Early lanthanoid substituted organic-inorganic hybrids of silico- and germano-tungstates: Syntheses, crystal structures and solid-state properties

Abstract

Organic-inorganic hybrid of 3<em>d</em>-4<em>f</em> heterometallic derivatives of lacunary Keggin type silico- and germano-tungstates: [{Cu₂(1,10-phen)₂(<em>µ</em>-CH₃COO)₂}Ln(α-XW₁₁O₃₉)₂]^11‒/10‒ {Ln = La^III, Ce^III and Ce^IV, X = Si^IV; La^III, Ce^III, Ce^IV, X = Ge^IV; 1,10-phen = 1,10-Phenanthroline} have been synthesized by conventional aqueous solution method under mild reaction conditions. Solid crystalline materials isolated from the solution as an alkali salts (Na⁺/K⁺) are characterized by single crystal X-ray diffraction, FT-IR spectroscopy, powder-XRD, ICP-AES, liquid UV/vis and thermogravimetric analysis. FT-IR spectra and PXRD suggest that these compounds are isomorphous. Further, single crystal XRD analyses show that all are organic-inorganic hybrids comprising Peacock and Weakley type sandwich-type [Ln(α-XW₁₁O₃₉)₂]^13−/12‒ (X = Si^IV and Ge^IV) polyanion as the fundamental building block unit. These sandwich type species form polymeric chain assistance with copper organic complexes. These polymeric chains further assemble into 2-D structures by π-π stacking.