Dr Simon Humphrey

Telephone: 01223 336396

1. Phosphine Coordination Materials for Gas Storage, Separation and Catalysis

We are interested in the preparation and characterization of new metal-organic framework materials based on phosphine ligands that exhibit important solid-state properties. Properties exhibited by Phosphine Coordination Materials (PCMs) that are of particular interest include:

Small molecule uptake and release, relating to gas storage
Separation of gas mixtures; gas sieving properties for applications in purification, carbon sequestration etc.
Selective heterogeneous catalysis

Using phosphine-based organic ligands, it is possible to design materials with pore dimensions and topologies that impart such properties. More specifically, the chemistry of the phosphine-based systems offers additional possibilities have not yet been explored in metal-organic framework synthesis. These include the incorporation of polar (R₃P=X) or ionic (R₃P⁺R') organic species into the PCMs, which may enhance their solid-state properties.

(a) Zn(II)-carboxylate honeycomb sheet; (b) 3-dimensional PCM-4 with square pore network based on phosphine oxide framework; (c) GC of a mixture of light gases separated in a single pass by CUK-1.

Selected Publications

1. Hysteretic sorption of light gases by a porous metal-organic framework containing tris(para-carboxylated) triphenylphosphine oxide, Chemical Communications2008, 2891.
2. Gas sorption selectivity of CUK-1: a porous coordination solid made of Co(II) and pyridine-2,4-dicarboxylic acid, Advanced Materials 2007, 19, 1830.
3. Porous Co(II)-organic frameworks with corrugated walls: structurally robust gas-sorption materials, Angewandte Chemie 2007, 46, 272.

2. Metal Nanoparticle Hybrid Catalysts

Schematic representation of alkene epoxidation using supported metal nanoparticles Polymer-capped metal nanoparticles are examples of model catalysts, which have favorable surface-area:volume ratios and defined surface structure. In collaboration with groups in the UK and the USA (R M Lambert, Cambridge; T D Tilley, G A Somorjai, Berkeley), we are interested in finding improved routes toward the solution-phase synthesis of near-monodisperse noble metal nanoparticles. The nanoparticle catalysts may then be used directly or when anchored on support media (e.g. silica), to study important small organic molecule transformations in the solution- or vapor-phase.

Selected Publications

1. Rhodium nanoparticles from cluster seeds: control of size and shape by precursor addition rate, Nano Letters, 2007, 7, 785.

Department of Chemistry