Hydrothermal synthesis, crystal structure and physical properties of {[Gd(H2O)4(μ2-C6NO2H5)2Gd(H2O)4](μ3-C6NO2H4)2(ZnCl3)2} • 2H2O •2Cl

A bimetallic 4f-3d tetranuclear complex {[Gd(H2O)4(mu(2)-C6NO2H5)(2)Gd(H2O)(4)](mu(3)-C6NO2H4)(2)(ZnCl3)(2)} center dot 2H(2)O center dot 2Cl (1) has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex I is characterized by a tetranuclear Gd2Zn2 structure with the gaidolinium and zinc atoms interconnected by isonicotinic acid ligands. The tetranuclear species of {[Gd(H2O)4(mu(2)-C6NO2H5)(2)Gd(H2O)(4)](mu(3)-C6NO2H4)(2)(ZnCl3)(2)} link to isolated chlorine ions and water molecules via pi...pi it interactions and hydrogen bonds to yield a 3-D supramolecular framework. Photoluminescent investigation reveals that the title complex displays an emission in ultraviolet region. The solid-state diffuse reflectance spectra of 1 reveal the presence of a sharp optical gap of 3.66 eV. (C) 2009 Published by Elsevier B.V.