The 1,1,3,3-Tetramethylguanidine–Borane Adduct: Theoretical Comparison of the Bonding Properties in Amine– and Guanidine–Borane Adducts

✍ Scribed by Oxana Ciobanu; Simone Leingang; Hubert Wadepohl; Hans-Jörg Himmel

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 292 KB
• Volume: 2008
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200700779

✦ Synopsis

Abstract

Herein we report on the synthesis and characterization of the adduct 1,1,3,3‐tetramethylguanidine–borane, H~3~B·N(H)C(NMe~2~)~2~, and a general inspection of the bonding properties of guanidine adducts to BH~3~. The new compound was characterized by its vibrational, NMR and mass spectra as well as single‐crystal X‐ray diffraction. Quantum chemical calculations match the experimental results. Particular attention was devoted to the evaluation of the dimeric assembly through H···H contacts of the molecules in the crystalline phase. The adduct is formed at 80 °C, but it also decomposes slowly at this temperature. The bonding properties in amine– and guanidine–borane adducts are compared in general on the basis of quantum chemical calculations carried out for several representative amine–borane adducts, namely H~3~B·NH~3~, H~3~B·NMe~3~ and H~3~B·quinuclidine, and guanidine–borane adducts, namely H~3~B·N(H)C(NH~2~)~2~, H~3~B·N(H)C(NMe~2~)~2~ and H~3~B·hppH, as well as the available experimental data for these species. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)