ic051579a_si_002.cif (43.88 kB)

Synthesis of Zinc, Copper, Nickel, Cobalt, and Iron Complexes Using Tris(pyrazolyl)methane Sulfonate Ligands:  A Structural Model for N,N,O Binding in Metalloenzymes

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posted on 06.03.2006, 00:00 by Elizabeth T. Papish, Michael T. Taylor, Finith E. Jernigan, Michael J. Rodig, Robert R. Shawhan, Glenn P. A. Yap, Fernando A. Jové
Ligands of intermediate steric bulk were designed to mimic metalloenzymes with histidine and carboxlyate binding sites. The reaction between tris(3-isopropylpyrazolyl)methane and butyllithium followed by SO3NMe3 in THF yielded the new ligand lithium tris(3-isopropylpyrazolyl)methane sulfonate (LiTpmsiPr). Various metal salts reacted with LiTpmsiPr to give the octahedral complexes M(TpmsiPr)2 (M = Zn, Cu, Ni, Co, Fe) in which each ligand has N,N,O binding to the metal. In the reaction between LiTpmsiPr and ZnCl2, in addition to the major product Zn(TpmsiPr)2, [LiTpmsiPrZnCl2]·2THF was also formed as a minor product with a tetrahedral zinc atom coordinated to either N,N,Cl,Cl in the solid phase or N,N,N,Cl in acetonitrile solution. Although TpmsiPr is coordinatively flexible and can act as a bipodal or tripodal ligand, it appears to favor the formation of octahedral L2M complexes.