Uranyl ion coordination polymers with the dibenzobarrelene-based rac- and (R,R)-trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylate ligands

Abstract

trans-9,10-Dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (deadcH₂), in its racemic or R,R enantiomeric forms, has been used to synthesize eight uranyl ion complexes under solvo-hydrothermal conditions. [UO₂(deadc)]·1.5CH₃CN (1) and [H₂NMe₂]₂[(UO₂)₂(deadc)₃]·2H₂O (2) crystallize as monoperiodic coordination polymers in which deadc²⁻ forms both 4- and 7-membered chelate rings. Although synthesized in the same conditions as 2, the enantiomerically pure complex [H₂NMe₂]₄[(UO₂)₂(O)(R,R-deadc)₂]₂ (3) is a discrete tetranuclear complex containing two μ₃-oxo anions. Association with the zwitterion Ni(tpyc)₂, where tpyc⁻ is 2,2′:6′,2′′-terpyridine-4′-carboxylate, gives [(UO₂)₂(deadc)(deadcH)(NO₃)Ni(tpyc)₂]·CH₃CN·2H₂O (4), a rake-shaped monoperiodic assembly. [UO₂(deadc)(DMA)] (5), [UO₂(deadc)] (6) and [PPh₄]₂[(UO₂)₂(R,R-deadc)₃] (7) crystallize as diperiodic networks with the fes, sql and hcb topologies, respectively, the thick layers formed being coated on both sides by protruding, hydrophobic dibenzobarrelene groups. Finally, [(UO₂)₂Ag₂(deadc)₃(CH₃CN)₂]·0.5H₂O (8) contains monoperiodic uranyl–deadc²⁻ subunits which are assembled into a triperiodic framework by bridging silver(I) cations, the latter interacting with both carboxylate groups and aromatic rings. Except for 6, all these complexes are emissive with photoluminescence quantum yields of 2–26%, and most spectra display the usual vibronic fine structure of uranyl emission.