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Title: Synthesis of electrospray-active phosphine ligands and their complexes
Author: Farrer, M. J.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2007
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Abstract:
This thesis is concerned with the synthesis and characterisation of electrospray-active phosphine ligands and their complexes, focusing on derivatives of proton sponges and bisphosphine monoxides (BPMOs). Phosphines containing Proton Sponge® (1,8-bis(dimethylamino)naphthalene, 1a) have been synthesised via sequential bromination, lithiation and phosphination to give [{1,8-bis(dimethylamino)naphthalen-4-yl}diphenylphosphine] (12b), [{1,8-bis(dimethylamino)naphthalen-2-yl}diphenylphosphine] (12a) and [bis{1,8-bis(dimethylamino)naphthalen-2-yl}phenylphosphine] (13a). Complexes of 12a were shown to provide strong ESI-MS signals through the exclusive coordination of H+; [Mn(MeCp)(CO)2(12a)] (14) and [W(CO)5(12a)] (15) and iron carbonyl complexes of the form [Fe(CO)4(P)] (P = PPh3, P(p-C6H4OMe)3, 12a) (16a-c) have been synthesised and characterised. The relative abilities of the phosphines ligands to act as electrospray handles within these complexes is discussed. The synthesis of a [Ru(η6-p-cymene)C1x(12a)] species from [Ru(η6-p-cymene)Cl2]2 monitored and was shown to proceed through a long-lived detectable intermediate. 12a has been substituted onto PdCl2(COD) and PtCl2(COD) to form the [MC12(12a)2] species. The interactions of 12a and 12a.HX with the Pd(0) complex [Pd(dba)2], both in the absence and presence of 4-bromonitrobenzene, have been analysed by ESI-MS. The behaviour of both 12a and 12b has been investigated in a Suzuki (i.e. palladium-mediated) coupling reaction. The characteristics of BPMOs and the potential for these species to act as electrospray handles is described. Via ortho-lithiation of triphenylphosphine oxide with phenylithium and the reactions of the lithiated intermediate with electrophiles (TMSC1, D2O, MeI, PR2Cl and PPhCl2) a number of ortho-substituted products have been obtained. For reaction with PR2Cl (where R = Ph, iPr, Cy, Et) a range of BPMOs of the form Ph2P(O)(o-C6H4)PR2 have been synthesised. Reduction of 26a to give the bisphosphine product o-C6H4(PPh2)2 (dppbz) is also discussed. The reaction of [MC12COD] (M = Pt, Pd) with 26a formed the following complexes as mixtures; cis[PtCl2(26a)2] (31), [PtCl2(26a)] (32), [PdCl2(26a)] (33), [PdCl2(26a)2] (34) and [Pd2Cl4(26a)2] (35). These were characterised by ESI-MS, 31P and 195Pt NMR. An X-ray crystallographic structure of 32 was also determined. Synthesis of [Fe(CO)4(26a)] (36) is described. The relevance of these results with a view to observance of metal complexes by ESI-MS is then discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.598946  DOI: Not available
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