Butterfly Methanes: Designing a Novel Class of anti‐van′t Hoff Carbons

Abstract

Among different possible non-classical structures, the stabilization of half-planar tetracoordinate carbon conformation is believed to be the most difficult one. Herein, we designed three types of half-planar tetracoordinate carbon compounds computationally by employing hybrid stabilization effects of substituents. The axial hydrogens of unstable half-planar methane are substituted with π-acceptor and σ-donor substituents such as À BH 2 , À Li and the equatorial substituents selected are a combination of electropositive atoms (σ-donors)/electronegative atoms (σ-acceptors and π-donors). To establish the stabilization factors, we conducted a detailed study on vibrational frequency analysis, molecular orbital analysis (including Natural Bond Orbitals) and electrostatic potential (ESP) analysis of optimized molecular geometries using density functional theory.

BAl4Mg−/0/+: Global Minima with a Planar Tetracoordinate or Hypercoordinate Boron Atom

“…Schleyer and co-workers computationally identified the real local minima in lithium-substituted cyclopropane and cyclopropene molecules for the first time in 1976 [34]. In the last five decades, a large array of molecules containing ptC atoms that are global and local minima were computationally identified [10,14,15,[46][47][48][49][50][51][52][53][54][55][56][57][58], and some were experimentally detected [5,[26][27][28][29][30][31][32][33]59]. Lately, the idea of ptC has been extended to planar hypercoordinate carbon (phC; Penta [60][61][62][63][64][65][66] and Hexa [67][68][69][70][71] coordination) and also to other elements such as B [72][73][74][75] or N [76] considering their potential applications in material science [77,78].…”