Protonation Studies of a Tungsten Dinitrogen Complex Supported by a Diphosphine Ligand Containing a Pendant Amine
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https://figshare.com/articles/dataset/Protonation_Studies_of_a_Tungsten_Dinitrogen_Complex_Supported_by_a_Diphosphine_Ligand_Containing_a_Pendant_Amine/2298448
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资源简介：
Treatment
of trans-[W(N2)2(dppe)(PEtNMePEt)] (dppe = Ph2PCH2CH2PPh2; PEtNMePEt = Et2PCH2N(Me)CH2PEt2) with 3 equiv of tetrafluoroboric acid (HBF4·Et2O) at −78 °C generated the
seven-coordinate tungsten hydride trans-[W(N2)2(H)(dppe)(PEtNMePEt)][BF4]. At higher temperatures, protonation of a pendant
amine is also observed, affording trans-[W(N2)2(H)(dppe)(PEtNMe(H)PEt)][BF4]2, with formation of the hydrazido
complex [W(NNH2)(dppe)(PEtNMe(H)PEt)][BF4]2 as a minor product. A similar
product mixture was obtained using triflic acid (HOTf). The protonated
products are thermally sensitive and do not persist at ambient temperature.
Upon acid addition to the carbonyl analogue cis-[W(CO)2(dppe)(PEtNMePEt)], the seven-coordinate
carbonyl hydride complex trans-[W(CO)2(H)(dppe)(PEtNMe(H)PEt)][OTf]2 was generated. A mixed diphosphine complex without the pendant
amine in the ligand backbone, trans-[W(N2)2(dppe)(depp)] (depp = Et2P(CH2)3PEt2), was synthesized and treated with HOTf,
selectively generating a hydrazido complex, [W(NNH2)(OTf)(dppe)(depp)][OTf].
Computational analysis probed the proton affinity of three sites of
protonation in these complexes: the metal, pendant amine, and N2 ligand. Room-temperature reactions with 100 equiv of HOTf
produced NH4+ from reduction of the N2 ligand (electrons come from W). The addition of 100 equiv of HOTf
to trans-[W(N2)2(dppe)(PEtNMePEt)] afforded 0.81 equiv of NH4+, while 0.40 equiv of NH4+ was formed upon treatment of trans-[W(N2)2(dppe)(depp)] with HOTf, showing that the complexes
containing proton relays produce more products of reduction of N2.
创建时间：
2016-02-17
