Platinum-metal complexes

Although Rh(PPh3)3Cl has been the only decarbonylating reagent employed to date, other platinum metal complexes may prove to be equally, if not more effective. Still to be tested are Ru(II), Pt(0), Pd(0), and other Rh(I) compounds, to mention a few. 

Nonsymmetrical ligand substitution reactions also play an important role in a number of biological processes. One of these concerns the antitumor activity of platinum metal complexes, for which substitution processes involving DNA moieties are generally accepted to... 

The study of C02 complexes of platinum metal complexes remains an enigma, at least in our hands. 

Mestroni G, Alessio E, Calligaris M, Attia WM, Quadrifoglio F, Cauci S, Sava G, Zorzet S, Pacor S (1989) Chemical, biological and antitumor properties of mthenium(II) complexes with dimethyl sulfoxide. In Alessio E, Clarke MJ (eds) Ruthenium and other non-platinum metal complexes in cancer chemotherapy. Springer-Verlag, Berlin, New York, pp 71-87... 

Although the visible and ultraviolet spectra of the platinum metal complexes serve as a valuable means to follow their reactions, this feature is especially disturbing to one who is trying to establish the energy states for a particular species. Some care is necessary to establish that the measured spectrum results from the particular complex species of interest, and not some of its reaction products. Water is an effective nucleophile for these complexes. To avoid solvation of some platinum complexes, Mason and Gray (21) have recently reported spectra of the tetrabutyl-... 

R.W. Cockman, E.A.V. Ebsworth, J.H. Holloway, H. Murdoch, N. Robertson, P.G. Watson, In Reaction of Non-metal Fluorides with some Platinum Metal Complexes, J. Thrasher, S. Strauss (Eds.), ACS Symposium Series, ACS Books, 1994. 

Tertiary phosphine complexes of the platinum metals Complexes in which the metal has an oxidation state of zero... 

Any detailed description of the mechanism of an octahedral substitution must also account for the stereochemical changes that accompany reaction. Werner recognized this and made use of it in his discussions of the stereochemistry of reactions of cobalt(III) complexes. The available experimental results can be explained on the basis of possible molecular rearrangements and some cautious predictions can even be made. The base hydrolysis of cobalt III)ammines appears to be unique in that it often occurs with rearrangement it also affords the few known examples of optical inversion. These results can be explained by formation of a 5-coordinated species with a trigonal bipyramidal structure. Optically active metal complexes racemize by either an intramolecular or an in-termolecular process. Substitution reactions of platinum metal complexes often occur with retention of configuration. 

However, it is kinetically inert and requires a catalyst for this and many other of its reactions. Generally, heterogeneous catalysts such as CuO and Rh203 are used, though homogeneous catalysis has been reported for some reactions of nitric oxide. For example, a number of platinum metal complexes, as well as metals and metal oxides, can catalyze the oxygen transfer reaction ... 

Recent literature describes the synthesis of vinyl esters in the presence of platinum metal complexes. Complexes which have proven particularly suitable in this context are those of ruthenium (eq. (15)), such as, for example, cyclooc-tadienylruthenium halides [36], ruthenium carbonyl complexes, and ruthenium acetate complexes [37]. A characteristic feature of these is their high selectivity with regard to acetylene, so that the production of acetylene polymers is reduced. 

R 388 M. A. Fedotov, Nuclear Magnetic Resonance of Donor Atoms as a Tool for Determination of the Structure of Platinum Metal Complexes in Solutions , Russ. Chem. Bull. (Translation of Izviestiya Akademii Nauk, Seriya Khimicheskaya), 2003,52, 781... 

More than 20 years ago, Pringle and co-workers showed that hydrophosphination is a suitable reaction to prepare useful phosphine ligands for homogeneous catalysis by using platinum metal complexes. More recently, this reaction has been extended to the preparation of P-stereogenic phosphines and derivatives. 

A series of mononuclear platinum metal complexes have also been prepared. 

These points all refer to alteration of the inherent chemistry of the bases, which, although not emphasized in relation to platinum metal complexes and their antitumour activity, is a recognized lesion which may lead to cell kill through inhibition of DNA synthesis. Further features of metal—nucleobase chemistry are the dynamic features of... 

Non-platinum metal complexes with antitumour activity in murine screens are known for a wide diversity of structural types and the transition metals most studied include rhodium, ruthenium, gold, copper and titanium. The spectrum of activity is generally different to cisplatin (Ti, Au) and in some cases the complexes show lack of cross-resistance with cisplatin-resistant lines. 

Blum J., Pickholtz Y. Homogeneous catalytic isomerization of allylbenzene and phenylbutenes by some platinum-metal complexes. Isr. J. Chem. Soc. 1969 7 723-733... 

A further interesting example is WO 96 16959 A1 (6 Jun 1996) granted to Borealis A/S. This describes a polymerization system based on a new type of platinum metal complex containing cyclic thioether ligands, activated by alumoxanes. High molar ratios of alumoxane to platinum are, however, still required and the activities are unremarkable. 

Reaction of Nonmetal Fluorides vdth Some Platinum Metal Complexes... 

The desulfonation of aromatic sulfonyl halides to aromatic halides can be catalyzed by platinum metal complexes [e.g., Rh(CO)Cl(PPh3)2] (Blum and Scharf, 1970). 

M. J. Clarke, Ruthenium and Other Non-Platinum Metal Complexes in Cancer Chemotherapy, Springer-Verlag, Berlin (1989). 

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