Oligonuclear 3d-4f complexes as tectons in designing supramolecular solid-state architectures: Impact of the nature of linkers on the structural diversity

Heteronuclear cationic complexes, [LCuLn](3+) and [(LCu)(2)Ln](3+), were employed as nodes in designing high-nuclearity complexes and coordination polymers with a rich variety of network topologies (L is the dianion of the Schiff base resulting from the 2:1 condensation of 3-methoxysalycilaldehyde with 1,3-propanediamine). Two families of linkers have been chosen: the first consists of exo-dentate ligands bearing nitrogen-donor atoms (bipyridine (bipy), dicyanamido (dca)), whereas the second consists of exodentate ligands with oxygen-donor atoms (anions derived from the acetylenedicarboxylic (H(2)acdca), fumaric (H(2)fum), trimesic (H,trim), and oxalic (H,ox) acids). The ligands belonging to the first family prefer copper(II) ions, whereas the ligands from the second family interact preferentially with oxophilic rare-earth cations. The following complexes have been obtained an crystallographically characterized [LCII(OH2)Gd-III(NO3)(3)] (1), [{(LCGdIII)-Gd-II (NO3)(3))}(2)(mu-4,4'-bipy)] (2), infinity(1)[(LCGdIII)-Gd-II(acdca), (H2O)(2)]center dot 13H(2)O (3), (2)(infinity)[(LCGdIII)-Gd-II (fum)(1.5)(H2O)(2)]center dot 4H(2)O center dot C2H5OH (4), (1)(infinity)[(LCuSmIII)-Sm-II(H2O)- (Hfum)(fum)] (5), (1)(infinity)[(LCErIII)-Er-II (H2O)(2)(fum)]NO3 center dot 3 H2O (6), (2)(infinity)[(LCuSmIII)-Sm-II (fum)(1.5)(H2O)(2)]center dot 4 H2O center dot C2H5OH (7), [{(LCuII)(2)Sm-III}(2) fum(2)] (OH)(2) (8), (1)(infinity)[(LCGdIII)-Gd-II(trim)(H2O)(2)]center dot H2O (9), (2)(infinity)[{(LCuII)(2)Pr-III}(C2O4)(0.5)(dca)]dca center dot 2H(2)O (10), [(LCGdIII)-Gd-II(ox)(H2O)(3)][Cr-III(2,2'bipy)(ox)(2)]center dot 9H(2)O (11), and [LCuGd(H2O)(4){Cr(CN)(6)}]center dot 3H(2)O (12). Compound I is representative of the whole family of binuclear C-II-Ln(III). complexes which have been used as precursors in constructing heteropolymetallic complexes. The rich variety of the resulting structures is due to several factors: 1)the nature of the donor atoms of the linkers, 2)the preference of the copper(ii) ion for nitrogen atoms, 3) the oxophilicity of the lanthanides, 4) the degree of deprotonation of the polycarboxylic acids, 5)the various connectivity modes exhibited by the carboxylato groups, and 6) the stoichiometry of the final products, that is, the C-II/Ln(III)/linker molar ratio. A unique cluster formed by 24 water molecules was found in crystal 11. In compounds 2, 3, 4, 9, and 11 the (CuGdIII)-Gd-III. exchange interaction was found to be ferromagnetic, with J values in the range of 3.53-8.96 cm(-1). Compound 12 represents a new example of a polynuclear complex containing three different paramagnetic ions. The intranode (CuGdIII)-Gd-II ferromagnetic interaction is overwhelmed by the antiferromagnetic interactions occurringbetween the cyanobridged Gd-III. and Cr-III ions.