Synthesis, Characterization and Crystal Structure of Novel Mixed Bridged Trinuclear Oxo‐Centered Iron(III), Chromium(III) Complexes Containing Terminal Unsaturated Carboxylato and Acrylic Acid Dimer Anion Ligands

Three new oxo‐centered trinuclear mixed‐bridged carboxylate complexes with terminal unsaturated ligands ([M 2 M′(μ 3 ‐O)(μ‐O 2 C 3 H 3 ) 5 (μ‐O 4 C 6 H 7 )(O 2 C 3 H 3 ) (H 2 O) 2 ]·2H 2 O [M = Fe, M′ = Fe ( 1 ); M = Fe, M′ = Cr ( 2 ); M = Cr, M′ = Fe ( 3 )]) have been synthesized and characterized by means of elemental analyses, IR spectra and crystal structure analyses. The compounds crystallize isotypically in the orthorhombic space group type Pbcn with a = 24.622(3) Å, b = 16.304(2) Å, c = 17.491(2) Å, V = 7021.5(15) Å 3 ( 1 ), a = 24.708(5) Å, b = 16.290(2) Å, c = 17.394(2) Å, V = 7001.0(18) Å 3 ( 2 ), a = 24.611(4) Å, b = 16.300(3) Å, c = 17.359(3) Å, V = 6964(2) Å 3 ( 3 ), and Z = 8. The infrared spectra show resolved bands arising from ν asym (OCO) and ν sym (OCO) vibrations of monodentate and bridging carboxylate ligands along with those of ν asym (M 2 M′O) vibrations in the complexes.