A model for the CO-inhibited form of [NiFe] hydrogenase: synthesis of CO3Fe(micro-StBu)3Ni{SC6H3-2,6-(mesityl)2} and reversible CO addition at the Ni site.
A [NiFe] hydrogenase model compound having a distorted trigonal-pyramidal nickel center, (CO)(3)Fe(micro-S(t)Bu)(3)Ni(SDmp), 1 (Dmp = C(6)H(3)-2,6-(mesityl)(2)), was synthesized from the reaction of the tetranuclear Fe-Ni-Ni-Fe complex [(CO)(3)Fe(micro-S(t)Bu)(3)Ni](2)(micro-Br)(2), 2 with NaSDmp at -40 degrees C. The nickel site of complex 1 was found to add CO or CN(t)Bu at -40 degrees C to give (CO)(3)Fe(S(t)Bu)(micro-S(t)Bu)(2)Ni(CO)(SDmp), 3, or (CO)(3)Fe(S(t)Bu)(micro-S(t)Bu)(2)Ni(CN(t)Bu)(SDmp), 4, respectively. One of the CO bands of 3, appearing at 2055 cm(-1) in the infrared spectrum, was assigned as the Ni-CO band, and this frequency is comparable to those observed for the CO-inhibited forms of [NiFe] hydrogenase. Like the CO-inhibited forms of [NiFe] hydrogenase, the coordination of CO at the nickel site of 1 is reversible, while the CN(t)Bu adduct 4 is more robust.
Ohki
Yasuhiro
Y
Department of Chemistry, Graduate School of Science, and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
Yasumura
Kazunari
K
Ando
Masaru
M
Shimokata
Satoko
S
Tatsumi
Kazuyuki
K
D002248:Carbon Monoxide / Q000737:chemistry*; D020134:Catalytic Domain; D006864:Hydrogenase / Q000037:antagonists & inhibitors* / Q000737:chemistry; D008958:Models, Molecular; D009532:Nickel / Q000737:chemistry*
D009532:Nickel; D002248:Carbon Monoxide; C043296:nickel-iron hydrogenase; D006864:Hydrogenase