in the undoped state though less so in the doped state. Planarization also induces a slight reduction in the ionization energy of the undoped polymer, consequently lowering the work function of the doped polymer. This is accompanied by small spectral shifts: a red shift in the first absorption band of the undoped polymer and a blue shift in the first absorption band of the polaron. Furthermore, this study unveils new fundamental features of TAF polymers: (i) Doping induces the formation of three polaron bands within the subgap. (ii) Absorption of both neutral and polaron segments exhibit a linear intensity relationship with doping level. (iii) Electrical conductivity reaches a maximum at the half-doped state, varying as σ ∼ (x (1 - x))3 for 0.1 ≲ x ≲ 0.9, where x is the doping level. Finally, we demonstrate the successful integration of these self-compensated hole-doped TAF polymers as efficient hole injection layers in organic semiconductor diodes.

Evaluating Fluorinated-Aniline Units with Functionalized Spiro[Fluorene-9,9'-Xanthene] as Hole-Transporting Materials in Perovskite Solar Cells and Light-Emitting Diodes.

In the field of perovskite optoelectronics, developing hole-transporting materials (HTMs) on the spiro[fluorene-9,9'-xanthene] (SFX) platform is one of the current research focuses. The SFX inherits the merits of spirobifluorene in terms of the configuration and property, but it is more easily derivatized and regulated by virtue of its binary structure. In this work, we design and synthesize four isomeric SFX-based HTMs, namely m-SFX-mF, p-SFX-mF, m-SFX-oF, and p-SFX-oF, through varying the positions of fluorination on the peripheral aniline units and their substitutions on the SFX core, and the optoelectronic performance of the resulting HTMs is evaluated in both perovskite solar cells (PSCs) and light-emitting diodes (PeLEDs) by the vacuum thermal evaporating hole-transporting layers (HTLs). The HTM p-SFX-oF exhibits an improved power conversion efficiency of 15.21% in an inverted PSC using CH3NH3PbI3 as an absorber, benefiting from the deep HOMO level and good HTL/perovskite interface contact. Meanwhile, the HTM m-SFX-mF provides a maximum external quantum efficiency of 3.15% in CsPb(Br/Cl)3-based PeLEDs, which is attributed to its perched HOMO level and shrunken band-gap for facilitating charge carrier injection and then exciton combination. Through elucidating the synergistic position effect of fluorination on aniline units and their substitutions on the SFX core, this work lays the foundation for developing low-cost and efficient HTMs in the future.

Synthesis and luminescent properties of a linear difluorene pyrazine (D-A-D) derivative as a selective indicator for a reversible acid-base vapour sensor.

We have synthesized a structure in which pyrazine is the core structure and fluorene derivatives are attached to both sides. Photo physical investigations such as aprotic solvents (Hexane to DMF) were carried out. A redshift was revealed from non-polar aprotic solvents to polar aprotic solvents. The luminescence intensity was gradually decreased, which is incredibly more complex towards changes in the solvent polarization than their UV/Vis absorption spectra. The compound showed a redshift from 445 nm to 473 nm when slowly increasing the water fraction (fw) from 0 to 30 %. Also, rising water fraction (fw > 40-90 %) effectively attenuated the instantaneous emission intensity was observed. At the same time, the intensity of the emission peak was reduced due to the TICT effect on fluorene and pyrazine rings due to enhanced solvent polarity. In addition, optically reversible acidofluorochromic properties were performed experimentally in both solvent and solid phases. For the acidic substances TFA and HF, which contain fluorine, new redshift peaks from 425 nm and 503 nm were observed upon reaction with the PDF solution, and the emission intensity was extinguished by more than 90 % and 60 %, respectively. Upon addition of TFA up to 1500 equal, the PDF mixture suffered from 50 % lower energy absorption intensity. The 1H NMR spectrum confirmed the proposed mechanism (TFA/TEA, ON-OFF-ON). Therefore, the present work presents a novel approach to fabricating ON-OFF-ON active-pull pyrazine scaffolds that can be used in DSEgens, referred to as "ON-OFF-ON" fluorescent sensors, for multifunctional applications.

Design and synthesis of novel fluorene derivatives as inhibitors of pyruvate dehydrogenase kinase.

Activation of pyruvate dehydrogenase (PDH) by inhibition of pyruvate dehydrogenase kinase (PDHK) has the potential for the treatment of diabetes mellitus and its complications, caused by the malfunction of the glycolytic system and glucose oxidation. In this paper, we describe the identification of novel PDHK inhibitors with a fluorene structure. High-throughput screening using our in-house library provided compound 6 as a weak inhibitor that occupied the allosteric lipoyl group binding site in PDHK2. Structure-based drug design (SBDD) while addressing physicochemical properties succeeded in boosting inhibitory activity approximately 700-fold. Thus obtained compound 32 showed favorable pharmacokinetics profiles supported by high membrane permeability and metabolic stability, and exhibited activation of PDH in rat livers and a glucose lowering effect in Zucker fatty rats.

Maternal exposure to polycyclic aromatic hydrocarbons during pregnancy and timing of pubertal onset in a longitudinal mother-child cohort in rural Bangladesh.

BACKGROUND: In experimental studies, several polycyclic aromatic hydrocarbons (PAHs) have shown endocrine disrupting properties, but very few epidemiological studies have examined their impact on pubertal development and results have been heterogenous. OBJECTIVE: To explore if maternal PAH exposure during pregnancy was associated with the offspring's timing of pubertal onset. METHODS: We studied 582 mother-daughter dyads originating from a population-based cohort in a rural setting in Bangladesh. Maternal urinary samples, collected in early pregnancy (on average, gestational week 8), were analyzed for monohydroxylated metabolites of phenanthrene (1-OH-Phe, Σ2-,3-OH-Phe, and 4-OH-Phe), fluorene (Σ2-,3-OH-Flu), and pyrene (1-OH-Pyr) using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The girls were interviewed on two separate occasions concerning date of menarche, as well as breast and pubic hair development according to Tanner. Associations were assessed using Kaplan-Meier analysis and multivariable-adjusted Cox proportional hazards regression or ordered logistic regression. RESULTS: In early pregnancy, the mothers' median urinary concentrations of Σ1-,2-,3-,4-OH-Phe, Σ2-,3-OH-Flu, and 1-OH-Pyr were 3.25 ng/mL, 2.0 ng/mL, and 2.3 ng/mL respectively. At the second follow-up, 78 % of the girls had reached menarche, and the median age of menarche was 12.7 ± 0.81 years. Girls whose mothers belonged to the second and third quintiles of ΣOH-Phe metabolites had a higher rate of menarche, indicating a younger menarcheal age (HR 1.39; 95 % CI 1.04, 1.86, and HR 1.41; 95 % CI 1.05, 1.88, respectively), than girls of mothers in the lowest quintile. This trend was not observed in relation to either breast or pubic hair development. None of the other maternal urinary PAH metabolites or the sum of all thereof in early pregnancy were associated with age at menarche or pubertal stage. CONCLUSIONS: Indications of non-monotonic associations of prenatal phenanthrene exposure with the daughters' age of menarche were found, warranting further investigation.

Synthesis and Application of Robust Spiro [Fluorene-9] CAAC Ruthenium Alkylidene Complexes for the "One-Pot" Conversion of Allyl Acetate to Butane-1,4-diol.

A series of a novel CAAC ligands featuring a spiro-fluorene group have been synthesized and complexed with ruthenium alkylidenes, yielding the corresponding Hoveyda-type derivatives as a new family of olefin metathesis catalysts. The novel complexes have been characterized by XRD, HRMS and NMR measurements. The synthetised complexes were tested in catalysis and showed good activity in olefin metathesis, as demonstrated on diethyl diallylmalonate and allyl acetate substrates. The unique backbone in the ligand with the large, yet inflexible condensed system renders interesting properties to the catalyst, exemplified by the good catalytic performance and improved Z-selectivity. In addition, the complex can also serve as a hydrogenation catalyst in a consecutive (one-pot) reaction. The latter reaction can convert allyl acetate to butane-1,4-diol, a valuable chemical intermediate for biodegradable polybutylene succinate (PBS).

The deleterious effects and potential therapeutic strategy of fluorene-9-bisphenol on circadian activity and liver diseases in zebrafish and mice.

Increasing evidence indicates that disturbance of the clock genes, which leads to systemic endocrine perturbation, plays a crucial role in the pathogenesis of metabolic and liver diseases. Fluorene-9-bisphenol (BHPF) is utilized in the manufacturing of plastic materials but its biological effects on liver homeostasis remain unknown. The impacts and involved mechanisms of BHPF on the liver diseases, metabolism, and circadian clock were comprehensively studied by zebrafish and mouse models. The therapeutic effect of melatonin (MT) was also verified. Zebrafish and mouse models with either acute exposure (0.5 and 1 µmol/L, 1-4 days post-fertilization) or chronic oral exposure (0.5 and 50 mg/(kg·2 days), 30 days) were established with various BHPF concentrations. Herein, we identified a crucial role for estrogenic regulation in liver development and circadian locomotor rhythms damaged by BHPF in a zebrafish model. BHPF mice showed chaos in circadian activity through the imbalance of circadian clock component Brain and Muscle Aryl hydrocarbon receptor nuclear translocator-like 1 in the liver and brain. The liver sexual dimorphic alteration along with reduced growth hormone and estrogens played a critical role in damaged glucose metabolism, hepatic inflammation, and fibrosis induced by BHPF. Besides, sleep improvement by exogenous MT alleviated BHPF-related glucose metabolism and liver injury in mice. We proposed the pathogenesis of metabolic and liver disease resulting from BHPF and promising targeted therapy for liver metabolism disorders associated with endocrine perturbation chemicals. These results might play a warning role in the administration of endocrine-disrupting chemicals in everyday life and various industry applications.

Development of Fluorenyl-Based Copolyimines with Adjustable Mechanical Properties, Recyclability and Friction Resistance.

Dynamic polyimines are a class of fascinating dynamic polymers with recyclability and reparability owing to their reversible Schiff-base reactions. However, balancing the dynamic properties and mechanical strength of dynamic polyimines presents a major challenge due to the dissociative and associative nature of the imine bonds. Herein, we introduced bulky fluorene groups and polyether amine into the skeleton of polyimine networks to achieve a tradeoff in comprehensive properties. The resulting dynamic polyimines with fluorene groups (Cardo-DPIs) were successfully synthesized by combining the rigid diamine 9,9-bis(4-aminophenyl)fluorene and the flexible polyether amine, demonstrating a high tensile strength of 64.7 MPa. Additionally, Cardo-DPIs films with more content of rigid fluorene groups exhibited higher water resistance, glass transition temperature and wear-resisting ability. Moreover, the Cardo-DPIs films not only efficiently underwent thermal reshaping, but also exhibited excellent self-healing capabilities and chemical degradation in acidic solutions. Furthermore, the resulting films can achieve fully closed-loop recovery by free amine solution for 2 h at room temperature. This study broadens the scope of dynamic polyimine materials and promotes the balanced development of their functional and mechanical properties.

A New Fluorene-Based Fluorescent Probe for Recognition of Hypochlorite Ions and its Applications.

Oxidative stress is a trigger for many diseases and occurs with the unstable hypochlorite (ClO-), known as one of the reactive oxygen species (ROS) in organisms. Then, HOCI is acknowledged as an oxidizing species that eliminates a variety of environmental pollutants. Hence, the development of novel methodologies for the selective and precise identification of HOCl/ ClO- is considered to be of utmost importance. In this study, the design, characterization, and applications of a fluorene-based fluorescent probe (FHBP) dependent on the ESIPT mechanism with a "turn-on" response for the sensitive/selective determination of ClO- against other competing samples were reported. The experimental results indicated that the detection limit for ClO-could be quantitatively determined by the probe to be 8.2 × 10-7 M. The binding constant of the probe FHBP with ClO- was computed as 9.75 × 103 M-1. In addition, the response time of FHBP was appointed to be 30 s, indicating a rapid reaction with ClO-. It has also been demonstrated that this probe can be successfully used for the detection of ClO- on filter papers, TLC sheets, cotton swabs, and real samples.

Surface Treatment with Tailored π-Conjugated Fluorene Derivatives Significantly Enhances the Performance of Perovskite Light-Emitting Diodes.

Surface defect passivation and carrier injection regulation have emerged as effective strategies for enhancing the performance of perovskite light-emitting diodes (Pero-LEDs). It usually requires two functional molecules to realize defect passivation and carrier injection regulation separately. In other words, developing one single molecule possessing these capabilities remains challenging. Herein, we utilized π-conjugated fluorene derivatives as surface treatment materials, 9,9-Spirobi[fluorene] (SBF), 9,9-Spirobifluoren-2-yl-diphenylphosphine oxide (SPPO1), and 2,7-bis(diphenylphosphoryl)-9,9'-spirobifluorene (SPPO13), to investigate the influence of their chemical structure on device optoelectronic performance, especially for defect passivation and carrier injection regulation. Consequently, the passivation capability of double-bonded SPPO13 surpassed single-bonded SPPO1 and nonbonded SBF, which all showed excellent electron transport properties, enhancing electron injection. The maximum external quantum efficiencies (EQE) for Pero-LEDs treated with SBF, SPPO1, and SPPO13 were 8.13, 17.48, and 22.10%, respectively, exceeding that of the derivative-free device (6.55%). Notably, SPPO13-treated devices exhibited exceptional reproducibility, yielding an average EQE of 20.00 ± 1.10% based on 30 devices. This result emphasizes the potential of tailored fluorene derivatives for enhancing the device performance of Pero-LEDs.

Effects of fluorene-9-bisphenol exposure on anxiety-like and social behavior in mice and protective potential of exogenous melatonin.

Fluorene-9-bisphenol (BHPF) is widely used in the manufacture of plastic products and potentially disrupts several physiological processes, but its biological effects on social behavior remain unknown. In this study, we investigated the effects of BHPF exposure on anxiety-like and social behavior in female mice and the potential mechanisms, thereby proposing a potential therapy strategy. We exposed female Balb/c mice to BHPF by oral gavage at different doses (0.5, 50 mg/kg bw/2-day) for 28 days, which were found BHPF (50 mg/kg) exposure affected motor activity in the open field test (OFT) and elevated cross maze (EPM), resulting in anxiety-like behaviors, as well as abnormal social behavioral deficits in the Social Interaction Test (SIT). Analysis of histopathological staining results showed that BHPF exposure caused damage to hippocampal neurons in the CA1/CA3/DG region and decreased Nissl pyramidal neurons in the CA1/CA3 regions of the hippocampus, as well as a decrease in parvalbumin neuron expression. In addition, BHPF exposure upregulated the expression of excitatory and inhibitory (E/I) vesicle transporter genes (Vglut1, Vglut2, VGAT, GAD67, Gabra) and axon growth gene (Dcc) in the mouse hippocampus. Interestingly, behavioral disturbances and E/I balance could be alleviated by exogenous melatonin (15 mg/kg bw/2-day) therapy. Our findings suggest that exogenous melatonin may be a potential therapy with protective potential for ameliorating or preventing BHPF-induced hippocampal neuronal damage and behavioral disturbances. This study provided new insight into the neurotoxicological effects on organisms exposed to endocrine-disrupting chemicals and aroused our vigilance in current environmental safety about chemical use.

Interpretation of adsorption isotherm and kinetics behind fluorene degradation.

The gradual release of slow-degrading polycyclic aromatic hydrocarbons into the environment creates a high level of threat to aquatic and terrestrial life worldwide. Remediation of these PAHs should be designed in such a way that it poses as few or no environmental hazards as possible. In our study, we examined the degradation ability of the synthesized MnO2 nanoparticles against fluorene. The MnO2 nanoparticle prepared was found to be spherical from the SEM analysis. XRD analysis confirms the average crystallite size as 31.8652 nm. Further, the characterization of nanoparticles was confirmed by UV-DRS, FT-IR, DLS, and HPLC techniques. The extent of adsorption potential of the synthesized nanoparticles was established from the batch adsorption studies and the kinetic and isotherm model was interpreted. The antimicrobial properties of the synthesized MnO2 nanoparticles were analyzed.

Fluorene-induced stress in the benthic oligochaete Tubifex tubifex: A multi-biomarker assessment of toxicological pathways and mechanisms under acute and subchronic exposures.

This study examined the multifaceted impacts of fluorene exposure on Tubifex tubifex, encompassing acute (survival analysis and behavioral responses) and subchronic exposure regimens (antioxidant enzyme response and histopathology), molecular docking studies, and generalized read-across analysis. Survival analysis revealed concentration-dependent increases in toxicity over varying time intervals, with LC50 values decreasing from 30.072 mg/L at 24 h to 12.365 mg/L at 96 h, emphasizing the time-sensitive and concentration-responsive nature of the stressor. Behavioral responses were both concentration- and duration-dependent. While Erratic Movement and Clumping Tendency exhibited earlier responses (within 24 h) at lower concentrations, the wrinkling effect and mucus secretion) exhibited delayed onset, suggesting intricate regulatory mechanisms underlying adaptability to environmental challenges; moreover, the wrinkling effect was consistently induced at higher concentrations, indicating greater sensitivity to the toxic effects of fluorene. With sublethal environmentally relevant concentrations-1.24 mg/l and 2.47 mg/L i.e., 10% and 20% 96 h, respectively-the antioxidant enzyme response (i.e., upregulation of SOD, CAT, and GST) with increasing fluorene concentration, revealing a nonlinear, hormetic response, suggested adaptive protection at lower doses but inhibition at higher concentrations. Histopathological examination indicated that higher fluorene concentrations caused cellular proliferation, inflammation, and severe tissue damage in the digestive tract and body wall. Molecular docking studies demonstrated robust interactions between fluorene and major stress biomarker enzymes, disrupting their functions and inducing oxidative stress. Interactions with cytochrome c oxidase suggested interference with cellular energy production. Generalized Read-Across (GenRA) analysis unveiled shared toxicity mechanisms among fluorene and its analogs, involving the formation of reactive epoxides and the influence of cytochrome P450 enzymes. The diverse functional groups of these analogs, particularly chlorine-containing compounds, were implicated in toxicity through lipid peroxidation and membrane damage. Adverse outcome pathways and broader consequences for aquatic ecosystem health are discussed.

Diverse hydrocarbon degradation genes, heavy metal resistome, and microbiome of a fluorene-enriched animal-charcoal polluted soil.

Environmental compartments polluted with animal charcoal from the skin and hide cottage industries are rich in toxic heavy metals and diverse hydrocarbon classes, some of which are carcinogenic, mutagenic, and genotoxic, and thus require a bio-based eco-benign decommission strategies. A shotgun metagenomic approach was used to decipher the microbiome, hydrocarbon degradation genes, and heavy metal resistome of a microbial consortium (FN8) from an animal-charcoal polluted site enriched with fluorene. Structurally, the FN8 microbial consortium consists of 26 phyla, 53 classes, 119 orders, 245 families, 620 genera, and 1021 species. The dominant phylum, class, order, family, genus, and species in the consortium are Proteobacteria (51.37%), Gammaproteobacteria (39.01%), Bacillales (18.09%), Microbulbiferaceae (11.65%), Microbulbifer (12.21%), and Microbulbifer sp. A4B17 (19.65%), respectively. The microbial consortium degraded 57.56% (28.78 mg/L) and 87.14% (43.57 mg/L) of the initial fluorene concentration in 14 and 21 days. Functional annotation of the protein sequences (ORFs) of the FN8 metagenome using the KEGG GhostKOALA, KofamKOALA, NCBI's conserved domain database, and BacMet revealed the detection of hydrocarbon degradation genes for benzoate, aminobenzoate, polycyclic aromatic hydrocarbons (PAHs), chlorocyclohexane/chlorobenzene, chloroalkane/chloroalkene, toluene, xylene, styrene, naphthalene, nitrotoluene, and several others. The annotation also revealed putative genes for the transport, uptake, efflux, and regulation of heavy metals such as arsenic, cadmium, chromium, mercury, nickel, copper, zinc, and several others. Findings from this study have established that members of the FN8 consortium are well-adapted and imbued with requisite gene sets and could be a potential bioresource for on-site depuration of animal charcoal polluted sites.

6aH-Benzo[α]fluorene: NMR evidence of the unexpected product of the reaction of butyryl chloride with 1,2-diphenylacetylene.

The reaction of butyryl chloride with ethynylbenzene in the presence of AlCl3 afforded a mixture of the Z/E-isomers of 1-chloro-2-phenylhex-1-en-3-one. 1,2-Diphenylethyne under these conditions gave a novel polycarbocycle core, 6aH-benzo[a]fluorene. The chemical structure of 11-chloro-5,6-diphenyl-6a-propyl-6aH-benzo[a]fluorene was established by means of IE-MS, 1 H, 13 C NMR, COSY, HSQC, HMBC, and 2D INADEQUATE technique.

Competition between Loss of H2 versus H+H in the Fragmentation of the Fluorene Cation.

The fluorene cation is a frequently studied molecule in the context of fragmentation experiments. This is because of its potential role in interstellar chemistry, notably as a precursor of PAH cages. In this paper, we analyze H, H+ , H2 and H 2 + ${{\rm{H}}_2^ + }$ losses from the fluorene cation using the SMF (Statistical Molecular Fragmentation) model. We calculate the probabilities of all the 534 possible fragmentation channels as a function of the excitation energy, up to the loss of three hydrogens. Four different types of hydrogen atom pairings (from the same carbon, from the same ring, from different rings and across-the-bay) have been tested in order to determine which types contribute to the actual production of hydrogen molecules. The simulated breakdown curves are in very good agreement with different experimental results when same ring pairing is taken into account. It was possible to deduce from the model the locations of the emitted H, H+ , H2 and H 2 + ${{\rm{H}}_2^ + }$ species.