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Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions. Beilstein J Org Chem 2024; 20:823-829. [PMID: 38655557 PMCID: PMC11035982 DOI: 10.3762/bjoc.20.74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 03/22/2024] [Indexed: 04/26/2024] Open
Abstract
A skeletal rearrangement of a series of 6,8-dioxabicyclo[3.2.1]octan-4-ols has been developed using SOCl2 in the presence of pyridine. An oxygen migration from C5 to C4 was observed when the C4 alcohols were treated with SOCl2/pyridine, giving a 2-chloro-3,8-dioxabicyclo[3.2.1]octane ring-system via the chlorosulfite intermediate. Analogous allylic alcohols with endocyclic and exocyclic unsaturations underwent chlorination without rearrangement due to formation of allylic cations. The rearrangement was also demonstrated using Appel conditions, which gave similar results via the alkoxytriphenylphosphonium intermediate. Several reactions of the products were investigated to show the utility of the rearrangement.
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2
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Intermolecular Enamine Mizoroki-Heck Reactions on a Bio-Derived Scaffold. J Org Chem 2024. [PMID: 38190610 DOI: 10.1021/acs.joc.3c02415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
The intramolecular enamine-Mizoroki-Heck reaction allows for the construction of nitrogen-containing heterocycles, although the related intermolecular version is less known. The reactions of enamines derived from Cyrene were investigated under Mizoroki-Heck conditions. An optimization study was used to identify that 1.5 mol % Pd(dba)2 with PCy3 in xylene at reflux temperature gave the highest yield with electron-rich aryl iodides. Arylation occurred predominantly at the C-N center of the enamine, while the diastereoselectivity was dependent on the nitrogen substitution in the enamine.
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3
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Tunable Energy Release in a Reversible Molecular Solar Thermal System. ACS Catal 2022. [DOI: 10.1021/acscatal.2c03043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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4
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Multi-Edge Resonant Tender X-ray Diffraction for Probing the Crystalline Packing of Conjugated Polymers. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00484] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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172P Men with breast cancer: Biology and stage at diagnosis in Eastern Europe - Balkan Collaborative Project. Ann Oncol 2021. [DOI: 10.1016/j.annonc.2021.03.186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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6
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123P Clinical and pathological characteristics of male breast cancer at the Institute for Oncology including first-line treatment in hormone receptor positive tumours. Ann Oncol 2021. [DOI: 10.1016/j.annonc.2021.03.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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7
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Photo- and Collision-Induced Isomerization of a Charge-Tagged Norbornadiene-Quadricyclane System. J Phys Chem Lett 2020; 11:6045-6050. [PMID: 32539402 PMCID: PMC7416310 DOI: 10.1021/acs.jpclett.0c01198] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Molecular photoswitches based on the norbornadiene-quadricylane (NBD-QC) couple have been proposed as key elements of molecular solar thermal energy storage schemes. To characterize the intrinsic properties of such systems, reversible isomerization of a charge-tagged NBD-QC carboxylate couple is investigated in a tandem ion mobility mass spectrometer, using light to induce intramolecular [2 + 2] cycloaddition of NBD carboxylate to form the QC carboxylate and driving the back reaction with molecular collisions. The NBD carboxylate photoisomerization action spectrum recorded by monitoring the QC carboxylate photoisomer extends from 290 to 360 nm with a maximum at 315 nm, and in the longer wavelength region resembles the NBD carboxylate absorption spectrum recorded in solution. Key structural and photochemical properties of the NBD-QC carboxylate system, including the gas-phase absorption spectrum and the energy storage capacity, are determined through computational studies using density functional theory.
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Norbornadiene photoswitches anchored to well-defined oxide surfaces: From ultrahigh vacuum into the liquid and the electrochemical environment. J Chem Phys 2020; 152:044708. [PMID: 32007072 DOI: 10.1063/1.5137897] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Employing molecular photoswitches, we can combine solar energy conversion, storage, and release in an extremely simple single molecule system. In order to release the stored energy as electricity, the photoswitch has to interact with a semiconducting electrode surface. In this work, we explore a solar-energy-storing model system, consisting of a molecular photoswitch anchored to an atomically defined oxide surface in a liquid electrolyte and under potential control. Previously, this model system has been proven to be operational under ultrahigh vacuum (UHV) conditions. We used the tailor-made norbornadiene derivative 2-cyano-3-(4-carboxyphenyl)norbornadiene (CNBD) and characterized its photochemical and electrochemical properties in an organic electrolyte. Next, we assembled a monolayer of CNBD on a well-ordered Co3O4(111) surface by physical vapor deposition in UHV. This model interface was then transferred into the liquid electrolyte and investigated by photoelectrochemical infrared reflection absorption spectroscopy experiments. We demonstrate that the anchored monolayer of CNBD can be converted photochemically to its energy-rich counterpart 2-cyano-3-(4-carboxyphenyl)quadricyclane (CQC) under potential control. However, the reconversion potential of anchored CQC overlaps with the oxidation and decomposition potential of CNBD, which limits the electrochemically triggered reconversion.
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Solar Energy Storage by Molecular Norbornadiene-Quadricyclane Photoswitches: Polymer Film Devices. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1900367. [PMID: 31380172 PMCID: PMC6662068 DOI: 10.1002/advs.201900367] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/03/2019] [Indexed: 06/10/2023]
Abstract
Devices that can capture and convert sunlight into stored chemical energy are attractive candidates for future energy technologies. A general challenge is to combine efficient solar energy capture with high energy densities and energy storage time into a processable composite for device application. Here, norbornadiene (NBD)-quadricyclane (QC) molecular photoswitches are embedded into polymer matrices, with possible applications in energy storing coatings. The NBD-QC photoswitches that are capable of absorbing sunlight with estimated solar energy storage efficiencies of up to 3.8% combined with attractive energy storage densities of up to 0.48 MJ kg-1. The combination of donor and acceptor units leads to an improved solar spectrum match with an onset of absorption of up to 529 nm and a lifetime (t 1/2) of up to 10 months. The NBD-QC systems with properties matched to a daily energy storage cycle are further investigated in the solid state by embedding the molecules into a series of polymer matrices revealing that polystyrene is the preferred choice of matrix. These polymer devices, which can absorb sunlight and over a daily cycle release the energy as heat, are investigated for their cyclability, showing multicycle reusability with limited degradation that might allow them to be applied as window laminates.
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Tuning Molecular Solar Thermal Properties by Modification of a Promising Norbornadiene Photoswitch. European J Org Chem 2019. [DOI: 10.1002/ejoc.201801781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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11
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Cover Feature: Molecular Solar Thermal Energy Storage Systems with Long Discharge Times Based on the Dihydroazulene/Vinylheptafulvene Couple (Eur. J. Org. Chem. 10/2019). European J Org Chem 2019. [DOI: 10.1002/ejoc.201900304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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12
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Molecular Solar Thermal Energy Storage Systems with Long Discharge Times Based on the Dihydroazulene/Vinylheptafulvene Couple. European J Org Chem 2019. [DOI: 10.1002/ejoc.201801776] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Cover Feature: Donor−Acceptor-Functionalized Subphthalocyanines for Dye-Sensitized Solar Cells (ChemPhotoChem 11/2018). CHEMPHOTOCHEM 2018. [DOI: 10.1002/cptc.201800216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Conformational Impact on Energy Storage Efficiency of Subphthalocyanine-Fullerene Hybrids. J Phys Chem A 2018; 122:6683-6692. [PMID: 30041520 DOI: 10.1021/acs.jpca.8b06064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hybrid molecules involving subphthalocyanine and Buckminsterfullerene derivatives are interesting candidates as heavy metal free triplet sensitizers. Subphthalocyanine efficiently absorbs visible photons and transfer the singlet excited state energy to the Buckminsterfullerene where intersystem crossing produces triplet states in high yield. Thus, far the efficiency of the triplet-generating photophysics in these systems has been hampered by back energy transfer to the subphthalocyanine triplet state resulting in loss of excitation energy. Herein an efficient strategy is realized to avoid loss of triplet energy by back energy transfer. A hybrid molecule based on subphthalocyanine and Buckminsterfullerene is presented in which dispersion-induced π-π interactions result in a molecular geometry where highly efficient through-space singlet excited state energy transfer takes place in one direction, whereas energy flow in the opposite direction via the triplet manifold is blocked by lack of orbital overlap. The approach opens for a new class of heavy-metal-free triplet sensitizers of particular relevance to the fields of photodynamic therapy and noncoherent photon upconversion.
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Cover Feature: Norbornadiene-Based Photoswitches with Exceptional Combination of Solar Spectrum Match and Long-Term Energy Storage (Chem. Eur. J. 49/2018). Chemistry 2018. [DOI: 10.1002/chem.201804035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Triazole-Functionalized Norbornadiene-Quadricyclane Photoswitches for Solar Energy Storage. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800558] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Norbornadiene-Based Photoswitches with Exceptional Combination of Solar Spectrum Match and Long-Term Energy Storage. Chemistry 2018; 24:12767-12772. [DOI: 10.1002/chem.201802932] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/05/2018] [Indexed: 11/11/2022]
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18
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19
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Synthesis and Properties of Subphthalocyanine–Tetracyanobutadiene–Ferrocene Triads. J Org Chem 2018; 83:2227-2234. [DOI: 10.1021/acs.joc.7b03122] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Liquid-Crystalline Properties of Thioesters. Aust J Chem 2018. [DOI: 10.1071/ch17540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An extension of a new method for forming thioesters with mesomorphic properties has been described, whereby the treatment of aryl tert-butylthioethers with long-chain acid chlorides in the presence of bismuth triflate afforded simple derivatives in good yields. This method in the case of 1-cyanoazulenes was, however, complicated by a competitive Friedel–Crafts-type acylation side reaction at the 3-position. Long-chain derivatives of cyanobiphenyl attached through a thioester linkage exhibited mesophases comparable with their ester analogues. The use of shorter chains to decorate the cyanobiphenyl moiety did not produce mesophasic behaviour, unlike their ester analogues. The cyanobiphenyl derivatives showing mesophasic behaviour were studied by small-angle X-ray diffraction, showing alignment for molecules possessing a smectic A phase. It was found that the layer spacing in the smectic A phase was ~1.5 times the length of the molecule, owing to antiparallel pairing arising from π-stacking between neighbouring units. Calculations suggest these derivatives should exhibit large dielectric anisotropy; however, instability made an exact value difficult to determine. For potential use in a liquid crystal display (LCD), the thioester holds some promise, although this may be limited by the relative stability of the thioester functionality.
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21
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Photoswitching of Dihydroazulene Derivatives in Liquid-Crystalline Host Systems. Chemistry 2017; 23:5090-5103. [PMID: 28195368 DOI: 10.1002/chem.201700055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Indexed: 11/08/2022]
Abstract
Photoswitches and dyes in the liquid-crystalline nematic phase have the potential for use in a wide range of applications. A large order parameter is desirable to maximize the change in properties induced by an external stimulus. A set of photochromic and nonphotochromic dyes were investigated for these applications. It was found that a bent-shaped 7-substituted dihydroazulene (DHA) photoswitch exhibited liquid-crystalline properties. Further investigation demonstrated that this material actually followed two distinct reaction pathways on heating, to a deactivated form by a 1,5-sigmatropic shift and to a linear 6-substituted DHA. In addition, elimination of hydrogen cyanide from the photoactive DHA gave both bent and linear azulene dyes. In a nematic host that has no absorbance around 350 nm, it was found that only the linear DHA derivative has nematic properties; however, both 6- and 7-substituted DHAs were found to have large order parameters. In the nematic host, ring opening of either DHA to the corresponding vinylheptafulvene resulted in a decrease in dichroic order parameter and an unusually fast back-reaction to a mixture of both DHAs. Likewise, only the linear azulene derivative showed mesomorphic properties. In the same nematic host, large order parameters were also observed for these dyes.
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Front Cover: Synthesis of Covalently Linked Oligo(phenyleneethynylene) Wires Incorporating Dithiafulvene Units: Redox-Active “H-Cruciforms” (Eur. J. Org. Chem. 9/2017). European J Org Chem 2017. [DOI: 10.1002/ejoc.201700230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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23
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An effective trigger for energy release of vinylheptafulvene-based solar heat batteries. Chem Commun (Camb) 2017; 53:5874-5877. [DOI: 10.1039/c7cc01050h] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient strategy to activate the release of energy in dihydroazulene/vinylheptafulvene systems is developed.
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24
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Synthesis of Covalently Linked Oligo(phenyleneethynylene) Wires Incorporating Dithiafulvene Units: Redox-Active “H-Cruciforms”. European J Org Chem 2016. [DOI: 10.1002/ejoc.201601367] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Synthesis and Single-Molecule Conductances of Neutral and Cationic Indenofluorene-Extended Tetrathiafulvalenes: Kondo Effect Molecules. J Org Chem 2016; 81:8406-14. [PMID: 27548751 PMCID: PMC5038357 DOI: 10.1021/acs.joc.6b01579] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Development of molecules
that can switch between redox states with
paired and unpaired electrons is important for molecular electronics
and spintronics. In this work, a selection of redox-active indenofluorene-extended
tetrathiafulvalenes (IF-TTFs) with thioacetate end groups was prepared
from a readily obtainable dibromo-functionalized IF-TTF building block
using palladium-catalyzed cross-coupling reactions, such as the Suzuki
reaction. The end groups served as electrode anchoring groups for
single-molecule conductance studies, and the molecules were subjected
to mechanically controlled break-junction measurements with gold contacts
and to low-bias charge transport measurements in gated three-terminal
electromigration junctions. The neutral molecules showed clear conductance
signatures, and somewhat surprisingly, we found that a meta–meta anchoring configuration gave a higher conductance than a para–meta configuration. We explain this behavior
by “through-space” coupling between the gold electrode
and the phenyl on which the anchoring group is attached. Upon charging
the molecule in a gated junction, we found reproducibly a Kondo effect
(zero-bias conductance) attributed to a net spin. Ready generation
of radical cations was supported by cyclic voltammetry measurements,
revealing stepwise formation of radical cation and dication species
in solution. The first oxidation event was accompanied by association
reactions as the appearance of the first oxidation peak was strongly
concentration dependent.
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26
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68. Sentinel lymph node biopsy in papillary thyroid carcinoma in decision for selective modified lateral neck dissection. Eur J Surg Oncol 2016. [DOI: 10.1016/j.ejso.2016.06.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Metal cation binding to acetylenic tetrathiafulvalene–pyridine conjugates: affinity tuned by preorganization and cavity size. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Aromaticity-Controlled Energy Storage Capacity of the Dihydroazulene-Vinylheptafulvene Photochromic System. Chemistry 2016; 22:14567-75. [DOI: 10.1002/chem.201601190] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 07/12/2016] [Indexed: 11/10/2022]
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29
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Multistate Switches: Ruthenium Alkynyl–Dihydroazulene/Vinylheptafulvene Conjugates. Chemistry 2016; 22:7514-23. [DOI: 10.1002/chem.201600178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Indexed: 11/10/2022]
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30
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Azulenium chemistry: towards new derivatives of photochromic dihydroazulenes. Org Biomol Chem 2016; 14:2403-12. [DOI: 10.1039/c5ob02523k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The reactivity of azulenium salts, derived from photochromic dihydroazulenes (DHAs), towards a nucleophile is reported, and one regioisomer product is tautomerised into a new photochromic DHA that undergoes a ring-opening to a vinylheptafulvene (VHF).
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31
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Fine-tuning the lifetimes and energy storage capacities of meta-stable vinylheptafulvenes via substitution at the vinyl position. RSC Adv 2016. [DOI: 10.1039/c6ra06045e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A novel set of photo/thermo switches is available by one-step synthesis from the parent system.
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Aluminum Chloride Mediated Alkynylation of Boron Subphthalocyanine Chloride Using Trimethylsilyl-Capped Acetylenes. J Org Chem 2015; 81:1-5. [DOI: 10.1021/acs.joc.5b02719] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Synthesis of dithiafulvene-quinone donor-acceptor systems: isolation of a Michael adduct. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2015; 71:452-5. [PMID: 26044325 DOI: 10.1107/s2053229615008578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 05/01/2015] [Indexed: 11/10/2022]
Abstract
π-Conjugated donor-acceptor systems based on dithiafulvene (DTF) donor units and various acceptor units have attracted attention for their linear and nonlinear optical properties. The reaction between p-benzoquinone and a 1,3-dithiole phosphonium salt, deprotonated by lithium hexamethyldisilazide (LiHMDS), gave a product mixture from which the Michael adduct [systematic name: dimethyl 2-(3-hydroxy-6-oxocyclohexa-2,4-dien-1-ylidene)-2H-1,3-dithiole-4,5-dicarboxylate], C13H10O6S2, was isolated. It is likely that one of the unidentified products obtained previously by others from related reactions could be a similar Michael adduct.
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Towards solar energy storage in the photochromic dihydroazulene-vinylheptafulvene system. Chemistry 2015; 21:7454-61. [PMID: 25847100 DOI: 10.1002/chem.201500100] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Indexed: 11/09/2022]
Abstract
One key challenge in the field of exploitation of solar energy is to store the energy and make it available on demand. One possibility is to use photochromic molecules that undergo light-induced isomerization to metastable isomers. Here we present efforts to develop solar thermal energy storage systems based on the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch. New DHA derivatives with one electron-withdrawing cyano group at position 1 and one or two phenyl substituents in the five-membered ring were prepared by using different synthetic routes. In particular, a diastereoselective reductive removal of one cyano group from DHAs incorporating two cyano groups at position 1 turned out to be most effective. Quantum chemical calculations reveal that the structural modifications provide two benefits relative to DHAs with two cyano groups at position 1: 1) The DHA-VHF energy difference is increased (i.e., higher energy capacity of metastable VHF isomer); 2) the Gibbs free energy of activation is increased for the energy-releasing VHF to DHA back-reaction. In fact, experimentally, these new derivatives were so reluctant to undergo the back-reaction at room temperature that they practically behaved as DHA to VHF one-way switches. Although lifetimes of years are at first attractive, which offers the ultimate control of energy release, for a real device it must of course be possible to trigger the back-reaction, which calls for further iterations in the future.
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P138 Comparison of breast cancer disease characteristics between female and male elderly patients. Breast 2015. [DOI: 10.1016/s0960-9776(15)70180-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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P334 The breast reconstruction in breast cancer patients with a history of Hodgkin lymphoma. Breast 2015. [DOI: 10.1016/s0960-9776(15)70364-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Abstract
This work presents the first study on how to employ the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch in photoactive liquid crystalline materials.
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41
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163. Male breast cancer – the same disease as female breast cancer? Eur J Surg Oncol 2014. [DOI: 10.1016/j.ejso.2014.08.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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42
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Comparison of Linear and Cross-Conjugation from Rates of Vinylheptafulvene Ring-Closure. European J Org Chem 2014. [DOI: 10.1002/ejoc.201403117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Mono- and Bis(pyrrolo)tetrathiafulvalene Derivatives Tethered to C60: Synthesis, Photophysical Studies, and Self-Assembled Monolayers. Chemistry 2014; 20:9918-29. [DOI: 10.1002/chem.201402623] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Indexed: 01/07/2023]
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44
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CuAAC and RuAAC with Alkyne-functionalised Dihydroazulene Photoswitches and Determination of Hammett σ-Constants for Triazoles. Aust J Chem 2014. [DOI: 10.1071/ch13544] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Dihydroazulene (DHA)–vinylheptafulvene (VHF) photoswitches have attracted attention as potentially useful components in molecular electronics. The π-conjugated dihydroazulene system is a rigid structure and can be strategically functionalised to place handles for further elaboration. Here we show that alkyne-functionalised dihydroazulenes can be subjected to copper and ruthenium catalysed azide–alkyne cycloadditions (CuAAC and RuAAC) with tolylazide, furnishing 1,4- and 1,5-disubstituted triazoles. The rates of ring-closure of the corresponding vinylheptafulvenes were compared with those of reference systems, which allowed determination of Hammett substituent constants (meta and para) for N-tolyl-substituted 1,2,3-triazoles.
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Prognostic factors for longer disease free survival and overall survival after surgical resection of isolated liver metastasis from breast cancer. JOURNAL OF B.U.ON. : OFFICIAL JOURNAL OF THE BALKAN UNION OF ONCOLOGY 2013; 18:859-865. [PMID: 24344009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
PURPOSE Isolated liver metastases (LMs) from breast cancer (BC) occur in only 1-3% of the cases. Resection of isolated LMs improves survival. We examined the prognostic factors for time to LM development, disease free survival (DFS) and overall survival (OS) after BCLM resection. METHODS From 2006 to 2009, 32 patients underwent LM resection. All of them had breast cancer surgery for their primary tumor and developed resectable LMs as the first and only site of disease progression. RESULTS LMs developed after a median of 25 months. With a median follow up of 37 months (range 7-66) after metastases resection, median DFS and OS (with 95% CI) were 22.5 (12-40) and 37 (≥23) months, respectively. Tumor size ≥3 vs <3 cm and adjuvant chemotherapy vs no adjuvant chemotherapy correlated with shorter time to LM development (p<0.01 for both parameters). These parameters and BC negative estrogen (ER)/ progesterone receptors (PR) (ER?/PR? vs other) were related with shorter DFS. Positive (vs negative) axillary lymph nodes and BC negative ER/ PR (ER?/PR? vs other) status correlated with shorter OS (p<0.01 for both parameters). A period to metastases development ≥ 24 months (vs ≤24) and single (vs multiple) metastases were related with longer DFS and OS (p<0.01 for both conditions). CONCLUSION Despite the relatively small number of patients in this study, we believe that positive ER/PR status for both BC and LMs, negative axillary lymph nodes, time to liver metastases development >24 months and single liver metastases predict longer DFS and OS after LM resection.
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Ultrathin reduced graphene oxide films as transparent top-contacts for light switchable solid-state molecular junctions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:4164-4170. [PMID: 23765569 DOI: 10.1002/adma.201300607] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 04/09/2013] [Indexed: 06/02/2023]
Abstract
A new type of solid-state molecular junction is introduced, which employs reduced graphene oxide as a transparent top contact that permits a self-assembled molecular monolayer to be photoswitched in situ, while simultaneously enabling charge-transport measurements across the molecules. The electrical switching behavior of a less-studied molecular switch, dihydroazulene/vinylheptafulvene, is described, which is used as a test case.
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Linear Free-Energy Correlations for the Vinylheptafulvene Ring Closure: A Probe for Hammett σ Values. Chemistry 2013; 19:9542-8. [DOI: 10.1002/chem.201300167] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/12/2013] [Indexed: 11/08/2022]
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Abstract
The orientation of different N-substituted [N@C60]fulleropyrrolidine derivatives hosted in a nematic liquid crystal matrix has been studied by electron spin resonance spectroscopy. In this study, variations on the zero field splitting parameter of the guest species are employed as a means of determining their degree of orientation. Fulleropyrrolidines with more rigid N-substituents are preferentially oriented in the liquid crystal matrix, whereas those with less rigid substituents are almost randomly distributed. Additionally, the orientation of a C60 fullerene cage bearing a nitroxide radical has also been investigated in comparison.
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