Stepwise introduction of flexibility into aromatic dicarboxylates forming uranyl ion coordination polymers. A comparison of 2-carboxyphenylacetate and 1,2-phenylenediacetate

2-Carboxyphenylacetate (cpa${}^{2-}$) and 1,2-phenylenediacetate (1,2-pda${}^{2-}$) have been reacted with uranyl cations under solvo-hydrothermal conditions to generate six homo- or heterometallic complexes. Both [UO${}_2$(cpa)] (1) and [UO${}_2$(cpa)(phen)] (2), where phen is 1,10-phenanthroline, crystallize as monoperiodic coordination polymers. [Ni(bipy)${}_3$][(UO${}_2$)${}_2$(cpa)${}_3$]⋅2.5H${}_2$O (3), is a diperiodic network with the hcb topology, in which the hexagonal cells distort to accommodate the counterions. [UO${}_2$(cpa)${}_2$Ni(R,S-Me${}_6$cyclam)] (4) crystallizes as a heterometallic diperiodic network in which uranyl dicarboxylate chains are assembled by bridging Ni${}^{II}$ cations. While [dmaepH${}_2$][(UO${}_2$)${}_2$(1,2-pda)${}_3$]⋅3H${}_2$O (5), where dmaep is 1,4-bis(2'-dimethylaminoethyl)piperazine, is a diperiodic hcb network, [QH]${}_2$[(UO${}_2$)${}_2$(1,2-pda)${}_3$]⋅3CH${}_3$CN (6), where Q is quinuclidine, is the first example of a triperiodic framework in the uranyl-phenylenediacetate family, its topological type being bto. The complex involving the related ligand 1,4-phenylenediacetate (1,4-pda${}^{2-}$), [QH]${}_2$[(UO${}_2$)${}_2$(1,4-pda)${}_3$]⋅2CH${}_3$CN (7), is a daisy-chain-like monoperiodic polymer. These and previously reported results are discussed in terms of ligand flexibility and ability to form large chelate rings. (© 2021 Wiley‐VCH GmbH)