Synthesis, crystal and molecular structures, UV–Vis spectroscopy and electrochemical properties of two iron(III) phenolate complexes

The synthesis and molecular structures of two iron(III) phenolate complexes [(L1)FeCl] (1) and [(L2)2Fe][BPh4] (2) are described, where L1H2 is 2,3-dimethyl-2,3-bis(3-tert-butylsalicylideneamino)butane and L2H 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 P212121 with a=9.588(2), b=14.722(2), c=18.921(2) Å and Z=4. On the basis of 2730 unique observed reflections with I≥2.5σ(I) the structure was refined to R=0.039. Complex 2 crystallizes in the monoclinic space group P21/c with a=15.975(1), b=15.627(2), c=17.773(2) Å, β=108.43(1)° and Z=4. On the basis of 5012 unique observed reflections with I≥3.0σ(I) the structure was refined to R=0.049. Complexes 1 and 2 both show quasi-reversible Fe(II)/Fe(III) redox couples at E1/2= –0.37 and -0.25 V, respectively