Coordination Polymers Utilizing N‑Oxide Functionalized Host Ligands

Pyridyl functionalized host molecules are oxidized to their N-oxide analogues and form a series of coordination polymers and discrete complexes with transition metal cations. Complex {[Ag3(NMP)6(L1)2]·3­(ClO4)}∞ where L1 = tris­(isonicotinoyl-N-oxide)­cyclotriguaiacylene, NMP = N-methylpyrrolidone, is a three-dimensional (3-D) 3,6-connected coordination polymer of pyrite-like (pyr) topology and features ligand unsupported argentophilic interactions, while two-dimensional (2-D) 3,6-connected coordination polymers with the rarely reported kagome dual (kgd) topology are found for [M­(L1)2]2+ where M = Zn, Cd, Cu. Ligand L2 = tris­(nicotinoyl-N-oxide)­cyclotriguaiacylene forms a 2-D coordination polymer with 44 (sql) grid topology in complexes {[M­(L2)2(DMF)2]·2ClO4·8­(DMF)}∞ M = Cd or Cu, DMF = N,N′-dimethylformamide, and a double-linked chain structure in {[Co­(L2)2(DMF)2]·2NO3·4­(DMF)·H2O}∞, and both types of structure feature hand-shake self-inclusion motifs either within or between the polymers. 2-D coordination networks with 63 (hcb) topologies are found in complexes {[M­(L3)­(NO3)2]·2­(DMF)}∞ (M = Cd, Zn) and {[Cu5(L3)2Cl10(NMP)4]}∞ where L3 = tris­(2-pyridylmethyl)­cyclotriguaiacylene, while [Ag2(L3)2(NMP)4]·2­(BF4)·2­(NMP) has a discrete dimeric structure which again shows hand-shake host–guest interactions supported by π–π stacking.