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Biomedical subjects

Peter G Jones

Publications and source records attributed to Peter G Jones.

At least 37 records · Page 2Linked to original sources
PubMed2004

(Fluoren-9-ylidene)methanedithiolato complexes of gold: synthesis, luminescence, and charge-transfer adducts.

Piperidinium 9H-fluorene-9-carbodithioate and its 2,7-di-tert-butyl-substituted analogue [(pipH)(S(2)CCH(C(12)H(6)R(2)-2,7)), R = H (1a), t-Bu (1b)] and 2,7-bis(octyloxy)-9H-fluorene-9-carbodithioic acid [HS(2)CCH(C(12)H(6)(OC(8)H(17))(2)-2,7), 2] and its tautomer [2,7-bis(octyloxy)fluoren-9-ylidene]methanedithiol [(HS)(2)C=C(C(12)H(6)(OC(8)H(17))(2)-2,7), 3] were employed for the preparation of gold complexes with the (fluoren-9-ylidene)methanedithiolato ligand and its substituted analogues. The gold(I) compounds Q(2)[Au(2)(mu-kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(2)], where Q(+) = PPN(+) or Pr(4)N(+) for R = H (Q(2)4a) or Q(+) = Pr(4)N(+) for R = OC(8)H(17) [(Pr(4)N)(2)4c], were synthesized by reacting Q[AuCl(2)] with 1a or 2 (1:1) and excess piperidine or diethylamine. Complexes of the type [(Au(PR'3))(2)(mu-kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(2)] with R = H and R' = Me (5a), Et (5b), Ph (5c), and Cy (5d) or R = t-Bu and R' = Me (5e), Et (5f), Ph (5g), and Cy (5h) were obtained by reacting [AuCl(PR'(3))] with 1a,b (1:2) and piperidine. The reactions of 1a,b or 2 with Q[AuCl(4)] (2:1) and piperidine or diethylamine gave Q[Au(kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(2)] with Q(+) = PPN(+) for R = H [(PPN)6a], Q(+) = PPN(+) or Bu(4)N(+) for R = t-Bu (Q6b), and Q(+) = Bu(4)N(+) for R = OC(8)H(17) [(Bu(4)N)6c]. Complexes Q6a-c reacted with excess triflic acid to give [Au(kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(kappa(2)-S,S-S(2)CCH(C(12)H(6)R(2)-2,7))] [R = H (7a), t-Bu (7b), OC(8)H(17) (7c)]. By reaction of (Bu(4)N)6b with PhICl(2) (1:1) the complex Bu(4)N[AuCl(2)(kappa(2)-S,S-S(2)C=C(C(12)H(6)(t-Bu)(2)-2,7))] [(Bu(4)N)8b] was obtained. The dithioato complexes [Au(SC(S)CH(C(12)H(8)))(PCy(3))] (9) and [Au(n)(S(2)CCH(C(12)H(8)))(n)] (10) were obtained from the reactions of 1a with [AuCl(PCy(3))] or [AuCl(SMe(2))], respectively (1:1), in the absence of a base. Charge-transfer adducts of general composition Q[Au(kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(2)].1.5TCNQ.xCH(2)Cl(2) [Q(+) = PPN(+), R = H, x = 0 (11a); Q(+) = PPN(+), R = t-Bu, x = 2 (11b); Q(+) = Bu(4)N(+), R = OC(8)H(17), x = 0 (11c)] were obtained from Q6a-c and TCNQ (1:2). The crystal structures of 5c.THF, 5e.(2)/(3)CH(2)Cl(2), 5g.CH(2)Cl(2), (PPN)6a.2Me(2)CO, and 11b were solved by X-ray diffraction studies. All the gold(I) complexes here described are photoluminescent at 77 K, and their emissions can be generally ascribed to LMMCT (Q(2)4a,c, 5a-h, 10) or LMCT (9) excited states.

Journal Article↗
PubMed2004

Secondary interactions in 3-bromopyridinium tribromoacetate.

The title compound, C(5)H(5)BrN(+).C(2)Br(3)O(2)(-), crystallizes with Z' = 2. The residues pack in two distinct (but interconnected) types of layer, namely, layers parallel to (102), in which the residues are connected by classical N-H...O hydrogen bonds, C-H...O interactions and Br...Br contacts, and anion layers parallel to the ab plane, connected by Br...O interactions. The two formula units are topologically equivalent with respect to all these contacts.

Journal Article↗
PubMed2004

Quinoline-2(1H)-thione, a structure with Z' = 8.

The title compound, C(9)H(7)NS, crystallizes as the thione tautomer with Z' = 8 (four independent dimers with local inversion symmetry via two N-H...S=C hydrogen-bond systems). The dimers are arranged in chains parallel to [-110], each chain being crystallographically independent. These chains are associated into layers via stacking of ring systems. The Z' value can be rationalized in terms of a factor 2 for dimer formation without crystallographic symmetry and an additional factor 4 for differing stacking environments.

Journal Article↗
PubMed2004

Selenolate gold complexes with aurophilic Au(I)-Au(I) and Au(I)-Au(III) interactions.

The gold(I) selenolate compound [Au(2)(SePh)(2)(mu-dppf)] (dppf = 1,1'-bis(diphenylphosphino)ferrocene) has been prepared by reaction of [Au(2)Cl(2)(mu-dppf)] with PhSeSiMe(3) in a molar ratio 1:2. This complex reacts with gold(I) or gold(III) derivatives to give polynuclear gold(I)-gold(I) or gold(I)-gold(III) complexes of the type [Au(4)(mu-SePh)(2)(PPh(3))(2)(mu-dppf)](OTf)(2), [Au(3)(C(6)F(5))(3)(mu-SePh)(2)(mu-dppf)], or [Au(4)(C(6)F(5))(6)(mu-SePh)(2)(mu-dppf)], with bridging selenolate ligands. The reaction of [Au(2)(SePh)(2)(mu-dppf)] with 1 equiv of AgOTf leads to the formation of the insoluble Ag(SePh) and the compound [Au(2)(mu-SePh)(mu-dppf)]OTf. The complexes [Au(4)(C(6)F(5))(6)(mu-SePh)(2)(mu-dppf)] and [Au(2)(mu-SePh)(mu-dppf)]OTf (two different solvates) have been characterized by X-ray diffraction studies and show the presence of weak gold(I)-gold(III) interactions in the former and intra- and intermolecular gold(I)-gold(I) inter-actions in the later.

Journal Article↗
PubMed2004

Synthesis and X-ray crystal structure of an anionic heteronuclear metallamacrocyclic triangle.

trans-[Pt(C[triple bond]C(Ar)C[triple bond]CH)2(PMe3)2](Ar = C(6)Me(4)-3,4,5,6) (1) reacts with PPN[Au(acac)(2)](Hacac = acetylacetone; 1 : 1.16 molar ratio; PPN = (Ph3P)2N) to give PPN[(Au[Pt(PMe3)2]2)(mu-Ar(C[triple bond]C)2)3] (2) the crystal structure of which showed the anions as quasi equilateral triangles stacked parallel to each other through C-HAu interactions, resulting in channels of rhombic cross-section.

Journal Article↗
PubMed2004

Secondary interactions in the isomorphous compounds 2,6-bis(chloromethyl)pyridinium chloride and 2,6-bis(bromomethyl)pyridinium bromide.

The title compounds, C7H8Cl2N+.Cl- and C7H8Br2N+.Br-, are isomorphous. In the crystal packing, layers parallel to the ac plane are formed by a classical N(+)-H...X- hydrogen bond (X = halogen) and two X...X contacts. A third X...X contact links the layers, and a fourth, which is however very long, completes a ladder-like motif of halogen atoms. Hydrogen bonds of the form C-H...X play at best a subordinate role in the packing.

Journal Article↗
PubMed2004

The ecology and epidemiology of whitefly-transmitted viruses in Latin America.

Whitefly-transmitted geminiviruses are the most important constraint to the production of common bean and vegetable crops in the tropical lowlands and mid-altitude valleys of Latin America. Currently, over 30 distinct species of geminiviruses that are transmitted by the whitefly Bemisia tabaci infect common bean, tomato, pepper, cucurbits and other horticultural crops. A climate probability model (using FloraMap) was obtained using data from 304 geo-referenced locations where B. tabaci and geminiviruses cause significant damage. Clustering of the 304 points produced a simple model with two climatic variables: a dry season of at least 4 months each with less than 80 mm of rain and a mean temperature of the hottest month exceeding 21 degrees C. A modified Koeppen climate classification showed that 55% of the geminivirus-affected localities are in the tropical wet/dry region, 22% in the tropical and subtropical dry/humid climates and the remaining locations belonged to the wet equatorial and trade wind litoral climates. These findings contribute to understanding whitefly/geminivirus epidemics and implementation of sustainable integrated pest and disease management practices.

Animals↗
PubMed2003

Synthesis of [Ag(NH=CMe(2))(2)]ClO(4) and its use as a source of acetimine. 1. Synthesis of the first acetimine rhodium complexes and the first crystal structure of a diacetonamine complex.

The reaction of AgClO(4) and NH(3) in acetone gave [Ag(NH=CMe(2))(2)]ClO(4) (1). The reactions of 1 with [RhCl(diolefin)](2) or [RhCl(CO)(2)](2) (2:1) gave the bis(acetimine) complexes [Rh(diolefin)(NH=CMe(2))(2)]ClO(4) [diolefin = 1,5 cyclooctadiene = cod (2), norbornadiene = nbd (3)] or [Rh(CO)(2)(NH=CMe(2))(2)]ClO(4) (4), respectively. Mono(acetimine) complexes [Rh(diolefin)(NH=CMe(2))(PPh(3))]ClO(4) [diolefin = cod (5), nbd (6)] or [RhCl(diolefin)(NH=CMe(2))] [diolefin = cod (7), nbd (8)] were obtained by reacting 2 or 3 with PPh(3) (1:1) or with Me(4)NCl (1:1.1), respectively. The reaction of 4 with PR(3) (R = Ph, To, molar ratio 1:2) led to [Rh(CO)(NH=CMe(2))(PR(3))(2)]ClO(4) [R = Ph (9), C(6)H(4)Me-4 = To (10)] while cis-[Rh(CO)(NH=CMe(2))(2)(PPh(3))]ClO(4) (11) was isolated from the reaction of 1 with [RhCl(CO)(PPh(3))](2) (1:1). The crystal structures of 5 and [Ag[H(2)NC(Me)(2)CH(2)C(O)Me](PTo(3))]ClO(4) (A), a product obtained in a reaction between NH(3), AgClO(4), and PTo(3), have been determined.

Journal Article↗
PubMed2003

1,1-ethylenedithiolato complexes of palladium(II) and platinum(II) with isocyanide and carbene ligands.

The reactions of [Tl(2)[S(2)C=C[C(O)Me](2)]](n) with [MCl(2)(NCPh)(2)] and CNR (1:1:2) give complexes [M[eta(2)-S(2)C=C[C(O)Me](2)](CNR)(2)] [R = (t)Bu, M = Pd (1a), Pt (1b); R = C(6)H(3)Me(2)-2,6 (Xy), M = Pd (2a), Pt (2b)]. Compound 1b reacts with AgClO(4) (1:1) to give [[Pt(CN(t)Bu)(2)](2)Ag(2)[mu(2),eta(2)-(S,S')-[S(2)C=C[C(O)Me](2)](2)]](ClO(4))(2) (3). The reactions of 1 or 2 with diethylamine give mixed isocyanide carbene complexes [M[eta(2)-S(2)C=C[C(O)Me](2)](CNR)[C(NEt(2))(NHR)]] [R = (t)Bu, M = Pd (4a), Pt (4b); R = Xy, M = Pd (5a), Pt (5b)] regardless of the molar ratio of the reagents. The same complexes react with an excess of ammonia to give [M[eta(2)-(S,S')-S(2)C=C[C(O)Me](2)](CN(t)Bu)[C(NH(2))(NH(t)Bu)]] [M = Pd (6a), Pt (6b)] or [M[eta(2)-(S,S')-S(2)C=C[C(O)Me](2)][C(NH(2))(NHXy)](2)] [M = Pd (7a), Pt (7b)] probably depending on steric factors. The crystal structures of 2b, 4a, and 4b have been determined. Compounds 4a and 4b are isostructural. They all display distorted square planar metal environments and chelating planar E,Z-2,2-diacetyl-1,1-ethylenedithiolato ligands that coordinate through the sulfur atoms.

Journal Article↗
PubMed2003

Cyclodextrin phosphanes as first and second coordination sphere cavitands.

The binding properties of two alpha-cyclodextrins, each containing two C(5)-linked "CH(2)PPh(2)" units, L 1 (A,D-substituted) and L 2 (A,C-substituted), have been investigated. Both ligands readily form transition-metal chelate complexes in which the metal centres are immobilised at the cavity entrance. Although diphosphane L 1 displays a marked tendency to behave only as a trans-spanning ligand, the ligand possesses a certain degree of flexibility, for example, allowing the stabilisation of a trigonal silver(I) complex in which the bite angle drops to 143 degrees. Another feature of L 1 concerns its ability to function as an hemilabile ligand. Together with four methoxy groups anchored onto the primary face, the two P(III) centres of L 1 form a circularly arranged P(2)O(4) 12-electron donor set able to complex an Ag(+) ion in a dynamic way, each of the four oxygen atoms coordinating successively to the silver ion. Furthermore, the particular structures of L 1 and L 2, characterised by the presence of P(III) units lying close to the cavity entrance, lead upon complexation to complexes whereby the first coordination sphere is partly entrapped in the cyclodextrin. Thus, when treated with metal chlorides, both ligands systematically produce complexes in which the Mbond;Cl unit is maintained inside the cyclodextrin through weak Cl.H-5 interactions. The chelate complex [Ag(L 1)]BF(4) reacts with acetonitrile in excess to afford a mixture of two equilibrating complexes, [Ag(acetonitrile)(L 1)]BF(4) and [Ag(acetonitrile)(2)(L 1)]BF(4), whose coordinated nitriles lie inside the cyclodextrin cavity. The inner-cavity ligands can be substituted by a benzonitrile molecule. The present study provides the first identification of an [Ag(acetonitrile)(2)(phosphane)(2)](+) ion. The unexpected stabilisation of this species probably rests on a cavity effect, the cyclodextrin walls favouring recombination of the complex after facile dissociation of the nitrile ligands.

Cyclodextrins↗
PubMed2003

The host-guest complex between cone-25,26:27,28-bis(methylenedioxy)calix[4]arene and dichloromethane.

The title compound, 25,26:27,28-bis(methylenedioxy)pentacyclo[19.3.1.1(3,7).1(9,13).1(15,19)]octacosa-1(25)3,5,7(28),9,11,13(27),15,17,19(26),21,23-dodecaene dichloromethane solvate, C(30)H(24)O(4).CH(2)Cl(2), possesses crystallographic twofold symmetry in both components. The calixarene shows a pinched cone conformation with an elliptical cavity, in which the guest dichloromethane solvent molecule is accommodated. The contact distance between guest and host (H.ring centroid = 2.44 A) is extremely short.

Journal Article↗
PubMed2003

Luminescent nido-carborane-diphosphine anions [(PR2)2C2B9H10](-) (R = Ph, (i)Pr). Modification of their luminescence properties upon formation of three-coordinate gold(I) complexes.

The free nido-diphosphine anions [(PR(2))(2)C(2)B(9)H(10)](-) (R = Ph, (i)Pr) show luminescence properties whereas the closo-diphosphines [(PR(2))(2)C(2)B(10)H(10)] do not. Four families of three-coordinate complexes of stoichiometry [Au[(PR(2))(2)C(2)B(10)H(10)]L]OTf (L = tertiary phosphine) and [Au[(PR(2))(2)C(2)B(9)H(10)]L] have been studied in order to analyze the influence of the closo- or nido-nature of the diphosphine, the monophosphine coordinated to gold and the substituent at the diphosphine on the luminescence of the complexes. Only the nido-derivatives show luminescence. The maxima of the emissions are shifted to lower energies than those of the corresponding free nido-diphosphines. When the substituent at the diphosphine is phenyl, a new emission appears, which has been assigned as arising from a metal to ligand charge transfer [Au-->pi(L)] excited state.

Journal Article↗
PubMed2003

Emergency ultrasound credentialling for focused assessment sonography in trauma and abdominal aortic aneurysm: A practical approach for Australasia.

OBJECTIVE: Focused assessment with sonography for trauma and emergency ultrasound for abdominal aortic aneurysm are now practiced widely by non-radiologists in emergency departments worldwide. Various credentialling programs have been proposed for novice sonographers; however, their feasibility has been questioned. We adopted the Australasian College for Emergency Medicine (ACEM) credentialling process for emergency ultrasound to determine whether it is feasible for emergency physicians in the Australasian environment. METHODS: Three full-time emergency medicine specialists and a post-Fellowship Examination trainee at Auckland Hospital undertook the credentialling process. RESULTS: All four participants had sufficient scans to complete the process after 16 months. Accuracy for focused assessment with sonography for trauma, 90% (95% CI 83-95%), and abdominal aortic aneurysm, 99% (95% CI 90-100%), is similar to that previously reported. CONCLUSION: The ACEM credentialling process for focused assessment with sonography for trauma and abdominal aortic aneurysm is practical and achievable for emergency medicine specialists working in the Emergency Department at Auckland Hospital. Further studies are necessary to determine whether this holds true for other major trauma centres in Australasia.

Aortic Aneurysm, Abdominal↗