Structural Diversity in Luminescent Three-Dimensional Cadmium Aliphatic Dicarboxylate Coordination Polymers Incorporating 4,4′-Dipyridylamine: Interpenetrated, Non-Interpenetrated, and Self-Penetrated Networks

Three cadmium coordination polymers incorporating both a flexible aliphatic α,ω-dicarboxylate and the hydrogen-bonding capable diimine 4,4′-dipyridylamine (dpa) have been prepared and structurally characterized. {[Cd(adp)(dpa)]} n ( 1, adp = adipate) adopts a doubly interpenetrated decorated primitive cubic three-dimensional (3D) coordination polymer network. {[Cd 7 (pim) 6 (dpa) 6 (H 2 O) 2 ](ClO 4 ) 2 ·6H 2 O} n ( 2, pim = pimelate) exhibits a complex (8,10)-connected binodal self-penetrated cationic 3D network with (3 8 4 14 5 4 6 2 )(3 10 4 18 5 14 6 3 ) topology constructed from the linkage of oligomeric {Cd 7 (dpa) 6 (H 2 O) 2 } 14+ secondary building units through pimelate ligands with different conformations. To the best of our knowledge, this is the highest-connected binodal self-penetrated lattice reported to date. Extending the length of the α,ω-dicarboxylate resulted in a CdSO 4 -type (6 5 8 topology) 4-connected 3D network in {[Cd(sub)(dpa)]·2H 2 O} n ( 3, sub = suberate). The length of the polymethylene unit within the dicarboxylate ligand, the coordination preferences at cadmium and anion inclusion, together with dpa-mediated hydrogen bonding, exert a cooperative structure directing effect in this system. All three coordination polymers undergo blue-violet luminescence under ultraviolet irradiation.