Specific and non-specific influence of the environment on dihydrogen bonding and proton transfer to [RuH2{P(CH2CH2PPh2)3}]

On the peculiarities of hydrogen bonding and proton transfer equilibria for organic vs organometallic bases

“…The complete DFT study with all the transition states localized shows comparable energies for hydrogen bonding and protonation and, thus, great competition between non-classical and classical sites of coordination: Ru, H(Ru), N(py). As proton acceptors, hydrides offer a relatively non-encumbered site for protonation, where the proton accepting orbital σ MH (mainly resembled by the spherically symmetrical 1s orbital of the H atom 36 ) is less affected by angular limitations for best interaction with the proton donor. Many examples of protonation of hydride positions by strong acids are known yielding a dihydrogen complex as the kinetically controlled protonation product, even when the classical di-or polyhydride product is thermodynamically favored.…”

Dihydrogen bond cooperativity in (HCCBeH)n clusters

“…A few studies have reported the cooperativity in systems where one of the interactions corresponds to DHB. 15,16 Thus, to the best of our knowledge, no previous study has addressed the cooperativity in DHBs alone.…”

Solvent‐Dependent Dihydrogen/Dihydride Stability for [Mo(CO)(Cp*)H2(PMe3)2]+[BF4]− Determined by Multiple Solvent⋅⋅⋅Anion⋅⋅⋅Cation Non‐Covalent Interactions

“…[47] Contrary to the behaviour in [D 8 ]THF, the 31 P{ 1 H} NMR signal in CD 2 Cl 2 is a singlet at all temperatures, consistent with a greater extent of dissociation of the ion pair in this solvent, which is expected to better solvate the BF 4 À ion through the establishment of F 3 B À F···H À CHCl 2 hydrogen bonds [20,48] (see also the computational work on 2·BF 4 ···solvent and 3·BF 4 ···solvent, described above). This leads to faster intermolecular anion exchange and consequently loss of P-F coupling.…”

“…[17,18] The solvent polarity effect on the proton-transfer thermodynamics and energy barrier has been shown for the protonation of [Ru(CO)(Cp)H-A C H T U N G T R E N N U N G (PCy 3 )] [19] and [RuH 2 A C H T U N G T R E N N U N G (PP 3 )] [20] [PP 3 =P(CH 2 CH 2 PPh 2 ) 3 ]. For the latter system, the ability of the hydrogen-bond-donating solvent to interfere with the formation of hydrogen bonds in the [ …”

“…One possibility is that the effect could be due to the ability of THF to establish hydrogen-bonding interactions as a proton acceptor with the H 2 ligand in 2 (supposedly a stronger acid than 3), whereas dichloromethane rather displays weak proton-donating properties and prefers to interact with the BF 4 À anion. [20,48,81] However, the computational work suggests that the cations establish much stronger non-covalent interactions with the BF 4 counterion than with the solvent molecules. Indeed, neither CH 2 Cl 2 nor THF break the [Mo(CO)A C H T U N G T R E N N U N G (Cp*)H 2 A C H T U N G T R E N N U N G (PMe 3 ) 2 ]BF 4 ion pair but merely alter the cation-anion interaction in a rather minor way.…”