D. James Wilson

Synthesis and Molecular Structures of Uranium and Thorium Diamidoamine Complexes

Treatment of UCl4 or ThCl4 with Li2[Me3SiN{CH2CH2NSiMe 3}2] affords the mono-diamidoamine complexes [M(Me3SiN{CH2CH2NSiMe3} 2)Cl2(THF)] (M=U, Th), and also the bis-diamidoamine complexes [M(Me3SiN{CH2CH2NSiMe3} 2)2] (M=U, Th). The base-free complex [U(Me3SiN{CH2CH2NSiMe3} 2)Cl2]2 was obtained by treatment of [U(Me3SiN{CH2CH2NSiMe3} 2)Cl2(THF)] with hot toluene. The X-ray structures of [Th(Me3SiN{CH2CH2NSiMe3} 2)Cl2(THF)] and [U(Me3SiN{CH2CH2NSiMe3} 2)Cl2]2 reveal a distorted octahedral geometry, whereas [M(Me3SiN{CH2CH2NSiMe3} 2)2] (M=U, Th) display trigonal bipyramidal geometry at the metal centre and the amino group on one of the diamidoamine ligands is non-bonding.

Syntheses of complexes containing the novel 1,2,3-azadiphosphole and 1,2,5-azadiphosphole ring systems: crystal and molecular structure of [Ir(η5-C5Me5)(η4-(ButCPNButPCBut)]

The first examples of complexes containing the novel 1,2,5-azadiphosphole and 1,2,3-azadiphosphole ring systems are presented, together with the molecular structure of [Ir(?5-C5Me5)(?4-(Bu(t)CPNBu(t)PCBu(t))] as established by a single crystal X-ray diffraction study.

A study of the molecular and electronic structure of iron(II)and ruthenium(II) 1,3-di- and 1,2,4-tri-phospholyl sandwich compoundsby photoelectron spectroscopy and density functional theory

The synthesis and variable temperature 1H NMR spectrum of the new tetraphosphaferrocene [Fe(η5-P2C3Bu3t)2] are presented and the photoelectron spectra are reported for [Fe(η5-P3C2Bu2t)2] 1a, [Fe(η5-P2C3Bu3t)2] 2a, [Fe(η5-P2C3Bu3t)(η5-P3C2Bu2t)] 3a and [Ru(η5-P3C2Bu3t)2] 4a. Density functional calculations were used to optimise the geometry and calculate the ionization energies of the parent analogues. Good agreement was obtained with the experimental results, giving support to the theoretical modelling of these sandwich compounds. Analysis of their electronic structure showed that replacement of RC fragments by P atoms in the η5-ligated cyclopentadienyl rings increases their acceptor properties. Extensive σπ mixing makes the description of the orbitals complex. Some higher lying Pσ levels are found to have similar ionization energies to the d electrons.

One- and two-step [2 + 2] cycloaddition reactions of group 4 imides with the phosphaalkyne ButCP. Crystal and molecular structures of [Zr(η5-C5H5)2(PCButNC6H3Me2-2,6)] and [TiCl2(P2C2But2NBut)(py)] (py) = pyridine)

The structures of novel complexes resulting from one- and two-step [2 + 2] cycloaddition reactions of four group 4 imides with the phosphaalkyne Bu(t)CP are described.

Comparison of the reactivity of [2.2]paracyclophane and p-xylene

The relative abilities of [2.2]paracyclophane (C16H16) and p-xylene (C6H4Me2-1,4) to form arene tricarbonyl complexes from chromium hexacarbonyl has been studied in dioxane using the Strohmeier reflux method, and the rate constants contrasted. The reactions are found to proceed more quickly with [2.2]paracyclophane by ca. 25%. Density functional molecular-orbital calculations have rationalised this observation, and indicate that the enhanced reactivity of the [2.2]paracyclophane system relative to p-xylene is a consequence of repulsive interactions between the two arene decks in the former, which are relieved to some extent by co-ordination of the electron-withdrawing Cr(CO)3 fragment.

Unexpected reactivity of two-coordinatepalladium–carbene complexes; synthetic and catalyticimplications

Ligand exchange reactions reveal unexpected lability of the carbene ligands in two coordinate palladium(0) N-heterocyclic carbene complexes; the latter are found to be very effective catalysts for amination of aryl chlorides.

First catalytic dihydroamination of a phosphaalkyne. Crystal and molecular structure of trans-[PdCl2{P(PriNH)2CH2But}2]

Treatment of a dichloromethane solution of ButCP, containing a catalytic amount of TiCl4, with an excess of the primary amines RNH2 (R = Pri, But) quantitatively affords the corresponding bis-dialkylaminophosphine P(ButNH)2- CH2But. P(PriNH)2CH2But is structurally characterised by a single crystal X-ray diffraction study of its bis-trans-PdCl2 complex.