Control of topology and dimensionality by aromatic dicarboxylate pendant arm position and length in cadmium coordination polymers incorporating a hydrogen-bonding capable kinked dipyridine ligand

Hydrothermal synthesis has afforded three cadmium coordination polymers incorporating both an aromatic dicarboxylate ligand and the kinked and hydrogen-bonding capable organodiimine 4,4'-dipyridylamine (dpa). The positions and length of the pendant arms of the aromatric dicarboxylate moiety exerts a strong structure directing effect in this system. {[Cd(hmph)(dpa)] center dot H2O}(n) (1, hmph = homophthalate) possesses interdigitated herringbone (6,3) grid layers with an ABAB stacking pattern. {[Cd(1,3-phda)(dpa)(H2O)] center dot 0.5H(2)O}(n) (2, 1,3-phda = 1,3-phenylenediacetate) exhibits a (4,4)-grid layer structure with two different aperture sizes and an unusual ABCD layer stacking pattern. Shortening the pendant arm length resulted in an uncommon CdSO4-type (6(5)8 topology) 4-connected 3-D network in {[Cd(iph)(dpa)] center dot 4H(2)O}(n) (3, iph = isophthalate), whose uncoordinated water molecules occupy a sizable incipient void space of 23.7% of the unit cell volume. All three coordination polymers underwent blue-violet luminescence under ultraviolet irradiation. (C) 2008 Elsevier B. V. All rights reserved.