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Geometries of Three‐Membered Rings in Triangulanes and Spirocyclopropanated Bicyclopropylidenes: Experimental Studies and a General Bond Increment Scheme
Author(s) -
Boese Roland,
Haumann Thomas,
Jemmis Eluvathingal D.,
Kiran B.,
Kozhushkov Sergei,
de Meijere Armin
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619960608
Subject(s) - chemistry , additive function , bond length , ab initio , crystallography , molecular geometry , ring (chemistry) , crystal (programming language) , double bond , single bond , computational chemistry , molecule , stereochemistry , crystal structure , group (periodic table) , organic chemistry , mathematics , mathematical analysis , computer science , programming language
Crystal structural studies of several linear and branched triangulanes, together with spiro‐cyclopropanated bicyclopropylidenes, by X‐ray diffraction reveal significant differences between proximal and distal bond lengths in the three‐membered rings. Combined with previously published structural data, these results allowed us to elaborate a general additivity scheme describing the geometry of such hydrocarbons. The π donor spirocyclopropane and a double bond shorten the proximal bonds by 0.0234 and 0.0327 Å and lengthen the distal bonds by 0.0227 and 0.0327 Å with respect to the unperturbed value of 1.5008 Å. The results of these calculations were compared with those obtained by semiempirical and ab initio methods and explained qualitatively by using the Fragment Molecular Orbital (FMO) approach.