Two unique entangling ZnII/CdII coordination frameworks featuring multiform helical motifs based on long mixed ligands

Abstract

Two novel entangled coordination polymers, [Zn(abda)(bimh)]_n (1) and [Cd(dtba)(bimh)]_n (2) (H₂abda = azobenzene-4,4′-dicarboxylic acid, H₂dtba = 2,2′-dithiobisbenzoic acid, bimh = 1,6-bis(2-methylimidazole-1-yl)hexane), have been synthesized using long mixed ligands. Complex 1 features rare 2D parallel interpenetrated 4⁴-sql networks which show the same handedness. Interestingly, in the interpenetrating nets, A-chains [Zn(bimh)]_n of one layer co-use the helical shaft with B-chains [Zn(abda)]_n of the other layer of double-layers. Complex 2 shows a unique 3D 3-fold interpenetrating homochiral 8⁶ network, and each single net is constructed from right-handed [Cd(dtba)]_n single helices and left-handed [Cd(bimh)]_n double-stranded helices.