Premium
Structure of [4.4.4]propellane and [4.4.4]propellatriene by X ‐ray Analysis
Author(s) -
Ermer O.,
Gerdil R.,
Dunitz J. D.
Publication year - 1971
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.19710540811
Subject(s) - propellane , chemistry , monoclinic crystal system , libration (molecule) , crystallography , group (periodic table) , crystal structure , x ray crystallography , stereochemistry , bicyclic molecule , diffraction , geometry , physics , quantum mechanics , point (geometry) , mathematics , organic chemistry
The crystal structures of [4.4.4]propellane (monoclinic, a =12.053, b =7.832, c =13.001 Å, β=104.89°, space group C 2/ c , Z =4) and [4.4.4]propellatriene (monoclinic, a =7.876, b =12.651, c =13.164 Å, β=122.81°, space group P 2 1 / c , Z =4) have been determined by X ‐ray analysis. In propellane the six‐membered rings are in the chair conformation, in propellatriene they adopt the ‘half‐chair’ conformation with a twofold axis passing through the centre of each double bond. In both cases the observed parameters correspond to virtual D 3 (32) molecular symmetry. Corrections have been applied for the effect of molecular libration. Strain‐minimization calculations based on semi‐empirical potential functions have been carried out and the molecular parameters so derived are compared with the experimental values.