TY - JOUR
T1 - Nickel-iron dithiolato hydrides relevant to the [NiFe]-hydrogenase active site
AU - Barton, Bryan E.
AU - Whaley, C. Matthew
AU - Rauchfuss, Thomas B.
AU - Gray, Danielle L.
PY - 2009/5/27
Y1 - 2009/5/27
N2 - The ferrous dithiolato carbonyl Fe(S 2C 3H 6)(CO) 2(dppe) (1) condenses with NiCl 2(dppe) to give [FeNi(pdt)(μ-Cl)(CO)(dppe) 2]BF 4 ([2Cl] +). The corresponding reaction of the ditosylate Ni(OTs) 2(dppe) gave the dication [(CO) 2(dppe)Fe(pdt)Ni(dppe)] (OTs) 2 ([ 2(CO)](OTs) 2) (pdt = 1,3-propanedithiolate; dppe = 1,2-C 2H 4(PPh 2) 2; OTs - = CH 3C 6H 4-4-SO 3 -). Reduction of the bimetallic dicarbonyl with borohydride salts afforded impure, thermally stable hydride, [(CO)(dppe)Fe(pdt)(μ-H)Ni(dppe)] + ([2H] +). A reliable route to NiFe(SR)2H species entailed protonation of (CO) 3Fe(pdt) Ni(dppe) to give [(CO) 3Fe(pdt)(μ-H)Ni(dppe)] + ([3H] +). The iron-nickel dithiolato hydride, [3H]BF4, was characterized crystallographically: as anticipated by biophysical studies, the hydride ligand is bridging, the Fe center is octahedral, and the Ni center is pentacoordinate. Solutions of [3H]BF4 undergo substitution by dppe to give [2H]+. The hydride undergoes rapid deprotonation and is an electrocatalyst for hydrogen evolution from trifluoroacetic acid. Oxidation of 3 gives a mixed valence species [3] +, a potential model for the Ni-L state.
AB - The ferrous dithiolato carbonyl Fe(S 2C 3H 6)(CO) 2(dppe) (1) condenses with NiCl 2(dppe) to give [FeNi(pdt)(μ-Cl)(CO)(dppe) 2]BF 4 ([2Cl] +). The corresponding reaction of the ditosylate Ni(OTs) 2(dppe) gave the dication [(CO) 2(dppe)Fe(pdt)Ni(dppe)] (OTs) 2 ([ 2(CO)](OTs) 2) (pdt = 1,3-propanedithiolate; dppe = 1,2-C 2H 4(PPh 2) 2; OTs - = CH 3C 6H 4-4-SO 3 -). Reduction of the bimetallic dicarbonyl with borohydride salts afforded impure, thermally stable hydride, [(CO)(dppe)Fe(pdt)(μ-H)Ni(dppe)] + ([2H] +). A reliable route to NiFe(SR)2H species entailed protonation of (CO) 3Fe(pdt) Ni(dppe) to give [(CO) 3Fe(pdt)(μ-H)Ni(dppe)] + ([3H] +). The iron-nickel dithiolato hydride, [3H]BF4, was characterized crystallographically: as anticipated by biophysical studies, the hydride ligand is bridging, the Fe center is octahedral, and the Ni center is pentacoordinate. Solutions of [3H]BF4 undergo substitution by dppe to give [2H]+. The hydride undergoes rapid deprotonation and is an electrocatalyst for hydrogen evolution from trifluoroacetic acid. Oxidation of 3 gives a mixed valence species [3] +, a potential model for the Ni-L state.
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U2 - 10.1021/ja902570u
DO - 10.1021/ja902570u
M3 - Article
C2 - 19413314
AN - SCOPUS:70149097294
SN - 0002-7863
VL - 131
SP - 6942
EP - 6943
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 20
ER -