Tubelike Uranyl-Phenylenediacetate Assemblies from Screening of Ligand Isomers and Structure-Directing Counterions.

Reaction of 1,2-, 1,3-, or 1,4-phenylenediacetic acids (1,2-, 1,3-, or 1,4-HPDA) with uranyl ions under solvo-hydrothermal conditions and in the presence of [M(L) ] cations, in which M = transition metal cation, L = 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen), n = 2 or 3, and q = 1 or 2, gave 10 complexes which have been crystallographically characterized. The diacetate ligands are bis-chelating and the uranyl cations are tris-chelated in all cases. [UO(1,2-PDA)Zn(phen)]·2HO (1) and [UO(1,4-PDA)Mn(bipy)]·HO (2) are heterometallic, neutral one-dimensional (1D) coordination polymers in which the carboxylate-coordinated 3d block metal cation is either decorating only (1) or participates in polymer building (2). [Zn(phen)][(UO)(1,3-PDA)] (3) and [Ni(phen)][(UO)(1,4-PDA)]·HO (4), with separate counterions, crystallize as anionic two-dimensional (2D) networks, as does [Cu(bipy)][HNMe][(UO)(1,4-PDA)] (5), which displays parallel 2D interpenetration. The complex [Zn(phen)][(UO)(1,2-PDA)]·7HO (6) crystallizes as a ladderlike, slightly inflated ribbon. The same topology is found in [Zn(bipy)][(UO)(1,3-PDA)] (7), but the larger separation between coordination sites and the coexistence of curved and divergent ligand conformations produce a tubelike assembly. An analogous but more regular and spacious tubular geometry is found in [M(bipy)][(UO)(1,4-PDA)], with M = Co (8) or Ni (9), and {Λ-[Ru(bipy)]}[(UO)(1,4-PDA)] (10). The disordered counterions in 8 and 9 are replaced by well-ordered, enantiomerically pure chiral counterions in 10. The tubular assemblies formed in 7-10 are characterized by an oblong section and the presence of gaps in the walls, which enable the inclusion of two rows of counterions in the cavity.