Solid- and Solution Phase Transformations in Novel Hybrid Iodoplumbate Derivatives Templated by Solvated Yttrium Complexes

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• 作者：Shashank Mishra ; Erwann Jeanneau ; Sté ; phane Daniele ; Gilles Ledoux ; Prakash N. Swamy
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：October 20, 2008
• 年：2008
• 卷：47
• 期：20
• 页码：9333-9343
• 全文大小：521K
• 年卷期：v.47,no.20(October 20, 2008)
• ISSN：1520-510X

文摘

Solvated yttrium iodide precursors [Y(L)₈]I₃ [L = dimethylformamide (DMF) or dimethylsulfoxide (DMSO)], prepared in situ by stirring YI₃(PrⁱOH)₄ in DMF/DMSO, react with 3 equiv of PbI₂ in the presence of NH₄I to give novel hybrid derivatives based on either a one-dimensional (1D) straight chain, [Y(DMF)₈][Pb₃(μ-I)₉]_1∞·DMF (1), or discrete pentanuclear iodoplumbates, [Y(DMSO)₈]₂[(DMSO)₂Pb₅(μ₃-I)₂(μ-I)₈I₆] (2a). The complex 2a and a closely related [Y(DMSO)₈][Y(DMSO)₇(DMF)][(DMSO)₂Pb₅(μ₃-I)₂(μ-I)₈I₆] (2b) were obtained in good yield by solution phase transformation of 1 in DMSO under slight different conditions. Derivatives 1 and 2 also undergo unique solid-state transformation in a confined environment of paratone to give 1D polymers based on zigzag iodoplumbate chains; crystals of 1 transform into [Y(DMF)₆(H₂O)₂][Pb₃(μ₃-I)(μ-I)₇I]_1∞ (3) via an exchange reaction, whereas those of 2a and 2b are converted into [Y(DMSO)₇][Pb₃(μ₃-I)(μ-I)₇I]_1∞ (4) via a decomposition pathway. The trifurcate H-bonding between water ligands on yttrium cation and iodide of the iodoplumbate anion plays a pivotal role in transforming the straight 1D polymeric Pb−I chain of 1 into a zigzag chain in 3. The thermogravimetry-differential thermal analysis studies indicate that complexes with DMF ligands are thermally more stable than those with DMSO ones, the mixed DMF-H₂O ligand complex 3 being the most stable one because of the presence of strong H-bonding. Diffuse-reflectance UV−visible spectral analyses of 1−4 show an optical band gap in the 1.86−2.54 eV range, indicating these derivatives as potential semiconductors. In contrast to non-emissive 3 and 4, derivatives 1, 2a, and 2b show remarkable luminescent emission with peak maxima at 703 nm, assigned as an iodine 5p-lead 6s to lead 6p charge transfer (XM-M-CT).