Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577289
Title: Synthesis and reactivity of peri-substituted phosphines and phosphonium cations
Author: Ray, Matthew James
Awarding Body: University of St Andrews
Current Institution: University of St Andrews
Date of Award: 2013
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Abstract:
The clean reaction of 5-lithio-6-diisopropylphosphinoacenaphthene (1') with dichlorophosphines, RPCl₂ (R = Ph, Fc, NMe₂, iPr), led to the formation of peri-substituted phosphino-phosphonium chloride salts 2-5. The synthetic utility of these salts was demonstrated in a range of reactions. Mixed tertiary/secondary bis(phosphines) (6 and 7) were prepared by the LiAlH₄ reduction of phenyl or ferrocenyl phosphino-phosphoniums (2 and 3), and the bis(borane) adduct of 6 was prepared by reduction of 2 with BH₃•SMe₂. Reaction of 2 and 3 with a large excess of MeOTf at elevated temperature gave 1,2-diphosphoniums (11 and 12), which were subjected to reduction and co-ordination to a molybdenum(0) centre. An investigation into the co-ordination chemistry of 2 revealed three distinct modes of reactivity. In the reaction with [(nor)Mo(CO)₄] the Mo(0) complex [(2)Mo(CO)₄Cl] (18) was isolated, in which monodentate co-ordination was observed. [PtCl₂(cod)] reacts with the chloride and triflate salts of 2 to form [(2Cl)PtCl₂] (19) and [((2Cl)PtCl)₂][TfO]₂ (21) respectively, both of which show co-ordination of 2 as a bidentate phosphine/chlorophosphine ligand. A palladium(II) dimer (22) in which 2 forms a chelating phosphine/phosphide ligand was isolated from the oxidative addition of 2 to a palladium(0) complex. The geminally bis(peri-substituted) tridentate phosphine (27) was prepared by reaction of 1' with half an equivalent of iPrPCl₂. 27 has a rather strained geometry, and displays restricted dynamics on an NMR timescale, which leads to anisochronicity of all three phosphorus nuclei at low temperatures. Strained bis and tris(sulfides) 28 and 29 and the bis(selenide) 30 have been isolated from the reaction of 27 with sulfur and selenium, respectively. A series of co-ordination complexes, [(27)Cu(MeCN)][BF₄] (32), [(27)PtCl][Cl] (33), [(27)FeCl₂] (34) and fac-[(27)Mo(CO)₃] (35), with tetrahedral, square planar, trigonal bipyramidal and octahedral geometries, respectively, were synthesised. In all of these complexes the tris(phosphine) backbone is distorted, but to a significantly smaller extent that in the chalcogenides 28-30.
Supervisor: Kilian, Petr Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.577289  DOI: Not available
Keywords: Phosphorus ; Peri-substitution ; Phosphino-phosphonium ; Tridentate phosphine ; QD406.R2 ; Organophosphorus compounds ; Organophosphorus compounds--Synthesis ; Cations
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