Platinum Group Metal Complexes

A comparison of platinum group metal complexes is illustrative of the relatively narrow window of reactivity and stability which generates complexes with suitable antitumour activity. Table 6.1 collects some comparative data of structurally analogous complexes, containing only ammonia and chloride ligands. The palladium complex, like the octahedral iridium analogue, shows little activity, while those of rhodium and ruthenium are somewhat intermediate. Palladium complexes are more labile than those of platinum, reacting approximately 10 times faster, and it is reasonable to accept that the palladium complex will be too reactive in vivo for any 

Comparison of antitumour activity of Group 8—10 ammine complexes.  

Complex Dose Range (rag/kg) Toxic Level (mg/kg) Comments 

Interestingly, the rhodium complex, reminiscent of cisplatin, displays some differences of toxicity, depending on the mode of its administration. No T/C values are included because no strictly comparable data are available but the general trend is conveyed. 

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CbHOROCARBONSANDCbHOROHYDROCARBONS - RDIG-CbHORINATED TOLUENES] (Vol 6) -in platinum-group metal complexes pLATINUM-GROUP METALS, COMPOUNDS] (Vol 19)... 

Costa, E., Pringle, P.G., Smith, M.B., and Worboys, K., Self-replication of tris(cyanoethyl)phosphine catalyzed by platinum group metal complexes, /. Chem. Soc., Dalton Trans., 4227, 1997. 

Hydrosilylations of fluorine-containing alkenes are free radical reactions initiated by UV light or organic peroxides The direction of addition is the same as with fluonnated alkyl halides However, the reaction between hydrosilanes and fluorine-containing olefins catalyzed by platinum group metal complexes may result in bidirectional addition and/or formation of a vinylic silane, the latter by de hydrogenative silylation[/] The natures of both the silane and the catalyst affect the outcome of the reaction[7] A random selection of some typical new reactions of silanes are shown in Table 1 [1, 2, 3 4]... 

The activation of C—H bonds in hydrocarbons by oxidative addition to low-valent platinum group metal complexes is also feasible. This problem is discussed in more detail in Section III.D.3). 

Fig. 4. Molecular structures of new platinum group metal complexes with high activity against animal cancers, a) Dichloroethylenediamineplatinum(II) b) substituted (R) malonatodi-ammineplatinum(II) c) d.s-dichlorobis(cyclohcxylarninc)platinum(II) d) sulfato-1,2 diamino-cyclohexaneplatinum(II) e) rhodium(II) carboxylate.

Demas JN, DeGraff BA. Apphcation of luminescent transition platinum group metal complexes to sensor technology and molecular probes. Coord Chem Rev 2001 211 317-51. 

Fig. 8.3 Warren R. Roper (born in 1938) studied chemistry at the University of Canterbury in Christchurch, New Zealand, and completed his Ph.D. in 1963 under the supervision of Cuthbert J. Wilkins. He then undertook postdoctoral research with James P. Collman at the University of North Carolina at Chapel Hill in the US, and returned to New Zealand as Lecturer in Chemistry at the University of Auckland in 1966. In 1984, he was appointed Professor of Chemistry at the University of Auckland and became Research Professor of Chemistry at the same institution in 1999. His research interests are widespread with the emphasis on synthetic and structural inorganic and organometallic chemistry. Special topics have been low oxidation state platinum group metal complexes, oxidative addition reactions, migratory insertion reactions, metal-carbon multiple bonds, metallabenzenoids and more recently compounds with bonds between platinum group metals and the main group elements boron, silicon, and tin. His achievements were recognized by the Royal Society of Chemistry through the Organometallic Chemistry Award and the Centenary Lectureship. He was elected a Fellow of the Royal Society of New Zealand and of the Royal Society London, and was awarded the degree Doctor of Science (honoris causa) by the University of Canterbury in 1999 (photo by courtesy from W. R. R.)...

Other workers have given results for the adsorption of a wide range of platinum-group metal complexes and have related the rapid rate of adsorption to the extent of surface impregnation. They attempt to correlate the rate... 

This mechanistic concept for the formation of nitrito-complexes of cobalt(iii) suggests that other analogous metal systems should yield similar materials. However, the corresponding nitrito-complexes of rhodium(iii) and of iridium(iii) were not known. One reason that previous investigators had not been successful in preparing these is that the platinum group metal complexes are usually very slow to react and rather drastic reaction conditions had been used. As a result, the stable nitro-product rather than the kinetic nitrito-product was isolated. Since the formation of M-ONO does not involve M-O bond cleavage, the reaction as shown in (18) is expected to occur even under rather mild experimental conditions. This was found to be the case and salts of the new complexes [M(ONO)(NH3)5] where M = rhodium(iii), iridium(iii) or plati-num(iv) have been prepared. ... 

Nilrosomonas eiiropaea, 727 Ammonium ions, alkyl-affinity series inorganic anions, 802 platinum group metal complexes affinity series, 808... 

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