Matthew P. Blake

A Generic One-Pot Route to Acyclic Two-Coordinate Silylenes from Silicon(IV) Precursors: Synthesis and Structural Characterization of a Silylsilylene

Si in sight: a one-pot, single-step synthesis of an acyclic silylsilylene, Si{Si(SiMe(3))(3)}{N(SiMe(3))Dipp} (Dipp=2,6-iPr(2)C(6)H(3)), from a silicon(IV) starting material is reported, together with evidence for a mechanism involving alkali metal silylenoid intermediates.

Heterobimetallic complexes containing Ca-Fe or Yb-Fe bonds: synthesis and molecular and electronic structures of [M{CpFe(CO)2}2(THF)3]2 (M = Ca or Yb).

Reaction of calcium or ytterbium amalgam with [CpFe(CO)(2)](2) (Fp(2)) gave the isostructural heavy alkaline earth or divalent rare earth compounds [MFp(2)(THF)(3)](2) (M = Ca or Yb) containing two direct Ca-Fe (3.0185(6) Å) or Yb-Fe (2.9892(4) Å) bonds. Density functional theory supports experiment in finding shorter Yb-Fe than Ca-Fe distances, and Ziegler-Rauk, molecular orbital, and atoms-in-molecules analyses find the M-Fe bonding to be predominantly electrostatic in nature. The Yb-Fe interaction energy and bond critical point electron density are slightly larger than for Ca-Fe, in agreement with the shorter M-Fe bond in the former. The corresponding reaction for magnesium gave MgFp(2)(THF)(4) with two O-bound Fp moieties and no Mg-Fe bond.

Enabling and Probing Oxidative Addition and Reductive Elimination at a Group 14 Metal Center: Cleavage and Functionalization of E–H Bonds by a Bis(boryl)stannylene

By employing strongly σ-donating boryl ancillary ligands, the oxidative addition of H2 to a single site Sn(II) system has been achieved for the first time, generating (boryl)2SnH2. Similar chemistry can also be achieved for protic and hydridic E-H bonds (N-H/O-H, Si-H/B-H, respectively). In the case of ammonia (and water, albeit more slowly), E-H oxidative addition can be shown to be followed by reductive elimination to give an N- (or O-)borylated product. Thus, in stoichiometric fashion, redox-based bond cleavage/formation is demonstrated for a single main group metal center at room temperature. From a mechanistic viewpoint, a two-step coordination/proton transfer process for N-H activation is shown to be viable through the isolation of species of the types Sn(boryl)2·NH3 and [Sn(boryl)2(NH2)](-) and their onward conversion to the formal oxidative addition product Sn(boryl)2(H)(NH2).

Synthesis and reactions of β-diketiminate-supported complexes with Mg–Fe or Yb–Fe bonds

Reaction of [M(NacNac)I(THF)]n (M = Mg, Ca or Yb; n = 1 or 2) with KFp gave Mg(NacNac)Fp(THF) (, Mg-Fe = 2.6326(4) Å) or [M(NacNac)(μ-Fp)(THF)]2 (M = Ca or Yb (10), no M-Fe bonds); reaction of with [YbFp2(THF)3]2 gave [{Yb(NacNac)(THF)}2(μ-YbFp4)] (Yb-Fe = 2.9758(5)-3.1702(5) Å) containing the first example of a lanthanide bound solely to four transition metals; reaction of with TolNCNTol gave Mg(NacNac){(NTol)2CFp} via the first net insertion of an unsaturated substrate into an alkaline earth-transition metal bond (NacNac = HC{C(Me)N(2,6-C6H3(i)Pr2)}2; Fp = CpFe(CO)2; Tol = 4-C6H4Me).

Chiral lanthanide complexes: coordination chemistry, spectroscopy, and catalysis

The coordination chemistry and catalytic applications of organometallic and related lanthanide complexes bearing chiral oxazoline ligands is an area that has been largely underdeveloped, in comparison to complexes based upon lanthanide triflates for use in Lewis acid catalysis. In this article we report on the coordination chemistry of the bis(oxazolinylphenyl)amide (BOPA) ligand with lanthanide alkyl and amide co-ligands (Ln = Y, La, Pr, Nd, Sm). Their structural and spectroscopic characterisation are reported, including an assessment of their photophysical properties using luminescence spectroscopy, and are supported by density functional calculations. The application of these complexes in the hydroamination/cyclisation of aminoalkenes, and in the ring-opening polymerisation of rac-lactide is reported.

Oxidative Bond Formation and Reductive Bond Cleavage at Main Group Metal Centers: Reactivity of Five-Valence-Electron MX2 Radicals

Monomeric five-valence-electron bis(boryl) complexes of gallium, indium, and thallium undergo oxidative M-C bond formation with 2,3-dimethylbutadiene, in a manner consistent with both the redox properties expected for M(II) species and with metal-centered radical character. The weaker nature of the M-C bond for the heavier two elements leads to the observation of reversibility in M-C bond formation (for indium) and to the isolation of products resulting from subsequent B-C reductive elimination (for both indium and thallium).

Electronic Delocalization in Two and Three Dimensions: Differential Aggregation in Indium “Metalloid” Clusters

Reduction of indium boryl precursors to give two- and three-dimensional M-M bonded networks is influenced by the choice of supporting ligand. While the unprecedented nanoscale cluster [In68 (boryl)12 ]- (with an In12 @In44 @In12 (boryl)12 concentric structure), can be isolated from the potassium reduction of a bis(boryl)indium(III) chloride precursor, analogous reduction of the corresponding (benzamidinate)InIII Br(boryl) system gives a near-planar (and weakly aromatic) tetranuclear [In4 (boryl)4 ]2- system.