173863-80-4Relevant academic research and scientific papers
Carboxyl-Bonded Low-Spin Iron(III). Chemistry of a Family of Coordination Type cis-FeN4O2
Karmakar, Soma,Chakravorty, Animesh
, p. 1935 - 1939 (1996)
Three tridentate ligands H2PhL (Ar = Ph), H2ToL (Ar = p-tolyl), and H2NpL (Ar = α-naphthyl) of structural type HON=C(Ar)N=NC6H4CO2H have been synthesized. These (general abbreviation H2ArL) react with iron(DI) chloride, affording the pink Et4N[Fe(ArL)2] (s= 1/2 ; μeff=1.98-2.04μB) in which azo oxime chelation ensures spin-pairing while carboxylate coordination stabilizes the trivalent state. The EPR spectra of the complexes in frozen dimethylformamide-toluene glass (77 K) are rhombic with g values in the range 1.997-2.173. The X-ray structure of Et4N[Fe(NpL)2]·H2O·CH 2Cl2 has been determined, revealing meridional binding of the two ligands affording Cis-FeN4O2 geometry. The effect of spin-pairing is expressed in the relatively short (～1.90 A?) Fe-O and Fe-N lengths. The water of crystallization is hydrogen-bonded to carboxyl O atoms. The iron(III)-iron(II) reduction potentials lie near ～0.1 V vs SCE. Crystal data for Et4N[Fe(NpL)2·H2CH2Cl 2:crystal system triclinic, space group P1?, a = 11.539(9) A?, b = 13.306(13) A?, c = 14.60(2) A?, α = 89.30(9)°, β= 82.65(9)°, y = 79.90(8)°, V = 2189(4) A?3, Z = 2, R = 6.59%, Rw = 6.23%.
