Diverse dimensionalities and structures in copper coordination polymers incorporating substituted aliphatic dicarboxylate ligands and 4,4′-bipyridine

• Published in: Inorganica Chimica Acta Vol. 363; no. 1; pp. 225 - 233
• Main Authors: Nettleman, Joseph H., Szymanski, Paul J., Sposato, Laura K., LaDuca, Robert L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 04.01.2010
• Subjects: Antiferromagnetism; Bipyridine; Coordination polymer; Copper; Crystal structure; Dicarboxylate; Thermogravimetric analysis; Antiferromagnetism; Dicarboxylate; Thermogravimetric analysis; Coordination polymer; Bipyridine; Copper; Crystal structure
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2009.08.031

Hydrothermal synthesis has afforded a series of divalent copper coordination polymers with substituted glutarate ligands and the rigid rod tether 4,4′-bipyridine (bpy): {[Cu(Hdmg) 2(bpy)]·H 2O} n ( 1, dmg = 3,3-dimethylglutarate), {[Cu 2(dmg)(bpy) 2](ClO 4)] n ( 2), [Cu 2(emg) 2(bpy)] n ( 3, emg = 3-ethyl, 3-methylglutarate) and [Cu 2(cda) 2(bpy)] n ( 4, cda = 1,1-cyclopentanediacetate). While 1 has a 1-D ribbon structure, 2 possesses mixed-valence tetrameric clusters linked into a 8-connected body-centered cubic lattice. Compounds 3 and 4 have strongly antiferromagnetically coupled {Cu 2(CO 2) 4} paddlewheels connected into (4,4)-grid coordination polymer layers. Hydrothermal synthesis has afforded a series of divalent copper coordination polymers with substituted glutarate ligands and the rigid rod tether 4,4′-bipyridine (bpy): {[Cu(Hdmg) 2(bpy)]·H 2O} n ( 1, dmg = 3,3-dimethylglutarate), {[Cu 2(dmg)(bpy) 2](ClO 4)] n ( 2), [Cu 2(emg) 2(bpy)] n ( 3, emg = 3-ethyl, 3-methylglutarate) and [Cu 2(cda) 2(bpy)] n ( 4, cda = 1,1-cyclopentanediacetate). All materials were characterized by single-crystal X-ray diffraction. Compound 1 manifests μ 2-oxygen bridged [Cu 2(Hdmg) 4] “X”-patterns connected into a ribbon motif by bpy linkers. On the other hand, 2 possesses mixed-valence [Cu ICu IICu IICu I] tetrameric clusters bridged by dmg ligands and pillared into an 8-connected body-centered cubic ( bcu) cationic lattice by bpy linkers. Compounds 3 and 4 are structurally very similar, displaying chain motifs with {Cu 2(CO 2) 4} paddlewheels connected by dicarboxylates, in turn conjoined into (4,4)-grid coordination polymer layers by bpy tethers. Variable temperature magnetic data indicate the presence of very strong antiferromagnetic coupling within the {Cu 2(CO 2) 4} paddlewheels in the latter two complexes, with g = 2.30(2) and J = −352(3) cm −1 for 3 and g = 2.35(2) and J = −352(5) cm −1 for 4. Significant structural contrasts are evident when compared to previously reported divalent copper/4,4′-bipyridine coordination polymers with unsubstituted or 2-methyl substituted glutarate ligands.