Peter L. Timms

Synthesereaktionen mit Metallatomen bei 10 bis 273°K

Metallatome, einfach durch Metallverdampfung im Vakuum bei hohen Temperaturen erzeugt, lassen sich mit anorganischen und mit organischen Verbindungen bei 80–273°K in Losung oder durch Cokondensation der Metall- und Substratdampfe bei 10–80°K umsetzen. Dabei werden in vielen Fallen Grammengen von Metallderivaten in niedrigen Wertigkeitsstufen erhalten, von denen manche auf herkommlichem Wege nicht zuganglich sind.

The matrix infrared spectrum of PN and SiS

Abstract Gaseous PN and SiS have been prepared at high temperatures from P 3 N 5 and from CS 2 + Si respectively, and the species have been trapped in krypton matrices at 10°K. Infrared studies using P 14 N and P 15 N showed matrix isolated PN monomer and its aggregation to P 3 N 3 , a molecule isostructural with Si 3 O 3 with D 3h symmetry; P 2 N 2 was not detected. Both SiS and Si 2 S 2 were detected by i.r. in the SiS/Kr matrix but no higher polymers could be characterised. The molecular parameters of SiS and Si 2 S 2 calculated from the infrared data are in line with those for other matrix isolated Group IV chalcogenides.

Reactions of silicon monoxide with organic compounds

Abstract Silicon monoxide has been shown to be a very reactive silylene. The gas has been condensed with organic compounds at -196° to give a direct synthesis of silicones. The products are thermally stable, infusible solids in which the silicon monoxide has added across multiple Cz.sbnd;C bonds and inserted into Cz.sbnd;H, Cz.sbnd;halogen, Oz.sbnd;H, or Nz.sbnd;H bonds. Some of the reactions suggest that diradical intermediates may be formed in the polymerization of silicon monoxide.

Metal atom preparation and ligand displacement reactions of bisnaphthalenechromium and related compounds

Bisnaphthalenechromium or bis(1-methylnaphthalene)chromium, prepared from the ligands and chromium atoms, react under mild conditions with CO or ButNC to form [CrL6] and with PF3, P(OMe)3, or PMe3 to form [Cr(naphthalene)L3] complexes; Mo, V, and Ti atoms also form exceptionally reactive complexes with naphthalene.

Reactions of organosulphur compounds with metal atoms

Abstract Co-condensation of metal atoms (Cr, Fe) and thiophenes, (R  R′  H, Me; R  H, R′  Me) at −196°C leads to desulphurization of the thiophene, and warm-up of the iron-thiophene co-condensate in a CO atmosphere produces tricarbonylferracyclopentadienetricarbonyliron, C 4 H 2 RR′Fe 2 (CO) 6 ; co-condensation of CH 3 SCH 2 Cl with Pd atoms, followed by addition of Ph 3 P in methylene chloride at −196°C, gives (Ph 3 P)Pd(π-CH 2 SCH 3 )Cl, whereas Ni atoms dehalogenate CH 3 SCH 2 Cl.

Naphthalene complexes. Part 1. Metal vapour preparation of bis(η6-naphthalene)chromium(0) and its arene replacement reactions

Bis(η6-naphthalene)chromium(0), formed in high yield from chromium atoms and naphthalene in solution at –80 °C, is a thermally stable but very reactive compound. Two-electron donor ligands displace one naphthalene ring [L = PF3, P(OMe)3, or PMe3] or both naphthalene rings (L = CO, CNBut, or CNC6H11) in rapid reactions at room temperature. The product [Cr(C10H8)(PMe3)3] is susceptible to further displacement of naphthalene by CO at 0 °C. The reaction of chromium atoms with 1,4-dimethylnaphthalene is stereospecific. More than 95% of the product is the isomer of [Cr(C10H8Me2)2] in which the unsubstituted ring is bonded to the metal. Bis(1-methylnaphthalene) chromium exists as a mixture of 10 isomers which can be distinguished on the basis of their 1H n.m.r. spectra.

The preparation of palladium–olefin complexes from palladium vapour

The reactions of palladium atoms with olefins have been studied by low-temperature i.r. spectroscopy and the most stable compounds observed, bis(cyclo-octa-1,5-diene)palladium and tris(bicyclo[2.2.1]heptene)-palladium have been prepared from palladium atoms on a gram scale.

Synthesis of new η4-hexafluorobenzene complexes of ruthenium and osmium from atoms of the metals: crystal structure of [Ru(η6-C6H3Me3-1,3,5)(η4-C6F6)]

Condensation of ruthenium or osmium atoms with mixtures of hexafluorobenzene and a second arene at –196 °C has given the novel compounds [M(η6-arene)(η4-C6F6)](M = Ru or Os; arene = C6H3Me3-1,3,5, C6H4Me2-1,3 or C6H6), these being further examples of compounds with a partially co-ordinated hexafluorobenzene ligand. The hapticity of the arene rings was determined from their proton and fluorine NMR spectra. This was confirmed for the specific case of [Ru(η6-C6H3Me3-1,3,5)(η4-C6F6)] by an X-ray crystallographic study. The bis(hexafluorobenzene) compounds could not be prepared.

Microfibrous solids derived from SiO and from other main group oxide vapours

The composition of “Monox”, the microfibrous or particulate solid formed by condensing gaseous silicon monoxide in inert gas streams, has been shown to be close to SiO if the solid was collected and analysed in the total absence of oxygen, but the solid oxidised quickly in air to the previously reported composition, Si4O5. Heating mixtures of Si, SiO2 with lithium or calcium silicates to 1800 °C, allowed co-liberation of SiO with Li or Ca vapours which gave microfibres of high aspect ratio when condensed in argon, an effect believed to be due to promotion of fibre growth by SiO2/Li2SiO3 or SiO2/CaSiO3 eutectics. Novel silicon-free microfibrous solids have been prepared by condensation of the vapours liberated at 1700–1800 °C when calcium gallate is reduced by carbon under argon, or when aluminium and gallium oxides are reduced by boron in hydrogen; in each case fibre growth is thought possible because of the formation of both metal and oxide phases in the hot condensate.

Crystal structure of [W(η-C6F6)2] synthesised together with other sandwich complexes of tungsten and molybdenum containing η6-C6F6 or η6-C6H3F3-1,3,5 ligands, from atoms of the metals

Reaction of molybdenum or tungsten atoms with hexafluorobenzene or 1,3,5-trifluorobenzene or with mixtures of these ligands and benzene or 1,3,5-trimethylbenzene gave the new compounds [M(C6F6)2], [M(C6H3F3-1,3,5)2], [M(C6F6)(C6H6)], [M(C6F6)(C6H3F3-1,3,5)] and [M(C6F6)(C6H3Me3-1,3,5)](M = Mo or W) in yields ranging from <1 to 5% as stable crystalline solids. A single-crystal X-ray study of [W(C6F6)2] showed it to have the same symmetry as [Cr(C6H6)2] and the same W–C bond lengths as in [W(C6H5Me)2]. The 19F and 1H NMR spectra of the mixed-ligand products show interring coupling with large coupling constants which make some of the spectra exceptionally easy to interpret.