Development of a (170)Tm source for mercury monitoring studies in humans using XRF.

The goals of the present study were to develop a (170)Tm radioisotope and generate a K XRF spectrum of mercury. Thulium foil and thulium oxide powder were both tested for impurities and the latter was found to be a better prospect for further studies. The (170)Tm radioisotope was developed from thulium oxide powder following the method of disolution and absorption.

Differences between the macroscopic and tracer level chemistry of rhenium and technetium: contrasting cage isomerisation behaviour of Re(I) and Tc(I) carborane complexes.

Carboranes form stable complexes with the [M(CO)(3)](+) (M = (99m)Tc, Re) core and are viable ligands for the development of targeted radiopharmaceuticals. (99m)Tc-carborane complexes were found to exhibit substantially different 1,2-->1,7 cage isomerisation behaviour than their Re counterparts, challenging the validity of the routine use of rhenium as a surrogate for the development of technetium-99m based molecular imaging agents.

Evaluation of single amino acid chelate derivatives and regioselective radiolabelling of a cyclic peptide for the urokinase plasminogen activator receptor.

Introduction: The aim of this work was to investigate the relative radiolabelling kinetics and affinity of a series of ligands for the [(99m)Tc(CO)(3)](+) core, both in the absence and in the presence of competing donors. This information was used to select a suitable ligand for radiolabelling complex peptide-based targeting vectors in high yield under mild conditions.

Methods: A series of alpha-N-Fmoc-protected lysine derivatives bearing two heterocyclic donor groups at the epsilon-amine (1a, 2-pyridyl; '1b, quinolyl; '1c, 6-methoxy-2-pyridyl; 1d, 2-thiazolyl; 1e, N-methylimidazolyl; '1f, 3-pyridyl) were synthesized and labelled with (99m)Tc.

A robust strategy for the preparation of libraries of metallopeptides. A new paradigm for the discovery of targeted molecular imaging and therapy agents.

A robust method for synthesizing structurally diverse metallopeptide libraries using a Re(i) complex of a non-natural amino acid was developed as a way to accelerate the discovery of novel molecular imaging probes.

The bioinorganic and medicinal chemistry of carboranes: from new drug discovery to molecular imaging and therapy.

The role of carboranes in medicinal chemistry has diversified in recent years and now extends into areas of drug discovery, molecular imaging, and targeted radionuclide therapy. An introduction to carborane chemistry is provided to familiarize the non-expert with some key properties of these molecules, followed by an overview of current medicinally-orientated research involving carboranes. The broad-ranging nature of this research is illustrated, with emphasis placed on recent highlights and advances in this field.

Microwave-assisted synthesis of tricarbonyl rhenacarboranes: steric and electronic effects on the 1,2 --> 1,7 carborane cage isomerization.

A series of tricarbonyl rhenacarboranes {[M][Re(CO)3(RR'C2B9H9)]} (M = Na, K) were synthesized in water using microwave radiation with reaction times of less than 15 min. The novel complexes were isolated in good yields (57-94%) as either 3,1,2-(R = H: R' = CH2Pyr 6; R' = CH2Cy, 20) or 2,1,8-(R = H: R' = H, 4; R' = CH2PyrMe 12; R' = CH2PyrH, 13; R' = Pyr, 15; R' = Ph, 17; R = R' = Bn, 19) metallacarboranes and characterized by multinuclear (1H, 11B, 13C) and NOE NMR spectroscopy, IR spectroscopy, mass spectrometry, and X-ray crystallography in the case of compounds 12 and 13. Carborane cage isomerization from the original 1,2 configuration to the 1,7 orientation occurred in cases where significant steric crowding was present at the metal center.

Guaianolides from Salvia nubicola (Lamiaceae).

A new sesquiterpene-lactone (nubenolide) belonging to the guaianolide class along with its acetate (nubenolide acetate) and a dimer (bisnubenolide) have been isolated from Salvia nubicola collected from Quetta, Pakistan. Structures of all three new metabolites were elucidated with the aid of spectroscopic techniques including 2D-NMR. However, the structure of nubenolide was finally confirmed via single-crystal X-ray diffraction method.

Microwave-assisted synthesis of 3,1,2- and 2,1,8-Re(I) and 99mTc(I)-metallocarborane complexes.

Microwave heating was used to prepare eta5-rhenium carborane complexes in aqueous reaction media. For carboranes bearing sterically demanding substituents, isomerization of the cage from 3,1,2 to 2,1,8 derivatives occurred concomitantly with complexation. Microwave heating was equally effective at the tracer level using technetium-99m, affording access to a new class of synthons for designing novel molecular imaging agents.

Theoretical investigation of paramagnetic group 13 diazabutadiene radicals: insights into the prediction and interpretation of EPR spectroscopy parameters.

The electronic structures and the spin density distributions of the group 13 1,4-diaza(1,3)butadiene (DAB) radicals [(R-DAB)2M]*, [(R-DAB)MX2] and {[(R-DAB)MX]2}** (M = Al, Ga, In; X = F, Cl, Br, I; R = H, Me, tBu, Ph) are studied using density functional theory at both non-relativistic and relativistic levels of theory. The calculations demonstrate that all systems share a qualitatively similar electronic structure and are primarily ligand centred pi-radicals. The calculated metal, nitrogen and hydrogen hyperfine couplings are found to be independent of the identity of the R-group and the halogen atom.

Cubic and spirocyclic radicals containing a tetraimidophosphate dianion [P(NR)3(NR')]*2-.

The reaction of Cl(3)PNSiMe(3) with 3 equiv of LiHNR (R = (i)Pr, Cy, (t)Bu, Ad) in diethyl ether produces the corresponding tris(amino)(imino)phosphoranes (RNH)(3)PNSiMe(3) (1a, R = (i)Pr; 1b, R = Cy; 1c, R = (t)Bu; 1d, R = Ad); subsequent reactions of 1b-d with (n)BuLi yield the trilithiated tetraimidophosphates {Li(3)[P(NR)(3)(NSiMe(3))]} (2a, R = Cy; 2b, R = (t)Bu; 2c, R = Ad). The reaction of [((t)BuNH)(4)P]Cl with 1 equiv of (n)BuLi results in the isolation of ((t)BuNH)(3)PN(t)Bu (1e); treatment of 1e with additional (n)BuLi generates the symmetrical tetraimidophosphate {Li(3)[P(N(t)Bu)(4)]} (2d). Compounds 1 and 2 have been characterized by multinuclear ((1)H, (13)C, and (31)P) NMR spectroscopy; X-ray structures of 1b,c were also obtained.