A Fourier transform ion cyclotron resonance spectrometry (FT-ICR) study of the gas-phase protonation of ammonia-borane and sixteen amine/boranes R(1)R(2)R(3)N-BH(3) (including six compounds synthesized for the first time) has shown that, without exception, the protonation of amine/boranes leads to the formation of dihydrogen. The structural effects on the experimental energetic thresholds of this reaction were determined experimentally. The most likely intermediate and the observed final species (besides H(2)) are R(1)R(2)R(3)N-BH(4)(+) and R(1)R(2)R(3)N-BH(2)(+), respectively. Isotopic substitution allowed the reaction mechanism to be ascertained. Computational analyses ([MP2/6-311+G(d,p)] level) of the thermodynamic stabilities of the R(1)R(2)R(3)N-BH(3) adducts, the acidities of the proton sources required for dihydrogen formation, and the structural effects on these processes were performed. It was further found that the family of R(1)R(2)R(3)N-BH(4)(+) ions is characterized by a three-center, two-electron bond between B and a loosely bound H(2) molecule. Unexpected features of some R(1)R(2)R(3)N-BH(4)(+) ions were found. This information allowed the properties of amine/boranes most suitable for dihydrogen generation and storage to be determined.

The typical Gibbs free energy difference between hydrocarbon substituted isocyanides and the corresponding cyanides is 25 to 28 kcal/mol in favor of the cyanides and is mostly independent of the substituent. Triple bonded species with a ―C ≡ C―RN,C (RN,C = CN, NC) structure can be considered as exceptions. Because isocyanide and cyanide species have very similar structures, the relative energy is independent of the pressure and temperature conditions. Theoretical and experimental gas‐phase investigations show that basicity of isocyanides ranges from 182.1 to 198.2 kcal/mol which is 14.0 to 19.7 kcal/mol higher than the basicity of respective cyanides. The most favored protonation centers are located on isocyanide or cyanide group depending on the species. The biggest increase of basicity was caused by bulkier substituents. The substitutions have greater influence on the basicity of cyanides than on the basicity of isocyanides. In regard to deprotonation, the cyanides are more acidic than the corresponding isocyanides. For most of the unsaturated cyanide and isocyanide species the (N,C)‐CHR′ hydrogen (the one connected to the carbon next to cyanide/isocyanide group) is the most acidic. Our work suggests that for derivatives bearing unsaturated substituent the favored deprotonation center may be different and some cyanides and isocyanides are unstable towards gas‐phase deprotonation equilibrium as the formed anion tends to isomerize. Copyright © 2016 John Wiley & Sons, Ltd.

Hydrazine-borane and hydrazine-diborane contain respectively 15.4 and 16.9 wt% of hydrogen and are potential materials for hydrogen storage. In this work we present the gas-phase complexation energies, acidities and basicities of hydrazineborane and hydrazine-bisborane calculated at MP2/6-311+G(d,p) level. We also report the release of dihydrogen from both protonated complexes (Ghydrazine-borane = -20.9 kcal/mol and Ghydrazine-bisborane = -27.2 kcal/mol) which is much more exergonic than from analogues amine-boranes. The addition of the first BH3 to the hydrazine

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Complexation energies and acidities of 19 primary, secondary and tertiary amine-boranes were investigated using MP2/6-311+G(d,p) and B3LYP/6-311+G(d,p) methods. Gas phase acidities for free amines were also calculated. Acidity values for studied complexes range from 327.3 to 349.1 kcal mol(-1) and the most acidic are the ones with direct connection between deprotonation center and a π-system. Results obtained by both computational methods are in good agreement with each other and with known experimental data. Addition of BH3 increases the acidity of amines by 30 to 50 kcal mol(-1). This enhancement effect was compared to the respective effect witnessed in phosphine-boranes and traced back to changes of charge delocalization on nitrogen. A question about the structural stability of several deprotonated amine-borane anions in the gas phase was also raised.