Co-reporter:Peter G. Edwards, Benson M. Kariuki, Paul D. Newman, and Wenjian Zhang
Organometallics 2014 Volume 33(Issue 19) pp:5440-5447
Publication Date(Web):August 29, 2014
DOI:10.1021/om500734b
The cationic complex (η4-1,2,3,4-tetramethylcyclobutadienyl)cobalt(trisacetonitrile), [(η4-C4Me4)Co(NCCH3)3]+ (1), allows the stepwise introduction of suitable phosphine precursors to the [(η4-C4Me4)Co]+ fragment by replacement of the labile acetonitrile ligands. These reactions give rise to the piano-stool complexes [(η4-C4Me4)Co(dppe)(NCCH3)]+ (2), [(η4-C4Me4)Co(dppe)(PH2Ph)]+ (3), [(η4-C4Me4)Co(dfppb)(NCCH3)]+ (4), and [(η4-C4Me4)Co(dfppb)(PH2Ph)]+ (5), where dfppb = 1,2-bis{di(2-fluorophenyl)phosphino}benzene and dppe = 1,2-bis(diphenylphosphino)ethane. Complex 5 is a template for the synthesis of the P3 macrocycle complex [(η4-C4Me4)Co{1,4-bis(2-fluorophenyl)-7-phenyl[b,e,h]tribenzo-1,4,7-triphosphacyclononane}]+ (6), through base-promoted intramolecular macrocyclization. The hydrogens of two of the ring methyls of the tetramethylcyclobutadienyl ligand in the macrocycle complex 6 are sufficiently acidic to undergo deprotonation by KOtBu, promoting nucleophilic attack at the fluorine-bearing ortho-carbons of the 2-fluoroaryl groups on two of the phosphorus donors in 6. The resultant hemi-incarcerand complex [{η4,κP,κP,κP-Me2C4-[1,4-bis(2-CH2C6H4)-7-C6H5-[b,e,h]tribenzo-1,4,7-triphosphacyclononane]-1,2}Co]+ (cis-7) contains a hybrid phosphorus/carbon donor ligand where the P3 macrocycle is connected to the cyclobutadienyl function through two cis-2-methylphenyl links. The new complexes have been characterized fully by spectroscopic and analytical techniques including single-crystal X-ray structure determinations of 2, 3, 4, 5, 6, and cis-7.
Co-reporter:Thomas Albers, Julia Baker (neé Johnstone), Simon J. Coles, Peter G. Edwards, Benson Kariuki and Paul D. Newman
Dalton Transactions 2011 vol. 40(Issue 37) pp:9525-9532
Publication Date(Web):19 Aug 2011
DOI:10.1039/C0DT01724H
Nine-membered 1,4,7-triphospha- and triarsamacrocycles with unsaturated benzo-backbones have been prepared using the [CpRFe]+ unit as a template. The cyclisation involves the attack of a coordinated phosphide (or arsenide) nucleophile at an activated, electrophilic ortho-fluorophenyl substituent on a neighbouring pnictide donor. The macrocycle assembly is of the 2 + 1 type where two new chelate rings are formed from appropriately derivatised bidentate and monodentate phosphines/arsines. Both [(η5-C5H5)Fe]+ and [(η5-C5Me5)Fe]+ may be employed for the cyclisation with higher yields generally being observed with the unsubstituted Cp. All new compounds have been characterised by spectroscopic and analytical methods including the single-crystal X-ray structure determination of [(η5-C5H5)Fe(tribenzo-9aneP3-Ph,PhF2)]+, 3a, and [(η5-C5H5)Fe(tribenzo-9aneAs3-Ph,PhF2)]+, 5, as the tetraphenylborate salts. The crystal structures are isomorphous and show the unique conformation of these new macrocycles with a ‘cup shaped’ cavity formed by the rigid benzo-backbones. The 9aneAs3 derivative is the first example of a nine-membered triarsamacrocycle.
Co-reporter:James C. Knight, Ravi Prabaharan, Peter G. Edwards, Angelo J. Amoroso
Journal of Molecular Structure 2011 Volume 989(1–3) pp:86-90
Publication Date(Web):15 March 2011
DOI:10.1016/j.molstruc.2011.01.009
We report the synthesis of a new bis-terpyridine ligand which could potentially yield a variety of polynuclear complexes. An investigation of the co-ordination chemistry of this ligand with Cu(II) ions in a 1:1 ratio yielded a complex with a 2:1 ratio of Cu to ligand. The crystal structure of the dinuclear copper(II) complex shows the two equivalent copper cations are co-ordinated via five donor atoms in a highly distorted square pyramidal arrangement. The structure was solved in a monoclinic space group C2/c with cell parameters, a = 21.340(5), b = 14.004(5), c = 18.368(5) Å, α = 90°, β = 106.575(5)°, γ = 90°, volume = 5261(3) Å3, Z = 4.
Co-reporter:Dennis Coleman, Peter G. Edwards, Benson M. Kariuki and Paul D. Newman
Dalton Transactions 2010 vol. 39(Issue 16) pp:3842-3850
Publication Date(Web):11 Mar 2010
DOI:10.1039/B924982F
The cis,cis (5) and trans,trans (9) forms of the bidentate ligand 1,1′-[1,2-phenylenebis(methylene)]bis(2,2,3,4,4-pentamethylphosphetane) have been prepared from common precursors using two separate synthetic routes. The cis,cis isomer is attained selectively through the direct reaction of two mol equivalents of 2,2,3,4,4-pentamethylphosphetane with α,α′-dibromo-o-xylene in acetone. Protection of the 2,2,3,4,4-pentamethylphosphetane with BH3 and conversion to the lithium phosphido-borane prior to adding the α,α′-dihalo-o-xylene leads to the isolation of the trans,trans isomer of 1,1′-[1,2-phenylenebis(methylene)]bis(2,2,3,4,4-pentamethylphosphetane). Both isomers have been fully characterised by spectroscopic and, in the case of the all-cis isomer, single-crystal X-ray methods. The two isomers have been coordinated to Mo(0) to give complexes of the type cis-Mo(CO)4(L). The solid state structures of cis-Mo(CO)4(5), 10, and cis-Mo(CO)4(9), 12, have been determined by single-crystal X-ray methods and reveal significant differences between the two forms, most notably in the chelate bite angle which is 100.68(18)° in 10 compared to 88.12(2)° in 12. Ligand 5 has also been coordinated to Pd(II) and Pd(0) and the structure of the complex Pd(5)Cl2 (11) determined by single-crystal methods. The solid-state structure of Pd(5)Cl2 reveals a significant tetrahedral distortion from the normal square planar geometry.
Co-reporter:Peter G. Edwards, James C. Knight and Paul D. Newman
Dalton Transactions 2010 vol. 39(Issue 16) pp:3851-3860
Publication Date(Web):11 Mar 2010
DOI:10.1039/B924983D
The novel primary phosphine (1R,3S)-[1,2,2-trimethyl-3-(phosphinomethyl)cyclopentyl]methyl methanesulfonate 3a (or tosylate 3b) has been prepared in three steps from (1R,3S)-camphoric acid with a view to utilising it as a synthon for the preparation of polycyclic phosphines. Efforts to prepare a [3.2.1] bicyclic product by internal cyclisation of 3a or 3b under various conditions were unsuccessful, but heating the neat compound at 140 °C for several hours gave the new asymmetric, bicyclic secondary phosphine, (1R,4S,6R)-5,5,6-trimethyl-2-phosphabicyclo[2.2.2]octane (PBO) as its methanesulfonic acid 5a (or p-toluenesulfonic acid 5b) salt. The cyclisation involves a skeletal rearrangement and occurs with high stereoselectivity to generate two new stereogenic carbon centres and a chiral phosphorus atom. The secondary phosphine was obtained after base treatment of 5a/b and several derivatives of the phosphine have been synthesised and characterised. Reaction of two mol equivalents of the borane adduct of PBO with α,α′-dichloro-ortho-xylene gave the bidentate derivative, o-C6H4(CH2PBO)2.2BH3, 12, and ultimately o-C6H4(CH2PBO)2, 13. Complexes of 13 with Pd(II), Pt(II), Pt(0) and Mo(0) have been prepared and characterised by spectroscopic and analytical methods including single-crystal X-ray structure determinations of cis-Pd{o-C6H4(CH2PBO)2}Cl2, 14, cis-Pt{o-C6H4(CH2PBO)2}Cl2, 15 and Mo(CO)4{o-C6H4(CH2PBO)2} 17.
Co-reporter:Christopher Wallis, David McGuinness, Paul D. Newman, Robert P. Tooze and Peter G. Edwards
Dalton Transactions 2009 (Issue 12) pp:2178-2184
Publication Date(Web):06 Feb 2009
DOI:10.1039/B816507F
A series of halo substituted triarylphosphinines have been synthesised and coordinated to tungsten(0) and rhodium(I) to give [(2-(2′-halo)-triarylphosphinine)W(CO)5] and [(2-(2′-halo)-triarylphosphinine)Rh(COD)Cl] respectively. The complexes have been examined by NMR and IR spectroscopy in an effort to elucidate the nature of the bonding between the phosphinines and the respective metal centre. The W(CO)5(L) systems reveal restricted C–C bond rotation as evidenced by temperature-dependent 31P{1H} NMR spectra. Thermodynamic barriers to the rotation are dependent upon the nature of the halide with ΔG‡ values of 72.5 kJ mol−1 and 50.8 kJ mol−1 being obtained for the chloro- and fluoro-derivatives, respectively; activation barriers for the iodo- and bromo- derivatives were beyond the accessible temperature range of the NMR experiment.
Co-reporter:Christopher Wallis, Peter G. Edwards, Martin Hanton, Paul D. Newman, Andreas Stasch, Cameron Jones and Robert P. Tooze
Dalton Transactions 2009 (Issue 12) pp:2170-2177
Publication Date(Web):04 Feb 2009
DOI:10.1039/B816499A
The 2,6-dixylyl-4-phenylphosphabarrelene has been synthesised from the parent phosphinine and its properties as a ligand explored through the preparation and characterisation of the complexes W(CO)5(L), Re(CO)4(L)Cl, (η6-cymene)RuCl2(L), [(η5-Me3SiC5H4)Fe(CO)2(L)]PF6, Rh(1,5-COD)(L)Cl, Ir(1,5-COD)(L)Cl, and cis-Pt(L)2Cl2, where L = 4-phenyl-2,10-bis-(2,4-dimethylphenyl)-4H-1,4-ethenophospholine (xPB), cymene = 4-isopropyltoluene, η5-Me3SiC5H4 = trimethylsilylcyclopentadienyl and 1,5-COD = 1,5-cyclooctadiene. The new complexes were characterised by spectroscopic and analytical techniques and, for [(η5-Me3SiC5H4)Fe(CO)2(L)]PF6 and Ru(η6-cymene)(L)Cl2, by single-crystal X-ray structure determination. The coordination properties of the phosphabarrelene have been established and compared with analogous complexes of triarylphosphines and triarylphosphites. Most spectroscopic and structural indicators suggest that the phosphabarrelene has coordination behaviour similar to that of simple triarylphosphines such as PPh3.
Co-reporter:Peter G. Edwards, F. Ekkehardt Hahn, Matthieu Limon, Paul D. Newman, Benson M. Kariuki and Andreas Stasch
Dalton Transactions 2009 (Issue 26) pp:5115-5119
Publication Date(Web):30 Apr 2009
DOI:10.1039/B822870A
The reaction of the manganese precursors [MnOTf(CO)3{1,2-(PH2)2C6H4}], 5, or [MnOTf(CO)3{1,2-(PH2)2C2H4}], 6, with either the silver complex of 1,3-diallylbenzimidazol-2-ylidiene or the free carbene, resulted in the formation of the new, dimeric phosphino-μ-phosphido manganese species 7 and 8. Complex 7 crystallises in two isomeric forms (cis and trans), depending upon the choice of solvent. The structures of both isomers have been determined by single-crystal X-ray techniques.
Co-reporter:Huw A. Tallis, Paul D. Newman, Peter G. Edwards, Liling Ooi and Andreas Stasch
Dalton Transactions 2008 (Issue 1) pp:47-53
Publication Date(Web):30 Oct 2007
DOI:10.1039/B715327A
1-Trimethylsilylphosphirane, C2H4PSiMe3, has been prepared on a multi gram scale from P(SiMe3)3via ClCH2CH2P(SiMe3)2. C2H4PSiMe3 is readily susceptible to protonolysis forming the thermally unstable parent phosphirane, C2H4PH, in good yields. Reaction of C2H4PSiMe3 with fac-M (CO)3(CH3CN)3 (M = Cr, Mo) or [Fe(η5-C5H5)(η6-C6H6)](PF6) give rise to fac-M(CO)3(C2H4PSiMe3)3 and [Fe(η5-C5H5)(C2H4PSiMe3)3](PF6) respectively. Protonolysis of the free or coordinated 1-trimethylsilylphosphirane readily causes P–Si cleavage to give rise to the parent C2H4PH or the respective complexes, fac-M(CO)3(C2H4PH)3 and fac-[Fe(η5-C5H5)(C2H4PH)3](PF6) in situ. All new complexes are characterised by analytical and spectroscopic methods and the X-ray crystal structures of fac-Cr(CO)3(C2H4PSiMe3)3 and fac-Mo(CO)3(C2H4PH)3 have also been determined.
Co-reporter:Oliver Kaufhold, Andreas Stasch, Peter G. Edwards and F. Ekkehardt Hahn
Chemical Communications 2007 (Issue 18) pp:1822-1824
Publication Date(Web):08 Feb 2007
DOI:10.1039/B617033A
Rhenium complex [5]Cl with the coordinated [11]ane-P2CNHC macrocycle was obtained by a metal template controlled ring formation reaction; in this reaction a coordinated NH,NH-stabilised imidazolidin-2-ylidene ligand was connected via the nitrogen atoms to two phenyl substituents of a 2-fluorophenyl substituted diphosphine ligand.
Co-reporter:Thomas Albers and Peter G. Edwards
Chemical Communications 2007 (Issue 8) pp:858-860
Publication Date(Web):23 Nov 2006
DOI:10.1039/B613672A
A 9-membered triphosphorus macrocycle with o-phenylene backbone functions has been stereoselectively prepared on a CpFe+ template by two successive nucleophilic attacks of coordinated phosphide on a coordinated o-fluorophenylbiphosphine.
Co-reporter:Peter G. Edwards and Mark L. Whatton
Dalton Transactions 2006 (Issue 3) pp:442-450
Publication Date(Web):28 Oct 2005
DOI:10.1039/B511502G
[η5-CpRFe(CH3CN)(1,2-diphosphinobenzene)]+ complexes are readily formed from [η5-CpRFeL3]+ salts and act as template precursors for the intramolecular hydrophosphination of co-ordinated trivinylphosphine with 1,2-diphosphinobenzenes. This sequence constitutes a versatile synthetic route to a new class of co-ordinated triphosphacyclononanes bearing a rigid o-phenylene backbone link. The efficiency of the synthesis depends markedly upon the nature of the CpR ligand. The new secondary phosphine macrocycles prepared by this route are readily alkylated to tritertiary triphosphine macrocycles bearing alkyl and pendant functions.
Co-reporter:Peter G. Edwards, K. M. Abdul Malik, Li-ling Ooi and Andrew J. Price
Dalton Transactions 2006 (Issue 3) pp:433-441
Publication Date(Web):28 Oct 2005
DOI:10.1039/B509627H
Primary and secondary phosphine piano-stool complexes of the type [η5-CpFeL3]+
(L = phenylphosphine, 3, (α-methyl)vinylphosphine, 4, allylphosphine, 5, (2-methylpropenyl)phosphine, 5b, allyl(phenyl)phosphine, 6) are described. The alkenyl phosphine complexes, 5 and 6, react by intramolecular hydrophosphination to give the corresponding [η5-CpFe]+ complexes of 1,5,9-triphosphacyclododecane (12-aneP3R3, 2, R = H), 9 and 10 respectively. Alkylation of the secondary phosphines in 9 is achieved by hydrophosphinations with ethene to give the 12-aneP3R3
(R = Et) derivative 11. These complexes are also obtained by reaction of suitable [η5-CpFe]+ containing precursor complexes with the corresponding free 12-aneP3R3 macrocycle as is the related [η5-Cp*Fe]+ derivative, 8. Direct substitution of acetonitrile in [Fe(CH3CN)6][BF4]2 by 12-aneP3Et3, leads to the macrocycle piano-stool complex, [(12-aneP3Et3)Fe(CH3CN)3][BF4]2, 7. The crystal structures of selected primary phosphine, η5-Cp, η5-Cp* complexes and 7, allow a comparison of steric influences upon key macrocycle ring closure reactions and hence an insight into parameters required for the formation of smaller ring sizes by template based methods.
Co-reporter:Peter G. Edwards, Andrew Harrison, Paul D. Newman, Wenjian Zhang
Inorganica Chimica Acta 2006 Volume 359(Issue 11) pp:3549-3556
Publication Date(Web):1 August 2006
DOI:10.1016/j.ica.2005.12.034
A series of cationic trispyrazolylmethane complexes of the general form [TmRM(CH3CN)3]2+ (Tm = tris(pyrazolyl)methane, 1, R = 3,5-Me2, M = Fe(II); 2, R = 3-Ph, M = Fe(II); 3, R = 3,5-Me2, M = Co(II); 4, R = 3-Ph, M = Co(II)) with ‘piano-stool’ structures was prepared by the reaction of the N3tripodal ligands (TmR)with [(CH3CN)6M](BF4)2 in a 1:1 stoichiometric ratio. Magnetic susceptibility measurements indicate that all four complexes with BF4− counter anions are paramagnetic, high-spin systems in the solid state with μeff at high temperatures of 5.2 (1, S = 2), 5.4 (2, S = 2), 4.9 (3, S = 3/2) and 4.6 (4, S = 3/2) BM, respectively. Comparisons of bond lengths from the metal centre to the TmR nitrogen donors, and from the metal centre to the acetonitrile nitrogen donors indicate that the neutral tripodal ligands appear to be more weakly coordinated to the metal centre than are the acetonitrile ligands. Reactions of these tripodal complexes with bidentate phosphine ligands, such as 1,2-diphosphinoethane or 1,2-bis(diallylphosphino)ethane leads to displacement of the tripodal ligand, or to the formation of more thermally stable bis-ligand complexes M(TmR)2 (R = 3,5-dimethyl).Stoichiometric control and manipulation of steric properties of tris-pyrazolylmethanes by variations in substituents R, allows the synthesis and isolation of ‘piano-stool’ complexes of iron and cobalt retaining labile monodentate ligands.
Co-reporter:Robert J. Baker, Peter G. Edwards, Robert D. Farley, Damien M. Murphy, James A. Platts and Karen E. Voss
Dalton Transactions 2003 (Issue 5) pp:944-948
Publication Date(Web):03 Feb 2003
DOI:10.1039/B211105P
The triphosphorus macrocycle 1,5,9-triethyl-1,5,9-triphosphacyclododecane, 12[ane]P3Et3, reacts with [V(CO)6]− under photolytic conditions to produce fac-[(12[ane]P3Et3)V(CO)3]−
(1) which has been isolated as its Et4N salt. This can be oxidised to the neutral 17 electron complex fac-(12[ane]P3Et3)V(CO)3
(2), which has been characterised by EPR spectroscopy. Density functional calculations support the spectroscopic observations and give insight into the bonding. The V(0) compound cannot be further oxidised, but the macrocycle reacts with CpV(CO)4 thermally or photolytically to produce cis-[(η2-12[ane]P3Et3)V(η5-Cp)(CO)2]
(3). The diamagnetic compounds have been characterised by IR and multinuclear (1H, 13C, 31P and 51V) NMR spectroscopy.
Co-reporter:Robert J. Baker and Peter G. Edwards
Dalton Transactions 2002 (Issue 15) pp:2960-2965
Publication Date(Web):05 Jul 2002
DOI:10.1039/B203002K
Some early transition metal (Ti, V, Cr) complexes of the triphosphorus macrocycle 1,5,9-triethyl-1,5,9-triphosphacyclododecane, [12]aneP3Et3, and related derivatives [12]aneP3R3 (R = Ph, C3H6OMe) have been examined for their reactivity towards ethene and propene. All complexes of the type [12]aneP3Et3MCl3 display moderate catalytic activity in the homogeneous polymerisation of ethene when combined with an alkyl aluminium co-catalyst to give very high molecular weight polymers. Preliminary activation of chromium complexes with alkylating agents was also studied but these were inactive in the absence of a co-catalyst. Substitution of the P-borne alkyl group with a pendant ether function was found to switch the catalytic activity of chromium(III) complexes from polymerisation to oligomerisation. A nickel halide complex of [12]aneP3Et3 was also
found to be active in alkene polymerisation.
Co-reporter:Robert J. Baker;Philip C. Davies;Peter G. Edwards;Robert D. Farley;Sudantha S. Liyanage;Damien M. Murphy;Ben Yong
European Journal of Inorganic Chemistry 2002 Volume 2002(Issue 8) pp:
Publication Date(Web):2 JUL 2002
DOI:10.1002/1099-0682(200208)2002:8<1975::AID-EJIC1975>3.0.CO;2-I
The reactions of 1,5,9-triethyl-1,5,9-triphosphacyclododecane, [12]aneP3Et3, with first-row transition metal halides MCl3 [M = Ti (1), V (2), and Cr (3)] or their THF adducts are reported. The oxidation of 2 gives the complex ([12]aneP3Et3)V(O)Cl2 (4). This is the first example of a phosphane ligand that is trans to a vanadyl moiety. Also reported are VIII (5) and CrIII (6) complexes of the pendant ether macrocycles [12]aneP3(C2H4OEt)3 and 12[ane]P3(C3H6OMe)3 respectively. The complexes 1−6 have been characterised crystallographically and represent a rare class of phosphane complexes of these metals. The paramagnetic d1 compounds are characterised by EPR and ENDOR spectroscopy, simulation of which gives valuable structural information of these species in frozen solution. With [12]aneP3Et3, NbIII and NbIV chlorides give air-sensitive materials which could not be fully characterised although by comparison with compound 4, EPR and ENDOR spectroscopy indicate the principal oxidation product to be ([12]aneP3Et3)Nb(O)Cl2 (7). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)
Co-reporter:Peter G. Edwards;Florent Ingold;Sudantha S. Liyanage;Paul D. Newman;Wai-Kwok Wong;Yang Chen
European Journal of Inorganic Chemistry 2001 Volume 2001(Issue 11) pp:
Publication Date(Web):26 SEP 2001
DOI:10.1002/1099-0682(200111)2001:11<2865::AID-EJIC2865>3.0.CO;2-D
The selective functionalisation of a single phosphorus atom in the parent [Mo(CO)3(12aneP3H3)], where 12aneP3H3 is 1,5,9-triphosphacyclododecane, has been achieved by deprotonation and subsequent reaction with an ether containing an alkyl halide group. Yields of the monosubstituted products are very sensitive to the reaction conditions, which must be carefully controlled in order to achieve reasonable selectivity. In addition, trisubstitution of [M(CO)3(12aneP3H3)] with carbon chains containing pendant donors such as ethers, thioethers, amines and phosphanes has been achieved by both deprotonation/addition (M = Mo0) and hydrophosphination (M = Cr0) protocols. The new compounds have been characterised by spectroscopic and analytical techniques, including X-ray crystallography, and a selection of the P3 macrocycles released from their templates by oxidation and base digestion.
Co-reporter:Andrew J. Price and Peter G. Edwards
Chemical Communications 2000 (Issue 11) pp:899-900
Publication Date(Web):09 May 2000
DOI:10.1039/B002174L
A new template synthesis of triphosphorus macrocycles has been
developed based upon the intramolecular hydrophosphination of
allylphosphine coordinated to the
(η5-cyclopentadienyl)iron(II) cation; the
resulting tri-secondary macrocycle 1,5,9-triphosphacyclododecane is readily
alkylated with ethene to give
(η3-1,5,9-[12]aneP3Et3)Fe(η5
-Cp)+ which is in turn liberated as the free ligand
stereospecifically as the syn–syn isomer; related reactions
with phenyl(allyl)phosphine lead directly to the triphenyl macrocycle
(1,5,9-[12]aneP3Ph3) which is also liberated
stereospecifically.
Co-reporter:Peter G. Edwards, Stephen J. Paisey and Robert P. Tooze
Organic & Biomolecular Chemistry 2000 (Issue 18) pp:3122-3128
Publication Date(Web):01 Sep 2000
DOI:10.1039/B004525J
The fused tricyclic dialkyl(phenyl)phosphine, 1,1,6,6-tetramethylphosphajulolidine 11, has been synthesised on a large scale with a view to verifying a computationally derived theory of ligand influence upon the catalytic alkoxycarbonylation of propyne.
Co-reporter:Athanasia Dervisi, Peter G. Edwards, Paul D. Newman and Robert P. Tooze
Dalton Transactions 2000 (Issue 4) pp:523-528
Publication Date(Web):27 Jan 2000
DOI:10.1039/A908050C
The zerovalent complexes Pd(Ph2Ppy)31 and Pd(Ph2Ppy)2(dba) 2, where Ph2Ppy is diphenyl-2-pyridylphosphine and dba = trans,trans-dibenzylideneacetone, have been synthesized and characterised. Reactions of 1 with alkynes have been studied and the dimethyl acetylenedicarboxylate complex Pd(Ph2Ppy)2(η2-DMAD) 3, where DMAD is dimethyl acetylenedicarboxylate, isolated and structurally characterised. The complexes trans-Pd(Ph2Ppy)2(PhCCH2)X, X = CF3CO2−4 or Cl−5, and trans-Pd(Ph2Ppy)2{CO(CH3)CCH2}Cl 6 result from oxidative addition of phenylacetylene/CF3CO2H, phenylacetylene/Et3NHCl and methacryloyl chloride respectively to 1, and the crystal structure of 4 is presented. The alkenyl ligand is bound to palladium through the α carbon in 4. Insertions into the M–C bond of the vinyl complexes have been studied. No isolable insertion product is obtained with carbon monoxide although the complex is active for the catalytic alkoxycarbonylation of phenylacetylene to 2-phenylpropenoate. Propadiene inserts into the Pd–C bond in 4 to give the cationic π-allyl complex [Pd(Ph2Ppy)2{η3-C3H4C(Ph)CH2}][CF3CO2] 7. The complex Pd(Ph2Ppy)3 is found to catalyse the vinylation of Ph2Ppy to the corresponding 2-propenylphosphonium trifluoromethanesulfonate.
Co-reporter:Peter G. Edwards ;Paul D. Newman Dr.;K. M. Abdul Malik Dr.
Angewandte Chemie 2000 Volume 112(Issue 16) pp:
Publication Date(Web):11 AUG 2000
DOI:10.1002/1521-3757(20000818)112:16<3044::AID-ANGE3044>3.0.CO;2-H
Co-reporter:Peter G. Edwards ;Paul D. Newman Dr.;David E. Hibbs Dr.
Angewandte Chemie 2000 Volume 112(Issue 15) pp:
Publication Date(Web):2 AUG 2000
DOI:10.1002/1521-3757(20000804)112:15<2834::AID-ANGE2834>3.0.CO;2-O
Co-reporter:Oliver Kaufhold, Andreas Stasch, Peter G. Edwards and F. Ekkehardt Hahn
Chemical Communications 2007(Issue 18) pp:NaN1824-1824
Publication Date(Web):2007/02/08
DOI:10.1039/B617033A
Rhenium complex [5]Cl with the coordinated [11]ane-P2CNHC macrocycle was obtained by a metal template controlled ring formation reaction; in this reaction a coordinated NH,NH-stabilised imidazolidin-2-ylidene ligand was connected via the nitrogen atoms to two phenyl substituents of a 2-fluorophenyl substituted diphosphine ligand.
Co-reporter:Thomas Albers and Peter G. Edwards
Chemical Communications 2007(Issue 8) pp:NaN860-860
Publication Date(Web):2006/11/23
DOI:10.1039/B613672A
A 9-membered triphosphorus macrocycle with o-phenylene backbone functions has been stereoselectively prepared on a CpFe+ template by two successive nucleophilic attacks of coordinated phosphide on a coordinated o-fluorophenylbiphosphine.
Co-reporter:Peter G. Edwards, F. Ekkehardt Hahn, Matthieu Limon, Paul D. Newman, Benson M. Kariuki and Andreas Stasch
Dalton Transactions 2009(Issue 26) pp:NaN5119-5119
Publication Date(Web):2009/04/30
DOI:10.1039/B822870A
The reaction of the manganese precursors [MnOTf(CO)3{1,2-(PH2)2C6H4}], 5, or [MnOTf(CO)3{1,2-(PH2)2C2H4}], 6, with either the silver complex of 1,3-diallylbenzimidazol-2-ylidiene or the free carbene, resulted in the formation of the new, dimeric phosphino-μ-phosphido manganese species 7 and 8. Complex 7 crystallises in two isomeric forms (cis and trans), depending upon the choice of solvent. The structures of both isomers have been determined by single-crystal X-ray techniques.
Co-reporter:Christopher Wallis, David McGuinness, Paul D. Newman, Robert P. Tooze and Peter G. Edwards
Dalton Transactions 2009(Issue 12) pp:NaN2184-2184
Publication Date(Web):2009/02/06
DOI:10.1039/B816507F
A series of halo substituted triarylphosphinines have been synthesised and coordinated to tungsten(0) and rhodium(I) to give [(2-(2′-halo)-triarylphosphinine)W(CO)5] and [(2-(2′-halo)-triarylphosphinine)Rh(COD)Cl] respectively. The complexes have been examined by NMR and IR spectroscopy in an effort to elucidate the nature of the bonding between the phosphinines and the respective metal centre. The W(CO)5(L) systems reveal restricted C–C bond rotation as evidenced by temperature-dependent 31P{1H} NMR spectra. Thermodynamic barriers to the rotation are dependent upon the nature of the halide with ΔG‡ values of 72.5 kJ mol−1 and 50.8 kJ mol−1 being obtained for the chloro- and fluoro-derivatives, respectively; activation barriers for the iodo- and bromo- derivatives were beyond the accessible temperature range of the NMR experiment.
Co-reporter:Thomas Albers, Julia Baker (neé Johnstone), Simon J. Coles, Peter G. Edwards, Benson Kariuki and Paul D. Newman
Dalton Transactions 2011 - vol. 40(Issue 37) pp:NaN9532-9532
Publication Date(Web):2011/08/19
DOI:10.1039/C0DT01724H
Nine-membered 1,4,7-triphospha- and triarsamacrocycles with unsaturated benzo-backbones have been prepared using the [CpRFe]+ unit as a template. The cyclisation involves the attack of a coordinated phosphide (or arsenide) nucleophile at an activated, electrophilic ortho-fluorophenyl substituent on a neighbouring pnictide donor. The macrocycle assembly is of the 2 + 1 type where two new chelate rings are formed from appropriately derivatised bidentate and monodentate phosphines/arsines. Both [(η5-C5H5)Fe]+ and [(η5-C5Me5)Fe]+ may be employed for the cyclisation with higher yields generally being observed with the unsubstituted Cp. All new compounds have been characterised by spectroscopic and analytical methods including the single-crystal X-ray structure determination of [(η5-C5H5)Fe(tribenzo-9aneP3-Ph,PhF2)]+, 3a, and [(η5-C5H5)Fe(tribenzo-9aneAs3-Ph,PhF2)]+, 5, as the tetraphenylborate salts. The crystal structures are isomorphous and show the unique conformation of these new macrocycles with a ‘cup shaped’ cavity formed by the rigid benzo-backbones. The 9aneAs3 derivative is the first example of a nine-membered triarsamacrocycle.
Co-reporter:Dennis Coleman, Peter G. Edwards, Benson M. Kariuki and Paul D. Newman
Dalton Transactions 2010 - vol. 39(Issue 16) pp:NaN3850-3850
Publication Date(Web):2010/03/11
DOI:10.1039/B924982F
The cis,cis (5) and trans,trans (9) forms of the bidentate ligand 1,1′-[1,2-phenylenebis(methylene)]bis(2,2,3,4,4-pentamethylphosphetane) have been prepared from common precursors using two separate synthetic routes. The cis,cis isomer is attained selectively through the direct reaction of two mol equivalents of 2,2,3,4,4-pentamethylphosphetane with α,α′-dibromo-o-xylene in acetone. Protection of the 2,2,3,4,4-pentamethylphosphetane with BH3 and conversion to the lithium phosphido-borane prior to adding the α,α′-dihalo-o-xylene leads to the isolation of the trans,trans isomer of 1,1′-[1,2-phenylenebis(methylene)]bis(2,2,3,4,4-pentamethylphosphetane). Both isomers have been fully characterised by spectroscopic and, in the case of the all-cis isomer, single-crystal X-ray methods. The two isomers have been coordinated to Mo(0) to give complexes of the type cis-Mo(CO)4(L). The solid state structures of cis-Mo(CO)4(5), 10, and cis-Mo(CO)4(9), 12, have been determined by single-crystal X-ray methods and reveal significant differences between the two forms, most notably in the chelate bite angle which is 100.68(18)° in 10 compared to 88.12(2)° in 12. Ligand 5 has also been coordinated to Pd(II) and Pd(0) and the structure of the complex Pd(5)Cl2 (11) determined by single-crystal methods. The solid-state structure of Pd(5)Cl2 reveals a significant tetrahedral distortion from the normal square planar geometry.
Co-reporter:Peter G. Edwards, James C. Knight and Paul D. Newman
Dalton Transactions 2010 - vol. 39(Issue 16) pp:NaN3860-3860
Publication Date(Web):2010/03/11
DOI:10.1039/B924983D
The novel primary phosphine (1R,3S)-[1,2,2-trimethyl-3-(phosphinomethyl)cyclopentyl]methyl methanesulfonate 3a (or tosylate 3b) has been prepared in three steps from (1R,3S)-camphoric acid with a view to utilising it as a synthon for the preparation of polycyclic phosphines. Efforts to prepare a [3.2.1] bicyclic product by internal cyclisation of 3a or 3b under various conditions were unsuccessful, but heating the neat compound at 140 °C for several hours gave the new asymmetric, bicyclic secondary phosphine, (1R,4S,6R)-5,5,6-trimethyl-2-phosphabicyclo[2.2.2]octane (PBO) as its methanesulfonic acid 5a (or p-toluenesulfonic acid 5b) salt. The cyclisation involves a skeletal rearrangement and occurs with high stereoselectivity to generate two new stereogenic carbon centres and a chiral phosphorus atom. The secondary phosphine was obtained after base treatment of 5a/b and several derivatives of the phosphine have been synthesised and characterised. Reaction of two mol equivalents of the borane adduct of PBO with α,α′-dichloro-ortho-xylene gave the bidentate derivative, o-C6H4(CH2PBO)2.2BH3, 12, and ultimately o-C6H4(CH2PBO)2, 13. Complexes of 13 with Pd(II), Pt(II), Pt(0) and Mo(0) have been prepared and characterised by spectroscopic and analytical methods including single-crystal X-ray structure determinations of cis-Pd{o-C6H4(CH2PBO)2}Cl2, 14, cis-Pt{o-C6H4(CH2PBO)2}Cl2, 15 and Mo(CO)4{o-C6H4(CH2PBO)2} 17.
Co-reporter:Christopher Wallis, Peter G. Edwards, Martin Hanton, Paul D. Newman, Andreas Stasch, Cameron Jones and Robert P. Tooze
Dalton Transactions 2009(Issue 12) pp:NaN2177-2177
Publication Date(Web):2009/02/04
DOI:10.1039/B816499A
The 2,6-dixylyl-4-phenylphosphabarrelene has been synthesised from the parent phosphinine and its properties as a ligand explored through the preparation and characterisation of the complexes W(CO)5(L), Re(CO)4(L)Cl, (η6-cymene)RuCl2(L), [(η5-Me3SiC5H4)Fe(CO)2(L)]PF6, Rh(1,5-COD)(L)Cl, Ir(1,5-COD)(L)Cl, and cis-Pt(L)2Cl2, where L = 4-phenyl-2,10-bis-(2,4-dimethylphenyl)-4H-1,4-ethenophospholine (xPB), cymene = 4-isopropyltoluene, η5-Me3SiC5H4 = trimethylsilylcyclopentadienyl and 1,5-COD = 1,5-cyclooctadiene. The new complexes were characterised by spectroscopic and analytical techniques and, for [(η5-Me3SiC5H4)Fe(CO)2(L)]PF6 and Ru(η6-cymene)(L)Cl2, by single-crystal X-ray structure determination. The coordination properties of the phosphabarrelene have been established and compared with analogous complexes of triarylphosphines and triarylphosphites. Most spectroscopic and structural indicators suggest that the phosphabarrelene has coordination behaviour similar to that of simple triarylphosphines such as PPh3.
Co-reporter:Huw A. Tallis, Paul D. Newman, Peter G. Edwards, Liling Ooi and Andreas Stasch
Dalton Transactions 2008(Issue 1) pp:NaN53-53
Publication Date(Web):2007/10/30
DOI:10.1039/B715327A
1-Trimethylsilylphosphirane, C2H4PSiMe3, has been prepared on a multi gram scale from P(SiMe3)3via ClCH2CH2P(SiMe3)2. C2H4PSiMe3 is readily susceptible to protonolysis forming the thermally unstable parent phosphirane, C2H4PH, in good yields. Reaction of C2H4PSiMe3 with fac-M (CO)3(CH3CN)3 (M = Cr, Mo) or [Fe(η5-C5H5)(η6-C6H6)](PF6) give rise to fac-M(CO)3(C2H4PSiMe3)3 and [Fe(η5-C5H5)(C2H4PSiMe3)3](PF6) respectively. Protonolysis of the free or coordinated 1-trimethylsilylphosphirane readily causes P–Si cleavage to give rise to the parent C2H4PH or the respective complexes, fac-M(CO)3(C2H4PH)3 and fac-[Fe(η5-C5H5)(C2H4PH)3](PF6) in situ. All new complexes are characterised by analytical and spectroscopic methods and the X-ray crystal structures of fac-Cr(CO)3(C2H4PSiMe3)3 and fac-Mo(CO)3(C2H4PH)3 have also been determined.
