Question

The extent of a push-pull mechanism in this type of reaction causes the rotation-inversion controversy. A kinked methyl group allows this reaction to occur through one bond flip and a triplet biradical (“bi-radical”) at a conical intersection. This type of reaction alternates with helix inversions on a crowded rotaxane (“ro-TAX-ane”) to power Ben Feringa’s first unidirectional molecular motor. This reaction turns the square planar compound bistriphenylphosphine platinum chloride yellow. The large change in molecular volume required for this reaction is accommodated by a hula twist. (-5[1])Azobenzene (-5[1])and stilbene act as molecular switches because they undergo this reaction (10[1])under UV light. (10[1]-5[1])When a conjugated aldehyde undergoes this reaction, an opsin is triggered in the retina. (10[2]-5[1])This reaction (10[4])temporarily breaks a stiff pi bond, (10[1])allowing its substituents to rotate 180 degrees. For 10 points, name this reaction that interconverts alkene isomers. ■END■ (10[5]0[6])

ANSWER: cis–trans isomerization [or cis–trans interconversion; or E–Z isomerization or E–Z interconversion; or geometrical isomerization or conversion between geometrical isomers; accept descriptions of switching between cis and trans or E and Z alkenes; prompt on double bond isomerization or alkene isomerization or olefin isomerization; prompt on isomerization or photoisomerization by asking “what is the chemical outcome of the isomerization?”; reject “rearrangement”]
<Chemistry>
= Average correct buzz position

Summary

2023 ACF Nationals04/22/2023Y1974%0%21%119.21

Buzzes

PlayerTeamOpponentBuzz PositionValue
Adam FineChicago ARutgers A82-5
Geoffrey ChenCornell AUC Berkeley A83-5
Vincent DuNorth Carolina AJohns Hopkins A9410
Dan NiCornell BMinnesota B9710
Geoffrey WuColumbia AMcGill A97-5
Alan XieYale BColumbia B111-5
Paul LeeWUSTL AIndiana A11110
Andrew HannaVanderbilt AHarvard A11110
Matt SchiavonePurdue AFlorida A11310
Jacob EgolDuke AGeorgia Tech A11310
Katherine LeiMIT AFlorida B11310
Daniel SheinbergYale AWUSTL B11310
Jason HongBrown AClaremont A11910
Joelle SmartRutgers AChicago A1370
S. A. ShenoyGeorgia Tech BStanford A13710
Conor ThompsonIowa State AImperial A13710
Ethan AshbrookMinnesota APenn A13710
Kevin FanMcGill AColumbia A1370
Shahar SchwartzUC Berkeley ACornell A13710
Todd MaslykMichigan AChicago C1370
Justin WytmarIllinois APenn State A1370
Connor BlakeChicago CMichigan A1370
Ameya PhadnisRutgers BOhio State A13710
Noah ChenColumbia BYale B1370