Bis(nitrate)diaquauranyl(VI) synthon to generate [1 × 2 + 1 × 1] and [1 × 1 + 1 × 1] co-crystalized 3d⋯5f self-assemblies

  • 10.1039/C0CE00332H
  • CrystEngComm
  • p 1-0, 13, 3,
The syntheses, characterization and crystal structures of four copper( II )/nickel( II )⋯uranyl( VI ) self-assemblies of composition [{Ni II L 1 } 2 ·{(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 }] ( 1 ), [{Cu II L 2 } 2 ·{(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 }]·0.68H 2 O ( 2 ), [{Ni II L 2 } 2 ·{(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 }] ( 3 ) and [{Cu II L 3 }·{(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 }] n ( 4 ) are described in this investigation (H 2 L 1 , H 2 L 2 and H 2 L 3 are the Schiff base ligands obtained on condensing 3-ethoxysalicylaldehyde with ethylenediamine, o -phenylenediamine and trans -1,2-diaminocyclohexane, respectively). Compounds1 and4 crystallized in the monoclinicP 2 1 / n andC 2/ c space groups, respectively, while compounds2 and3 crystallized in the triclinic space groupP . Two water molecules of the [(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 ] moiety in1–4 , have a linear H 2 O–U–OH 2 arrangement. Each of these two water molecules in1–3 interacts with the O(phenoxo) 2 O(ethoxy) 2 compartment of a mononuclear copper( II ) or nickel( II ) moiety due to the formation of bifurcated hydrogen bonds between each of the two water hydrogen atoms and a pair of one phenoxo and one ethoxy oxygen atoms resulting in the interlinking of the two mononuclear 3d units by the [(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 ] synthon and therefore these three compounds may be considered as supramolecular dimers. Compounds1–3 are also two component [1 × 2 + 1 × 1] co-crystals consisting of two mononuclear copper( II ) or nickel( II ) units and one [(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 ] moiety. On the other hand, in4 , two water molecules, from two different [(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 ] moieties, interact with one O(phenoxo) 2 O(ethoxy) 2 compartment resulting in the formation of a self-assembled one-dimensional topology. Again, since one mononuclear copper( II ) unit and one [(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 ] moiety exist in a single crystal in4 , this compound is a two component [1 × 1 + 1 × 1] co-crystal. The outcomes of the present study utilize [(U VI O 2 )(NO 3 ) 2 (H 2 O) 2 ] synthon to derive 3d⋯5f co-crystals, provide the first observation of the interaction of two water molecules with one O(phenoxo) 2 O(ethoxy) 2 compartment, demonstrate the formation of supramolecular dimers and show the first example of a one-dimensional self-assembly resulting from water⋯O 4 compartment hydrogen bonds, and the first example of [1 × 2 + 1 × 1] co-crystals in 3-ethoxysalicylaldehyde-diamine ligand system.