Seven-coordinate tetraoxolate complexes

Abstract The reaction of TPypA (tris(2-pyridylmethyl)amine) and Fe(BF 4 ) 2 and sodium nitraniIate (Na 2 1 NO2 ) or Mn(O 2 CMe) 2 with chloranilic acid (H 2 1 Cl ) respectively forms [Fe III (TPyA) 1 NO2 ] 2 O and Mn II (TPyA )1 Cl , respectively. The structures of these 7-coordinate compounds have been determined. The former is a dinuclear Fe III compound possessing equivalent Fe(III) sites, and the latter forms a 1-D zigzag chain based upon the two bridging 1 NO2 2− ions. The isomer shift and quadrupole splitting of the 57 Fe Mossbauer spectra of [Fe(TPyA) 1 NO2 ] 2 O are consistent binuclear seven-coordinate high-spin Fe III state. Below 35 K a single quadrupole doublet split onto two doublets of equal intensities and equal isomer shifts as a result of structural non-equivalency of two iron sites within a dimer. The magnetic properties of [Fe III (TPyA) 1 NO2 ] 2 O can be fit the a homonuclear S  = 5/2 ± 5/2 dinuclear spin model with strong intradimer antiferromagnetic coupling of J / k B  = −146 K (−101 cm −1 ) and g  = 2.00, and interdimer coupling of θ  = −5 K ( H  = −2 J S a ·S b ). Mn II (TPyA )1 Cl can be fit the a homonuclear S  = 5/2 1-D Fisher chain expression with weak intrachain antiferromagnetic coupling with J / k B  = −0.33 K (−0.23 cm −1 ) and g  = 2.06.