Reaction between the dichloroboryl complex, Os(BCl2)Cl(CO)(PPh3)2, and water replaces both chloride substituents on the boryl ligand, without cleavage of the Os---B bond, giving yellow Os[B(OH)2]Cl(CO)(PPh3)2 (1). Compound 1 can be regarded as an example of a ‘metalla–boronic acid’ (LnM---B(OH)2) and in the solid state, X-ray crystal structure determination reveals that molecules of 1 are tetragonal pyramidal in geometry (Os---B, 2.056(3) Å) and are arranged in pairs, as hydrogen-bonded dimers. This same arrangement is found in the crystalline state for simple boronic acids. Reaction between the dichloroboryl complex, Os(BCl2)Cl(CO)(PPh3)2, and methanol and ethanol produces yellow Os[B(OMe)2]Cl(CO)(PPh3)2 (2a) and yellow Os[B(OEt)2]Cl(CO)(PPh3)2 (2b), respectively. The crystal structure of 2b reveals a tetragonal pyramidal geometry with the diethoxyboryl ligand in the apical site and with an Os---B bond distance of 2.081(5) Å. Reaction between Os(BCl2)Cl(CO)(PPh3)2, and N,N′-dimethyl-o-phenylenediamine and N,N′-dimethyl-ethylenediamine produces yellow
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(5) and yellow
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(6), respectively. Compounds 1, 2a, 2b, 5, and 6 all react with carbon monoxide to give the colourless, six-coordinate complexes Os[B(OH)2]Cl(CO)2(PPh3)2 (3), Os[B(OMe)2]Cl(CO)2(PPh3)2 (4a), Os[B(OEt)2]Cl(CO)2(PPh3)2 (4b),
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(7), and
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(8), respectively, but in the case of 6 only, this CO uptake is easily reversible. The crystal structure of 5 is also reported. 相似文献
The iridium(I) complex [Ir(CO2Me)(CO)2(PPh3)2] undergoes a transesterification reaction with the alcohols CH2C(R)CH2OH (R = H, Me), MeCCCH2CH2OH, and HOCH2CH2OH to afford the complexes [Ir(CO2CH2CH2CMe)(CO)2(PPh3)2] and [Ir(CO2CH2CH2OH)(CO)2(PPh3)2], respectively. In contrast the acetylenic alcohol HCCCH2CH2OH gives [Ir(CCCH2CH2OH)(CO)PPh3)2]. Some reactions of the new complexes are described. 相似文献
[OS(η2-CS2Me)(CO)2(PPH3)2]+ and [Ir(η2-CS2Me)Cl(CO)(PPh3)2)+ react with NaBH4 giving OsH(CS2Me)(CO)2(PPh3)2 and IrH(CS2Me)Cl(CO)(PPh3)2 respectively; These compounds contain mutually hydride and η1-dithiomethylester ligands and upon heating undergo 1,2-elimination of MeSH producing Os(CS)(CO)2(PPh3)2 and IrCl(CS)(PPh3)2. 相似文献
A high-yield synthesis of trans-RuCl2(CS)(H2O)(PPh3)2 from RuCl2(PPh3)3 and CS2 is described. The coordinated water molecule is labile, and introduction of CNR (R p-toyl or p-chlorophenyl) leads to yellow trans-RuCl2(CS)(CNR)(PPh3)2, which isomerises thermally to colourless cis-RuCl2(CS)(CNR)(PPh3)2. Reaction of AgClO4 with cis-RuCl2(CS)(CNR)(PPh3)2 gives [RuCl(CS)(CNR)(H2O)(PPh3)2]+, from which [RuCl(CS)(CO)(CNR)(PPh3)2]+ and [RuCl(CS)(CNR)2(PPh3)2]+ are derived. Reaction of trans-RuCl2(CS)(H2O)(PPh3)2 with sodium formate gives Ru(η2-O2CH)Cl(CS)(PPh3)2, which undergoes decarboxylation in the presence of (PPh3) to give RuHCl(CS)(PPh3)3. Ru(η2-O2CH)H(CS)(PPh3)2 and Ru(η2-O2CMe)-H(CS)(PPh3)2 are also described. 相似文献
An energy-dependent phase-shift analysis of 0–21 MeV n-α scattering is presented and compared to the previous 0–23 MeV p-α analysis. The error matrix and inverse error matrix for both the n-α and the p-α analyses are given. 相似文献
Free fatty acid (FFA) compositions are examined in feedstock for biodiesel production, as source-specific markers in soil, and because of their role in cellular signaling. However, sample preparation of FFAs for gas chromatography-mass spectrometry (GC-MS) analysis can be time and labor intensive. Therefore, to increase sample preparation throughput, a glass microfluidic device was developed to automate derivatization of FFAs to fatty acid methyl esters (FAMEs). FFAs were delivered to one input of the device and methanolic-HCl was delivered to a second input. FAME products were produced as the reagents traversed a 29 μL reaction channel held at 55 °C. A Design of Experiment protocol was used to determine the combination of derivatization time (T(der)) and ratio of methanolic-HCl:FFA (R(der)) that maximized the derivatization efficiencies of tridecanoic acid and stearic acid to their methyl ester forms. The combination of T(der) = 0.8 min and R(der) = 4.9 that produced optimal derivatization conditions for both FFAs within a 5 min total sample preparation time was determined. This combination of T(der) and R(der) was used to derivatize 12 FFAs with a range of derivatization efficiencies from 18% to 93% with efficiencies of 61% for tridecanoic acid and 84% for stearic acid. As compared to a conventional macroscale derivatization of FFA to FAME, the microfluidic device decreased the volume of methanolic-HCl and FFA by 20- and 1300-fold, respectively. The developed microfluidic device can be used for automated preparation of FAMEs to analyze the FFA compositions of volume-limited samples. 相似文献
This paper explores Mechanical Engineering students’ conceptions of and preferences for conceptions of the derivative, and their views on mathematics. Data comes from pre-, post- and delayed post-tests, a preference test, interviews with students and an analysis of calculus courses. Data from Mathematics students is used to make comparisons with Mechanical Engineering students. The results show that Mechanical Engineering students’ conceptions of and preferences for the derivative develop in the direction of the rate of change aspects while those of Mathematics students develop in the direction of tangent aspects, and that Mechanical Engineering students view mathematics as a tool and want the application aspects in their course. Students’ developing conceptions, preferences and views with regard to teaching and departmental affiliation are considered and educational implications are suggested for the mathematical education of engineering students. 相似文献