Substituent dependent dimensionalities in cobalt isophthalate supramolecular complexes and coordination polymers containing dipyridylamine ligands

Hydrothermal synthesis has afforded cobalt 5-substituted isophthalate complexes with 4,4′-dipyridylamine (dpa) ligands, showing different dimensionalities depending on the steric bulk and hydrogen-bonding facility of the substituent. [Co(tBuip)(dpa)(H2O)]n (1, tBuip = 5-tert-butylisophthalate) is a (4,4) grid two-dimensional coordination polymer featuring 2-fold parallel interpenetration. [Co(MeOip)2(Hdpa)2] (2, MeOip = 5-methoxyisophthalate) is organized into 3-fold parallel interpenetrated (4,4) grids through strong N–H+⋯O− hydrogen bonding. {([Co(OHip)(dpa)(H2O)3])3·2H2O}n (3, OHip = 5-hydroxyisophthalate) possesses 1-D chain motifs. The 5-methyl derivative {[Co(mip)(dpa)]·3H2O}n (4, mip = 5-methylisophthalate) has a 3-D 658 cds topology. {[Co(H2O)4(Hdpa)2](nip)2·2H2O} (5, nip = 5-nitroisophthalate) and {[Co(sip)(Hdpa)(H2O)4]·2H2O} (6, sip = 5-sulfoisophthalate) are coordination complexes. Antiferromagnetic superexchange is observed in 1 and 4, with concomitant zero-field splitting. Thermal decomposition behavior of the higher dimensionality complexes is also discussed.