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Substitution Process (substitution + process)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Bis(fluoromesityl) Palladium Complexes, Archetypes of Steric Crowding and Axial Protection by ortho Effect , Evidence for Dissociative Substitution Processes , Observation of 19F,19F Through-Space Couplings

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2004
Camino Bartolomé
Abstract Bisarylated complexes trans -[Pd(Fmes)2(SR2)2] [Fmes = 2,4,6-tris(trifluoromethyl)phenyl (fluoromesityl); SR2 = SMe2, tht; tht = tetrahydrothiophene] are precursors for various bisarylated fluoromesityl palladium(II) complexes by ligand-substitution reactions. Boiling under reflux in acetonitrile gives the mixed complexes trans -[Pd(Fmes)2(NCMe)(SR2)], whereas boiling under reflux in toluene leads to trans -[PdCl2L2] (L = PMe3, tBuNC, pTol-NC, 4-MePy), in the presence of neutral monodentate ligands, or to (NnBu4)[trans -Pd(Fmes)2I(SR2)] when treated with (NnBu4)I. trans -[Pd(Fmes)2(SMe2)2] reacts with bidentate ligands, also boiling under reflux in toluene, to give [Pd(Fmes)2(L,L)] [L,L = Me2bipy, 2,2, - biquinolyl, ,2N,N, -OCPy2, dppm (Ph2PCH2PPh2), dppe (Ph2PCH2CH2PPh2), pte (PhSCH2CH2SPh), ,2S,N -SPPh2Py, ,2O,N -OPPhPy2], or the bimetallic complex [Pd(Fmes)2(,-1,N:1,2,O:2,N -Py2MeCO)Pd(Fmes)(SMe2)] (characterized by X-ray diffractometry) when treated with (OH)(CH3)CPy2. The crowding associated with two Fmes groups produces several interesting features: (1) trans complexes are preferred over cis complexes, against the expected electronic preferences; (2) the low-temperature NMR spectra of several complexes, or the X-ray diffraction structure of [Pd(Fmes)2(2,2, - biquinolyl)], reveal significant structural distortions associated with steric crowding; (3) the need for boiling under reflux in the synthesis suggests a dissociative substitution mechanism, which is unknown so far for Pd; (4) some of the complexes show 19F,19F through-space couplings. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Green Tax Reform and Competitiveness

GERMAN ECONOMIC REVIEW, Issue 1 2001
Erkki Koskela
This paper studies a revenue-neutral green tax reform that substitutes energy for wage taxes in an open economy with unemployment. As long as the labour tax rate exceeds the energy tax rate, such a reform will increase employment, reduce the domestic firms' unit cost of production and hence increase international competitiveness and output of the economy. The driving force behind these results is the technological substitution process that a green tax reform will bring about. The resulting reduction in unemployment is welfare increasing since energy, which the country has to buy at its true national opportunity cost, is replaced with labour, whose price is above its social opportunity cost. [source]

TETRASAT: a program for the population analysis of allotetraploid microsatellite data

MOLECULAR ECOLOGY RESOURCES, Issue 3 2006
S. H. MARKWITH
Abstract Microsatellite markers are quite popular due to their degree of polymorphism and efficiency; however, the utility of such markers for analysing allotetraploid species is often hampered by an inability to determine allele copy number for partial heterozygotes. tetrasat is a program that uses an iterative substitution process to account for all probable combinations of allele copy numbers in populations with partial heterozygote samples. The program subsequently calculates allele frequencies, and mean Hardy,Weinberg expected heterozygosity (HE), Shannon,Weiner Diversity Index (H,) and Nei's measure of population differentiation (GST) are reported for each locus and population. Of equal importance is the calculation of statistical variability generated by the missing data and allele substitution process, which allows for assessment of the strength of conclusions drawn from the statistics. [source]

Point substitution processes for decagonal quasiperiodic tilings

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 5 2009
Nobuhisa Fujita
A general construction principle for the inflation rules for decagonal quasiperiodic tilings is proposed. The prototiles are confined to be polygons with unit edges. An inflation rule for a tiling is the combination of expansion and division of the tiles, where the expanded tiles can be divided arbitrarily as long as the set of prototiles is maintained. A certain kind of point decoration process turns out to be useful for the identification of possible division rules. The method is capable of generating a broad range of decagonal tilings, many of which are chiral and have atomic surfaces with fractal boundaries. Two new families of decagonal tilings are presented; one is quaternary and the other ternary. The properties of the ternary tilings with rhombic, pentagonal and hexagonal prototiles are investigated in detail. [source]