Guy K. B. Clentsmith

An improved synthesis of bis(1,3-di-N-tert-butylimidazol-2-ylidene)palladium(0) and its use in C–C and C–N coupling reactions

A new, improved synthesis of [Pd{CN(tBu)(CH)2N(tBu)}2] (1) and its use as a catalyst in coupling reactions, including aminations, is presented. An interesting side product formed in the synthesis of 1, [Pd(?3-C4H7){(CN(tBu)(CH) 2N(tBu)}Cl] (2), is also discussed.

Nucleophilic attack at pyridine nitrogen and its use to access a novel mono-anionic ligand for iron-based ethylene polymerisation catalystsElectronic supplementary information (ESI) available: further characterisation data for 2a–5a. See http://www.rsc.org/suppdata/cc/b2/b203805f/

Addition of MeLi to bis(imino)pyridines results in an unprecedented nucleophilic attack at pyridine nitrogen to afford novel mono-anionic [N,N,N] ligands: their treatment with FeCl3, followed by MAO activation, affords highly active ethylene polymerisation catalysts.

Synthesis of the dicarbonyl ruthenium(0) triphosphole complex [Ru(CO)2{η5-P3C2But2CH(SiMe3)2}] and its conversion into a tricarbonyl complex containing the novel 4-electron donor triphosphorus-ring system {CButPP(H)CH(SiMe3)2CButP(O)H}

Abstract 1,5-Cyclo-octadiene is readily displaced from [Ru(η4-COD){η5-P3C2But2CH(SiMe3)2}] to give the dicarbonyl complex [Ru(CO)2{η5-P3C2But2CH(SiMe3)2}], which on treatment with water in the presence of CO is converted into a tricarbonyl complex containing the novel 4-electron donor triphosphorus-ring system {CButPP(H)CH(SiMe3)2CButP(O)H}which has been structurally characterised.

Theoretical investigation of the pathway for reductive cleavage of dinitrogen by a vanadium diamidoamine complex

Density functional calculations show that [HN(CH2CH2NH)2V] will bind N2 in a sideways fashion; further reaction with another molecule of [HN(CH2CH2NH)2V] leads to reductive cleavage of the N2 moiety to form a bridged nitrido dimer, [HN(CH2CH2NH)2V(µ-N)]2; this study provides a model for the formation of [RN(CH2CH2NR)2V(µ-N)]2 (R = SiMe3) by reduction of [RN(CH2CH2NR)2V(µ-Cl)]2 under an N2 atmosphere.

A study of the molecular and electronic structures of the indium(I) phospholyls [In(η5-P2C3But3)] and [In(η5-P3C2But2)] by X-ray diffraction, photoelectron spectroscopy and density functional theory

The crystal and molecular structures of [In(η5-P2C3But3)] are reported. He I and He II photoelectron (PE) spectra of [In(η5-P3C2But2)] and of [In(η5-P2C3But3)] are assigned by comparison with related systems and with the aid of density functional calculations of the ionisation energies (IE). In both cases the first PE band comprises ionisation from the ring π levels together with an ionisation from a Pσ orbital. The second band is due to ionisation from an In-ring antibonding orbital with In s character. Other Pσ ionisation bands lie at higher IE. Substitution of CBut by P within the five membered aromatic ring increases the IE of related bands. Geometry optimisation of the parent complexes [In(η5-P3C2H2)] and [In(η5-P2C3H3)] gave structural parameters in good agreement with the X-ray data. Attempts to find an energy minimum corresponding to η1-coordination were unsuccessful, the structures reverting to the η5-coordination mode. Bonding of the ring is principally due to overlap of the two upper occupied π orbitals with the In 5p orbitals. Some rehybridisation at the P atoms assists this overlap. Mulliken population analysis shows the In 5p occupation to be ca. half an electron in both cases.

Electron-acceptor properties of phospha-alkynes as probed by electron transmission and dissociative electron attachment spectroscopies

Abstract Electron transmission spectroscopy is applied for the first time to a phospha-alkyne derivative, (CH 3 ) 3 CCP. Electron attachment to the π * LUMO in the gas-phase occurs at 0.63 eV. Formation of the temporary π * anion state is also observed in measurements of the total anion current, as a function of the incident electron energy. Comparison with the ethyne analogue shows that replacement of a CH group with a P atom causes a very strong increase (2.3 eV) of the vertical electron affinity. Simple Koopmans’ theorem calculations reproduce the experimental data.

Vanadium(III) complexes incorporating the silylamino(disilylamido) ligand [(Me3Si)N{CH2CH2N(SiMe3)}2]2– [N{N″}2]2–. Synthesis and crystal structure of the dimeric, non-metallocene vanadium(III) hydride [{V(N{N″}2)}2(µ-H)2]

Three vanadium(III) complexes incorporating the chelating silylamino(disilylamido) ligand [(Me3Si)N{CH2CH2N(SiMe3)}2]2– ([N{N″}2]2–) have been reported. Addition of Li2[N{N″}2] to VCl3·3THF cleanly yielded the vanadium(III) chloride [{V(N{N″}2)Cl}2] 1, from which the vanadium(III) hydrocarbyl [V(N{N″}2){CH(SiMe3)2}] 2 could be generated by means of salt metathesis. Hydrogenolysis of 2 under dihydrogen produced the thermally stable, dimeric vanadium(III) hydride [{V(N{N″}2)}2(µ-H)2] 3. The solid state structure of 3 was determined.