1404458-45-2Relevant academic research and scientific papers
Detection of unusual reaction intermediates during the conversion of W(N2)2(dppe)2 to W(H)4(dppe) 2 and of H2O into H2
Eguillor, Beatriz,Caldwell, Patrick J.,Cockett, Martin C. R.,Duckett, Simon B.,John, Richard O.,Lynam, Jason M.,Sleigh, Christopher J.,Wilson, Ian
, p. 18257 - 18265 (2013/01/15)
W(N2)2(dppe-κ2P)2 reacts with H2 to form WH3{Ph(C6H4)PCH 2CH2PPh2-κ2P}(dppe- κ2P) and then W(H)4(dppe-κ2P) 2. When para-hydrogen is used in this study, polarized hydride signals are seen for these two species. The reaction is complicated by the fact that trace amounts of water lead to the formation of H2, PPh 2CH2CH2Ph2P(O) and W(H) 3(OH)(dppe-κ2P)2, the latter of which reacts further via H2O elimination to form W(H)4(dppe- κ2P)2 and [WH3{Ph(C6H 4)PCH2CH2PPh2-κ2P} (dppe-κ2P)]. These studies demonstrate a role for the 14-electron intermediate W(dppe-κ2P)2 in the CH activation reaction pathway leading to [WH3{Ph(C6H 4)PCH2CH2PPh2-k2P}(dppe- k2P)]. UV irradiation of W(H)4(dppe-κ2P) 2 under H2 led to phosphine dechelation and the formation of W(H)6(dppe-k2P)(dppe-k1P) rather than H 2 loss and W(H)2(dppe-κ2P)2 as expected. Parallel DFT studies using the simplified model system W(N 2)2((Ph)HPCH2CH2PH 2-κ2P)(H2PCH2CH 2PH2-κ2P) confirm that ortho-metalation is viable via both W(dppe-κ2P)2 and W(H) 2(dppe-κ2P)2 with explicit THF solvation being necessary to produce the electronic singlet-based reaction pathway that matches with the observation of para-hydrogen induced polarization in the hydride signals of [WH3{Ph(C6H4)PCH 2CH2PPh2-κ2P}(dppe- κ2P)], W(H)3(OH)(dppe-κ2P) 2 and W(H)4(dppe-κ2P)2 during this study. These studies therefore reveal the existence of differentiated and previously unsuspected thermal and photochemical reaction pathways in the chemistry of both W(N2)2(dppe-κ2P) 2 and W(H)4(dppe-κ2P)2 which have implications for their reported role in N2 fixation.
