Round 1: 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 (10[1])for electrocyclic reactions whose stereochemistry (-5[1])is predicted by Woodward–Hoffman rules. This process alternatively names conformers that sample gauche, staggered, and eclipsed (10[1]-5[1])geometries. This process can be depicted using Newman projections. (10[2])High energy barriers exist for cis-trans isomerization because this process does not occur about alkenyl carbons. (10[2])For 10 points, name this process where a molecule changes torsion angles about certain connections between two atoms. ■END■ (0[5])

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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