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The two series of title compounds are prepared from mixtures of MF3 (M: La—Nd, Sm, Gd—Ho), M2O3, M, and Se using excess CsI as a flux (Nb tubes, 850 °C, 10 d).

The title compounds are synthesized from mixtures of Ln (Ln: La—Nd, Sm, Gd), LnF3, Ln2O3 (resp.

Metalloproteomics is a rapidly developing field of science that involves the comprehensive analysis of all metal-containing or metal-binding proteins in a biological sample. The purpose of this review is to offer an overview of the research involving Metal Isotope native RadioAutography in Gel Electrophoresis (MIRAGE), a powerful new method to visualize and study the proteome of a particular metal ion. MIRAGE involves four steps: i) labelling of target proteins with a radioisotope; ii) separation of intact holo-proteins using native isoelectric focusing (1D) combined with Blue Native PAGE (2D); iii) spot visualization and quantification using autoradiography; and iv) protein identification by tandem mass spectrometry. MIRAGE Investigations of the soluble Cu, Zn, and Fe metalloproteomes of Escherichia coli, and of the soluble Mo and W proteomes of the hyperthermophilic archaeon Pyrococcus furiosus are reviewed.

The fully conjugated diimide (III), an organic semiconductor that exhibits ambipolar transport properties, is synthesized in a convenient one-pot, two-step reaction.

The title compounds are synthesized by reaction of LnF3 (Ln: Nd, Sm, Gd—Ho), Ln2O3, Ln, and S (molar ratio 2:5:1:3) in a NaCl flux (850 °C, 7 d).

Over the past 20 years, organic transistors have developed from a laboratory curiosity to a commercially viable technology. This critical review provides a short summary of several important aspects of organic transistors, including materials, microstructure, carrier transport, manufacturing, electrical properties, and performance limitations (200 references).

A series of 5-methyl-4-oxo-3-quinolinecarboxylic acids was prepared in which the eight-position was substituted with fluorine, chlorine, methyl, or hydrogen. These quinolones were synthesized from the appropriate 2-methyl-3,4,6-trifluorobenzoic acids which were derived from oxazolines 8 and 16. The oxazoline moiety served as both an ortho-director (where feasible) and a protecting group; a trimethylsilyl moiety was used to block the most acidic site in the molecule.

The molecular structure and conformational composition of 2-methylpropenoyl chloride (MPC), H 2 CC(CH 3 )OCl, has been determined by gas phase electron diffraction at 303 and 573 K. The molecules consist of a mixture of two conformers, a more stable anti form and a less stable syn form, ( anti and syn referring to the double bonds). Both forms are planar or near planar. The mole fraction of the anti form, with uncertainties estimated at 2α, was found to be 0.89(9) and 0.82(17) at 303 and 573 K, respectively. This corresponds to Δ E ° = E ° s − E ° a = 3.3± 3.9 kJ mol −1 , and Δ S °= S ° s − S ° a = −6.6±4.6 J mol −1 K −1 . Assuming the two conformers to have the same geometry except for the C (CH 3 )COCl torsion angles, the bond distances ( r a ) and valence angles (∠ α ) values at 303 K are: 〈 r (CH)〉=1.100(7) A, Δ r (CH)=0.01 A (assumed), r (C0)=1.189(3) A, 〈 r (CC)〉 =0.5·[ r (C 2 -C 3 )+ r (C 2 -C 6 )]=1.497(2) A, Δ r (CC)= r(C 2 C 6 )- r (C 2 -C 3 )=0.02 A (assumed), r (CC)=1.336(3) A, r (CCl)=1.792(83) A, ∠C CO=125.8(4)°, ∠CCCl=114.8(3)°, ∠CCC=115.3(3)°, ∠CCC=124.2(6)°, ∠CCH=120.0° (assumed), ∠CCH=110.5° (assumed).

AbsbPct Second-order rate constants for the reactions of para-substituted diarylmrbenium ions (ArAr‘CH’ = 1) with allylsilanes 2, allylgermanes 3, and allylstannanes 4 have been determined in CH2C12 solution at -70 to -30 OC. Generally, the attack of ArAr’CH+ at the CC double bond of the allylelement compounds 2-4 is rate-determining and leads to the formation of the j3-element-stabilized carbenium ions 5, which subsequently react with the negative counterions to give the substitution products 6 or the addition products 7. For compounds H2C=CHCH2MPh3, the relative reactivities are 1 (M = Si), 5.6 (M = Ge), and 1600 (M = Sn). From the relative reactivities of compounds H2C==CHCH2X (X .= H, SiBu3, SnBu3), the activating effect of an allylic trialkylsilyl (5 X IOs) and trialkylstannyl group (3 X lo9) is derived. This effect is strongly reduced, when the alkyl groups at Si or Sn are replaced by inductively withdrawing substituents, and an allylic SiCI, group deactivates by a factor of 300 (comparison isobutene/2k). A close analogy between the reactions of alkenes and allylelement compounds with carbenium ions is manifested, and the different reaction series are connected by well-behaved linear free energy relationships. The relative reactivities of terminal alkenes and allylelement compounds are almost independent of the electrophilicities of the reference carbenium ions (constant selectivity relationship), thus allowing the construction of a general nucleophilicity scale for these compounds. Allylsilanesl and allylstannanes2 have extensively been used as allyl anion equivalents during the last two decades. Their regioselective reactions with electrophiles have been explained by the intermediate formation of carbenium ions, which are hyperconjugatively stabilized by the carbonsilicon or carbon-tin bond in the 8-position (Scheme I).3 Competition experiments have shown that allyltrimethylsilane is 5 orders of magnitude more reactive toward in situ generated diarylcarbenium ions than propene; Le., the allylic trimethylsilyl group reduces the activation energy for electrophilic attack at the CC double bond by 18 kJ m01-I.~ Analogous investigations on the effect of allylic germy1 or stannyl groups on the nucleophilicity of CC double bonds have, to our best knowledge, not been performed. Indirect evidence for the magnitude of these effects can be obtained from the solvolysis rates of 8-element-substituted alkyl halidesS or trifluoroacetates (Chart 1): rates of acid-catalyzed R3MOH eliminations from 8-metal-substituted alcohols,6 or the rates of hydride abstraction in alkyl-substituted silanes, germane, and stannanes (Scheme II),’

Rates of hydride transfer from hydrosilanes HSiR 1 R 2 R 3 with widely varying substitution to para-substituted diarylcarbenium ions have been measured in dichloromethane solution. Generally the reactions follow a second-order rate law, -d[Ar 2 CH + ]/dt=k 2 [Ar 2 CH + ] [HSiR 1 R 2 R 3 ], and k 2 is independent of the degree of ion-pairing and the nature of the counterion (exceptions are reported). The reaction rates are almost independent of solvent polarity

Three sequential treatments of an N-protected tribromoimidazole with n-BuLi / electrophile in a 1-pot process leads to N-protected 2,4,5-trisubstituted imidazoles. The method can be applied to the preparation of the immediate of carmethizole.

The molecular structure of [Ta(NMe 2 ) 5 ] has been studied by gas-phase electron diffraction. Attempts were made to fit two models, each containing planar C 2 -N-Ta groups, to the experimental data. In model I, the TaN 5 core was given a pyramidal geometry of C 2υ symmetry, while in model II it was assigned a trigonal bipyramidal structure, i.e. D 3h symmetry. I gave the best fit to the experimental data

The molecular structures of phenylglyoxal and 1-phenyl-1,2-propanedione have been studied by gas-phase electron diffraction at nozzle temperatures of 74 and 73 o C, respectively. For both molecules the data are consistent with nonplanar models with the torsional angle O(O=C-C=O) of about 130 o . The phenyl rings are nearly coplanar with the carbonyl group (O ph =11(9) o and 8(11) o , respectively)