Development of Donor-π-Acceptor-Type Fluorinated Tolanes as Compact Condensed Phase Luminophores and Applications in Photoluminescent Liquid-Crystalline Molecules.

Fluorinated tolanes, produced by introducing fluorine atoms into one of the aromatic rings of tolane, emitted almost no fluorescence in a solution state, but the fluorescence intensity increased dramatically in the crystalline state because of intermolecular H⋅⋅⋅F hydrogen bonds. The photoluminescent (PL) colors depend on the molecular orbitals, dipole moments, and molecular aggregated structures can be varied by controlling terminal substituents along the major molecular axis. The introduction of a long alkoxy or semifluoroalkoxy unit as a flexible chain into the terminal positions along the major molecular axis induced the formation of a liquid-crystalline (LC) phase; fluorinated tolanes act both as luminophores and as mesogens, leading to the molecular design of new photoluminescent LC molecules (PLLCs). The results also indicated that a fluorinated tolane dimer, which consists of two fluorinated tolanes linked by a flexible alkylene spacer, also becomes a novel PLLC.

Diverse Synthetic Transformations Using 4-Bromo-3,3,4,4-tetrafluorobut-1-ene and Its Applications in the Preparation of CF2 CF2 -Containing Sugars, Liquid Crystals, and Light-Emitting Materials.

Organic molecules with fluoroalkylene scaffolds, especially a tetrafluoroethylene (CF2 CF2 ) moiety, in their molecular structures exhibit unique biological activities, or can be applied to functional materials such as liquid crystals and light-emitting materials. Although several methods for the syntheses of CF2 CF2 -containing organic molecules have been reported to date, they have been limited to methods using explosives and fluorinating agents. Therefore, there is an urgent need to develop simple and efficient approaches to synthesize CF2 CF2 -containing organic molecules from readily available fluorinated substrates using carbon-carbon bond formation reactions. This personal account summarizes the simple and efficient transformation of functional groups at both ends of 4-bromo-3,3,4,4-tetrafluorobut-1-ene and discusses its synthetic applications to biologically active fluorinated sugars and functional materials, such as liquid crystals and light-emitting molecules.

Donor-π-Acceptor-Type Fluorinated Tolane Containing a Semifluoroalkoxy Chain as a Condensed-Phase Luminophore.

Photoluminescent liquid-crystalline (PLLC) molecules, which can easily tune the PL behavior through the crystal (Cry)-LC phase transition, have attracted significant attention. Previously, we have demonstrated that the incorporation of a semifluoroalkoxy chain into π-conjugated mesogen is a promising approach for developing PLLC molecules with PL and SmA LC characteristics. We focused on the LC and PL characteristics of the molecules induced by the semifluoroalkoxy chain and fluorinated tolanes in the condensed phase. In this study, we developed cyano- or ethoxycarbonyl-terminated donor-π-acceptor-type fluorinated tolanes containing a semifluoroalkoxy flexible chain. The cyano-terminated fluorinated tolanes exhibited intense light-blue photoluminescence in the crystalline phase and did not exhibit any LC phase. In contrast, blue photoluminescence in the ethoxycarbonyl-terminated analogs was slightly weak; however, they exhibited Cry-SmA phase transition during the heating and cooling processes. The PL intensity of the ethoxycarbonyl-terminated fluorinated tolanes significantly decreased in the SmA phase; however, their PL colors changed during the Cry-SmA phase transition. This indicates that the developed tolanes are promising temperature-dependent PL materials, such as PL thermosensors or PL thermometers.

Development of Yellow-to-Orange Photoluminescence Molecules Based on Alterations in the Donor Units of Fluorinated Tolanes.

Since the aggregation-induced emission (AIE) phenomenon was first reported by Tang et al., much effort has been devoted to the development of solid-state luminescent molecules by chemists worldwide. Our group successfully developed fluorinated tolanes as novel compact π-conjugated luminophores with blue photoluminescence (PL) in the crystalline state. Moreover, we reported the yellow-green PL molecules based on their electron-density distributions. In the present study, we designed and synthesized fluorinated tolanes with various amine-based donors and evaluated their photophysical properties. The carbazole-substituted fluorinated tolane exhibited strong PL in the solution state, whereas piperidine- or phenothiazine-substituted fluorinated tolanes showed a dramatic decrease in PL efficiency. Notably, fluorinated tolanes with piperidine or phenothiazine substituents displayed yellow-to-orange PL in the crystalline state; this may have occurred because these tolanes exhibited tightly packed structures formed by intermolecular interactions, such as H···F hydrogen bonds, which suppressed the non-radiative deactivation process. Moreover, fluorinated tolanes with amine-based donors exhibited AIE characteristics. We believe that these yellow-to-orange solid PL molecules can contribute to the development of new solid luminescent materials.

Practical Synthesis of α-Trifluoromethylated Pyridines Based on Regioselective Cobalt-Catalyzed [2+2+2] Cycloaddition using Trifluoromethylated Diynes with Nitriles.

Regioselective cobalt-catalyzed [2+2+2] cycloaddition using fluorine-containing diynes with nitriles was described. Cycloaddition of fluorinated diynes with nitriles under the influence of CoCl2(phen), zinc bromide, and zinc dust in dichloroethane at 80°C for 3 h took place smoothly, exclusively affording the corresponding α-fluoroalkylated pyridines in excellent yields. In addition, dinitriles as substrate were also found to be suitable for this reaction, giving the corresponding fluoroalkylated bipyridine derivatives in excellent yields.

Cobalt-Catalyzed C-H Activation/Annulation of Benzamides with Fluorine-Containing Alkynes: A Route to 3- and 4-Fluoroalkylated Isoquinolinones.

The C-H activation/annulation reaction of various benzamides with fluoroalkylated alkynes in the presence of a Co(acac)2·2H2O catalyst proceeded very smoothly to give the corresponding 3- and 4-fluoroalkylated isoquinolinones in excellent yields with approximately 70% regioselectivities. These regioisomers could be successfully separated and obtained in pure form. Major or minor regioisomers were determined as 4- or 3-fluoroalkylated isoquinolinones, respectively, based on X-ray crystallographic analyses.

Impact of cancer therapy on post-treatment ejaculation disorder and sexual life in testicular cancer survivors.

OBJECTIVE: To evaluate the impact of cancer therapy on post-treatment ejaculation in patients with testicular cancer. METHODS: A total of 74 testicular cancer survivors provided completed International Index of Erectile Function-15 questionnaires before and after treatment between 2010 and 2017. Sexual function, particularly ejaculatory function, was evaluated before and after treatment. In this study, patients who answered "1 = almost never/never" or "2 = a few times" for questionnaire number 9 (ejaculation frequency) were defined as having "ejaculation disorder." RESULTS: Of 74 testicular cancer survivors, 50 (68%) had no ejaculation disorders before treatment. Four (44%) of nine survivors, who received chemotherapy and retroperitoneal lymph node dissection, developed ejaculation disorders after treatment. On multivariate analysis, retroperitoneal lymph node dissection was a significant predictor of post-treatment ejaculation disorder (P = 0.042). Of 60 survivors with evaluable ejaculation function after treatment, 24 (40%) did not attempt sexual intercourse, and multivariate analysis showed ejaculation disorder had a significant negative impact on having sexual intercourse (P = 0.035). Furthermore, the mean International Index of Erectile Function-15 scores in the groups with and without ejaculation disorders after treatment were 24.0 and 51.9, respectively (P < 0.001). CONCLUSION: Ejaculation disorders occur at high rate after retroperitoneal lymph node dissection. Many testicular cancer survivors reporting no sexual intercourse have ejaculation disorders, suggesting an adverse impact on sexual life. Urologists should provide proper counselling regarding the risk of ejaculation disorder and its possible impact on sexual life.

Fertility and reproductive technology use in testicular cancer survivors in Japan: A multi-institutional, cross-sectional study.

OBJECTIVE: To evaluate fertility and use of reproductive technology of testicular cancer survivors in a multi-institutional, cross-sectional study. METHODS: This study recruited testicular cancer survivors who were followed after treatment for testicular cancer at eight high-volume institutions between 2018 and 2019. The participants completed the questionnaires on marital status, fertility and use of reproductive technology. RESULTS: A total of 567 testicular cancer survivors, with a median age of 43 years, responded to the questionnaire. Chemotherapy was given to 398 survivors, including three cycles of cisplatin-based chemotherapy in 106 patients and four cycles in 147 patients. Among 153 survivors who attempted sperm cryopreservation, 133 (87%) could preserve sperm. Of the 28 survivors whose cryopreserved sperm was used, 17 (61%) fathered children. Of the 72 survivors who fathered children without the use of cryopreserved sperm, 59 (82%) fathered naturally. Whereas 33 (20%) of 169 survivors treated without chemotherapy fathered children without using cryopreserved sperm, 39 (10%) of 398 treated with chemotherapy fathered children (P < 0.05). Furthermore, the paternity rate was 12% and 5% in testicular cancer survivors with three and four cycles of cisplatin-based chemotherapy, respectively (P < 0.05). However, of 121 survivors who wanted to have children, 14 (12%) received counseling about infertility treatment. CONCLUSIONS: Testicular cancer survivors preserving their sperm have a higher paternity rate after chemotherapy, especially after four cycles, than those not using cryopreserved sperm. Physicians who give chemotherapy for testicular cancer need to take particular care not only with respect to recurrence of testicular cancer, but also to post-treatment fertility.

Validation study of the Japanese version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Testicular Cancer 26 for patients with testicular cancer.

OBJECTIVE: To validate the Japanese version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Testicular Cancer 26 in Japanese-speaking testicular cancer survivors. METHODS: A total of 200 testicular cancer survivors were recruited at eight high-volume institutions in Japan. The participants completed the Japanese version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Testicular Cancer 26, the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 and the International Index of Erectile Function 15 questionnaires. A total of 40 participants completed a retest of the questionnaires 2 weeks after the first response. The psychometric properties of the Japanese version including test-retest reliability, internal consistency and concurrent validity were evaluated. RESULTS: The mean age at response was 43 years (range 22-74 years), and the mean period after treatment was 77 months (range 0-416 months). The response rate for each item, except sexual function, was high, and the percentage of missing values was less than 3.5%. For test-retest reliability, seven of 12 scales met the criteria (intraclass correlation 0.70-0.86). For internal consistency, four of seven scales met the criteria (Cronbach's alpha 0.62-0.91). For concurrent validity, treatment side effects of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Testicular Cancer 26 were related to some domains of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30. The sex-related subscales of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Testicular Cancer 26 were moderately correlated with some International Index of Erectile Function 15 domains. CONCLUSIONS: The psychometric properties of the Japanese version are equivalent to the properties of the original European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Testicular Cancer 26. The Japanese version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Testicular Cancer 26 questionnaire is a useful tool to assess the health-related quality of life of testicular cancer patients.

Systematic Studies on the Effect of Fluorine Atoms in Fluorinated Tolanes on Their Photophysical Properties.

In this study, we synthesized a series of fluorinated and non-fluorinated tolanes, in which one or more fluorine atoms were systematically introduced into one aromatic ring of a tolane scaffold, and systematically evaluated their photophysical properties. All the tolanes with or without fluorine substituents were found to have poor photoluminescence (PL) in tetrahydrofuran (THF) solutions. On the other hand, in the crystalline state, non-fluorinated and fluorinated tolanes with one or four fluorine atoms were less emissive, whereas fluorinated tolanes with three or five fluorine atoms exhibited high PL efficiencies (ФPL) up to 0.51. X-ray crystallographic analyses of the emissive fluorinated tolanes revealed that the position of the fluorine substituent played a key role in achieving a high ФPL. Fluorine substituents at the ortho (2/6) and para (4) positions led to tight and rigid packing due to plural π-π stacking and/or hydrogen bonding interactions, resulting in enhanced ФPL caused by the suppression of non-radiative deactivation. Additionally, fluorinated tolanes with three fluorine atoms exhibited notable aggregation-induced PL emission enhancement in THF/water mixed solvents. This demonstrates that the PL characteristics of small PL materials can be tuned depending on the usage requirements.

Trends in Age and Histology of Testicular Cancer from 1980-2019: A Single-Center Study.

Testicular cancer occurs in the testes of the male reproductive system and is the most common cancer in adolescent and young adult (AYA) men. However, recently, there have been more cases of testicular cancer in men older than 40 years. Therefore, trends of testicular cancer during the past 40 years were retrospectively examined, focusing on age and histology. Patients who were diagnosed with testicular cancer at our institution between 1980 and 2019 were enrolled in this study. The patients were divided into groups by the year of diagnosis (1980s, 1990s, 2000s, and 2010s), age at diagnosis (14, 15 to 39, and older than 40 years), and histological type (seminoma and non-seminoma). A total of 563 patients were diagnosed with testicular cancer over the 40-year period. The median age at diagnosis increased continuously, from 28 years to 31 years, 34 years, and 38 years in each period, respectively (p < 0.001). Moreover, most testicular cancer patients were of the AYA generation, whereas the ratio of patients older than 40 years increased significantly since 2000 (p < 0.001). The relative proportion of seminoma also increased more than 50% since 2000. In the seminoma group, median age increased from 31 years to 41 years during the 40-year period (p < 0.001). In conclusion, the age at diagnosis is rising for testicular cancer patients. Clinicians should recognize that testicular cancer affects not only the AYA generation, but there has been a shift to older than 40 years, especially in seminoma.

Regioselective cobalt(II)-catalyzed [2 + 3] cycloaddition reaction of fluoroalkylated alkynes with 2-formylphenylboronic acids: easy access to 2-fluoroalkylated indenols.

[2 + 3] cycloaddition reactions of fluorinated alkynes with 2-formylphenylboronic acids under the influence of Co(acac)2·2H2O in two-component solvents of acetonitrile/2-propanol at reflux temperature for 18 h took place smoothly, affording the corresponding fluoroalkylated indenol derivatives in good yields. This reaction shows excellent regioselectivity, giving 2-fluoroalkylated indenols, together with a very small amount of 3-fluoroalkylated indanones as side products.

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules.

Pure organic phosphorescent molecules are attractive alternatives to transition-metal-complex-based phosphores for biomedical and technological applications owing to their abundance and nontoxicity. This article discloses the design, synthesis, and photophysical properties of fluorinated benzil and bisbenzil derivatives as potential pure organic room-temperature phosphorescent molecules. These compounds were separately converted from the corresponding fluorinated bistolanes via PdCl2-catalyzed oxidation by dimethyl sulfoxide, while nonfluorinated bistolane provided the corresponding bisbenzil derivatives exclusively in a similar manner. Intensive investigations of the photophysical properties of the benzil and bisbenzil derivatives in toluene at 25 °C showed both fluorescence with a photoluminescence (PL) band at a maximum wavelength (λPL) of around 400 nm and phosphorescence with a PL band at a λPL of around 560 nm. Interestingly, intersystem crossing effectively caused fluorinated benzils to emit phosphorescence, which may arise from immediate spin-orbit coupling involving the 1(n, π)→3(π, π) transition, unlike the case of fluorinated or nonfluorinated bisbenzil analogues. These findings offer a useful guide for developing novel pure organic room-temperature phosphorescent materials.

Synthesis and characterization of bent fluorine-containing donor-π-acceptor molecules as intense luminophores with large Stokes shifts.

Herein, we prepared novel bent fluorine-containing donor-π-acceptor (D-π-A) molecules from commercially available octafluorocyclopentene using a facile two-step procedure, revealing that the above molecules absorb UV-light and exhibit yellow photoluminescence (PL) with high PL efficiencies (ΦPL) in solution. The corresponding Stokes shifts exceeded 10 000 cm-1, and the maximum PL wavelength (λPL) strongly depended on solvent polarity or intermolecular interactions in the solid state. On the basis of a Lippert-Mataga plot, PL was confidently assigned to radiative relaxation from an intramolecular charge-transfer excited state. Moreover, the synthesized luminophores showed intense PL even in the crystalline state and exhibited alkoxy chain length-dependent PL behavior (e.g., high ΦPL, λPL = 486-540 nm).

A Case of Adult Metastatic Rhabdomyosarcoma of the Prostate Cured by Long-Term Chemotherapy with Local Radiation.

A 32-year-old man visited our hospital due to urinary retention. Prostate-specific antigen was 13.7 ng/mL. Imaging examinations showed a large prostatic tumor and lung and internal iliac lymph node metastases. Transrectal biopsy confirmed embryonal rhabdomyosarcoma of the prostate classified as cT2bN1M1 (stage IV) by the International Rhabdomyosarcoma Study (IRS) Group staging system. Systemic chemotherapy was started according to the IRS III regimen 36, which consisted of 16 weeks of induction chemotherapy with radiation. After 20 weeks, magnetic resonance imaging showed the disappearance of metastases, and the prostate tumor shrunk markedly. Moreover, prostatic re-biopsy showed no viable tumor cells. Maintenance chemotherapy, excluding vincristine because of severe peripheral nerve disorder, was performed for 2 years. There has been no recurrence for 49 months after the termination of maintenance chemotherapy. To the best of our knowledge, this is the longest surviving case of adult-onset metastatic rhabdomyosarcoma of the prostate reported in the literature.

Stabilization of SF5- with Glyme-Coordinated Alkali Metal Cations.

The stabilization of complex fluoroanions derived from weakly acidic parent fluorides is a significant and ongoing challenge. The [SF5]- anion is recognized as one such case, and only a limited number of [SF5]- salts are known to be stable at room temperature. In the present study, glyme-coordinated alkali metal cations (K+, Rb+, and Cs+) are employed to stabilize [SF5]-, which provides a simple synthetic route to a [SF5]- salt. The reactivities of KF and RbF with SF4 are significantly enhanced by complexation with G4, based on Raman spectroscopic analyses. A new room-temperature stable salt, [Cs(G4)2][SF5] (G4 = tetraglyme), was synthesized by stoichiometric reaction of CsF, G4, and SF4. The vibrational frequencies of [SF5]- were assigned based on quantum chemical calculations, and the shift of the G4 breathing mode accompanying coordination to metal cations was confirmed by Raman spectroscopy. Single-crystal X-ray diffraction revealed that Cs+ is completely isolated from [SF5]- by two G4 ligands and [SF5]- is disordered along the crystallographic two-fold axis. Hirshfeld surface analysis reveals that the H···H interaction between two neighboring [Cs(G4)2]+ moieties is more dominant on the Hirshfeld surface than the interaction between the H atom in glyme molecules and the F atom in [SF5]-, providing a CsCl-type structural model where the large and spherical [Cs(G4)2]+ cations contact each other and the [SF5]- anions occupy interstitial spaces in the crystal lattice. The [SF5]- anion, combined with [Cs(G4)2]+, exhibits a very limited deoxofluorinating ability toward hydroxyl groups in both neat conditions and THF solutions.

Thermoresponsive luminescence properties of polyfluorinated bistolane-type light-emitting liquid crystals.

We developed and characterized four polyfluorinated bistolane derivatives. These compounds, which possess either two alkoxy substituents or an alkoxy group and a bromine atom in their two molecular terminals, were synthesized from readily available 4-alkoxy-1-ethynylbenzene with a facile three-step procedure. Their thermodynamic and photophysical properties were evaluated in detail, and they were found to display both liquid-crystalline (LC) and photoluminescence properties. Remarkably, the photoluminescence behaviors dramatically changed during the thermal phase transition between the crystal and LC phases. Thus, these polyfluorinated bistolanes may be promising candidates for thermoresponsive luminous molecules.

Practical tetrafluoroethylene fragment installation through a coupling reaction of (1,1,2,2-tetrafluorobut-3-en-1-yl)zinc bromide with various electrophiles.

(1,1,2,2-Tetrafluorobut-3-en-1-yl)zinc bromide was prepared by insertion of the zinc-silver couple into the CF2-Br bond of commercially available 4-bromo-3,3,4,4-tetrafluorobut-1-ene in DMF at 0 °C for 0.5 h, The resultant polyfluorinated zinc reagent was found to be thermally stable at ambient temperature and storable for at least 1.5 years in the refrigerator. This CF2CF2-containing organozinc reagent could be easily transmetallated to copper species, which underwent cross-coupling reactions with various aromatic iodides or acyl chlorides to produce a broad range of CF2CF2-containing organic molecules in good-to-excellent yields. Therefore, the zinc reagent could become a new and practical synthetic tool for producing functional molecules with a CF2CF2 fragment.

Gram-scale preparation of negative-type liquid crystals with a CF2CF2-carbocycle unit via an improved short-step synthetic protocol.

Herein, we demonstrate an improved short-step protocol for the synthesis of multicyclic molecules having a CF2CF2-containing cyclohexadiene or cyclohexane framework in a mesogenic structure. These molecules are promising candidates for vertical alignment (VA)-mode liquid crystal (LC) display devices owing to their large negative dielectric constant. The tetrafluorinated multicyclic molecules were successfully obtained in only five or six reaction steps without the need for special handling techniques, as is generally required for thermally unstable organometallic species, representing a reduction of three reaction steps. The improved short-step synthetic protocol was also amenable to the multigram preparation of these promising molecules, which may contribute significantly to the development of novel negative-type LC molecules containing CF2CF2 carbocycles.

Mesogenic gold complexes showing aggregation-induced enhancement of phosphorescence in both crystalline and liquid-crystalline phases.

Mesogenic Au complexes with a biphenyl core were synthesized as new AIEgens, and their thermodynamic and photophysical properties were discussed. Similar to Au complexes with a phenyl core which have been reported previously, the complexes with a short alkoxy chain formed dimers in the crystal form. However, the complexes with a long alkoxy chain formed two-dimensional layer structures through multiple intermolecular interactions in both the crystalline and liquid-crystalline (LC) phases. The present Au complexes showed a high thermochemical stability against thermal decomposition and a high thermodynamic stability of the LC phase. Moreover, these materials exhibited intensive phosphorescence with a large quantum yield (∼66%) in the crystals. In the crystal and LC phase with a layer structure, the phosphorescence intensity was enhanced only on aggregation. Thus, these mesogenic Au complexes can be expected to be useful as phosphorescent AIEgens.