Quantitative resonant soft x-ray reflectivity from an organic semiconductor single crystal.

Resonant soft X-ray reflectivity at the carbon K-edge was applied to a trigonal tetracene single crystal. The angular resolved reflectivity was quantitatively simulated describing the tetracene crystal in terms of its dielectric tensor, which was derived from the anisotropic absorption cross section of the single molecule, as calculated by density functional theory. A good agreement was found between the experimental and theoretically predicted reflectivity. This allows us to assess the anisotropic optical constants of the organic material, probed at the carbon K-edge, in relation to the bulk/surface structural and electronic properties of the crystal, through empty energy levels.

Tailoring precursors for deposition: synthesis, structure, and thermal studies of cyclopentadienylcopper(i) isocyanide complexes.

We report here the synthesis and characterization of a family of copper(I) metal precursors based around cyclopentadienyl and isocyanide ligands. The molecular structures of several cyclopentadienylcopper(I) isocyanide complexes have been unambiguously determined by single-crystal X-ray diffraction analysis. Thermogravimetric analysis of the complexes highlighted the isopropyl isocyanide complex [(η(5)-C5H5)Cu(CN(i)Pr)] (2a) and the tert-butyl isocyanide complex [(η(5)-C5H5)Cu(CN(t)Bu)] (2b) as possible copper metal chemical vapor deposition (CVD) precursors. Further modification of the precursors with variation of the substituents on the cyclopentadienyl ligand system (varying between H, Me, Et, and (i)Pr) has allowed the affect that these changes would have on features such as stability, volatility, and decomposition to be investigated. As part of this study, the vapor pressures of the complexes 2b, [(η(5)-MeC5H4)Cu(CN(t)Bu)] (3b), [(η(5)-EtC5H4)Cu(CN(t)Bu)] (4b), and [(η(5)-(i)PrC5H4)Cu(CN(t)Bu)] (5b) over a 40-65 °C temperature range have been determined. Low-pressure chemical vapor deposition (LP-CVD) was employed using precursors 2a and 2b to synthesize thin films of metallic copper on silicon, gold, and platinum substrates under a H2 atmosphere. Analysis of the thin films deposited onto both silicon and gold substrates at substrate temperatures of 180 and 300 °C by scanning electron microscopy and atomic force microscopy reveals temperature-dependent growth features: Films grown at 300 °C are continuous and pinhole-free, whereas films grown at 180 °C consist of highly crystalline nanoparticles. In contrast, deposition onto platinum substrates at 180 °C shows a high degree of surface coverage with the formation of high-density, continuous, and pinhole-free thin films. Powder X-ray diffraction and X-ray photoelectron spectroscopy (XPS) both show the films to be high-purity metallic copper.

Inorganic and organozinc fluorocarboxylates: synthesis, structure and materials chemistry.

The organozinc fluorocarboxylates RZnO2CRf and RZnO2CRf·TMEDA, along with Zn(O2CRf)2·TMEDA (R = Me, Et; Rf = C2F5, C3F7) have been synthesized. The structures of EtZnO2C2F5 (5), EtZnO2C3F7 (7), EtZnO2C2F5·TMEDA (11), Zn(O2C2F5)2·TMEDA (13), along with products from the adventitious reaction with either O2 or H2O, Zn10Me4(OMe)4(O2CC2F5)12 (2), Zn9Et2(O2CC2F5)12(O)2 (6), Zn8Et4(OEt)4(O2CC3F7)6(O) (8), [Zn(O2CC3F7)2·TMEDA]2·H2O (15) have been determined. Thin films of oriented ZnO have been deposited on glass substrates by low-pressure chemical vapor deposition (LPCVD) using 3 and 10 as precursors, though no fluorine incorporation in the films was noted. LPCVD using 13 as precursor also yielded fluorine-free ZnO, but lacking the oriented growth observed using 3, 10. However, 5, which exhibits short intermolecular Zn···F contacts in the solid state, thermally decomposes to bulk ZnF2.

Formation of PbS materials from lead xanthate precursors.

Six lead xanthate adducts Pb(S(2)COR)(2).L [R = Et, (n)Bu, L = bipy, TMEDA (tetramethylethylenediamine), PMDETA (pentamethyldiethylenetriamine)] have been synthesised and the structures of all, save Pb(S(2)COBu(n))(2).TMEDA (4) which is an oil, determined. Pb(S(2)COEt)(2).TMEDA (3) is seven-coordinate at lead through three chelating ligands and one weak intermolecular Pb‥S interaction. Both Pb(S(2)COR)(2).bipy [R = Et (1), (n)Bu (2)] are dimers in which one xanthate is terminal and the other µ(2) bridging at each sulphur, generating an eight-coordinate lead when the bipy donor is included. Both Pb(S(2)COR)(2).PMDETA [R = Et (5), (n)Bu (6)] are seven-coordinate at lead by virtue of two bidentate chelating xanthate ligands and a tridentate PMDETA; there are no intermolecular interactions. Trends in the (207)Pb NMR chemical shifts mirror the changes in the intramolecular coordination number across the series. Pb(S(2)COEt)(2).TMEDA (3) has been used to deposit PbS films on glass, Mo-coated glass and Si by AACVD. Pb(S(2)COEt)(2) also generated PbS nanocubes when decomposed under an autogenerated pressure.

Monoclinic modification of 1,1,3,3,5,5-hexa-methyl-cyclo-1,3,5-tris-tannathiane.

The asymmetric unit of the title compound, [Sn(3)(CH(3))(6)S(3)], contains two molecules with twist-boat conformations. There are intermolecular S⋯H (2.929 Å), S⋯S (3.433 Å), S⋯C (3.465 Å) and C⋯H (2.898 Å) inter-actions in addition to prominent intermolecular Sn⋯S inter-actions of 3.692 and 3.769 Å.