Synthesis, structural characterization, and some properties of 2-acylmethyl-6-ester group-difunctionalized pyridine-containing iron complexes related to the active site of [Fe]-hydrogenase

Dalton Trans. 2014 Jun 7;43(21):8062-71. doi: 10.1039/c4dt00335g. Epub 2014 Apr 10.

Abstract

As biomimetic models for [Fe]-hydrogenase, the 2-acylmethyl-6-ester group-difunctionalized pyridine-containing iron(II) complexes 1-4 have been successfully prepared via the following three separate steps. In the first step, the acylation or esterification of difunctionalized pyridine 2-(p-MeC6H4SO3CH2)-6-HOCH2C5H3N with acetyl chloride or benzoic acid gives the corresponding pyridine derivatives 2-(p-MeC6H4SO3CH2)-6-RCO2CH2C5H3N (A, R = Me; B, R = Ph). The second step involves reaction of A or B with Na2Fe(CO)4 followed by treatment of the intermediate Fe(0) complexes [Na(2-CH2-6-RCO2CH2C5H3N)Fe(CO)4] (M1, R = Me; M2, R = Ph) with iodine to afford 2-acylmethyl-6-acetoxymethyl or 6-benzoyloxymethyl-difunctionalized pyridine-containing Fe(II) iodide complexes [2-C(O)CH2-6-RCO2CH2C5H3N]Fe(CO)2I (1, R = Me; 3, R = Ph). Finally, when 1 or 3 is treated with sodium 2-mercaptopyridinate, the corresponding difunctionalized pyridine-containing Fe(ii) mercaptopyridinate complexes [2-C(O)CH2-6-RCO2C5H3N]Fe(CO)2(2-SC5H4N) (2, R = Me; 4, R = Ph) are produced. While the structures of model complexes 1-4 are confirmed by X-ray crystallography, the electrochemical properties of 2 and 4 are compared with those of the two previously reported models. In addition, complexes 2 and 4 have been found to be catalysts for H2 production in the presence of TFA under CV conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acylation
  • Biomimetic Materials / chemical synthesis
  • Biomimetic Materials / chemistry*
  • Catalysis
  • Catalytic Domain
  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry*
  • Crystallography, X-Ray
  • Hydrogenase / chemistry*
  • Iron / chemistry*
  • Iron-Sulfur Proteins / chemistry*
  • Methylation
  • Models, Molecular
  • Pyridines / chemical synthesis
  • Pyridines / chemistry*

Substances

  • Coordination Complexes
  • Iron-Sulfur Proteins
  • Pyridines
  • Iron
  • iron hydrogenase
  • Hydrogenase
  • pyridine