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Nidal Saleh, Radovan Bast, Nicolas Vanthuyne, Christian Roussel, Trond Saue, Benoît Darquié, Jeanne Crassous
In our effort towards measuring the parity violation energy difference between two enantiomers, a simple chiral oxorhenium complex 5 bearing enantiopure 2-mercaptocyclohexan-1-ol has been prepared as a potential candidate species. Vibrational circular dichroism revealed a chiral environment surrounding the rhenium atom, even though the rhenium is not a stereogenic center itself, and enabled to assign the (1S,2S)-(-) and (1R,2R)-(+) absolute configuration for 5. For both compound 5 and complex 4, previously studied by us and bearing a propane-2-olato-3-thiolato ligand, relativistic calculations predict parity violating vibrational frequency differences of a few hundreds of millihertz, above the expected sensitivity attainable by a molecular beam Ramsey interferometer that we are constructing...
November 15, 2017: Chirality
Paul F Hoffman, Dorian S Abbot, Yosef Ashkenazy, Douglas I Benn, Jochen J Brocks, Phoebe A Cohen, Grant M Cox, Jessica R Creveling, Yannick Donnadieu, Douglas H Erwin, Ian J Fairchild, David Ferreira, Jason C Goodman, Galen P Halverson, Malte F Jansen, Guillaume Le Hir, Gordon D Love, Francis A Macdonald, Adam C Maloof, Camille A Partin, Gilles Ramstein, Brian E J Rose, Catherine V Rose, Peter M Sadler, Eli Tziperman, Aiko Voigt, Stephen G Warren
Geological evidence indicates that grounded ice sheets reached sea level at all latitudes during two long-lived Cryogenian (58 and ≥5 My) glaciations. Combined uranium-lead and rhenium-osmium dating suggests that the older (Sturtian) glacial onset and both terminations were globally synchronous. Geochemical data imply that CO2 was 10(2) PAL (present atmospheric level) at the younger termination, consistent with a global ice cover. Sturtian glaciation followed breakup of a tropical supercontinent, and its onset coincided with the equatorial emplacement of a large igneous province...
November 2017: Science Advances
Hajar Molaee, S Masoud Nabavizadeh, Mahboubeh Jamshidi, Max Vilsmeier, Arno Pfitzner, Mozhgan Samandar Sangari
Heterobimetallic compounds [(C^N)LMe2Pt(μ-O)ReO3] (C^N = ppy, L = PPh3, 2a; C^N = ppy, L = PMePh2, 2b; C^N = bhq, L = PPh3, 2c; C^N = bhq, L = PMePh2, 2d) containing a discrete unsupported Pt(iv)-O-Re(vii) bridge have been synthesized through a targeted synthesis route. The compounds have been prepared by a single-pot synthesis in which the Pt(iv) precursor [PtMe2I(C^N)L] complexes are allowed to react easily with AgReO4 in which the iodide ligand of the starting Pt(iv) complex is replaced by an ReO4(-) anion...
November 9, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Miguel Pinto, Indranil Chakraborty, Jorge Martinez-Gonzalez, Pradip Mascharak
Carbon monoxide (CO) has recently been identified as a gaseous signaling molecule that exerts various salutary effects in mammalian pathophysiology. Photoactive metal carbonyl complexes (photoCORMs) are ideal exogenous candidates for more controllable and site-specific CO delivery compared to gaseous CO. Along this line, our group has been engaged for the past few years in developing group-7-based photoCORMs towards the efficient eradication of various malignant cells. Moreover, several such complexes can be tracked within cancerous cells by virtue of their luminescence...
November 1, 2017: Acta Crystallographica. Section C, Structural Chemistry
Lawrence Cho-Cheung Lee, Kam-Keung Leung, Kenneth Kam-Wing Lo
There has been fast-growing interest in the exploitation of the photophysical and photochemical properties of luminescent transition metal complexes in biological applications, with a focus on both diagnostic and therapeutic aspects. In particular, the design of luminescent rhenium(i) tricarbonyl polypyridine complexes as cellular imaging reagents and anticancer drugs has received considerable attention for a number of reasons. First, most rhenium(i) tricarbonyl polypyridine complexes possess diverse photophysical and photochemical properties through the coordination of functionalized ligands...
November 7, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Jamaladin Shakeri, Hassan Hadadzadeh, Hossein Farrokhpour, Mohammad Joshaghani, Matthias Weil
Oxo-rhenium compounds, such as perrhenate salts, have demonstrated preferable activity in catalyzing the deoxydehydration (DODH) reaction in the presence of reductants. Here, the first computational details of the reported DODH mechanisms are presented using the density functional theory (DFT) (M06/6-311+G(d,p)/LANL2DZ) to investigate the conversion of a vicinal diol into the corresponding alkene by ReO4(-) as a catalyst. The DFT studies were carried out to evaluate the DODH mechanisms, from the energy point of view, for the conversion of phenyl-1,2-ethanediol to styrene by perrhenate anion in the presence of PPh3 as a reductant through a detailed comparison of two potential pathways including pathway A and pathway B...
November 8, 2017: Journal of Physical Chemistry. A
Benjamin K Liebov, W Dean Harman
This review covers publications ranging from 2005 to 2017 concerning the organic reactions of aromatic ligands η(2)-coordinated to tungsten or molybdenum and the use of these reactions in the synthesis of novel organic substances. An emphasis is placed on C-C bond-forming reactions using conventional building blocks of organic synthesis such as acetals, enolates, Michael acceptors, acylating reagents, and activated aromatics. Substrates activated by the metal include arenes, pyridines, pyrroles, pyrimidines, furans, and thiophenes...
October 24, 2017: Chemical Reviews
Moustafa T Gabr, F Christopher Pigge
The synthesis and photophysical properties of luminescent Re(i) tricarbonyl complexes prepared from bis(pyridyl)- and bis(quinolyl) tetraarylethylene (TAE) ligands are reported. Emission wavelengths of the complexes are influenced by structural variation in the tetraarylethylene ligands, and several complexes display aggregation-induced enhanced emission in aqueous solution. A Re(i) complex prepared from an indole-functionalized TAE ligand shows significant enhancement in its luminescence intensity accompanied by a remarkable blue shift (∼95 nm) upon specific binding to site II of human serum albumin...
November 7, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Kimberly M Reinig, Rachel Seibert, Daniel Velazquez, Jakob Baumeister, Firouzeh Najafi Khosroshahi, Wei Wycoff, Jeff Terry, John E Adams, Carol A Deakyne, Silvia S Jurisson
Technetium-99 ((99)Tc) is important to the nuclear fuel cycle as a long-lived radionuclide produced in ∼6% fission yield from (235)U or (239)Pu. In its most common chemical form, namely, pertechnetate ((99)TcO4(-)), it is environmentally mobile. In situ hydrogen sulfide reduction of pertechnetate has been proposed as a potential method to immobilize environmental (99)TcO4(-) that has entered the environment. Reactions of (99)TcO4(-) with sulfide in solution result in the precipitation of Tc2S7 except when olefinic acids, specifically fumaric or maleic acid, are present; a water-soluble (99)Tc species forms...
November 6, 2017: Inorganic Chemistry
Shishu Zhang, Nannan Mao, Na Zhang, Juanxia Wu, Lianming Tong, Jin Zhang
The Raman tensor of a crystal is the derivative of its polarizability tensor and is dependent on the symmetries of the crystal and the Raman-active vibrational mode. The intensity of a particular mode is determined by the Raman selection rule, which involves the Raman tensor and the polarization configurations. For anisotropic two-dimensional (2D) layered crystals, polarized Raman scattering has been used to reveal the crystalline orientations. However, due to its complicated Raman tensors and optical birefringence, the polarized Raman scattering of triclinic 2D crystals has not been well studied yet...
October 24, 2017: ACS Nano
Anastasiya O Solovieva, Kaplan Kirakci, Anton A Ivanov, Pavel Kubát, Tatiana N Pozmogova, Svetlana M Miroshnichenko, Elena V Vorontsova, Anton V Chechushkov, Kristina E Trifonova, Maria S Fufaeva, Evgeniy I Kretov, Yuri V Mironov, Alexander F Poveshchenko, Kamil Lang, Michael A Shestopalov
Octahedral rhenium cluster complexes have recently emerged as relevant building blocks for the design of singlet oxygen photosensitizing materials toward biological applications such as blue-light photodynamic therapy. However, their singlet oxygen generation ability as well as biological properties have been studied only superficially. Herein we investigate in detail the singlet oxygen photogeneration, dark and photoinduced cytotoxicity, cellular uptake kinetics, cellular localization and in vitro photoinduced oxidative stress, and photodynamic cytotoxicity of the series of octahedral rhenium cluster complexes [{Re6Q8}(CN)6](4-), where Q = S, Se, Te...
November 6, 2017: Inorganic Chemistry
Yong-Kwang Jeong, Young Min Lee, Jeonghun Yun, Tomasz Mazur, Minju Kim, Young Jae Kim, Miroslaw Dygas, Sun Hee Choi, Kwang S Kim, Oh-Hoon Kwon, Seok Min Yoon, Bartosz A Grzybowski
Materials exhibiting excitation-wavelength-dependent photoluminescence, PL, are useful in a range of biomedical and optoelectronic applications. This paper describes a nanoparticulate material whose PL is tunable across the entire visible range and is achieved without adjusting particle size, any postsynthetic doping, or surface modification. A straightforward thermal decomposition of rhenium (VII) oxide precursor yields nanoparticles that comprise Re atoms at different oxidation states. Studies of time-resolved emission spectra and DFT calculations both indicate that tunable PL of such mixed-valence particles originates from the presence of multiple emissive states that become "active" at different excitation wavelengths...
October 16, 2017: Journal of the American Chemical Society
Sebastian Mai, Hugo Gattuso, Maria Fumanal, Aurora Muñoz-Losa, Antonio Monari, Chantal Daniel, Leticia González
We present a quantum-chemical investigation of the excited states of the complex [Re(CO)3(Im)(Phen)](+) (Im = imidazole; Phen = 1,10-phenanthroline) in solution including spin-orbit couplings and vibrational sampling. To this aim, we implemented electrostatic embedding quantum mechanics/molecular mechanics (QM/MM) in the Amsterdam Density Functional program suite, suitable for time-dependent density functional calculations including spin-orbit couplings. The new implementation is employed to simulate the absorption spectrum of the complex, which is compared to the results of implicit continuum solvation and frozen-density embedding...
October 18, 2017: Physical Chemistry Chemical Physics: PCCP
Kate Horan, Robert G Hilton, David Selby, Chris J Ottley, Darren R Gröcke, Murray Hicks, Kevin W Burton
Over millions of years, the oxidation of organic carbon contained within sedimentary rocks is one of the main sources of carbon dioxide to the atmosphere, yet the controls on this emission remain poorly constrained. We use rhenium to track the oxidation of rock-bound organic carbon in the mountain watersheds of New Zealand, where high rates of physical erosion expose rocks to chemical weathering. Oxidative weathering fluxes are two to three times higher in watersheds dominated by valley glaciers and exposed to frost shattering processes, compared to those with less glacial cover; a feature that we also observe in mountain watersheds globally...
October 2017: Science Advances
Mathias Glatz, Berthold Stöger, Karl Kirchner
Crystals of cis-Re[(PNP(CH2)-iPr)(CO)2Cl] (1) are made up of two geometrically non-equivalent polytypes with respective symmetries of P21/c and I2/a. The structures were determined in a concurrent refinement, taking into account overlap of diffraction spots. The polytypes are composed of layers with px121/c1 symmetry and are of the non-order-disorder (OD) type (the layer interfaces are non-equivalent). Whereas the molecules of (1) differ in both polytypes, the Re atoms are located at nearly identical positions...
October 1, 2017: Acta Crystallographica Section B, Structural Science, Crystal Engineering and Materials
Zandria Lamprecht, Shankara G Radhakrishnan, Alexander Hildebrandt, Heinrich Lang, David C Liles, Nora-Ann Weststrate, Simon Lotz, Daniela I Bezuidenhout
The oxidative cleaving of a rhenium-rhenium bond by bromine in binuclear Fischer carbene complexes proves to be an effective method to prepare mononuclear bromido-carbene complexes. The reaction of mono- and dilithiated thieno[2,3-b]thiophene (2,3-b-TTH2) and thieno[3,2-b]thiophene (3,2-b-TTH2) with [Re2(CO)10] affords dirhenium nonacarbonyl ethoxycarbene complexes, [Re2(CO)9{C(OEt)2,3-b-TTH}] (1a) and [Re2(CO)9{C(OEt)3,2-b-TTH}] (1b), and the tetrarhenium bis(ethoxycarbene) complexes from the dilithiated thiophene substrates, [Re2(CO)9-μ-{C(OEt)-2,3-b-TT-C(OEt)}Re2(CO)9] (2a) and [Re2(CO)9-μ-{C(OEt)-3,2-b-TT-C(OEt)}Re2(CO)9] (2b) featuring bridging thiophene linkers...
October 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Xiancui Su, Hongkun Nie, Yiran Wang, Guoru Li, Bingzheng Yan, Baitao Zhang, Kejian Yang, Jingliang He
A novel two-dimensional (2D) material member in the transition metal dichalcogenides family, few-layered rhenium disulfide (ReS2) was prepared by liquid phase method successfully. By using the open-aperture Z-scan method, the saturable absorption properties at 2.8 μm were characterized with a saturable fluence of 22.6  μJ/cm(2) and a modulation depth of 9.7%. A passively Q-switched solid-state laser at 2.8 μm was demonstrated by using the as-prepared ReS2 saturable absorber successfully. Under an absorbed pump power of 920 mW, a maximum output power of 104 mW was obtained with a pulse width of 324 ns and a repetition rate of 126 kHz...
September 1, 2017: Optics Letters
Yutian Feng, Tim E Phelps, Valerie Carroll, Fabio Gallazzi, Gary Sieckman, Timothy J Hoffman, Charles L Barnes, Alan R Ketring, Heather M Hennkens, Silvia S Jurisson
The chemistry and radiochemistry of high specific activity radioisotopes of arsenic, rhenium and rhodium are reviewed with emphasis on University of Missouri activities over the past several decades, and includes recent results. The nuclear facilities at the University of Missouri (10 MW research reactor and 16.5 MeV GE PETtrace cyclotron) allow research and development into novel theranostic radionuclides. The production, separation, enriched target recovery, radiochemistry, and chelation chemistry of (72,77)As, (186,188)Re and (105)Rh are discussed...
October 31, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Licia Uccelli, Petra Martini, Micol Pasquali, Alessandra Boschi
Rhenium-188, obtained from an alumina-based tungsten-188/rhenium-188 generator, is actually considered a useful candidate for labeling biomolecules such as antibodies, antibody fragments, peptides, and DNAs for radiotherapy. There is a widespread interest in the availability of labeling procedures that allow obtaining (188)Re-labeled radiopharmaceuticals for various therapeutic applications, in particular for the rhenium attachment to tumor-specific monoclonal antibodies (Mo)Abs for immunotherapy. Different approaches have been developed in order to obtain (188)Re-radioimmunoconjugates in high radiochemical purity starting from the generator eluted [(188)Re]ReO4(-)...
2017: BioMed Research International
Kevin M Knopf, Brendan L Murphy, Samantha N MacMillan, Jeremy M Baskin, Martin P Barr, Eszter Boros, Justin J Wilson
Seven rhenium(I) complexes of the general formula fac-[Re(CO)3(NN)(OH2)](+) where NN = 2,2'-bipyridine (8), 4,4'-dimethyl-2,2'-bipyridine (9), 4,4'-dimethoxy-2,2'-bipyridine (10), dimethyl 2,2'-bipyridine-4,4'-dicarboxylate (11), 1,10-phenanthroline (12), 2,9-dimethyl-1,10-phenanthroline (13), or 4,7-diphenyl-1,10-phenanthroline (14), were synthesized and characterized by (1)H NMR spectroscopy, IR spectroscopy, mass spectrometry, and X-ray crystallography. With the exception of 11, all complexes exhibited 50% growth inhibitory concentration (IC50) values that were less than 20 μM in HeLa cells, indicating that these compounds represent a new potential class of anticancer agents...
October 11, 2017: Journal of the American Chemical Society
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