Structural and Magnetic Analysis of Retrosynthetically Designed Architectures Built from a Triply Bridged Heterometallic (CuL) 2 Co Node and Benzenedicarboxylates

The flexible trinuclear metallatecton {(CuL) 2 Co} 2+ [H 2 L = N , N′ ‐bis(salicylidene)‐1,3‐propanediamine] has been used as a building block, and its coordinative interaction with ortho ‐, meta ‐, and para ‐benzenedicarboxylates (BDCs) has been investigated to evaluate the positional isomeric effect of these carboxylate ligands on the resulting compounds. Structural characterization reveals that o ‐H 2 BDC produces a discrete trinuclear complex, namely [(CuL) 2 Co( o ‐HBDC) 2 ] · H 2 O ( 1 ). As expected from the retrosynthetic design, one‐dimensional (1D) coordination polymers, i.e., [{(CuL) 2 Co( m ‐BDC)} · CH 3 OH] ∞ ( 2 ) and [{(CuL) 2 Co( p ‐BDC)} · 2CH 3 OH] ∞ ( 3 ), are obtained with m ‐BDC and p ‐BDC linkers, respectively. In all three complexes, the triply bridged bimetallic trinuclear coordination clusters are linear and solely a syn‐syn bridging mode is observed for the carboxylates. In 2 , the nodes are connected sidewise and are inclined toward each other to be accommodated by the 120°‐angular m ‐BDC units, whereas in 3 , the linear p ‐BDC linkers connect the parallel nodes diagonally. These differences in connectivity give rise to one‐dimensional “great wall”‐like chains for 2 and to quasi‐linear coordination chains for 3 . These distinct one‐dimensional propagations induced by the different BDC isomers influence the three‐dimensional columnar packing of 2 and 3 . Magnetic susceptibility measurements and fitting of the results confirm that these three compounds are made by analogous magnetic building blocks, with very similar antiferromagnetic intramolecular magnetic exchange (with J in the –16.96 to –11.80 cm –1 range, using the –2 JS 1 S 2 convention). The structural homogeneity of the magnetic fragment within this family of compounds has allowed magnetostructural correlations to be explored, which has not previously been attempted.