Lucite International Technology Center

Middlesbrough, United Kingdom

Lucite International Technology Center

Middlesbrough, United Kingdom
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Coetzee J.,University of St. Andrews | Eastham G.R.,Lucite International Technology Center | Slawin A.M.Z.,University of St. Andrews | Cole-Hamilton D.J.,University of St. Andrews
Dalton Transactions | Year: 2014

The coordination chemistry and solution behaviour of Rh(i) and Ru(ii) complexes derived from mixed anhydride ligands of carboxylic acids and phosphorus acids were explored. Similar to the free ligand systems, mixed anhydride complexes rearranged in solution via a number of pathways, with the pathway of choice dependent on the mixed anhydride employed, the auxiliary ligands present as well as the nature of the metal centre. Plausible mechanisms for some of the routes of rearrangement and by-product formation are proposed. Where stability allowed, new complexes were fully characterised, including solid state structures for four of the unrearranged mixed anhydride complexes and two of the interesting rearrangement products. © 2014 The Royal Society of Chemistry.


Coetzee J.,University of St. Andrews | Eastham G.R.,Lucite International Technology Center | Slawin A.M.Z.,University of St. Andrews | Cole-Hamilton D.J.,University of St. Andrews
Dalton Transactions | Year: 2015

The utilisation of the PNP iridium pincer complex [Ir(PNP)(COE)][BF4] [PNP = 2,6-bis{(di-tert-butylphosphino)methyl}pyridine; COE = cyclooctene] in the sp3 C-H activation of methyl propanoate and other related esters was explored. In particular, this study provides further insight into the factors that govern the regioselectivity of such reactions. These included factors such as the steric demands of the substrate, the formation of favourable ring systems as well as the electronic effects that may influence the pKa values of protons. In particular, the effects of water on the outcome of these reactions were of great interest, since earlier literature reports have shown the presence of water to promote selective C-H activation in the α-position of ketones. © 2015 The Royal Society of Chemistry.


Fanjul T.,University of Bristol | Eastham G.,Lucite International Technology Center | Fey N.,University of Bristol | Hamilton A.,University of Bristol | And 3 more authors.
Organometallics | Year: 2010

The coordination chemistry and ethene hydromethoxycarbonylation catalysis with the diphosphine o-C6H4(CH2P tBu2)(CH2PPh2) (L3) is reported and the results compared with the analogous chemistry of the symmetrical diphosphines o-C6H4(CH2P tBu2)2 (L1) and o-C 6H4(CH2PPh2)2 (L 2). Palladium-catalyzed ethene hydromethoxycarbonylation studies under the commercial catalytic conditions are reported. The results obtained using L1-3 as supporting ligands show that the catalysts derived from L3 and L1 have similar activity and selectivity for methyl propanoate (MeP). In addition, the Pd-L3 catalyst has much greater longevity than the Pd-L1 catalyst. Treatment of the appropriate [Pt(X)(Y)(cod)] with L3 gave [PtCl2(L 3)] (3), [Pt(CH3)2(L3)] (6), and [PtCl(CH3)(L3)] (9). At equilibrium, complex 9 is a 90:1 mixture of geometric isomers 9a (with CH3 trans to the tBu2P) and 9b (with Cl trans to the tBu 2P). The fluxionality of complex 3, detected by 1H NMR, is interpreted in terms of the conformation of the seven-membered chelate. The complexes [Pt(CH3)(PMe3)(L3)]Cl (10b) and [PtH(PPh3)(L3)]Cl (12b) are formed as essentially single isomers with CH3/H trans to the Ph2P group. The palladium complexes [PdCl2(L3)] (13), [PdCl(CH3)(L 3)] (14a/14b), and [PdH(PCy3)(L3)]BF 4 (15b) have been made by similar methods to their platinum analogues. The factors controlling the relative isomer stabilities are explored experimentally and computationally. The complexes [PtCl2(L 4)] (16) and [PtCl(CH3)(L4)] (17a/17b) where L4 = o-C6H4(CH2PnBu 2)(CH2PPh2) are reported, and the geometric isomers of 17 are almost isoenergetic. The crystal structures of 3, 14a, 15b, and 16 have been determined by X-ray crystallography. DFT calculations on complexes of the type [Pt(X)(Y)(L3)] gave only small calculated differences in energy between the geometrical isomers (0-4 kcal mol -1), which are consistent with the experimental observations. It is suggested that repulsive intramolecular HAAAH interactions (between the Pt-CH3 and PC(CH3)3 groups) determine which isomer predominates. The reasons for the favorable catalytic properties of the Pd-L3 catalyst are probed by 13CO reactions with the model complexes 9a/9b and 14a/14b, and the structures of the resulting acyl complexes are assigned on the basis of 13C and 31P NMR and IR spectroscopy. From these studies, it is suggested that the reason for the Pd-L3 catalyst resembling the Pd-L1 catalyst in terms of selectivity is that the crucial acyl intermediates are similar. © 2010 American Chemical Society.


Coetzee J.,University of St. Andrews | Eastham G.R.,Lucite International Technology Center | Slawin A.M.Z.,University of St. Andrews | Cole-Hamilton D.J.,University of St. Andrews
Organic and Biomolecular Chemistry | Year: 2012

Simple mixed anhydrides are known to pose synthetic difficulties relating to their thermal lability and ways to stabilise such mixed anhydride systems by relying on either electronic or steric effects were therefore explored. Thus, a series of acyloxyphosphines and acylphosphites derived from either propanoic acid or phenylacetic acid were prepared and their in solution stability assessed. These compounds were, where stability allowed, fully characterised using standard analytical techniques. NMR studies, in particular, unearthed interesting coupling behaviour for a number of the acyloxyphosphines and acylphosphites as well as their rearrangement products which could be linked to their chiral nature. Furthermore, the crystal structures for three of the prepared mixed anhydrides were determined using X-ray crystallography and are reported herein. © 2012 The Royal Society of Chemistry.

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