CF 3–Ph reductive elimination from [(Xantphos)Pd(Ph)(CF 3)] ( 1) and [( i-Pr-Xantphos)Pd(Ph)(CF 3)] ( 2) has been studied by experimental and computational methods. Complex 1 is cis in the solid state and predominantly cis in solution, undergoing degenerate cis–cis isomerization (Δ G ≠ exp = 13.4 kcal mol –1; Δ G ≠ calc = 12.8 kcal mol –1 in toluene) and slower cis–trans isomerization ( Δ G calc = +0.9 kcal mol –1; Δ G ≠ calc = 21.9 kcal mol –1). In contrast, 2 is only trans in both solution and the solid state with trans-2 computed to be 10.2 kcal mol –1 lower in energy than cis-2. ![]() Kinetic and computational studies of the previously communicated ( J. 2006, 128, 12644), remarkably facile CF 3–Ph reductive elimination from 1 suggest that the process does not require P–Pd bond dissociation but rather occurs directly from cis-1. ![]() Firmation for Ernest Becker's claim that the fear of death is a powerful un. Solomon, Jeff Greenberg, and Tom Pyszczyinski share Ernest Becker's belief that the. EMBED (for wordpress.com hosted blogs and archive.org item tags). 9942 - With Chapters on Snipe and Woodcock in Ireland and on Cookery (1903), L H De Visme Shaw 8892, Michelin 0014 - The Easy Way to a Perfect Lawn, Philip Sharples, Steven Hayman 2242, Unknown 8857 - Satb with Ssaattbbb Soli (German Language Edition), Comb Bound Book, George Frideric Handel 5550, Kerry Saadien-Raad 4441 - Comb Bound Miniature Score, Johann Sebastian Bach 1101, Charles Dickens 000046879, YMCA of the USA. 221X - Gr 1 - 3 3376 - Their Eyes?, Lynn Stone 4428, Julio Torri, Martin Buber 77207523, Da Vila Martinho, Martinho Da Vila 5518, Sidney Dark 8848, Albert Ernest Jenks 4454, Standard Publishing 8867 - [Includes 64 Flash Cards, Audio CD, Wall Chart & Learning Guide], Linda Hibbs 1187 - A Daily Guide for December, January, February, Gary Allen 664432826 - A History of the Hamburg Unit of the Pennsylvania Army National Guard, Craig A Kleinsmith 2629044524, Phil Fulmer 3326, Keith Skipper 1129 - International Case Studies and Perspectives, Roger B. F., RF & Lili de La Mora 6602 - Le bonhomme de pain d'epice 4439, Mikel Dufrenne, Edward S. Casey, Paul Ricoeur 231, Copperhead Meets Mjokes 924, By: Ric Sanders 5528, Roald Dahl, Quentin Blake, Miguel Azaola 5555, Andreas Bresinsky, Christian Karner, Joachim W. Vse formuli trigonometrii v tablice 1. The experimentally determined activation parameters (Δ H ≠ = 25.9 ± 2.6 kcal mol –1; Δ S ≠ = 6.4 ± 7.8 e.u.) are in excellent agreement with the computed data (Δ H ≠ calc = 24.8 kcal mol –1; Δ G ≠ calc = 25.0 kcal mol –1). Δ G ≠ calc for CF 3–Ph reductive elimination from cis-2 is only 24.0 kcal mol –1; however, the overall barrier relative to trans-2 is much higher (Δ G ≠ calc = 34.2 kcal mol –1) due to the need to include the energetic cost of trans–cis isomerization. This is consistent with the higher thermal stability of 2 that decomposes to PhCF 3 only at 100 °C and even then only in a sluggish and less selective manner. The presence of excess Xantphos has a minor decelerating effect on the decomposition of 1. A steady slight decrease in k obs in the presence of 1 and 2 equiv of Xantphos then plateaus at [Xantphos]: 1 = 5, 10, and 20. Specific molecular interactions between 1 and Xantphos are not involved in this kinetic effect (NMR, T 1 measurements). A deduced kinetic scheme accounting for the influence of extra Xantphos involves the formation of cis-[(η 1-Xantphos) 2Pd(Ph)(CF 3)] that, by computation, is predicted to access reductive elimination of CF 3–Ph with Δ G ≠ calc = 22.8 kcal mol –1. A series of new, dicationic platinum(II) CNC pincer complexes were prepared and characterized by NMR and X-ray diffraction analysis. Oxidative addition of methyl iodide and iodine yielded the mostly unstable platinum(IV) complexes, which readily underwent reductive elimination to yield the platinum(II) precursors. Nonetheless, a platinum(IV) iodide adduct was isolated and was characterized by X-ray diffraction analysis. Additionally, a platinum(II) ethylene complex was isolated and found to be a moderately active yet highly selective catalyst in the co-dimerization of 2-methyl-2-butene with ethylene.
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