ORCID Profile
0000-0002-1498-9652
Current Organisation
University of St Andrews
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Publisher: American Chemical Society (ACS)
Date: 31-07-2014
DOI: 10.1021/IC5014768
Abstract: A group of sterically encumbered peri-substituted acenaphthenes have been prepared, containing tin moieties at the 5,6-positions in 1-3 ([Acenap(SnR3)2], Acenap = acenaphthene-5,6-diyl R3 = Ph3 (1), Me3 (2) [(Acenap)2(SnMe2)2] (3)) and phosphorus functional groups at the proximal peri-positions in 4 and 5 ([Acenap(PR2)(P(i)Pr2)] R2 = Ph2 (4), Ph((i)Pr) (5)). Bis(stannane) structures 1-3 are dominated by repulsive interactions between the bulky tin groups, leading to peri-distances approaching the sum of van der Waals radii. Conversely, the quasi-linear CPh-P···P three-body fragments found in bis(phosphine) 4 suggest the presence of a lp(P)-σ*(P-C) donor-acceptor 3c-4e type interaction, supported by a notably short intramolecular P···P distance and notably large JPP through-space coupling (180 Hz). Severely strained bis(sulfides) 4-S and 5-S, experiencing pronounced in-plane and out-of-plane displacements of the exocyclic peri-bonds, have also been isolated following treatment of 4 and 5 with sulfur. The resulting nonbonded intramolecular P···P distances, ∼4.05 Å and ∼12% longer than twice the van der Waals radii of P (3.60 Å), are among the largest ever reported peri-separations, independent of the heteroatoms involved, and comparable to the distance found in 1 containing the larger Sn atoms (4.07 Å). In addition we report two metal complexes with square planar [(4)PtCl2] (4-Pt) and octahedral cis-[(4)Mo(CO)4] (4-Mo) geometries. In both complexes the bis(phosphine) backbone is distorted, but notably less so than in bis(sulfide) 4-S. All compounds were fully characterized, and except for bis(phosphine) 5, crystal structures were determined.
Publisher: Wiley
Date: 16-12-2013
Abstract: A new structural arrangement Te3 (RP(III) )3 and the first crystal structures of organophosphorus(III)-tellurium heterocycles are presented. The heterocycles can be stabilized and structurally characterized by the appropriate choice of substituents in Tem (P(III) R)n (m=1: n=2, R=OMes* (Mes*=supermesityl or 2,4,6-tri-tert-butylphenyl) n=3, R=adamantyl (Ad) n=4, R=ferrocene (Fc) m=n=3: R=trityl (Trt), Mesor by the installation of a P(V) 2 N2 anchor in RP(III) [TeP(V) (tBuN)(μ-NtBu)]2 (R=Ad, tBu).
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC01073F
Abstract: Reaction of Woollins' reagent ( WR ) with pyridine yields the P(V) species PhPSe 2 stabilised by pyridine coordination. Its potential as a selenation reagent under mild conditions was shown by calculations and an experimental comparison to WR .
Publisher: Informa UK Limited
Date: 03-03-2016
Publisher: American Chemical Society (ACS)
Date: 24-09-2012
DOI: 10.1021/IC301627Y
Abstract: Twelve related monocation chalconium salts [{Nap(EPh)(E'Ph)Me}(+){CF(3)SO(3)}(-)] 2-4, [{Acenap(Br)(EPh)Me}{CF(3)SO(3)}(-)] 5-7, and [{Acenap(EPh)(E'Ph)Me}(+){CF(3)SO(3)}(-)] 8-13 have been prepared and structurally characterized. For their synthesis naphthalene compounds [Nap(EPh)(E'Ph)] (Nap = naphthalene-1,8-diyl E/E' = S, Se, Te) N2-N4 and associated acenaphthene derivatives [Acenap(X)(EPh)]/[Acenap(EPh)(E'Ph)] (Acenap = acenaphthene-5,6-diyl E/E' = S, Se, Te X = Br) A5-A13 were independently treated with a single molar equivalent of methyl trifluoromethanesulfonate (MeOTf). In addition, reaction of bis-tellurium compound A10 with 2 equiv of MeOTf afforded the doubly methylated dication salt [{Acenap(TePhMe)(2)}(2+){(CF(3)SO(3))(2)}(2-)}] 14. The distortion of the rigid naphthalene and acenaphthene backbone away from ideal was investigated in each case and correlated in general with the steric bulk of the interacting atoms located at the proximal peri positions. Naturally, introduction of the ethane linker in acenaphthene compounds increased the splay of the bay region compared with equivalent naphthalene derivatives resulting in greater peri distances. The conformation of the aromatic rings and subsequent location of p-type lone pairs has a significant impact on the geometry of the peri region, with anomalies in peri separations correlated to the ability of the frontier orbitals to take part in attractive or repulsive interactions. In all but one of the monocations a quasi-linear three-body C(Me)-E···Z (E = Te, Se, S Z = Br/E) fragment provides an attractive component for the E···Z interaction. Density functional studies confirmed these interactions and suggested the onset of formation of three-center, four-electron bonding under appropriate geometric conditions, becoming more prevalent as heavier congeners are introduced along the series. The increasingly large J values for Se-Se, Te-Se, and Te-Te coupling observed in the (77)Se and (125)Te NMR spectra for 1, 3, 4, 9, 10, and 13 give further evidence for the existence of a weakly attractive through-space interaction.
Publisher: American Chemical Society (ACS)
Date: 05-03-2012
DOI: 10.1021/OM201253T
Publisher: Wiley
Date: 24-02-2014
Publisher: Georg Thieme Verlag KG
Date: 03-02-2015
Publisher: American Chemical Society (ACS)
Date: 09-06-2014
DOI: 10.1021/IC500697M
Abstract: The reactions of peri-substitution-stabilized phosphanylidene-phosphorane 1 with [AuCl(tht)] or [PtCl2(cod)] afford binuclear complexes [((1)(AuCl)2)2] 2 and [((1)(PtCl2))2] 3, in which four electrons of the ligand are used in bonding to two metal atoms in the bridging arrangement. Reactions of 1 with [Mo(CO)4(nbd)] or (RhCl2Cp*)2 afford mononuclear complexes [(1)2Mo(CO)4] 4 and [(1)RhCl2Cp*] 5, in which two electrons of the ligand are used to form terminal complexes. Formation of these complexes disrupts the negative hyperconjugation at the P-P bond to various extents, which is mirrored by variations in their P-P bond distances (2.179(4)-2.246(4) Å). The P-P bond is ruptured upon formation of Pd diphosphene complex 6, which is likely to proceed through a phosphinidene intermediate. In air, 1 is fully oxidized to phosphonic acid 7. Reactions of 1 with chalcogens under mild conditions generally afford mixtures of products, from which the trithionated 8, dithionated 9, diselenated 10, and monotellurated 11 species were isolated. The bonding in the chalcogeno derivatives is discussed using DFT (B3LYP) and natural bond orbital analysis, which indicate a contribution from dative bonding in 8-10. The buttressing effect of the peri backbone is shown to be an essential factor in the formation of the single push-double-pull bis(borane) 13. This is demonstrated experimentally through a synthesis parallel to that used to make 13, but lacking the backbone, which leads to different products. The P-P bond distances in the reported products, as well as additional species, are correlated with Wiberg bond indices, showing very good agreement for a variety of bonding modes, including the negative hyperconjugation.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5RA27594F
Abstract: The fundamental synthetic building blocks FcPH 2 and FcPCl 2 are obtained in high yield and excellent purities via the fully regiospecific electrophilic monofunctionalisation of ferrocene with P 4 S 10 , thus replacing inconvenient t BuLi based procedures.
Publisher: American Chemical Society (ACS)
Date: 02-10-2014
DOI: 10.1021/OM500755W
Publisher: Springer Science and Business Media LLC
Date: 25-02-2016
Publisher: Wiley
Date: 24-09-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5DT02542G
Abstract: Subtle changes in the structure of the backbone can lead to profound differences in the binding modes of dithiolato ligands in rhodium and iridium half sandwich complexes.
Publisher: American Chemical Society (ACS)
Date: 26-02-2015
DOI: 10.1021/ACS.INORGCHEM.5B00161
Abstract: A comprehensive investigation of reactions of alkali-metal derivatives of the ditelluro dianion [TePV(NtBu)(μ-NtBu)]22– (L2–, E = Te) with p-block element halides produced a series of novel heterocycles incorporating P2VN2 rings, tellurium, and group 13–16 elements. The dianion engages in Te,Te′-chelation to the metal center in Ph2Ge and R2Sn (R = tBu, nBu, Ph) derivatives similar behavior was noted for group 14 derivatives of L2– (E = S, Se). In the case of group 13 trihalides MCl3 (M = Ga, In), neutral spirocyclic complexes (L)M[NtBu(Te)PV(μ-NtBu)2PIIIN(H)tBu)] (M = Ga, In) comprised of a Te,Te′-chelated ligand L2– and a N,Te-bonded ligand resulting from loss of Te and monoprotonation were obtained. In reactions with RPCl2 (R = tBu, Ad, iPr2N) a significant difference was observed between Se- and S-containing systems. In the former case, Se,Se′-chelated derivatives were formed in high yields, whereas the N,S-chelated isomers predominated for sulfur. All complexes were characterized by multinuclear (1H, 31P, 77Se, 119Sn, and 125Te) NMR spectroscopy this technique was especially useful in the analysis of the mixture of (L)(Se) and (L)(SeSe) obtained from the reaction of Se2Cl2 with L2– (E = Te). Single-crystal X-ray structures were obtained for the spirocyclic In complex (9), (L)GePh2 (E = Te, 10), (L)SntBu2 (E = Te, 12a) E = Se, 12aSe, E = S, 12aS) and (L)(μ-SeSe) (E = Te, 16).
Publisher: American Chemical Society (ACS)
Date: 18-02-2015
DOI: 10.1021/IC503056Z
Abstract: A series of peri-substituted phosphorus-tellurium systems R'Te-Acenap-PR2 (R' = Ph, p-An, Nap, Mes, Tip Acenap = acenaphthene-5,6-diyl (-C12H8) R = (i)Pr, Ph) exhibiting large "through-space" spin-spin coupling constants and the "onset" of three-center four-electron type interactions is presented. The influence of the substituents at the phosphorus and tellurium atoms as well as their behavior upon oxidation (with S, Se) or metal-coordination (Pt, Au) is discussed using NMR spectroscopy, single-crystal X-ray diffraction, and advanced density functional theory studies including NBO, AIM, and ELI-D analyses.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2DT32716C
Abstract: Oxidation of alkali metal derivatives of [Te((t)BuN)P(μ-N(t)Bu)(2)P(N(t)Bu)Te](2-) with I(2) produces the intermediate ditelluride dianion [Te((t)BuN)P(μ-N(t)Bu)(2)P(N(t)Bu)Te](2)(2-) with a planar PTeTeP conformation and, subsequently, the cyclic tritelluride [((t)BuN)P(μ-N(t)Bu)(2)P(N(t)Bu)(μ-TeTeTe)].
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2DT12031C
Abstract: Sterically crowded peri-substituted selenium and tellurium acenaphthene donors D1-D7 [Acenap(EPh)(Br) E = Se, Te Acenap(SePh)(EPh) E = Se, S Acenap(TePh)(EPh) E = S, Se, Te] react with dibromine and diiodine acceptors to afford a group of structurally erse addition products 1-12, comparable in some cases to previously reported naphthalene analogues. Tellurium donors D4-D6 react conventionally with the dihalogens to afford insertion adducts 6-11 (X-R(2)Te-X) exhibiting molecular see-saw geometries, characterised by hypervalent X-Te-X quasi-linear fragments. The reactions of selenium donors D1-D3 with diiodine afford expected neutral charge-transfer (CT) spoke adducts 1, 4 and 5 (R(2)Se-I-I) containing quasi-linear Se-I-I alignments. Conversely, treatment of D2 and D3 with dibromine results in the formation of two tribromide salts 2 and 3 containing bromoselanyl cations [R(2)Se-Br](+)···[Br-Br(2)](-), each exhibiting a quasi-linear three-body Br-Se···E (E = Se, S) fragment. The peri-bonding in these species can be thought of as a weak hypervalent G···Se-X three-centre, four-electron (3c-4e) type interaction, closely related to the T-shaped 3c-4e interaction. Density-functional calculations performed on 2 and 3 and their bare cations (2a and 3a) reveal Wiberg bond indices of 0.25-0.37, suggesting substantial 3c-4e character in these systems. The presence of such an interaction operating in 2 and 3 alleviates steric strain within the peri-region and minimises the degree of molecular distortion required to achieve a relaxed geometry. Ditellurium donor D7 reacts with dibromine to afford an unorthodox insertion adduct 12 containing a Te-O-Te bridge and two quasi-linear Br-Te-O fragments, with the central tellurium atoms assuming a molecular see-saw geometry. Whilst DFT calculations indicate 12 is thermodynamically unfavourable, its formation is viable under experimental conditions.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4DT03257H
Abstract: The versatile coordinating ability of a novel spirocyclic, P 2 N 2 -supported Te 5 dianion is exemplified by N , N ′-bonding to Na + ions and Te,Te′,Te′′ linkages to a Cp*Rh( iii ) group.
Publisher: Elsevier BV
Date: 02-2009
Publisher: American Chemical Society (ACS)
Date: 08-05-2014
DOI: 10.1021/OM500289B
Publisher: American Chemical Society (ACS)
Date: 05-05-2015
DOI: 10.1021/JACS.5B03353
Abstract: Solid-state NMR spectra of new P-Se heterocycles based on peri-substituted naphthalene motifs show the presence of unusual J couplings between Se and P. These couplings are between atoms in adjacent molecules and occur "through space", rather than through conventional covalent bonds. Experimental measurements are supported by relativistic DFT calculations, which confirm the presence of couplings between nonbonded atoms, and provide information on the pathway of the interaction. This observation improves the understanding of J couplings and offers insight into the factors that affect crystal packing in solids, for future synthetic exploitation.
Publisher: Elsevier BV
Date: 2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4DT00408F
Abstract: A series of eight 5-(TeAr)-6-(SePh)acenaphthenes (Ar = aryl) were prepared and structurally characterised by X-ray crystallography, solution and solid-state NMR spectroscopy and DFT/B3LYP calculations.
Publisher: Wiley
Date: 28-06-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5DT00159E
Abstract: Reactions of the dianions [ t BuN(E)P(μ-N t Bu)] 2 2− (E = Se,S) with M( i ) reagents (M = Ag, Au) or HgCl 2 produce complexes of [ t Bu(H)N(E)P(μ-N t Bu) 2 P(E)N t Bu] − with spirocyclic, macrocyclic or ladder structures.
Publisher: American Chemical Society (ACS)
Date: 19-07-2011
DOI: 10.1021/JA2049786
Abstract: We report on the use of the hydrogen bond acceptor properties of some phosphorus-containing functional groups for the assembly of a series of [2]rotaxanes. Phosphinamides, and the homologous thio- and selenophosphinamides, act as hydrogen bond acceptors that, in conjunction with an appropriately positioned amide group on the thread, direct the assembly of amide-based macrocycles around the axle to form rotaxanes in up to 60% yields. Employing solely phosphorus-based functional groups as the hydrogen bond accepting groups on the thread, a bis(phosphinamide) template and a phosphine oxide-phosphinamide template afforded the corresponding rotaxanes in 18 and 15% yields, respectively. X-ray crystallography of the rotaxanes shows the presence of up to four intercomponent hydrogen bonds between the amide groups of the macrocycle and various hydrogen bond accepting groups on the thread, including rare ex les of amide-to-phosphinamide, -thiophosphinamide, and -selenophosphinamide groups. With a phosphine oxide-phosphinamide thread, the solid-state structure of the rotaxane is remarkable, featuring no direct intercomponent hydrogen bonds but rather a hydrogen bond network involving water molecules that bridge the H-bonding groups of the macrocycle and thread through bifurcated hydrogen bonds. The incorporation of phosphorus-based functional groups into rotaxanes may prove useful for the development of molecular shuttles in which the macrocycle can be used to hinder or expose binding ligating sites for metal-based catalysts.
Publisher: Wiley
Date: 22-12-2014
Abstract: Three related series of peri-substituted bis(tellurides) bearing naphthalene, acenaphthene and acenaphthylene backbones (Nap/Acenap/Aceyl(TeY)2 (Nap = naphthalene-1,8-diyl N Acenap = acenaphthene-5,6-diyl A Aceyl = acenaphthylene-5,6-diyl Ay Y = Ph 1 Fp 2 Tol 3 An-p- 4 An-o- 5 Tp 6 Mes 7 Tip 8) have been synthesised and their solid-state structures determined by X-ray crystallography. Molecular conformations were classified as a function of the two C9-C-Te-C(Y) dihedral angles (θ) in the solid all members adopt AB or CCt configurations, with larger Te(aryl) moieties exclusively imposing the CCt variant. Exceptionally large J((125)Te,(125)Te) spin-spin coupling constants between 3289-3848 Hz were obtained for compounds substituted by bulky Te(aryl) groups, implying these species are locked in a CCt-type conformation. In contrast, compounds incorporating smaller Te(aryl) moieties are predicted to be rather dynamic in solution and afford much smaller J values (2050-2676 Hz), characteristic of greater populations of AB conformers with lower couplings. This conformational dependence of through-space coupling is supported by DFT calculations.
Location: United Arab Emirates
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for John Derek Woollins.