TY - JOUR
T1 - Diiron Dithiolate Hydrides Complemented with Proton-Responsive Phosphine–Amine Ligands
AU - Carlson, Michaela R.
AU - Gilbert-Wilson, Ryan
AU - Gray, Danielle R.
AU - Mitra, Joyee
AU - Rauchfuss, Thomas B.
AU - Richers, Casseday P.
N1 - Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2017
Y1 - 2017
N2 - The reaction of Fe2(pdt)(CO)6 with two equivalents of Ph2PC6H4NH2 (PNH2) affords the amido hydride HFe2(pdt)(CO)2(PNH2)(PNH) {[H1H]0, pdt2– = CH2(CH2S–)2}. Isolated intermediates in this conversion include Fe2(pdt)(CO)5(κ1-PNH2) and Fe2(pdt)(CO)4(κ2-PNH2). X-ray crystallographic analysis of [H1H]0 shows that the chelating amino/amido–phosphine ligands occupy trans-dibasal positions. The 31P NMR spectrum indicates that [H1H]0 undergoes rapid proton exchange between the amido and amine centers. No exchange was observed for the hydride. Protonation of [H1H]0 gives [HFe2(pdt)(CO)2(PNH2)2]+ ([H21H]+), which contains two equivalent amino–phosphine ligands. Single-crystal X-ray crystallographic analysis of [H21H]+ also reveals hydrogen bonds between the exo amine protons with a THF molecule and BF4. Deprotonation of [H1H]0 with potassium tert-butoxide gave [HFe2(pdt)(CO)2(PNH)2]– ([1H]–), which was characterized spectroscopically. The complex has time-averaged C2 symmetry with two amido–phosphine ligands. FTIR spectroscopic measurements show that υCO shifts by approximately 20 cm–1 in the series [1H]–, [H1H]0, and [H21H]+. These shifts are comparable to those seen for the S-protonation of the (NC)2(CO)Fe(µ-Scys)2Ni(Scys)2 site in the [NiFe]-hydrogenases.
AB - The reaction of Fe2(pdt)(CO)6 with two equivalents of Ph2PC6H4NH2 (PNH2) affords the amido hydride HFe2(pdt)(CO)2(PNH2)(PNH) {[H1H]0, pdt2– = CH2(CH2S–)2}. Isolated intermediates in this conversion include Fe2(pdt)(CO)5(κ1-PNH2) and Fe2(pdt)(CO)4(κ2-PNH2). X-ray crystallographic analysis of [H1H]0 shows that the chelating amino/amido–phosphine ligands occupy trans-dibasal positions. The 31P NMR spectrum indicates that [H1H]0 undergoes rapid proton exchange between the amido and amine centers. No exchange was observed for the hydride. Protonation of [H1H]0 gives [HFe2(pdt)(CO)2(PNH2)2]+ ([H21H]+), which contains two equivalent amino–phosphine ligands. Single-crystal X-ray crystallographic analysis of [H21H]+ also reveals hydrogen bonds between the exo amine protons with a THF molecule and BF4. Deprotonation of [H1H]0 with potassium tert-butoxide gave [HFe2(pdt)(CO)2(PNH)2]– ([1H]–), which was characterized spectroscopically. The complex has time-averaged C2 symmetry with two amido–phosphine ligands. FTIR spectroscopic measurements show that υCO shifts by approximately 20 cm–1 in the series [1H]–, [H1H]0, and [H21H]+. These shifts are comparable to those seen for the S-protonation of the (NC)2(CO)Fe(µ-Scys)2Ni(Scys)2 site in the [NiFe]-hydrogenases.
KW - Amido ligands
KW - Hydrides
KW - Hydrogenases
KW - Iron
KW - Oxidative addition
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U2 - 10.1002/ejic.201700474
DO - 10.1002/ejic.201700474
M3 - Article
AN - SCOPUS:85024091379
SN - 1434-1948
VL - 2017
SP - 3169
EP - 3173
JO - European Journal of Inorganic Chemistry
JF - European Journal of Inorganic Chemistry
IS - 25
ER -