Reactions of [{bis(2-pyridylmethyl)amino}trichloroiron(III] with (HOCH₂)₃CNHCO(CH₂)nCONHC(CH₂OH)₃ (n = 0-2): crystal structures of (u-oxo)bis{oxalato){[bis(pyridylmethyl)amine]iron(III)} and (HOCH₂)₃CNHCO(CH₂)₂CONHC(CH₂0H)₃

The crystal structure and Mossbauer spectrum of the dinuclear complex [(ox)(BMPA)Fe-III(mu-O)Fe-III(BMPA)(ox)](.)5H(2)O (4), isolated from the reactions between [(BMPA)FeCl3] and (HOCH2)(3)CNHCO(CH2)(n)CONHC(CH2OH)(3), (1: n = 0) or HO2CCO2H in basic media, are reported: BMPA = bis-(2-pyridylmethyl)amine; ox = oxalato. Each iron centre in 4 is coordinated to all three nitrogen atoms of a BMPA ligand, to two oxygen atoms from a chelating oxalato ligand and to a bridging oxide linking the two metals. The central Fe-O-Fe bond in centrosymmetric 4 is linear. The Fe(III) centres have distorted octahedral geometries with the three oxygen donor centers trans to nitrogen centres. Molecules of 4 are linked mainly via the water solvate molecules into a supramolecular network by an extensive array of hydrogen bonds, involving both strong O-(HO)-O-... interactions as well as weaker C-(HO)-O-... interactions. The amido NH group only takes part in an intramolecular interaction with a carbonyl oxygen of the oxalate ligand. Reactions of (HOCH2)(3)CNHCO(CH2)(n)CONHC(CH2OH)(3), (2: n = 1: 3: n = 2) with BMPA led to no identifiable products. The crystal structure and supramolecular arrangement in 3 are reported and are compared with those of 1 and 2. Compounds, 1-3, have elaborate, but different, H-bonding networks. (C) 2004 Elsevier Ltd. All rights reserved.