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Rapid and complete fluorination of the complexes [MCl 3 (L)] (L ¼ Me 3-tacn, BzMe 2-tacn, M ¼ Al, Ga, In) occurs at room temperature via reaction of a MeCN solution of the complex with 3 mol equiv. of KF in water. The Ga and In complexes are also readily fluorinated using R 4 NF (R ¼ Me or n Bu) in MeCN solution, whereas no reaction occurs with the Al species under these conditions. The distorted octahedral fac-trifluoride coordination at M is confirmed in solution by multinuclear (19 F, 27 Al, 71 Ga and 115 In) NMR spectroscopic studies, leading to sharp resonances with 19 F-71 Ga and 19 F-115 In couplings evident. The [MF 3 (L)] are extremely stable in aqueous solution and at low pH; they crystallise as tetrahydrates, [MF 3 (Me 3-tacn)]$4H 2 O, with extended H-bonding networks formed through both F/H-O and O/H-O contacts. [InF 3 (BzMe 2-tacn)]$1.2H 2 O also shows intermolecular F/H-O hydrogen bonding contacts. The prospects for developing this coordination chemistry further to take advantage of the high metal-fluoride bond energies to enable rapid, late-stage fluorination of large macromolecules under mild conditions for PET imaging applications in nuclear medicine are discussed. This work also demonstrates that F-18 radiolabelling to form [F-18] [GaF 3 (BzMe 2-tacn)] is effected readily at room temperature in aqueous MeCN over 30-60 min on addition of 2.99 mol equiv. of [ 19 F]-KF aq and 0.4 mL [ 18 F]-KF aq (100-500 MBq) to [GaCl 3 (BzMe 2-tacn)] with ca. 30% incorporation. Recent efforts towards boron-based agents for F-18 capture include the work of Perrin, 6 Gabbaï 7 and Tsien. 8 Recently McBride and others have reported the use of Al-F complexes based upon functionalised bis-carboxylate derivatives of 1,4,7-triazacyclononane for F-18 imaging (Scheme 1). Incorporation of F-18 via formation of M-F bonds with biologically relevant ligand scaffolds provides an exciting alternative to C-F based PET agents. 9 McBride et al. have also used the formation of Al-F bonds to label a wide range of biomolecules rapidly in a single step. 9 However, the need for elevated temperatures (100 C) for uorination in this 'one-pot'

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A fast and efficient nickel-catalysed iodination reaction of aryl and heteroaryl bromides has been developed. The transformation was found to be general for a wide range of substrates and was used for the synthesis of iodo-PK11195, an imaging agent of Alzheimer's disease and iniparib, a compound used in the treatment of breast cancer.

As part of a study to investigate the factors influencing the development of new, more effective metal-complex-based positron emission tomography (PET) imaging agents, the distorted octahedral complex, [GaCl(L)]⋅2 H2O has been prepared by reaction of 1-benzyl-1,4,7-triazacyclononane-4,7-dicarboxylic acid hydrochloride (H2L⋅HCl) with Ga(NO3)3⋅9 H2O, which is a convenient source of GaIII for reactions in water. Spectroscopic and crystallographic data for [GaCl(L)]⋅2 H2O are described, together with the crystal structure of [GaCl(L)]⋅MeCN. Fluorination of this complex by Cl−/F− exchange was achieved in high yield by treatment with KF in water at room temperature over 90 minutes, although the reaction was complete in approximately 30 minutes if heated to 80 °C, giving [GaF(L)]⋅2 H2O in good yield. The same complex was obtained by hydrothermal synthesis from GaF3⋅3 H2O and Li2L, and has been characterised by single-crystal X-ray analysis, IR, 1H and 19F{1H} NMR spectroscopy and ESI+ MS.Radiofluorination of the pre-formed [GaCl(L)]⋅2 H2O has been demonstrated on a 210 nanomolar scale in aqueous NaOAc at pH 4 by using carrier-free 18F−, leading to 60–70 % 18F-incorporation after heating to 80 °C for 30 minutes. The resulting radioproduct was purified easily by using a solid-phase extraction (SPE) cartridge, leading to 98–99 % radiochemical purity. The [Ga18F(L)] is stable for at least 90 minutes in 10 % EtOH/NaOAc solution at pH 6, but defluorinates over this time scale at pH of approximately 7.5 in phosphate buffered saline (PBS) or human serum albumin (HSA). The subtle role of the Group 13 metal ion and co-ligand donor set in influencing the pH dependence of this system is discussed in the context of developing potential new imaging agents for PET.

Copper(I) complexes of the ligand cis-1, 3,5-tris(cinnamylideneamino)cyclohexane (L) have been prepared from a versatile precursor complex, [Cu I (L)NCMe]BF 4 , which incorporates a labile acetonitrile ligand that can be exchanged to give a range of new Cu(L)X complexes (where X = Cl, Br, NO 2 , SPh). 1 H NMR spectra and X-ray structures of the Cl, Br and NO 2 complexes show L coordinated in a symmetric fashion about the copper centre. The complexes have been further characterised using UV/Visible spectroscopy and cyclic voltammetry. CuLCl shows an electrochemically reversible Cu I/II redox couple at 0.51 V (vs. Ag/AgCl) while the CuLNO 2 complex shows an analogous quasi-reversible wave at 0.41 V (vs. Ag/AgCl).