Chemical assembly of an antiferromagnetic macrocyclic molecule containing two inner CoII centers from polymeric cobalt pivalate

Abstract The reaction of the polymer {Co(Piv) 2 } n (Piv is the pivalic acid anion) with triethylenetetramine (L 1 ) (M:L 1  = 2:1) in MeCN affords the polymeric compound [Co 2 L 1 (η 2 -Piv) 2 (μ-Piv) 2 ] n ( 1 ) containing asymmetric dicobalt units coordinated by one chelate ligand L 1 . The reaction of 1 with an additional amount of L 1 (M:L 1  = 1:1) in MeCN gives rise to the binuclear molecule Co 2 L 1 2 (Piv) 4 ( 2 ), where L 1 acts as a chelate-bridging ligand. Compounds analogous to 2 with M = Fe ( 3 ) were prepared by the reaction of the polymer {Fe(Piv) 2 } n with L 1 in MeCN using the reagent ratio M:L 1  = 1:1. The reaction of the compound Co L 1 2 (Piv) 4 ( 2 ) with isophthalaldehyde (L 2 ) produces the binuclear complex Co 2 L 3 (Piv) 4 ( 4 ) containing the new [2 + 2] macrocyclic ligand L 3 as a result of condensation of L 1 with L 2 . All newly synthesized compounds were characterized by X-ray diffraction and magnetic measurements.