Emissive f-block coordination complexes constitute an important class of optical probes, with applications ranging from sensing of bioactive species, high throughput assays and screening protocols in vitro, to time-resolved imaging studies in cellulo or in vivo. The key chemistry issues to be addressed in complex design and characterisation are defined, with an emphasis on the use of emissive europium and terbium complexes and their conjugates in molecular imaging. Both luminescent 'tags' useful in energy transfer studies and 'responsive' systems for sensing are discussed.

Experimental measurements and theoretical analysis of magnetic properties, structural dynamics and acid-base equilibria for several lanthanide(III) complexes with tetraazacyclododecane derivatives as 19F NMR chemical shift pH probes are presented; pKa values vary between 6.9 and 7.7, with 18 to 40 ppm chemical shift differences between the acidic and basic forms for Ho(III) complexes possessing T1 values of 10 to 30 ms (4.7-9.4 T, 295 K).

The crystal structures of the hydrated salts of [Gd.DOTAM]3+ and its more hydrophobic derivative [Gd.]3+, bearing 4 alpha-phenylethyl groups, (both Gd and Yb salts) are reported and compared. The nature of the anion determines the degree of ordering in the lattice and the extent of hydration. These effects are correlated with the results of 17O and 1H NMR measurements of water exchange dynamics in solution. With [Gd.DOTAM]3+, structural ordering or the extent of hydration in the hydrated lattice follows the sequence Cl->Br->I- and this order also defines the water exchange rate in solution: 7.3, 19.5, 33.3x10(4) s-1 (298 K), respectively. For [Gd.]3+ salts, the measured relaxivity is determined purely by the outer sphere term and the water exchange rate at 298 K is very similar (typically 1x10(4) s-1) for chloride, bromide, iodide, acetate, triflate and nitrate salts, notwithstanding the different nature and extent of hydration found in the crystalline lattice.

Poly(9,9-dioctylfluorene-2,7-diyl-co-2,8-dihexyldibenzothiophene-S,S-dioxide-3,7-diyl) copolymers (pF-S 6 8-10) of varying composition have been synthesized by Suzuki-Miyaura polymerization. The hexyl substituents on the dibenzothiophene-S,S-dioxide (S) units improve the solubility of the copolymers and increase the dihedral angles in the backbone; this shifts the emission deep into the blue (λ max 420 nm for films of 10) and increases the photoluminescence quantum yield compared with previous pF-S copolymers containing non-alkylated S units. The backbone twist restricts formation of the intramolecular charge transfer (ICT) state for low incorporation ratios of S 6 units. The triplet energy of these new copolymers increases as the percentage of the S 6 unit increases (i.e., 15, 30, 50%: 8 f 9 f 10). The alternating copolymer 10 has a sufficiently high triplet energy (E T 2.46 eV for onset of phosphorescence) to host a green phosphorescent iridium guest emitter, as demonstrated in electroluminescence studies which showed emission exclusively from the guest complex.

The zinc-mediated reduction of nitroalkanes and nitroarenes in the presence of aldehydes is an efficient method to synthesize a wide range of nitrones. This method is mild enough to accommodate a variety of functional groups. It is particularly useful when the intermediate hydroxylamines are unstable and/or watersoluble. We used it to prepare several aromatic, aliphatic and highly functionalized sugar-derived nitrones.