Related Experiment Video
Updated: Mar 11, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Revealing Germylene Compounds to Attain Superbasicity with Sigma Donor Substituents: A Density Functional Theory
Abul Kalam Biswas1, Bishwajit Ganguly1
1Analytical Discipline and Centralized Instrument Facility, Academy of Scientific and Innovative Research, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar-, 364002, India.
Abstract:
Compounds of GeII are shown for the first time to function as superbases. Two B(N=PiPr3 )2 groups attached to a germanium(II) center show a gas-phase proton affinity of 296.2 kcal mol-1 , which is close to the range of a hyperbase as revealed by B3LYP-D3/6-31G(2d,p) level of theory. These DFT calculations showed better agreement of geometrical parameters for the reported stable germylene compound 1 than previously reported calculations. A systematic study with different substitutions of GeII revealed that such a system can achieve basicity close to a hyperbase. The stabilities of these superbases were examined with dimerization energy and singlet-triplet state energy difference (ΔES-T ). Furthermore, the calculated gas-phase proton affinity values also show good correlation with the most negative valued point (Vmin ) in electron-rich regions from the molecular electrostatic potential. The high PA values of compounds were also supported by ionization potential, electron affinity, absolute electronegativity, and absolute hardness calculations. The energetics for the reaction with BH3 and AlMe3 further suggest that the lone pair of GeII can act as a Lewis base and display higher donor-acceptor bond strengths.
More Related Videos
08:15Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups
Published on: February 11, 2012
06:55Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
Published on: September 26, 2016
Related Concept Videos
ortho–para-Directing Deactivators: Halogens
Diels–Alder Reaction: Characteristics of Dienophiles
Characteristics of Dienophiles
Generally, the best dienophiles are alkenes containing electron-withdrawing substituents such as carbonyl, nitrile, and nitro groups. The feasibility of a Diels–Alder reaction depends...
Directing Effect of Substituents: meta-Directing Groups
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Radicals: Electronic Structure and Geometry
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Directing Effect of Substituents: ortho–para-Directing Groups