Hydrogen/Hydrogen Exchange and Formation of Dihydrogen Derivatives of Rhenium Hydride Complexes in Acidic Solutions

Vibrational Spectra of Nitrosyl-Substituted Transition-Metal Hydride Complexes: An Experimental and Theoretical Study of Carbonyldihydronitrosyl(trimethylphosphine)rhenium ([Re(CO)H2(NO)(PMe3)2])

“…The ideal coordination polyhedron is distorted in a way that the two phosphine ligands are bent towards the Hligands. This structural motif is characteristic for all calculated complexes, and can also be found in the solid-state structure [2] of [Re(CO)H 2 (NO)(P(OMe) 3 ) 2 ] (4). A brief inspection of selected optimized geometric parameters (Table 1) reveals that all calculations for a given molecule result in comparable molecular structures, in which the bond distances and bond angles typically differ by only 1 ± 2 pm or 1 ± 2 degree, respectively.…”

“…The calculations reveal the following trends (cf. Table 4): n Ä XO (1 a)`n Ä XO (2)`n Ä XO (3), and n Ä ReH (1 a)`n Ä ReH (2)`n Ä ReH (3). Both of these observations lead to the expected ranking in s-donor strength: PMe 3 b PH 3 b PF 3 .…”

“…All calculations show that the force constant F 33 belonging to the ReÀH t-NO stretch 3 ) is lower than that of the ReÀH t-CO stretch (F 44 ). This is indicative for a somewhat weaker or more activated ReÀH t-NO bond.…”

“…In the context of exploring the structural chemistry and reactivity of this class of compounds, we have synthesized a variety of dihydrorhenium complexes of the type [Re(CO)H 2 (NO)(PR 3 ) 2 ] (R Me, Et, Cy, OMe, OEt, O i Pr) [2]. We then performed protonation reactions to probe the hydridicity of these molecules [3]. During the course of our studies, we found that dihydrorhenium complexes are capable of undergoing a novel type of H-bonding interaction of the form MH´´´HX ( M metal), which is termed dihydrogen bonding [4].…”

“…The reported structural parameters [2] for [Re(CO)H 2 (NO)(P(OMe) 3 ) 2 ] (4), namely ReÀC 196 (1) pm, ReÀN 178 (1) pm, ReÀP 237.5 (5) and 234.2 (5) pm, NÀReÀC 102.5 (6)8, and PÀReÀP 160.0 (2)8 are in fair agreement with the calculated values for 2, which resembles 4 closest in the combination of electronic and steric properties [19]. Although the bond distances seem to be overestimated in the calculation, which is most pronounced for the ReÀN bond, the overall geometric arrangement is well reproduced.…”