Qu 1. George Olah (b. 1927 – d.2017), Professor at University of Southern California and winner of the 1994Nobel Prize in chemistry, famously made a career of quantitatively preparing and characterizing exotic cations(e.g. CH;* – yes, it's 'a thing'!) in 'superacid' solutions. Dissolving tetramethylcyclobutenyl dichloride (X, 3,4-dichloro-1,2,3,4-cyclobut-1-ene) in the super Lewis acid (the solvent is excess SbFs, SO2, -65 °C) generated acationic species, Y, with an 'H NMR spectrum (60 MHz, -75 "C), showing a single peak.Hint: SbFs is highly 'halophilie', SbFs + Cl -> [SbF;CI]r. c.f. AICI, and FeCls.(a) Draw the Lewis structure of Y, all resonance forms, and explain the 'H NMR chemical shift.CI SbFg, SO25.Y"CI- 75 "Ci 81.0ii 8 3.7iji 80 iv 8 -2.0 ppm(b) Which chemical shift, 8, best fits Y (circle)?Explain (briefly):(c) When X was dissolved in a different solvent (FSO3H, SO2, -78 °C) a different cation, Z, appeared"completely stable for at least 2 weeks". The 'H NMR spectrum (60 MHz) showed three singlets, & 2.7, 2.2,2.1 in a ratio of 2:1:1. Give the structure of Z, resonance forms (by 'arrow pushing'), & assign the NMR.

SbF5 is a strong Lewis acid and can capture any halogen from any halide compound that leads to the…

Qu 1. George Olah (b. 1927 – d.2017), Professor at University of Southern California and winner of the 1994 Nobel Prize in chemistry, famously made a career of quantitatively preparing and characterizing exotic cations (e.g. CHs* – yes, it's 'a thing'!) in 'superacid solutions. Dissolving tetramethylcyclobutenyl dichloride (X, 3,4- dichloro-1,2,3,4-cyclobut-1-ene) in the super Lewis acid (the solvent is excess SbFs, SO2, –65 °C) generated a cationic species, Y, with an 'H NMR spectrum (60 MHz, –75 °C), showing a single peak. Hint: SbF, is highly 'halophilic', SbF; + CI* > [SbF;CI]". c.F. AICI, and FeCls. (a) Draw the Lewis structure of Y, all resonance forms, and explain the 'H NMR chemical shift. •cı SbFs, SO2 Y "CI - 75 °C (b) Which chemical shift, 8 , best fits Y (circle)? Explain (briefly): i 81.0 i 8 3.7 ii 80 iv 8 -2.0 ppm (c) When X was dissolved in a different solvent (FSO3H, SO2, –78 °C) a different cation, Z, appeared "completely stable for at least 2 weeks". The 'H NMR spectrum (60 MHz) showed three singlets, 8 2.7, 2.2, 2.1 in a ratio of 2:1:1. Give the structure of Z, resonance forms (by 'arrow pushing'), & assign the NMR.

Qu 1. George Olah (b. 1927 – d.2017), Professor at University of Southern California and winner of the 1994 Nobel Prize in chemistry, famously made a career of quantitatively preparing and characterizing exotic cations (e.g. CHs* – yes, it's 'a thing'!) in 'superacid solutions. Dissolving tetramethylcyclobutenyl dichloride (X, 3,4- dichloro-1,2,3,4-cyclobut-1-ene) in the super Lewis acid (the solvent is excess SbFs, SO2, –65 °C) generated a cationic species, Y, with an 'H NMR spectrum (60 MHz, –75 °C), showing a single peak. Hint: SbF, is highly 'halophilic', SbF; + CI* > [SbF;CI]". c.F. AICI, and FeCls. (a) Draw the Lewis structure of Y, all resonance forms, and explain the 'H NMR chemical shift. •cı SbFs, SO2 Y "CI - 75 °C (b) Which chemical shift, 8 , best fits Y (circle)? Explain (briefly): i 81.0 i 8 3.7 ii 80 iv 8 -2.0 ppm (c) When X was dissolved in a different solvent (FSO3H, SO2, –78 °C) a different cation, Z, appeared "completely stable for at least 2 weeks". The 'H NMR spectrum (60 MHz) showed three singlets, 8 2.7, 2.2, 2.1 in a ratio of 2:1:1. Give the structure of Z, resonance forms (by 'arrow pushing'), & assign the NMR.

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter7: Statistical Data Treatment And Evaluation

Section: Chapter Questions

Problem 7.26QAP

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