Acetonitrile Adduct [MoReCp(μ-H)(μ-PCy₂)(CO)₅(NCMe)]: A Surrogate of an Unsaturated Heterometallic Hydride Complex

Abstract

The title compound was prepared upon irradiation of acetonitrile solutions of the readily available hexacarbonyl [MoReCp(μ-H)(μ-PCy)(CO)]. The acetonitrile ligand in this compound could be replaced easily by donor molecules or displaced upon two-electron reduction. In most cases, the substitution step was followed by additional processes such as insertion into the M-H bonds, E-H bond cleavage, H elimination, and other transformations.

Acceptor Behavior and E–H Bond Activation Processes of the Unsaturated Heterometallic Anion [MoReCp(μ-PCy2)(CO)5]−(Mo═Re)

“…This complex has been recently identified by us as the product following from the photolysis of fac-[MoReCp(-H)(-PCy2)(CO)5(PPh2H)], an isomer of 3 bearing a PPh2H ligand positioned cis to the phosphanide group. 9 In the photolysis of 3, however, we noticed that the use of prolonged irradiation times led to the progressive decomposition of the initial bis(phosphanide) complex (P 189.9 and 153.0 ppm ) to give a green product displaying much more shielded resonances (P 80.3 and 44.0 ppm). We afterwards found that this product can be actually prepared in better yield (ca.…”

Constructing Organometallic Architectures from Aminoalkylidyne Diiron Complexes

“…Our original purpose was to modify the aminoalkylidyne unit: the replacement in 1 of one carbonyl ligand with the more labile acetonitrile, being a classical method to generate the equivalent of one vacant site at a metal center, appeared as a possible strategy to by‐pass the chemical inertness of the carbyne center. In a range of similar diruthenium systems, the direct metal coordination of different species via acetonitrile removal permits the subsequent intramolecular coupling with bridging unsaturated hydrocarbyl ligands.…”

“…In a range of similar diruthenium systems, the direct metal coordination of different species via acetonitrile removal permits the subsequent intramolecular coupling with bridging unsaturated hydrocarbyl ligands. [32d],…”

Trapping of an Heterometallic Unsaturated Hydride: Structure and Properties of the Ammonia Complex [MoMnCp(μ-H)(μ-PPh2)(CO)5(NH3)]

“…Protonation of these anions with (NH 4 )PF 6 did not yield the sought unsaturated hydride-bridged derivatives [MoMCp(µ-H)(µ-PR 2 )(CO) 5 ] but gave instead the corresponding ammonia complexes [MoMCp(µ-H)(µ-PR 2 )(CO) 5 (NH 3 )], this suggesting that the targeted unsaturated hydrides were very reactive species. Shortly after that, we found that the acetonitrile adduct [MoReCp(µ-H)(µ-PCy 2 )(CO) 5 (NCMe)] underwent easy displacement of NCMe with different molecules such as phosphines, thiols or alkynes, thus effectively acting as a surrogate of the unsaturated hydride [MoReCp(µ-H)(µ-PCy 2 )(CO) 5 ] [14]. Given the similarity between the above Re complex and the ammonia complexes mentioned above, we wondered if the latter could also be used as synthetic equivalents of the elusive [MoMCp(µ-H)(µ-PR 2 )(CO) 5 ] hydrides.…”

“…However, there are precedents indicating that organometallic substrates with heterometallic multiple bonds have a large potential for the stoichiometric and catalytic activation of small molecules. For instance, Chetcuti et al studied complexes with Co=Ni bonds able to induce under mild conditions different isomerisation processes, as well as regiospecific C-C couplings and P-C bond cleavages [8,9] [14]. Given the similarity between the above Re complex and the ammonia complexes mentioned above, we wondered if the latter could also be used as synthetic equivalents of the elusive [MoMCp(μ-H)(μ-PR2)(CO)5] hydrides.…”