SYNTHESIS, CRYSTAL AND MOLECULAR-STRUCTURES, UV-VIS SPECTROSCOPY AND ELECTROCHEMICAL PROPERTIES OF 2 IRON(III) PHENOLATE COMPLEXES

The synthesis and molecular structures of two iron(III) phenolate complexes [(L(1))FeCl] (1) and [(L(2))(2)Fe][BPh(4)] (2) are described, where L(1)H(2) is 2,3-dimethyl-2,3-bis(3-tert-butylsalicylideneamino) butane and L(2)H is 2-(2-pyridyl)-1-salicylideneaminoethane. The complexes have been characterized by analytical, spectroscopic and electrochemical methods. Complex 1 crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a=9.588(2), b=14.722(2), c=18.921(2) Angstrom and Z=4. On the basis of 2730 unique observed reflections with I greater than or equal to 2.5 sigma(I) the structure was refined to R=0.039. Complex 2 crystallizes in the monoclinic space group P2(1)/c with a=15.975(1), b=15.627(2), c=17.773(2) Angstrom, beta=108.43(1)degrees and Z=4. On the basis of 5012 unique observed reflections with I greater than or equal to 3.0 sigma(I) the structure was refined to R=0.049. Complexes 1 and 2 both show quasi-reversible Fe(II)/Fe(III) redox couples at E(1/2)=-0.37 and -0.25 V, respectively.