摘要：

The preparation and magnetic investigation of five mononuclear copperiicomplexes of formula CupyimC2O4H2O·2H2O1, CupyimC4O4H2O2·2H2O2, CupyimC5O5·2.5H2O3, CuH2bimC2O4H2O·H2O4and CubpzC5O5H2O5pyim  2-2-pyridylimidazole, H2bim  2,2′-biimidazole, bpz  2,2′-bipyrazine, C2O42−dianion of oxalic acid, C4O42−dianion of squaric acid and C5O52−dianion of croconic acid are reported. The crystal structures of1,2,4and5have been determined. The copper atom has a distorted square pyramidal geometry in this family of complexes: two nitrogen atoms from the bidentate nitrogen donor pyim1and2, H2bim4and bpz5and two oxygen atoms either from a chelating oxalate1and4croconate5or from a monodentate squarate and a water molecule2build the basal plane whereas a water molecule fills the apical position1,2,4and5. A semi-coordinated oxalate1and4croconate5oxygen atom of a neighbouring molecule occupies the sixth coordination position, leading to centrosymmetric dinuclear units. Magnetic susceptibility measurements for1–5in the temperature range 2–290 K reveal the occurrence of weak intermolecular ferro-1and antiferromagnetic2–5interactions. The different strategies to use these neutral complexes as ligands in order to design polynuclear species are analyzed and discussed.

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