TY - JOUR
T1 - Iron carbonyl sulfides, formaldehyde, and amines condense to give the proposed azadithiolate cofactor of the Fe-only hydrogenases
AU - Li, Hongxiang
AU - Rauchfuss, Thomas B.
PY - 2002/2/6
Y1 - 2002/2/6
N2 - The azadithiolate (SCH2NHCH2S) cofactor proposed to occur in the Fe-only hydrogenases forms efficiently by the condensation of Fe2(SH)2(CO)6 (1), formaldehyde, and ammonia (as (NH4)2CO3). The resulting Fe2[(SCH2)2NH](CO)6 reacts with Et4NCN to give (Et4N)2[Fe2[(SCH2)2NH](CO)4(CN)2], for which crystallographic characterization confirmed an axial N-H and an elongated C-S bond of 1.858(3) Å. Primary amines RNH2 (R = Ph, t-Bu) also participate in the condensation reaction, and Fe3S2(CO)9 can be employed in place of 1. Mechanistically, the Fe2[(SCH2)2NH] moiety is shown to arise via two pathways: (i) via the intermediacy of Fe2[(SCH2OH)2](CO)6, which was detected and shown to react with amines, and (ii) via the reaction of 1 with cyclic imines (CH2)3(NR)3 (R = Ph, Me). The reaction of 1 with (CH2)6N4 (hexamethylenetetramine) gives Fe2[(SCH2)2NH](CO)6. Trace amounts of Fe2[(SCH2)2N-t-Bu](CO)6 arise via the reaction of aqueous FeSO4, formaldehyde, NaSH, and t-BuNH2 under an atmosphere of CO.
AB - The azadithiolate (SCH2NHCH2S) cofactor proposed to occur in the Fe-only hydrogenases forms efficiently by the condensation of Fe2(SH)2(CO)6 (1), formaldehyde, and ammonia (as (NH4)2CO3). The resulting Fe2[(SCH2)2NH](CO)6 reacts with Et4NCN to give (Et4N)2[Fe2[(SCH2)2NH](CO)4(CN)2], for which crystallographic characterization confirmed an axial N-H and an elongated C-S bond of 1.858(3) Å. Primary amines RNH2 (R = Ph, t-Bu) also participate in the condensation reaction, and Fe3S2(CO)9 can be employed in place of 1. Mechanistically, the Fe2[(SCH2)2NH] moiety is shown to arise via two pathways: (i) via the intermediacy of Fe2[(SCH2OH)2](CO)6, which was detected and shown to react with amines, and (ii) via the reaction of 1 with cyclic imines (CH2)3(NR)3 (R = Ph, Me). The reaction of 1 with (CH2)6N4 (hexamethylenetetramine) gives Fe2[(SCH2)2NH](CO)6. Trace amounts of Fe2[(SCH2)2N-t-Bu](CO)6 arise via the reaction of aqueous FeSO4, formaldehyde, NaSH, and t-BuNH2 under an atmosphere of CO.
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U2 - 10.1021/ja016964n
DO - 10.1021/ja016964n
M3 - Article
C2 - 11817928
AN - SCOPUS:0037028563
SN - 0002-7863
VL - 124
SP - 726
EP - 727
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 5
ER -