Platinum complexes diketonates

An MlP-catalyzed ene reaction between a diketone and an alkene was used to further investigate this phenomenon. The most easily accessible binding sites of an MIP-containing chiral phosphine platinum complexes were poisoned by using diamine derivatives of binaphthol (i.e., 2,2 -diamino-l,l -binaphthalene BINAM) to block access to the substrate (Scheme 20)." ... 

One or both carbonyls in /3-diketones can be reduced, as well as the carbonyl function in acyl cyanides (210). Similar treatment of a,/3-unsat-urated ketones and aldehydes can lead to the saturated carbonyl products via selective reduction of the olefinic bond (207, 208, 210) see Eq. (51) in Section III,A,4. Some terpenes (a- and /3-ionone, pulegone) were reduced in this way (208). Platinum(II) phosphine complexes have been used for the hydrosilylation of saturated ketones and could be used for the reduction (211). 

Complexes of platinum(II) with /J-monothiodiketonates, derived by deprotonation of the parent acid (207), can be prepared from PtCl -. The dark red complex Pt(C3H(Ph)2SO 2 (R = R = Ph) shows IR bands at 1535 cm-1 [v(C=C)], 1410 cm-1 [v(O O)] and 1270 cm-1 [v(O S)].1824 Electronic spectra and dipole moment data for these complexes have been compared with the O.O -diketonate complexes.182s 1826 The structure of the phenyl derivative has been confirmed by X-ray crystallography.1827 Detailed dipole moment measurements using static polarization have been made with fluorinated jS-monothiodiketone complexes. Variations with substituent depend on the magnitude and vector directions of the Ph—X bond moments (aryl substituents), the inductive effect of the meta and para substituent on the phenyl ring, and the mesomeric effect of the substituent X.1828 A useful separation method for bis(monothiotrifluoroacetylacetonates) of platinum(II) is gas chromatography.1829... 

The complexes (l,5-cyclooctadiene)(2,4-pentanedionato)-palladium(II) and platinum(II) tetrafluoroborate are air-stable solids, soluble in polar organic solvents such as chloroform, methylene chloride, acetonitrile, acetone, or methanol but insoluble in nonpolar solvents such as alkanes, benzene, or ether. Their solutions in acetone have conductivities typical of 1 1 electrolytes. Their proton magnetic resonance spectra (in CDC13 solutions, internal tetramethylsilane reference at 60 MHz.) show peaks due to coordinated cyclooctadiene at 3.78 and 6.7-7.4r (Pd) and at 4.25 and 6.9-7.6r (Pt) and due to the chelated /3-diketone at 4.39 and 7.88r (Pd) and at 4.15 and 7.81r (Pt) with the expected area ratios. In the spectrum of the platinum compound coupling with the 95Pt isotope (33 %... 

Recent studies indicate the reaction of platina-/3-diketone with bipyridines via oxidative addition yields the diacyl hydrido Pt(IV) complex. Further ligand abstraction may result in H bond bridged dimer and a double-deck dimer through Pt Pt interaction (Scheme 17). On the other hand, the prototype of unsupported cis- diacyl platinum(II) species was obtained either via nucleophilic addition to cationic acyl carbonyl complexes or CO insertion into a trans acyl alkyl complex (Scheme 18). In the latter process for propionyl methyl or acetyl ethyl complex. 

Dianions of /3-diketones are also known to form metal complexes, but are much less common than systems containing the monoanion. Such complexes usually involve main group elements or members of the platinum group, and may be coordinated to the O atoms (18) or terminal C-atoms (19). ... 

After the serendipitous discovery of the antitumor properties of cisplatin (m-diaminedichloro-platinum), much effort has been devoted to finding other anticancer metal agents, and several Sn, Ti, Zr, and Hf /3-diketonates have been proven to possess interesting biological activity. For example, budotitane ((EtO)2Ti(bzac)2) was the first non-Pt metal complex to reach clinical trials as a potential anticancer agent.11-15... 

One of the most versatile classes of ligands in coordination chemistry is that of the /3-diketonates, of which the most common is the acetylacetonate, (acac), Figure 9.1. The coordination chemistry of this ligand first appears in the literature in work by Combes in 1887-1894. Alfred Werner also published on the chemistry of the acac ligand in 1901. The acac ligand is remarkable in that it forms complexes with virtually any metal, including beryllium, lead, aluminum, chromium, platinum, and gadolinium. 

Various metal complexes including palladium, platinum and nickel catalysts can be used in the two reactions. Thus 1,4-diketones are available in high yields from siloxycyclopropanes and acid chlorides in the presence of bis(triphenylphosphane)palladium(II) chloride [(Ph3P)2PdCl2], bis(triphenylphosphane)platinum(II) chloride [ Ph3P)2PtCl2] or similar catalysts. ... 

Figure 2.48 Mesomorphic platinum(II) imine / -diketonate complex...

In subsequent investigations, in which solutions of salts the cations of which form complexes with unsaturated organic compounds were used as stationary phases, palladium and platinum derivatives were suggested [76]. Dicarbonylrhodium j3-diketonates show more interesting selectivity relative to olefins [77, 78]. Of the series of the rhodium compounds investigated, the best selectivity was shown by Rh(CO)2(3-trifluoroacetyl-camphorate) (1) [144—149] ... 

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