- Nickel as a Lewis Base in a T-Shaped Nickel(0) Germylene Complex Incorporating a Flexible Bis(NHC) Ligand
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Flexible, chelating bis(NHC) ligand 2, able to accommodate both cis- and trans-coordination modes, was used to synthesize (2)Ni(η2-cod), 3. In reaction with GeCl2, it produced (2)NiGeCl2, 4, featuring a T-shaped Ni0 and a pyramidal Ge center. Complex 4 could also be prepared from [(2)GeCl]Cl, 5, and Ni(cod)2, in a reaction that formally involved Ni–Ge transmetalation, followed by coordination of the extruded GeCl2 moiety to Ni. A computational analysis showed that 4 possesses considerable multiconfigurational character and the Ni→Ge bond is formed through σ-donation from the Ni 4s, 4p, and 3d orbitals to Ge. (NHC)2Ni(cod) complexes 9 and 10, as well as (NHC)2GeCl2 derivative 11, incorporating ligands that cannot accommodate a wide bite angle, failed to produce isolable Ni–Ge complexes. The isolation of (2)Ni(η2-Py), 12, provides further evidence for the reluctance of the (2)Ni0 fragment to act as a σ-Lewis acid.
- Gendy, Chris,Mansikkam?ki, Akseli,Valjus, Juuso,Heidebrecht, Joshua,Hui, Paul Chuk-Yan,Bernard, Guy M.,Tuononen, Heikki M.,Wasylishen, Roderick E.,Michaelis, Vladimir K.,Roesler, Roland
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- Combined effect of ether and siloxane substituents on imidazolium ionic liquids
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Ionic liquids (ILs) in combination with ether and siloxane substituents on the imidazolium cation, comprising of bis(trifluoromethylsulfonyl)imide (NTf2) anions, have been synthesized due to their low viscosities, high thermal stabilities and low melting or glass transition temperatures(Tg). The structural flexibility of the ether and siloxane substituents on the imidazolium center overcomes the effect of van der Waals forces and gives them desirable and unique physical properties. These novel ILs show low viscosities (~72 mPa s at 25 °C), high thermal stabilities up to 430°C, and a wide liquid range over 500°C. In addition, these ILs exhibit only an amorphous glassy state on cooling at Tg below -74°C and cannot order properly to afford crystallization. The detailed thermal stability, phase transitions and heat capacity were studied by TGA, DSC and temperature-modulated DSC analysis. More importantly, we have also reported the large-scale (one kilogram) microwave-assisted synthesis of ILs [BMIM]Br and [1O2O2-Im-2O1]I as efficient and greener processes.
- Chavan, Santosh N.,Mandal, Debaprasad
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p. 64821 - 64831
(2015/08/18)
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- Novel pyridinium iodide containing siloxane high performance electrolyte for dye-sensitized solar cell
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A new type of solid and gel-state ionics based on siloxane pyridinium iodides was synthesized and used as electrolytes in dye-sensitized solar cells. The resulting electrolytes were characterized by 1H NMR spectroscopy, TGA and diffusion coefficient. The synthesized siloxane pyridinium iodide electrolytes have characteristics of different chain length of siloxane moieties. The ion conductivities were given 2.7-3.2 S/cm. Among the three SiDPIs based electrolytes, DSSC employing the SiDPI2 gives an open circuit voltage of 0.704 V, a short-circuit current of 15.85 mA/cm2 and conversion efficiency of 6.8% under light intensity of 100 mW/cm2. In addition, the performance of the DSSCs showed relatively reasonable compared with the propylpyridinium iodide (PPI) electrolyte.
- Lee, Soonho,Jeon, Youngtae,Lim, Youngdon,Cho, Younggil,Lee, Sangyoung,Kim, Whangi
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p. 2583 - 2588
(2013/10/22)
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- CARBON DIOXIDE ABSORBENT AND METHOD OF USING THE SAME
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In accordance with one aspect, the present invention provides a composition which contains the amino-siloxane structures I, or III, as described herein. The composition is useful for the capture of carbon dioxide from process streams. In addition, the present invention provides methods of preparing the amino-siloxane composition. Another aspect of the present invention provides methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention, as species which react with carbon dioxide to form an adduct with carbon dioxide.
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- Oligosiloxanes end-functionalized with N-heterocycles. A comparative study of the Si-R-X bond reactivities
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A simple method is reported for the synthesis of di- and oligosiloxanes containing nitrogen heterocycles groups at the end of the chains such as: α,ω-bis-(3-(1-pyridinio)-propyl)-oligodimethylsiloxane iodide (P2Py), α,ω-bis-(3-(1-(3methylpyridinio))-propyl)-oligodimethylsiloxane iodide (P2Pyc), 1,3-bis-(3-(1-pyridinio)-propyl)-tetramethyldisiloxane iodide (P3Py) and 1,3-bis-(3-(1-(3-methylpyridinio))-methyl)-tetramethyldisiloxane iodide (P4Pyc). A comparative study was made of the Si-R-X group reactivity in the reaction with two various pyridines. The obtained oligomers were analyzed by IR and 1H-NMR spectrometries. Solubility tests were also made, emphasizing their modification depending on the siloxane chain length and end-groups nature.
- R?mniceanu, Cristina,Cazacu, Maria,Marcu, Mihai,R?mniceanu, Ionut
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p. 551 - 557
(2007/10/03)
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