A copper-mediated radiofluorination of aryl- and vinylboronic acids with K18F is described. This method exhibits high functional group tolerance and is effective for the radiofluorination of a range of electron-deficient, -neutral, and -rich aryl-, heteroaryl-, and vinylboronic acids. This method has been applied to the synthesis of [18F]FPEB, a PET radiotracer for quantifying metabotropic glutamate 5 receptors.

A copper-mediated nucleophilic radiofluorination of aryl- and vinylstannanes with [18F]KF is described. This method is fast, uses commercially available reagents, and is compatible with both electron-rich and electron-deficient arene substrates. This method has been applied to the manual synthesis of a variety of clinically relevant radiotracers including protected [18F]F-phenylalanine and [18F]F-DOPA. In addition, an automated synthesis of [18F]MPPF is demonstrated that delivers a clinically validated dose of 200 ± 20 mCi with a high specific activity of 2400 ± 900 Ci/mmol.

Thermodynamic versus kinetic control: Small‐angle neutron scattering (SANS) and single‐crystal X‐ray diffraction data have been used to elucidate the effect of temperature, solvent, and metal identity on the formation of dimeric or hexameric metal‐seamed pyrogallol[4]arene capsules. Higher temperatures, methanol solution, and the use of nickel metal favor dimer formation (see scheme).

In a relatively short period of time, transition metal-mediated radiofluorination reactions have changed the PET radiochemistry landscape. These reactions have enabled the radiofluorination of a wide range of substrates, facilitating access to radiopharmaceuticals that were challenging to synthesize using traditional fluorine-18 radiochemistry. However, the process of adapting these new reactions for automated radiopharmaceutical production has revealed limitations in fitting them into the confines of traditional radiochemistry systems. In particular, the presence of bases (e.g. K2CO3) and/or phase transfer catalysts (PTC) (e.g. kryptofix 2.2.2) associated with fluorine-18 preparation has been found to be detrimental to reaction yields. We hypothesized that these limitations could be addressed through the development of alternate techniques for preparing [18F]fluoride. This approach also opens the possibility that an eluent can be individually tailored to meet the specific needs of a metal-catalyzed reaction of interest. In this communication, we demonstrate that various solutions of copper salts, bases, and ancillary ligands can be utilized to elute [18F]fluoride from ion exchange cartridges. The new procedures are effective for fluorine-18 radiochemistry and, as proof of concept, have been used to optimize an otherwise base-sensitive copper-mediated radiofluorination reaction.

Nickel and cobalt seamed metal-organic capsules have been isolated and studied using structural, 5 magnetic and computational approaches. Antiferromagnetic exchange in the Ni capsule results from coordination environments enforced by the capsule framework. The synthesis and characterisation of polymetallic cages of paramagnetic transition metal ions is an area of intense current research since such molecules may exhibit fascinating physical properties,1 potentially acting as, for example, single-molecule magnets (SMMs),2 molecular coolants3 and spin 10 phonon traps.4 Indeed the initial (serendipitous) discovery of all these phenomena has subsequently inspired much beautiful chemistry and physics that promises exciting potential application.5 Introducing new preparative routes towards the synthesis of transition metal cages is thus of interest for the discovery of completely new structural types and as a means of building up families of related compounds so that structure-property relations can be developed.6 Organic ligands thus play a crucial 15 role in successful cage construction, but their nature and variety is surprisingly restricted.7 A family of ligands almost completely ignored in this respect, with a few notable exceptions are calixarenes.8 C-Alkylpyrogallol[4]arenes (general formula PgCn) are cyclic molecules that are typically bowl-shaped and that have been shown to assemble through non-covalent interactions into a) nanotubular arrays,9 b) dimeric capsules,10 and c) hexameric nano-capsules.11 The dimeric and hexameric 20 capsules possess typical internal volumes of ~150 and ~1250 Å3 respectively, and this feature provides them with great potential for study as new host-guest systems. Nanometer scale metal-organic polyhedra are often assembled from many molecular components,12 and we have recently shown that various PgCns can be assembled with different metals into either open or closed shell hexameric metal-organic nano-capsules from Cu, Ga, Ga+Cu or Ga+Zn.13 In addition to this, closed shell 25 dimeric octa-metallated capsules have also been synthesized by reaction of PgCns with a pre-formed zinc(II) nitrate pyridine complex in either pyridine or methanol.14 Given that we had formed a Zn8 wheel as part of a molecular metal-organic capsule, we reasoned that the incorporation of paramagnetic metal centres (e.g. Co or Ni in place of Zn) in the capsule seam may be possible, though a search of the CCDC database reveals that there are no known isostructural Co8, Ni8 and Zn8 cages. 30This would therefore afford species with potential interest in molecular nanomagnetism, whilst also representing a paradigm shift in the chemistry of molecular capsules and their uses. We also reasoned that the inner phase of the capsule arrangement may have an important effect on the overall magnetic properties of these species by the incorporation of different guest molecules. Herein we report an expedient route to a new family of octa-metallated dimeric capsules comprising Ni8 and Co8 wheels, 35and their initial magnetic pro...