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Einkristall‐Strukturen eines Donator‐Akzeptor‐substituierten Cyclopentadiens, seines Kations und seines dimeren Anions: Verschiedenartige Störungen eines Kohlenstoff‐Fünfringes
Author(s) -
Bock Hans,
Nick Sabine,
Näther Christian,
Bats Jan W.
Publication year - 1994
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19940770810
Subject(s) - chemistry , cyclopentadiene , dimethoxyethane , dimer , crystallography , mndo , ring (chemistry) , crystal structure , molecule , deprotonation , stereochemistry , adduct , ion , organic chemistry , electrode , electrolyte , catalysis , biochemistry
Single‐Crystal Structures of a Donor‐Acceptor‐Substituted Cyclopentadiene, Its Cation and Its Anion Dimer: Different Distortion of a Five‐Membered Carbon Ring 1,4‐Dimethyl‐2,3,4,6‐tetrahydro‐1 H ‐cyclopentapyrazine‐5,7‐dicarbonitrile, its molecular cation, and its dimer dianion, generated by hydride abstraction or deprotonation, and crystallized, differ remarkably in their structures: the five‐membered ring in the neutral compound is of ( Z )‐butadiene‐type, whereas, in the tetrafluorborate salt, a peripheric NN⊕ cyanine distortion occurs and in the sodium derivatives, solvated by either one or two 1,2‐dimethoxyethane molecules, a cyclopentadienyl anion is formed. The structural perturbations induced by changing molecular charges are rationalized by extensive MNDO calculations, which on geometry optimization, reproduce the experimental structures and, in addition, provide charge distributions, further confirming the n N /π and π/π interactions already recognizable from the structural parameters.