Stereochemistry Controls Dihydrogen Bonding Strengths in Chiral Amine Boranes Adducts

Abstract

The growing interest in exploiting novel concepts of non-covalent interactions in catalysts and supramolecular chemistry made us revisit a special kind of hydrogen bonding: the dihydrogen bond (DHB), formed between a classical hydrogen bond donor and a hydridic hydrogen as acceptor. Herein, we investigate how the strength of the NÀ H δ + ••• δÀ HÀ B interaction and hence the DHB-driven self-aggregation of amine-borane adducts is governed by steric effects by comparing the structures and binding enthalpies of various chiral derivatives. For a diastereomeric pair of amine-boranes prepared from a chiral secondary amine, we show that the stereochemistry at the nitrogen has significant influence on the interaction enthalpy. Based on this finding, N-chiral amine boranes can be envisioned to become interesting building blocks in supramolecular chemistry to fine-tune the formation dynamics of assemblies.

Modelling solute–solvent interactions in VCD spectra analysis with the micro-solvation approach

“…Likewise, any intermolecular interactions that alter conformational preferences or that affect the VCD signature of single conformer must also be considered explicitly in the spectra calculations. Hence, although we extensively utilized this sensitivity, for instance, to study substrate-catalyst interactions in asymmetric catalysis [8][9][10][11][12] and other stereochemical aspects, [13][14][15][16][17] it can quickly turn into a major obstacle in routine AC determinations due to strong interactions solvent molecules.…”