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Two new polymeric iodoargentate hybrids induced by rare earth metal complexes and conjugated organic cations, {[Er(DMF)8][Ag6I9]}n (1) and [(MMP)(AgI2)]n (2) (MMP = 1-methyl-4-methylpyridinium) were obtained by the routine synthetic reaction and structurally determined. In compound 1, a (Ag6I9)n3n– chain is defined by edge-sharing Ag6I12 units, and in 2, the (Ag2I4)n2– chains are constructed by edge-sharing AgI4 tetrahedra. C–H···I hydrogen bonds between cations and iodoargentate polyanions contribute to their structural extension from 1D to a 2D layer (for 1) and a 3D network (for 2). The UV/Vis spectra indicate that compared with 2, compound 1 exhibits a narrower adsorption scope with an onset at about 360 nm, and it has a much wider bandgap of about 3.50 eV.

The 2,6- (6b, c) and 3,7–substituted 1,5–dimethylbicyclo-[3.3.0]octadienes C2- and Cs-9b and c are brominated by N-bromosuccinimide in the allylic positions to afford the dibromides 7b, exo,exo-7c, 10b and c, respectively. An excess of N-bromosuccinimide converts 10b into the unsymmetrical tetrabromide 11. On chromatography over silica gel, exo,exo-7c is epimerized to endo,endo-7c, while methanolysis occurs on reversed–phase chromatography yielding the dimethoxy compound 8. Under ultrasonic irradiation, the zinc–copper couple converts the bromides 7b, exo,exo-7c, 10c, and 11 into the semibullvalenes 1b, c, 2c, and 12 which are persistent in dilute solutions when atmospheric oxygen is strictly excluded. The UV/Vis spectra of 1b, c, 2c, and 12 have been recorded during reversed–phase HPLC on a Bruker ChromScan detector. Notwithstanding the absence of a classical chromophor, 1c does absorb at no less than 450 nm.

The six donor-acceptor spiro compounds spiro[1,3-dioxolane-2,2′-indan]-1′,3′-dione (8), spiro[indan-2,2′-[1,3]oxathiolane]-1,3-dione (9), spiro[1,3-dithiolane-2,2′-indan]-1′,3′-dione (10), spiro[1,3-benzodioxole-2,2′-indan]-1′,3′-dione (11), 5-methylspiro[1,3-benzodithiole-2,2′-indan]-1′,3′-dione (12), and spiro[indan-2,2′-naphtho[2,3-d]-1,3-dioxole]-1,3-dione (13) have been prepared. Their He (I) photoelectron spectra and their UV/Vis spectra have been investigated. A comparison between the first PE bands of the spiro compounds and the corresponding fragments indicates only a very weak interaction between both parts. The UV/Vis spectra of 11-13 show a moderate long-wavelength shift of the first band as compared to 1,3-indandione. This band is assigned to a transition from the HOMO(π), localized at the donor fragment, to the LUMO(π*) of the acceptor moiety (charge transfer). X-ray investigations of 8-10 and 13 show no interaction between the two perpendicularly arranged moieties.

The structure of SrCu(OH)4·H2O has been determined from a single-crystal X-ray refinement and shown to contain isolated square-planar [Cu(OH)4]2– groups separated by strontium ions and hydrogen bonded to water molecules. ESR, IR and UV/VIS spectra are also reported for this compound and are consistent with the presence of discrete [Cu(OH)4]2– square planes. Thermal decomposition of this material proceeded by a complex multistage process via Sr2(OH)2Cu(OH)4, through CuO and Sr(OH)2, to Sr2CuO3 and CuO. Consideration of the structure of SrCu(OH)4·H2O shows that the relative orientation of the [Cu(OH)4]2– units is such that they do not crosslink to form infinite CuO2 sheets.

Remarkable suitability for single-molecule spectroscopy in a polyethylene matrix is demonstrated by the highly pink fluorescent peryleneimidazoimides 2 (quantum yield 84 %), which, as well as 1, was prepared in a one-step reaction from perylene-3,4-imido-9,10-anhydride. The photostable dye 2 shows the same UV/Vis spectra as terrylene, but exceeds the latter in other properties.

The sodium dizirconium tris(phosphate) structural family ([NZP]) includes compounds that may be represented by the general formula M‘M‘ ‘1-3A2(PO4)3. The ability of KZr2(PO4)3, a member of the [NZP] structural family, to accommodate U(IV) on the octahedrally coordinated A site has been demonstrated for compounds in the series KZr2-xUx(PO4)3 (0 ≤ x ≤ 0.20). KU2(PO4)3, the end member of the series, was found to adopt a monoclinic structure with 9-fold coordination of U(IV) that does not belong to the [NZP] family. The compounds were prepared from sol−gel derived precursors in an argon environment. X-ray microanalyses indicated that the precursor powders had reacted fully to produce compounds of the expected stoichiometries. Rietveld refined X-ray powder diffraction data of KZr2-xUx(PO4)3 (0 ≤ x ≤ 0.20) confirmed a rhombohedral (R3c) structure and suggested random occupation of the A site by U/Zr. The presence of U(IV) was established by comparison of the UV/vis spectra of KZr2-xUx(PO4)3 (0 ≤ x ≤ 0.20) with...

A new compound (NaCuAsO 4 .1.5H 2 O) was synthesized, and its composition was determined by means of the methods of ignition loss-in-weight and chemical analysis. The standard molar enthalpies of dissolution of the mixtures (Na 3 AsO 4 ·12H 2 O(s)+ CuSO 4 ·5H 2 O(s)} and {NaCuAsO 4 ·1.5H 2 O(s) + Na 2 SO 4 (s)} in 1.498 mol·dm - 3 HCl solution at 298.15 K have been determined to be respectively Δ s H 0 m.1 = (64322 ±63) J·mol -1 and Δ s H 0 m.2 = -(20558 ±25) J·mol -1 using an isoperibol solution-reaction calorimetry. From these values and other thermodynamic data, the standard molar enthalpy of formation of NaCuAsO 4 ·1.5H 2 O(s) has been derived: Δ f H 0 m (NaCuAsO 4 ·1.5H 2 O, s, 298.15 K) = -(1469.33 ± 0.65) kJ.mol -1 . In addition, UV/Vis spectra and refractive indexes of solution A and solution A' were measured to examine the reliability of the designed thermodynamic cycle.