Graeme A. Horley

Atmospheric Pressure CVD of Antimony Oxides

Communication: Thin films of Sb2O3 (senarmonite) have been deposited from antimony(III) n-butoxide at atmospheric pressure from 500 to 550 degreesC without the addition of a separate oxygen source. Films are analyzed using SEM (see Figure), EDX, and XRD, which indicates a strong (111) texture. On the other hand, the decomposition of antimony(iii) ethoxide in the same temperature range produces only antimony metal. However, when the deposition temperature is increased to 600 degreesC Sb6O13, is deposited.

Synthesis and materials chemistry of bismuth Tris-(di-i-propylcarbamate): deposition of photoactive Bi2O3 thin films

The bismuth carbamate Bi(O2CNPr(i)2)3, a tetramer in the solid-state, has been synthesized and used to deposit mixtures of bismuth oxides by aerosol-assisted chemical vapor deposition (AACVD). The nature of the deposited oxide is a function of both temperature and run-time. Initially, δ-Bi2O3 is deposited, over which grows a thick layer of β-Bi2O3 nanowires, the latter having an increasing degree of preferred orientation at higher deposition temperatures. The photocatalytic activity of a thin film of δ-Bi2O3 for the degradation of methylene blue dye was found to be similar to that of a commercial TiO2 film on glass, while the film overcoated with β-Bi2O3 nanowires was less active. Exposure of Bi(O2CNPr(i)2)3 to controlled amounts of moist air affords the novel oxo-cluster Bi8(O)6(O2CNPr(i)2)12, whose structure has also been determined.

Antimony β-diketonates and alkoxide/β-diketonates: remarkable formation of a 3,4-dihydro-2H-pyran ring by coupling of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione ligands

Homoleptic antimony(III) β-diketonates Sb(thd)3 (Hthd = 2,2,6,6-tetramethyl-3,5-heptanedione) and Sb(fod)3 (Hfod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-heptanedione) have been synthesised from Sb(OEt)3 and three equivalents of the appropriate ligand. Both compounds have been characterised crystallographically and are monomeric with pseudo seven-coordination at antimony, where each ligand chelates the metal in an anisobidentate manner. Attempts to prepare Sb(hfac)3 (Hhfac = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione) by the same route generated a compound of formula [(EtO)Sb(hfac)2]2 but in which the two β-diketonate ligands have combined to produce a functionalised 3,4-dihydro-2H-pyran ring; the dimer arises from a bridging ethoxy group. Heteroleptic (EtO)Sb(thd)2 has also been synthesised and crystallographically characterised as a monomeric structure in which the ethoxy group is terminal. In addition, Sb(OEt)2(fod) and Sb(OEt)4(thd) have been prepared for comparison.