Examination of the silver colloid binding behavior of disulfide-tethered bipyridine ligands and their fac-tricarbonylrheniumI complexes.

The syntheses of 2,2'-bipyridin-5-ylmethyl-5-(1,2-dithiolan-3-yl)pentanoate (L1) and N-(2,2'-bipyridin-5-ylmethyl)-5-(1,2-dithiolan-3-yl)pentanamide (L2) and their neutral fac carbonylrhenium(I) complexes [Re(L1)(CO)(3)Br] and [Re(L2)(CO)(3)Br] are reported. The electronic absorption and emission spectra of the complexes are similar to the spectrum of the reference compound [Re(bipy)(CO)(3)Br] and correlate well with the density functional theory calculations undertaken. The surface-enhanced Raman spectroscopy (SERS) spectra (excited at both 532 and 785 nm) of the ligands and complexes were examined and compared to the spectrum of ethyl 5-(1,2-dithiolan-3-yl)pentanoate (L3), revealing that there is very little contribution to the spectra of these species from the dithiolated alkyl chains.

Asymmetric spin crossover behaviour and evidence of light-induced excited spin state trapping in a dinuclear iron(II) helicate.

Reported herein are the synthesis, structural and magnetic characterisation of a dinuclear FeII triple helicate that displays an unprecedented reversible asymmetric high spin to low spin crossover characterised by a thermal hysteresis: indeed the high spin state can be recovered by white light irradiation at 10 K.

Anion detection driven by a surprising internal hydrogen-bonding association in a dinuclear rhenium(I) complex.

A neutral dinuclear rhenium(I) bipyridinetricarbonyl bromide complex has been investigated with a range of anions, giving a remarkable binding affinity for dihydrogenphosphate. These studies highlight that anion sensing can be achieved with structurally simple species provided that the compound adopts an unconventional conformation, through, for example, intramolecular hydrogen bonding in solution.