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Wei Huang - One of the best experts on this subject based on the ideXlab platform.

  • stimuli responsive solid state emission from o Carborane tetraphenylethene dyads induced by twisted intramolecular charge transfer in the crystalline state
    Journal of Materials Chemistry C, 2018
    Co-Authors: Junfeng Li, Chenglong Yang, Xuelei Peng, Ying Chen, Qi Qi, Wei Huang
    Abstract:

    We described herein a unique dual emission switching process from o-Carborane–tetraphenylethene (TPE) dyads induced by twisted intramolecular charge transfer (TICT) in the crystalline state. Two novel o-Carborane–tetraphenylethylene dyads, composed of a TPE core bearing o-Carborane units, were designed, synthesized and characterized. Crystalline o-1 and o-2 were obtained with mono-substituted and bi-substituted o-Carborane units, respectively. Both dyads presented locally excited (LE) emission and TICT induced emission in solutions. Crystalline o-1 demonstrated aggregation-induced emission (AIE), crystallization-induced emission (CIE), thermochromism, vapochromism, and mechanical luminescence (MCL) properties via TICT, while crystalline o-2 showed only the AIE and CIE properties orginating from the inherent ICT states. From the mechanistic investigations and theoretical calculations, it was demonstrated that the emission was reversible and switchable between green and orange colors for o-1, which was assigned to the facile TICT modulation in the solid state. The results manifest that the unique three-dimensional o-Carborane cluster's structure plays an important role in precisely controlling the molecular packing patterns and conformations to achieve TICT emission.

Francesc Teixidor - One of the best experts on this subject based on the ideXlab platform.

  • electrochemistry and photoluminescence of icosahedral Carboranes boranes metallaCarboranes and their derivatives
    Chemical Reviews, 2016
    Co-Authors: Rosario Nunez, Marius Tarres, Albert Ferrerugalde, Fabrizia Fabrizi De Biani, Francesc Teixidor
    Abstract:

    Icosahedral boranes, Carboranes, and metallaCarboranes are extraordinarily robust compounds with desirable properties such as thermal and redox stability, chemical inertness, low nucleophilicity, and high hydrophobicity, making them attractive for several applications such as medicine, nanomaterials, molecular electronics, energy, catalysis, environmental chemistry, and other areas. The hydrogen atoms in these clusters can be replaced by convenient groups that open the way to a chemical alternative to conventional “organic” or “organometallic” realms. Icosahedral boron cluster derivatives have been reviewed from different perspectives; however, there is a need for a review dedicated to the redox and photophysical characteristics of easily accessible borane and Carborane derivatives, which are excellent materials for a wide range of applications. This review deals with the redox properties and photoluminescence behavior of this collection of compounds, as well as their influence on the properties of materi...

  • A new class of purely inorganic ligands: carboranylphosphinic acids
    Revista de la Societat Catalana de Química, 2016
    Co-Authors: Elena Oleshkevich, Francesc Teixidor, Clara Vinas
    Abstract:

    Els dicarba-closo-carborans (o carborans) són poliedres icosaèdrics de fórmula empírica C2B10H12. Depenent de la posició dels dos àtoms de carboni en els diferents vèrtexs del clúster, podem tenir tres isòmers diferents: orto- (1,2–C2B10H12), meta- (1,7–C2B10H12) i para- (1,12–C2B10H12). Aquests clústers són molt estables i mostren una gran simetria i una capacitat de ser substituïts, sigui als vèrtexs de carboni, als de bor o a ambdós, de manera que s’obtenen així diferents clústers funcionalitzats per emprar-los en l’aplicació desitjada. El grup de recerca té una llarga experiència en la síntesi de lligands tipus fosfina que contenen el clúster de carborà que van emprar-se en la preparació de complexos de metalls de transició per usar-los en catàlisi homogènia. L’oxidació d’aquestes fosfines, de P(III) a P(V), és difícil, cal forçar-la. Aquesta és una propietat important de cara a la seva aplicació com a catalitzadors. Pocs exemples es troben a la literatura sobre àcids fosfònics i fosfínics que continguin clústers de carborà. En aquest treball, s’han sintetitzat i caracteritzat àcids fosfònics i fosfínics de clústers icosaèdrics de carborà fent servir com a reactius de partida els isòmers orto- i meta- del closo-carborà. S’ha estudiat la capacitat coordinant d’aquestes noves famílies de lligands que són purament inorgànics amb metalls amb l’objectiu d’obtenir complexos de coordinació polimèrics solubles en aigua. La influència dels clústers de bor en la reactivitat dels lligands també s’ha estudiat.Paraules clau: Carborans, àcid fosfònic, àcid fosfínic.Dicarba-closo-dodecaboranes (or Carboranes) are icosahedral clusters of empirical formula C2B10H12. Depending on the relative position of the carbon atoms in the cluster, three isomers can be distinguished: ortho- (1,2), meta- (1,7) and para- (1,12). Our group focused this research on the first two: ortho- and meta-Carborane isomers. The high symmetry, remarkable stability and versatile reactivity of these clusters allow their functionalization according to a desired application. Our group and others were interested in carboranylphosphorus compounds, mostly due to their properties as ligands for organometallic chemistry and enantioselective catalysis. Among them are carboranylphosphines and carboranylphosphines with P(V) moieties, except carboranyl phosphinates and carboranyl phosphonates. Few studies are found in the literature on carboranyl phosphinic and phosphonic acids. Our research goal has been devoted to developing preparation and characterization of carboranyl phosphinates, aiming towards the designing of purely inorganic ligands that are capable to coordinate to metals producing stable water-soluble polynuclear systems. The influence of the boron cluster on the reactivity of the phosphinate group was studied as well.Keywords: Carboranes, phosphinates, phosphonates

  • iodinated ortho Carboranes as versatile building blocks to design intermolecular interactions in crystal lattices
    Chemistry: A European Journal, 2009
    Co-Authors: Alberto V Puga, Francesc Teixidor, Reijo Sillanpaa, Raikko Kivekas, Clara Vinas
    Abstract:

    The crystal structures of numerous iodinated ortho-Carboranes have been studied, which has revealed the diversity of intermolecular interactions that these substances can adopt in the solid state. The nature-mostly as it relates to hydrogen and/or halogen bonds-and relative strength of such interactions can be adjusted by selectively introducing substituents onto the cluster, thus enabling the rational design of crystal lattices. In this work we present the newly determined crystal structures of the following iodinated ortho-Carboranes: 9-I-1,2-closo-C(2)B(10)H(11), 4,5,7,8,9,10,11,12-I(8)-1,2-closo-C(2)B(10)H(4), 3,4,5,6,7,8,9,10,11,12-I(10)-1,2-closo-C(2)B(10)H(2), 1-Me-8,9,10,12-I(4)-1,2-closo-C(2)B(10)H(7), 1,2-Me(2)-8,9,10,12-I(4)-1,2-closo-C(2)B(10)H(6), and 1,2-Ph(2)-8,9,10,12-I(4)-1,2-closo-C(2)B(10)H(6). Their 3D supramolecular organization has been thoroughly investigated and compared to similar previously published crystal structures. Such a systematic survey has allowed us to draw some general trends. C(c)-HI--B hydrogen bonds (C(c)= cluster carbon atoms) appear to be significant in the growth of the crystal lattices of these compounds, given the acidity of hydrogen atoms bonded to C(c), and the polarization of B-I bonds. These hydrogen bonds can be disrupted by selectively blocking the positions next to C(c), that is, B(3) and B(6), with bulky substituents that prevent iodine atoms from approaching as hydrogen acceptors. Halogen bonds of the type B-II-B are frequently observed in most cases, thus suggesting that these interactions could be attractive in boron clusters. In addition, different substituents can be grafted onto the ortho-Carborane surface, thereby providing further possibilities for homomeric or heteromeric molecular assembly.

Kenneth Wade - One of the best experts on this subject based on the ideXlab platform.

  • reactions of icosahedral Carboranes with iminotris dimethylamino phosphorane hnp nme2 3 a deboronation intermediate nido c2b10h12 n h p nme2 3 deboronation reactions and hydrogen bonded closo Carborane systems
    Journal of Cluster Science, 2006
    Co-Authors: Andrei S Batsanov, Royston C B Copley, Matthew G Davidson, Mark A Fox, Thomas G Hibbert, Judith A K Howard, Kenneth Wade
    Abstract:

    Reactions between the icosahedral Carboranes 1,2-C2B10H12 (1), 1,7-C2B10H12 (2) and 1,12-C2B10H12 (3) and the iminophosphorane HNP(NMe2)3 (4) are described that have afforded a variety of products whose structures have been characterised by X-ray diffraction. They include the adduct between (1) and (4), C2B10H12·HNP(NMe2)3 (5) the 12-atom 14-skeletal pair supra-icosahedral nido structure of which illustrates an early step in the deboronation of ortho-Carborane (1) by Lewis Bases, and the C–H⋯N hydrogen-bonded adducts of meta- and para-Carborane with the iminophosphorane, [1,7-C2B10H12⋯HNP(NMe2)3] n and 1,12-C2B10H12 $$\cdot$$ 2HNP(NMe2)3. The iminophosphorane (4) readily converts ortho-Carborane (1) into the nido anion [7,8-C2B9H12]− and less readily meta-Carborane (2) into the nido-anion [7,9-C2B9H12]−, which have been isolated from solution as salts of the cations [H2NP(NMe2)3]+ or [{(Me2N)3PN}2BNHP(NMe2)3]+, the latter evidently incorporating a boron atom removed from the Carborane cage. Adventitious presence of water in the attempted recrystallization of [{(Me2N)3PN}2BNHP(NMe2)3]+ [7,8-C2B9H12]− led to a salt of the cation [{(Me2N)3PNBN(H)P(NMe2)3}2O]2+. Other unexpected products isolated from reactions carried out under moist air included the salt [H2NP(NMe2) 3 + ]2[CO 3 2− ]·2B(OH)3 (from the reaction between 2 and 4) and the salt 1,12-C2B10H12·2H2NP(NMe2) 3 + HCO 3 − (from the reaction between 3 and 4).

  • synthesis and crystal structure of an assembly of three ortho Carborane cages linked via para phenylene units effect of aryl orientation on cage c c bond lengths in c aryl ortho Carboranes
    Applied Organometallic Chemistry, 2003
    Co-Authors: Elena S Alekseyeva, Mark A Fox, Judith A K Howard, J Hugh A Macbride, Kenneth Wade
    Abstract:

    The synthesis and crystal and molecular structure are described of (C 2 B 10 H 11 )C 6 H 4 (C 2 B 10 H 10 )C 6 H 4 (C 2 B 10 H 11 ) (4), an acyclic assembly of three ortho-Carborane units connected through their carbon atoms by two para-phenylene units. For this compound, and published structures of other aryl-ortho-Carboranes, correlations are noted between the orientations of aryl substituents and cage carbon-carbon distances (C1-C2). Ab initio RHF/6-31G* and MP2/6-31G* studies on 1-phenyl-ortho-Carborane, PhC 2 B 10 H 11 , and other model systems have been used to explore the variations in their energies, C1-C2 bond lengths, and C2-C1-C aryl bond angles with the orientation of their aryl groups, variations believed to reflect weak interactions between the aryl substituents' π systems and the Carborane cages. The synthesis of a pentafluorophenyl derivative of 4, (C 2 B 10 H 11 )C 6 H 4 (C 2 B 10 H 10 )C 6 H 4 (C 2 B 10 H 10 )C 6 F 5 , is also described.

Yasuyuki Endo - One of the best experts on this subject based on the ideXlab platform.

  • ba321 a novel Carborane analog that binds to androgen and estrogen receptors acts as a new selective androgen receptor modulator of bone in male mice
    Biochemical and Biophysical Research Communications, 2016
    Co-Authors: Kenta Watanabe, Yasuyuki Endo, Masaki Inada, Michiko Hirata, Tsukasa Tominari, Chiho Matsumoto, Gillian Murphy, Hideaki Nagase, Chisato Miyaura
    Abstract:

    Carboranes are a class of carbon-containing polyhedral boron cluster compounds with globular geometry and hydrophobic surface that interact with hormone receptors such as estrogen receptor (ER) and androgen receptor (AR). We have synthesized BA321, a novel Carborane compound, which binds to AR. We found here that it also binds to ERs, ERα and ERβ. In orchidectomized (ORX) mice, femoral bone mass was markedly reduced due to androgen deficiency and BA321 restored bone loss in the male, whilst the decreased weight of seminal vesicle in ORX mice was not recovered by administration of BA321. In female mice, BA321 acts as a pure estrogen agonist, and restored both the loss of bone mass and uterine atrophy due to estrogen deficiency in ovariectomized (OVX) mice. In bone tissues, the trabecular bone loss occurred in both ORX and OVX mice, and BA321 completely restored the trabecular bone loss in both sexes. Cortical bone loss occurred in ORX mice but not in OVX mice, and BA321 clearly restored cortical bone loss due to androgen deficiency in ORX mice. Therefore, BA321 is a novel selective androgen receptor modulator (SARM) that may offer a new therapy option for osteoporosis in the male.

  • design and synthesis of Carborane containing androgen receptor ar antagonist bearing a pyridine ring
    Bioorganic & Medicinal Chemistry, 2008
    Co-Authors: Kiminori Ohta, Tokuhito Goto, Shinya Fijii, Tomoharu Suzuki, Shigeru Ohta, Yasuyuki Endo
    Abstract:

    We previously developed Carborane-containing potent AR antagonists, BA321 and BA341, on the basis of our hypothesis that the Carborane cage would be an excellent hydrophobic pharmacophore in place of steroidal C and D rings. As an extension of that work, we designed and synthesized Carborane-containing AR antagonist candidates with a pyridine ring. Compound 6b, which has a pyridine ring directly bound to the p-Carborane cage at the 3-position, exhibited potent AR-antagonistic activity in transcriptional activation assay using NIH3T3 cells transfected with a hAR-expression plasmid. In addition, it showed more potent antiandrogenic activity than that of the well-known antiandrogen flutamide and comparable activity to that of (R)-bicalutamide in SC-3 cell proliferation assay.

  • identification of an intermediate in the deboronation of ortho Carborane an adduct of ortho Carborane with two nucleophiles on one boron atom
    Chemical Communications, 2008
    Co-Authors: Yoshiyuki Taoda, Yasuyuki Endo, Takehiko Sawabe, Kentaro Yamaguchi, Shinya Fujii, Hiroyuki Kagechika
    Abstract:

    The 1 : 2 adduct of 1-bromo-ortho-Carborane and pyridine has been identified as a significant intermediate in the deboronation of ortho-Carborane to a nido-anion

  • design and synthesis of novel androgen receptor antagonists with sterically bulky icosahedral Carboranes
    Bioorganic & Medicinal Chemistry, 2005
    Co-Authors: Tokuhito Goto, Kiminori Ohta, Tomoharu Suzuki, Shigeru Ohta, Yasuyuki Endo
    Abstract:

    Carboranes (dicarba-closo-dodecaboranes) are a class of carbon-containing polyhedral boron-cluster compounds having remarkable chemical and thermal stability, and hydrophobic character. These features may allow application of Carboranes as a new hydrophobic core structure in biologically active molecules that interact hydrophobically with receptors. Here, we report the design and synthesis of novel androgen antagonists bearing a Carborane moiety. These compounds, particularly 8a, 8c, and 9d, exhibited anti-androgenic activity similar to that of the well-known anti-androgen flutamide in reporter gene assay using NIH3T3 cells transfected with a human AR expression plasmid. The Carborane cage seems to be a privileged hydrophobic pharmacophore for the expression of AR-antagonistic activity.

  • potent estrogen agonists based on Carborane as a hydrophobic skeletal structure a new medicinal application of boron clusters
    Chemistry & Biology, 2001
    Co-Authors: Yasuyuki Endo, Toru Iijima, Yuko Yamakoshi, Hiroshi Fukasawa, Chisato Miyaura, Masaki Inada, Asako Kubo, Akiko Itai
    Abstract:

    Abstract Background: Carboranes (dicarba- closo -dodecaboranes) are a class of carbon-containing polyhedral boron-cluster compounds having remarkable thermal stability and exceptional hydrophobicity. Applications of the unique structural and chemical properties offered by icosahedral Carboranes in boron neutron capture therapy have received increasing attention over the past 30 years. However, these features of Carboranes may allow another application as a hydrophobic pharmacophore in biologically active molecules that interact hydrophobically with receptors. Results: We have designed candidate estrogen-receptor-binding compounds having Carborane as a hydrophobic skeletal structure and synthesized them. The most potent compound bearing a Carborane cage exhibited activity at least 10-fold greater than that of 17β-estradiol in the luciferase reporter gene assay. Estrogen receptor-α-binding data for the compound were consistent with the results of the luciferase reporter gene assay. The compound also showed potent in vivo effects on the recovery of uterine weight and bone loss in ovariectomized mice. Conclusion: Further development of the potent Carborane-containing estrogenic agonists described here, having a new skeletal structure and unique characteristics, should yield novel therapeutic agents, especially selective estrogen receptor modulators. Furthermore, the suitability of the spherical Carborane cage for binding to the cavity of the estrogen receptor-α ligand-binding domain should provide a basis for a similar approach to developing novel ligands for other steroid receptors.

Zuowei Xie - One of the best experts on this subject based on the ideXlab platform.

  • 8 aminoquinoline as a bidentate traceless directing group for cu catalyzed selective b 4 5 h disulfenylation of o Carboranes
    Chemical Communications, 2020
    Co-Authors: Yu Chen, Yangjian Quan, Zuowei Xie
    Abstract:

    A traceless bidentate directing group guided copper catalyzed direct cage B(4,5)–H disulfenylation of o-Carboranes has been achieved, leading to a series of B(4,5)–disulfenylated o-Carborane derivatives in high yields with excellent regioselectivity. The in situ departure of the 8-aminoquinoline bidentate auxiliary circumvents additional processes for directing group removal, thus enhancing the atom-/step-economy.

  • Catalytic Regioselective Cage B(8)–H Arylation of o‑Carboranes via “Cage-Walking” Strategy
    2019
    Co-Authors: Hairong Lyu, Yangjian Quan, Jie Zhang, Jingting Yang, Zuowei Xie
    Abstract:

    A proof-of-concept example of catalytic regioselective cage B(8)–H functionalization of o-Carboranes has been disclosed for the first time. Under the help of an acylamino directing group at cage B(3), a series of B(8)-arylated, B­(4,7,8)-triarylated and B­(4,7,8)-trifluorinated o-Carborane derivatives were conveniently prepared. On the basis of isolation of a key intermediate, deuterium labeling experiments and DFT calculations, a reaction mechanism involving a high-valent palladium induced “cage-walking” from B(4) to B(8) vertex is proposed to account for the regioselective B(8)–H activation

  • Enantioselective Synthesis of Chiral-at-Cage o‑Carboranes via Pd-Catalyzed Asymmetric B–H Substitution
    2018
    Co-Authors: Ruofei Cheng, Zaozao Qiu, Jie Zhang, Wenjun Tang, Shu-li You, Yong Tang, Zuowei Xie
    Abstract:

    Carborane cage chirality is an outstanding issue of great interest as the icosahedral Carboranes have wide applications in medicinal and materials chemistry. The synthesis of optically active Carborane derivatives, whose chirality is associated with the substitution patterns on the polyhedron, will open new avenues to Carborane chemistry. We report herein an efficient method to achieve chiral-at-cage arylation of o-Carboranes with high regio- and enantioselectivities by a strategy of palladium-catalyzed asymmetric intramolecular B–H arylation and cyclization. This represents the first example of the enantioselective reaction on Carboranes, providing an efficient way for the construction of chiral-at-cage compounds with new skeletons

  • visible light promoted photocatalytic b c coupling via a boron centered carboranyl radical facile synthesis of b 3 arylated o Carboranes
    Angewandte Chemie, 2016
    Co-Authors: Da Zhao, Zuowei Xie
    Abstract:

    A visible-light-mediated in situ generation of a boron-centered carboranyl radical (o-C2 B10 H11(.)) has been described. With eosin Y as a photoredox catalyst, 3-diazonium-o-Carborane tetrafluoroborate [3-N2-o-C2B10H11][BF4] was converted into the corresponding boron-centered carboranyl radical intermediate, which can undergo efficient electrophilic substitution reaction with a wide range of (hetero)arenes. This general and simple procedure provides a metal-free alternative for the synthesis of 3-(hetero)arylated-o-Carboranes.

  • An Unprecedented Formal [5 + 2] Cycloaddition of Nitrones with o‑Carboryne via Tandem [3 + 2] Cycloaddition/Oxygen Migration/Aromatization Sequence
    2015
    Co-Authors: Da Zhao, Jiji Zhang, Zuowei Xie
    Abstract:

    Heterocyclic skeletons are widespread among natural products as well as bioactive molecules. Cycloaddition reaction has created new opportunities to access heterocycles of great complexity due to its advantage of multiple bond formation in a single step. Here, we describe an unprecedented formal [5 + 2] cycloaddition of nitrone with o-carboryne to afford Carborane-fused seven-membered heterocycles. Experimental and theoretical data suggest that a sequence of [3 + 2] cycloaddition, N–O bond cleavage, oxygen migration and rearomatization is involved in this unprecedented reaction. In this process, the nitrone moieties serve as five-atom coupling partners with both heteroatoms being incorporated into the framework of the final products. This new methodology also offers new insight into the chemistry of nitrones