title: Solid- and solution phase transformations in novel hybrid iodoplumbate derivatives templated by solvated yttrium complexes.
abstract: Solvated yttrium iodide precursors [Y(L)8]I3 [L = dimethylformamide (DMF) or dimethylsulfoxide (DMSO)], prepared in situ by stirring YI3(Pr(i)OH)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(mu-I)9](1infinity) x DMF (1), or discrete pentanuclear iodoplumbates, [Y(DMSO)8]2[(DMSO)2Pb5(mu3-I)2(mu-I)8I6] (2a). The complex 2a and a closely related [Y(DMSO)8][Y(DMSO)7(DMF)][(DMSO)2Pb5(mu3-I)2(mu-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(mu3-I)(mu-I)7I](1infinity) (3) via an exchange reaction, whereas those of 2a and 2b are converted into [Y(DMSO)7][Pb3(mu3-I)(mu-I)7I](1infinity) (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).
authors.affiliation: IRCELYON, Universite Lyon 1, 2 Avenue A. Einstein, 69626 Villeurbanne, France. mishrashashank74@rediffmail.com
authors.forename: Shashank
authors.initials: S
authors.lastname: Mishra
authors.forename: Erwann
authors.initials: E
authors.lastname: Jeanneau
authors.forename: Stéphane
authors.initials: S
authors.lastname: Daniele
authors.forename: Gilles
authors.initials: G
authors.lastname: Ledoux
authors.forename: Prakash N
authors.initials: PN
authors.lastname: Swamy
mesh_terms: D018360:Crystallography, X-Ray; D007455:Iodine / Q000737:chemistry*; D007854:Lead / Q000737:chemistry*; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D044367:Phase Transition; D012997:Solvents / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D015019:Yttrium / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D010087:Oxides; D012997:Solvents; D007854:Lead; C047365:lead oxide; D015019:Yttrium; D007455:Iodine