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Hemispiroalkaplanes: Hydrocarbon Cage Systems with a Pyramidal‐Tetracoordinate Carbon Atom and Remarkable Basicity
Author(s) -
Rasmussen Danne R.,
Radom Leo
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20000703)6:13<2470::aid-chem2470>3.0.co;2-k
Subject(s) - tetracoordinate , chemistry , hydrocarbon , protonation , lone pair , molecule , proton affinity , ab initio , neopentane , computational chemistry , carbon fibers , atom (system on chip) , crystallography , carbon atom , organic chemistry , ring (chemistry) , materials science , ion , computer graphics (images) , composite number , computer science , composite material , planar , embedded system
A new class of saturated hydrocarbons, in which a spiropentane‐type unit is bound by a cyclic hydrocarbon, has been investigated by using ab initio molecular orbital calculations at the B3‐LYP and MP2 levels. These molecules have been given the trivial name hemispiroalkaplanes. Hemialkaplanes, which are analogous molecules built‐up from a neopentane‐type unit and a cyclic hydrocarbon, have also been examined. The hemispiroalkaplanes are predicted to contain a pyramidal‐tetracoordinate carbon atom that possesses a lone pair of electrons. Protonation at this apical carbon atom is found to be highly favourable, resulting in a remarkably high basicity for a saturated hydrocarbon. The proton affinities of the hemispiroalkaplanes are calculated to be more than 1170 kJ mol −1 , even greater than that of the diamine “proton sponges”. Structural parameters, heats of formation and strain energies for the novel hydrocarbons are detailed.