Round 3: Tossup 19
Molecular complexes characterized by this process often use bridged phenylene (“phenyl-een”) or naphthalene groups. This process notably does not occur in compounds like dinitrodiphenic (“di-nitro-di-phenic”) acid or BINAP (“BY-nap”), giving them a form of axial chirality called atropisomerism (“AY-trope-eye-SOM-er-ism”). The prefixes “con” and “dis” describe a set of these processes for electrocyclic reactions whose stereochemistry is predicted by Woodward–Hoffman rules. This process alternatively names conformers that sample gauche, staggered, and eclipsed geometries. This process can be depicted using Newman projections. High energy barriers exist for cis-trans isomerization because this process does not occur about alkenyl carbons. For 10 points, name this process where a molecule changes torsion angles about certain connections between two atoms. ■END■
ANSWER: bond rotation [accept rotation about a bond or word forms; prompt on rotation; prompt on torsion angle changes until read by asking “what physical process causes that?”; reject “molecular rotation”]
<AL, Chemistry> | Packet C - Virginia Tech A, Waterloo A, UCSD A, UBC A
= Average correct buzzpoint
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