Andrew J. Kingsley

Exclusive formation of SnO by low temperature single-source AACVD

An easily synthesised Sn(II) bis(ureide) derivative is shown to be a single-source precursor for the aerosol-assisted CVD of SnO, providing unprecedented levels of oxidation state control at temperatures as low as 250 °C.

Unprecedented double migratory insertion of phenyl isocyanide into cyclopentadienyl C-H bonds

The reaction of [(eta(5)-C(5)H(5))Cu(CNPh)] with phenyl-isocyanide results in an unprecedented double migratory insertion into two sp(2) C-H bonds of a eta(5)-coordinated cyclopentadienyl group, and formation of the 6-aminofulvene-2-aldimine complexes [(CNPh)Cu{kappa(2)-N,N-C(5)H(3)-1,2-(CHNPh)(2)}] and [(CNPh)(2)Cu{kappa(2)-N,N-C(5)H(3)-1,2-(CHNPh)(2)}], respectively, both of which have been structurally characterised.

Synthesis, Characterization, and Materials Chemistry of Group 4 Silylimides

This paper focuses on the development of potential single source precursors for M-N-Si (M = Ti, Zr or Hf) thin films. The titanium, zirconium, and hafnium silylimides (Me(2)N)(2)MNSiR(1)R(2)R(3) [R(1) = R(2) = R(3) = Ph, M = Ti(1), Zr (2), Hf (3); R(1) = R(2) = R(3) = Et, M = Ti (4), Zr (5), Hf (6); R(1) = R(2) = Me, R(3) = (t)Bu, M = Ti (7), Zr (8), Hf (9); R(1) = R(2) = R(3) = NMe(2), M = Ti (10), Zr (11), Hf (12)] have been synthesized by the reaction of M(NMe(2))(4) and R(3)R(2)R(1)SiNH(2). All compounds are notably sensitive to air and moisture. Compounds 1, 2, 4, and 7-10 have been structurally characterized, and all are dimeric, with the general formula [M(NMe(2))(2)(μ-NSiR(3))](2), in which the μ(2)-NSiR(3) groups bridges two four-coordinate metal centers. The hafnium compound 3 possesses the same basic dimeric structure but shows additional incorporation of liberated HNMe(2) bonded to one metal. Compounds 11 and 12 are also both dimeric but also incorporate additional μ(2)-NMe(2) groups, which bridge Si and either Zr or Hf metal centers in the solid state. The Zr and Hf metal centers are both five-coordinated in these species. Aerosol-assisted CVD (AA-CVD) using 4-7 and 9-12 as precursors generates amorphous films containing M, N, Si, C, and O; the films are dominated by MO(2) with smaller contributions from MN, MC and MSiON based on XPS binding energies.

Cobalt(I) Olefin Complexes: Precursors for Metal-Organic Chemical Vapor Deposition of High Purity Cobalt Metal Thin Films.

We report the synthesis and characterization of a family of organometallic cobalt(I) metal precursors based around cyclopentadienyl and diene ligands. The molecular structures of the complexes cyclopentadienyl-cobalt(I) diolefin complexes are described, as determined by single-crystal X-ray diffraction analysis. Thermogravimetric analysis and thermal stability studies of the complexes highlighted the isoprene, dimethyl butadiene, and cyclohexadiene derivatives [(C5H5)Co(η(4)-CH2CHC(Me)CH2)] (1), [(C5H5)Co(η(4)-CH2C(Me)C(Me)CH2)] (2), and [(C5H5)Co(η(4)-C6H8)] (4) as possible cobalt metal organic chemical vapor deposition (MOCVD) precursors. Atmospheric pressure MOCVD was employed using precursor 1, to synthesize thin films of metallic cobalt on silicon substrates under an atmosphere (760 torr) of hydrogen (H2). Analysis of the thin films deposited at substrate temperatures of 325, 350, 375, and 400 °C, respectively, by scanning electron microscopy and atomic force microscopy reveal temperature-dependent growth features. Films grown at these temperatures are continuous, pinhole-free, and can be seen to be composed of hexagonal particles clearly visible in the electron micrograph. Powder X-ray diffraction and X-ray photoelectron spectroscopy all show the films to be highly crystalline, high-purity metallic cobalt. Raman spectroscopy was unable to detect the presence of cobalt silicides at the substrate/thin film interface.

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.

Titanium and zirconium neopentyl chloro complexes, MNpxCl4−x (x = 1−4)

Abstract The comproportionation reaction between the titanium and zirconium homoleptic neopentyl complexes, TiNp 4 and ZrNp 4 (Np = 2,2′-dimethylpropyl; CH 2 CMe 3 ) and the metal tetrachlorides, TiCl 4 and ZrCl 4 provides a facile route to all of the titanium and zirconium neopentyl chloro complexes, MNp x Cl 4− x ( x = 1,2,3). All the complexes described are moisture-sensitive, and in the case of the titanium complexes, light-sensitive also. The stability of the complexes at room temperature has also been estimated. The neopentyl chloro complexes, and the isotopically labelled species (where (Np- d ) = CH(D)CMe 3 ), have been spectroscopically characterised, the 1 H NMR resonance of the CH 2 protons displays an increasing shift to high frequency in the series MNp 4 , MNp 3 Cl, MNp 2 Cl 2 , MNpCl 3 . A modified synthesis of Me 3 CCHDCI from Me 3 CCHDOH is reported.