Synthesis and Bonding in the Diamagnetic Dinuclear
Tantalum(IV) Hydride Species ([P<sub>2</sub>N<sub>2</sub>]Ta)<sub>2</sub>(μ-H)<sub>4</sub> and the
Paramagnetic Cationic Dinuclear Hydride Species
{([P<sub>2</sub>N<sub>2</sub>]Ta)<sub>2</sub>(μ-H)<sub>4</sub>}<sup>+</sup>I<sup>-</sup> ([P<sub>2</sub>N<sub>2</sub>] =
PhP(CH<sub>2</sub>SiMe<sub>2</sub>NSiMe<sub>2</sub>CH<sub>2</sub>)<sub>2</sub>PPh): The Reducing Ability
of a Metal−Metal Bond
Michael D. Fryzuk
Samuel A. Johnson
Steven J. Rettig
10.1021/om000359w.s001
https://acs.figshare.com/articles/journal_contribution/Synthesis_and_Bonding_in_the_Diamagnetic_Dinuclear_Tantalum_IV_Hydride_Species_P_sub_2_sub_N_sub_2_sub_Ta_sub_2_sub_-H_sub_4_sub_and_the_Paramagnetic_Cationic_Dinuclear_Hydride_Species_P_sub_2_sub_N_sub_2_sub_Ta_sub_2_sub_-H_sub_4_sub_sup_sup_I_sup_-_sup_/3762861
The controlled reaction of the Ta(V) trimethyl species [P<sub>2</sub>N<sub>2</sub>]TaMe<sub>3</sub>, where [P<sub>2</sub>N<sub>2</sub>] =
PhP(CH<sub>2</sub>SiMe<sub>2</sub>NSiMe<sub>2</sub>CH<sub>2</sub>)<sub>2</sub>PPh, under 0.5 atm of hydrogen gas produces a partially
hydrogenated Ta(V) species, ([P<sub>2</sub>N<sub>2</sub>]TaMe<sub>2</sub>(H), of unknown structure. Under 4 atm of
hydrogen gas, further hydrogenation does not produce the complex [P<sub>2</sub>N<sub>2</sub>]TaH<sub>3</sub>; instead,
reduction of the tantalum center occurs to yield the dinuclear Ta(IV) hydride ([P<sub>2</sub>N<sub>2</sub>]Ta)<sub>2</sub>(μ-H)<sub>4</sub>. This diamagnetic tetrahydride fails to react with many reagents, including ethylene
and carbon monoxide; however, upon addition of iodomethane, {([P<sub>2</sub>N<sub>2</sub>]Ta)<sub>2</sub>(μ-H)<sub>4</sub>}<sup>+</sup>I<sup>-</sup> is
produced as a paramagnetic green crystalline solid. The number of hydrides in this reaction
product was confirmed by a deuterium labeling study. The results of a variable-temperature
magnetic susceptibility study of this tetrahydride cation can be partially modeled with the
Curie−Weiss law and a large correction for temperature-independent magnetism. Ab initio
calculations using density functional theory were performed in an attempt to further
understand the influence of the macrocyclic ligand in the bonding in these complexes.
2000-08-24 00:00:00
Ab initio calculations
CH
P 2 N 2
hydrogen gas
Ta