Contrasting Structure-Directing Effects in the Uranyl-Phthalate/Isophthalate Isomer Systems

Reaction of uranyl cations with phthalic (H(2)pht) or isophthalic (H(2)ipht) acids under solvohydrothermal conditions was performed in the presence of 3d-block metal cations associated with chelating nitrogen donors to give nine zero-, mono-, and diperiodic complexes. [UO2(pht)(2)Zn(phen)(2)](2)center dot 4H(2)O (1), where phen is 1,10-phenanthroline, is a heterometallic, tetranuclear complex, while the counterion separation in [Ni(bipy)(3)][UO2(pht)(NO3)](2) (2), where bipy is 2,2'-bipyridine, yields a monoperiodic, helical uranyl ion complex crystallizing in a pure enantiomeric form. The diperiodic network in [Ni(phen)(3)][(UO2)(3)(O)(pht)(3)]center dot 6H(2)O (3) displays pseudotrigonal, cuplike cavities containing part of the bulky counterions. [(UO2)(2)(O)(pht)(2)Ni(cyclam)(H2O)] 2 center dot H2O (4), where cyclam is 1,4,8,11-tetraazacyclotetradecane, is a discrete, bis(mu(3)-oxo)-bridged tetranuclear uranyl complex of common geometry, to which two Ni(cyclam)(2+) moieties are attached through oxo bonding to uranyl. Separation of the 3d-block metal ion complex in [Ni(cyclam)](2)[(UO2)(7)(pht)(8)(NO3)(2)] (5) and [Cu(R,S-Me(6)cyclam)][(UO2)(5)(O)(2)(pht)(4)(H2O)(2)]center dot 4H(2)O (6), where R,S-Me(6)cyclam is 7(R),14(S)-5,5,7,12,12,14-hexamethylcyclam, results in the formation of quasi-planar diperiodic networks hydrogen bonded to the counterions. The three isophthalate complexes [(UO2)(2)(ipht)(3)Cu(bipy)(2)]center dot H2O (7), [(UO2)(2)(ipht)(2)(HCOO)(2)Ni-(cyclam)] (8), and [(UO2)(2)(ipht)(2)(HCOO)(2)Cu(R,S-Me(6)cyclam)] (9) crystallize as heterometallic diperiodic species with Cu(bipy)(2)(2+) being only decorating in 7, while Ni2+ and Cu2+ in 8 and 9 bridge uranyl-containing chains into a network with a V2O5 topology.

Automated summary

In this study, nine zero-, mono-, and diperiodic complexes of uranyl cations were successfully synthesized under solvohydrothermal conditions, with the formation of heterometallic complexes and those associated with 3d-block metal cations.