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A series of 1-alkyl-4-aryl-1,2,3-triazoles (1-methyl-4-phenyl-1,2,3-triazole (1a); 1-propyl-4-phenyl-1,2,3-triazole (1b); 1-benzyl-4-phenyl-1,2,3-triazole (1c); 1-propyl-4-p-tolyl-1,2,3-triazole (1d)) have been prepared through a one-pot procedure involving in situgeneration of the alkyl azide from a halide precursor followed by copper catalysed alkyne/azide cycloaddition (CuAAC) with the appropriate aryl alkyne. Cationic Re(i) complexes [Re(bpy)(CO)3(1a–d)]PF6(2a–d) were then prepared by stirring [Re(bpy)(CO)3Cl] with AgPF6in dichloromethane in the presence of ligands 1a–d. X-ray crystal structures were obtained for 2aand 2b. In the solid state, 2aadopts a highly distorted geometry, which is not seen for 2b, in which the plane of the triazole ligand tilts by 13° with respect to the Re–N bond as a result of a π-stacking interaction between the Ph substituent and one of the rings of the bpy ligand. This π-stacking interaction also results in severe twisting of the bpy ligand. Infrared spectra of 2a–dexhibit νCObands at ∼2035 and ∼1926 cm−1suggesting that these ligands are marginally better donors than pyridine (νCO= 2037, 1932 cm−1). The complexes are luminescent in aerated dichloromethane at room temperature with emission maxima at 542 to 552 nm comparable to that of the pyridine analogue (549 nm) and blue shifted relative to the parent chloride complex. Long luminescent lifetimes are observed for the triazole complexes (475 to 513 ns) in aerated dichloromethane solutions at room temperature. [ABSTRACT FROM AUTHOR]

The synthesis of the potentially hexadentate ditopic ligand L1, which contains both N-donor and crown ether binding units, is described. Reaction of L1 with Zn(ii) results in the formation of a dinuclear double helicate ([Zn2(L1)2](ClO4)4), which has been structurally characterized. In the solid state, each ligand splits into two tridentate binding domains with two Zn(ii) ions coordinated by two bridging ligands in a double helicate arrangement. This complex can further react with s-block metal ions via the crown ether unit resulting in the structurally characterized zinc-containing helicate [Zn2(L1)2Ba2](ClO4)8. Ligand recognition studies of this helicate with a ligand that does not contain the crown ether unit but does contain the same N-donor array (L2) demonstrates, via both 1H NMR and ESI-MS studies, that a ligand recognition process does occur and the major species observed are the homoleptic species ([Zn2(L1)2](ClO4)4 and [Zn2(L2)2](ClO4)4). Addition of barium ions to the mixture increases the amount of the heteroleptic species ([Zn2(L1)(L2)](ClO4)4) present, resulting in an equal amount of homoleptic and heteroleptic species. This change in ligand recognition properties is attributed to electrostatic effects. [ABSTRACT FROM AUTHOR]

A diamino-functionalised cryptate can react irreversibly with butanal in water, in the presence of an excess of a metal ion, to form a cyclised bis-aminal complex, which displays metal-dependent luminescence properties. [ABSTRACT FROM AUTHOR]

The reaction of a potentially tetradentate bis(pyridyl–thiazole) ligand with acetone is allosterically activated upon complexation with Cd(ii) but deactivated by reaction with Cu(i), demonstrating metal-specific allosteric controlled reactivity. [ABSTRACT FROM AUTHOR]