New 3d-4f supramolecular systems constructed by [Fe(bipy)(CN)(4)](-) and partially blocked lanthanide cations

作者：Visinescu Diana; Toma Luminita M; Fabelo Oscar; Ruiz Perez Catalina; Lloret Francesc; Julve Miguel^*

来源：Polyhedron, 2009, 28(4): 851-859.

DOI：10.1016/j.poly.2008.12.032

• Iron(III)
• Lanthanide(III)
• Heterometallic systems
• Crystallography
• Cyanide complexes

The reaction of acetonitrile (1-5) and mixed acetonitrile/water 1:1 (6-9) solutions containing the cyanide-bearing [Fe(bipy)(CN)(4)](-) building block (bipy = 2,2'-bipyridine) and the partially blocked [Ln(bpym)](3 ) cation (Ln = lanthanide trivalent cation and bpym = 2,2'-bipyrimidine) has afforded two new families of 3d-4f supramolecular assemblies of formula [Ln(bpym)(NO3)(2)(H2O)(3)][Fe(bipy)(CN)(4)] center dot H2O center dot CH3CN [Ln = Sm (1), Gd (2), Tb (3), Dy (4) and Ho (5)] and [Ln(bpym)(NO3)(2)(H2O)(4)][Fe(bipy)(CN)(4)] [Ln = Pr (6), Nd (7), Sm (8), Gd (9)]. They crystallize in the P2(1)/c (1-5) and P2/c (6-9) space groups and their structures are made up of [Fe(bipy)(CN)(4)](-) anions (1-9) and [Ln(bpym)(NO3)(2)(H2O)(n)]( ) cations [n = 3 (1-5) and 4 (6-9)] with uncoordinated water and acetonitrile molecules (1-5) which are interlinked through an extensive network of hydrogen bonds and pi-pi stacking into three-dimensional motifs. Both families have in common the occurrence of the low-spin iron(III) unit [Fe(bipy)(CN)(4)](-) where two bipy-nitrogen and four cyanide-carbon atoms build a somewhat distorted octahedral surrounding around the iron atom [Fe-N = 1.980(3)-1.988(3) angstrom (1-5) and 1.988(2)-1.992(2) angstrom (6-9): Fe-C=1.904(5)-1.952(4)angstrom (1-5) and 1.911(2)-1.948(3)angstrom (6-9)]. The main structural difference between both families concerns the environment of the lanthanide atom which is nine-(1-5)/10-coordinated (6-9) with a chelating bpym, two bidentate nitrate and three (1-5)/four (6-9) water molecules building distorted monocapped (1-5)/bicapped (6-9) square antiprisms. This different lanthanide environment is at the origin of the different hydrogen bonding pattern of the two families of compounds.

• 出版日期2009-3-12