In recent years, the development of optical probes to analyse trace palladium ions (Pd2+) has attracted great attention because of the residual palladium released by catalytic converters or from various Pd-catalysed reactions. These residual palladium ions may cause potential health hazards. This review provides a brief introduction to the new methods used to determine trace amounts of Pd2+, which then mainly focuses on the different reporting systems and unique mechanisms of the colourimetric and fluorescent probes used to detect Pd2+, including Pd2+ complex formation or Pd-catalysed reactions.

Colourimetric and fluorescent probes for the optical detection of palladium ions.

Oximes as spectrophotometric reagents-a review.

Electrochemical properties of the first Re(I)-carbonyl compound of di-2-pyridyl ketone.oxime (dpk.oxime), fac-Re(CO) 3 (dpk.oxime)Cl, in non-aqueous media

In contrast to the facile formation of fac-[Re(CO)3(dpk)Cl] 1 from the reaction between [Re(CO)5Cl] and dpk [(C5H4N)2C(O)], in refluxing toluene, [Re(CO)5Cl] was recovered unchanged when di-2-pyridylamine, dpa [(C5H4N)2NH], was allowed to react with [Re(CO)5Cl] under a variety of conditions. However, a mixture of [Re(CO)5Cl] and PPh3 in refluxing toluene followed by a CH2Cl2 solution of dpa gave cis-[Re(CO)2(PPh3)(dpa)Cl]. The intermediate involved appears to be a general synthon for the binding of the ReI(CO)2(PPh3)Cl chromophore to a variety of bi- and mono-dentate nitrogen-donor ligands and has been utilized to isolate cis-[Re(CO)2(PPh3)(dpk)Cl]. Nucleophilic addition of water at the carbonylic carbon atom of co-ordinated dpk in 1 and cis-[Re(CO)2(PPh3)(dpk)Cl] resulted in the hydration of the keto group and formation of fac-[Re(CO)3{(C5H4N)2C(O)(OH)}] and cis-[Re(CO)2(PPh3){(C5H4N)2C(O)(OH)}]. The compounds isolated exhibit rich electrochemical and photochemical properties and the potential application of fac-[Re(CO)3(dpk)Cl] as an electrochemical sensor for electrophiles and Group I and II metal ions is demonstrated.

Rhenium(I) di- and tri-carbonyl compounds of polypyridyl-like ligands: electrochemical reactions of fac-[Re(CO)3(dpk)Cl] (dpk = di-2-pyridyl ketone) with electrophiles and Group I and II metal ions

Spectrophotometric determination of traces of cobalt in water after preconcentration on reagent-loaded polyurethane foams

Spectrophotometric determination of palladium with 2,2'-dipyridyl ketoxime

Rapid spectrophotometric determination of cobalt with 2,2'-dipyridyl ketoxime.

Spectrophotometric determination of gold with 2,2'-dipyridyl ketoxime

Di-2-pyridyl ketoxime is proposed for the gravimetric determination of palladium. The chelate is precipitated over a pH range of between 3 and 11 and weighed as Pd(C11H8ON3)2. An extensive study of foreign ions and analytical conditions for precipitation indicates the procedure to be widely applicable, rapid and simple.

William J. Holland

Papers

Spectrophotometric determination of palladium with 2,2'-dipyridyl ketoxime

Rapid spectrophotometric determination of cobalt with 2,2'-dipyridyl ketoxime.

Spectrophotometric determination of gold with 2,2'-dipyridyl ketoxime

Di-2-pyridyl ketoxime, a new reagent for the rapid gravimetric determination of palladium

Di-2-Pyridylketoxime, a new reagent for the spectrophotometric determination of iron(II)