Platinum complexes cyclopentadienyl

F,SCH, Methanesulfonic acid, trifluoro-iridium, manganese and rhenium complexes, 26 114, 115, 120 platinum complex, 26 126 OiFeCgH, Iron, acetyl dicarbonyl (if -cyclopentadienyl)-, 26 239 0,FeN2C2 Hll(, Iron, tricarbonylbis(2-isocy-ano-l,3-dimethylbenzene)-, 26 54 0.iMoNaCHH5-2 C4H ,02, Molybdate 1 -), tricarbonyl(T) -cyclopentadienyl)-sodium, compd. with 1,2-dimethoxy-ethane-(l 2), 26 343 0,NaWC H5-2 C4H ,02, Tungstate(l -), tricarbonyl(ris-cyclopentadienyl)-... 

OBFaMoPCssHso, Molybdenum(l +), car-bony (ti -cyclopentadienyl)(di-pheny acety ene)(triphenylphosphine)-, tetrafluoroborate(l -), 26 104 OBPjRhSsCwH, Rhodiurn(m), [[2-[(di-phenylphosphino)methyl]-2-methyl-l,3-propanediyl]bis(diphenylphos-phine)l(dithiocarbonato)-, tetraphenyl-borate(l-), 27 287 OCH4, Methanol, platinum complexes, 26 135... 

Formation of a siloxane network via hydrosilylation can also be initiated by a free-radical mechanism (300-302). A photochemical route makes use of photosensitizers such as peresters to generate radicals in the system. Unfor-timately, the reaction is quite sluggish. Several complexes of platinum such as (jj-cyclopentadienyl)trialkylplatinum(rV) compoimds have been found to be photoactive. The mixture of silicone polymer containing alkenyl functional groups with silicon hydride cross-linker materials and a catalytic amoimt of a cy-clopentadienylplatinum(IV) compound is stable in the dark. Under UV radiation, however, the platinum complex imdergoes rapid decomposition with release of platinum species that catalyze rapid hydrosilylation and network formation (303-308). Other UV-active hydrosilylation catalyst precursors include (acetylacetonate)Pt(CH3)3 (309), (acetylacetonate)2Pt (310-312), platinum tri-azene compounds (313,314), and other sytems (315,316). 

The Group VIII cyclopentadienyl complexes of formula CpM(NO) (M = Ni, Pd, Pt) have all been synthesized. The nickel complex is best prepared from nickelocene and nitric oxide, and a method for the preparation of the nickelocene m situ without its isolation has been described (56). The palladium complex can be prepared from [Pd(NO)Cl] and sodium cyclopentadienide (23) and the platinum complex from Pt2(CO)2Cl4 and sodium cyclopentadienide and nitric oxide (22). The microwave (13) and infrared spectra (18) of CpNi(NO) have received detailed study, and the electronic structure of the complex is discussed in an early paper (77). 

G. K. Anderson, Synlett, 1995, 681-686. Novel Bonding Modes in Monomeric and Dimeric Palladium and Platinum Complexes with Cyclopentadienyl Ligands. 

Bis(benzenethiolato)titanocene functions as the metallaligand of a platinum complex with two pentafluorophenyl ligands (281, Equation (77)), and the Mo-Ti-Pt ternary complex 282 has been prepared by using a Ti-Mo dinuclear precursor with bridging diphenyl(cyclopentadienyl)phosphine (Equation (78)). ... 

The early miscellaneous studies have been summarized [2, 3] and cover a wide range of structural types. Systematic studies have included amines, cyclopentadienyls and macrocycles, although much of the recent data has been accumulated for amines, because of the structural similarities to the platinum complexes. As of early 1987 no nonplatinum metal complexes are undergoing full clinical trials, but there are promising leads from animal studies. This chapter, rather than presenting an exhaustive account of all complexes studied, will attempt to demonstrate the great diversity of metal complexes that have been shown to have antitumour activity in standard screens. Some systems have been examined in detail and these will be summarized. Perhaps of more importance than the diversity of structural types is the range of mechanisms by which these complexes are believed to act. 

Electric neutraUty of the compounds, postulated as an essential prerequisite for the achievement of cytostatic properties in the case of platinum complexes is obviously not a crucial condition for cyclopentadienyl metal complexes to exhibit antitumor properties. There exist, on the one hand, numerous neutral compounds such as the metallocene diaddo complexes I-XLIU and the decasubstituted main group IV metallocenes LVn-LIX exhibiting antiproliferative properties on the other hand, marked tumor-inhibitmg potendes were also found with the charged ferricenium salts XLIX-LVI as well as with the ionic cyclopentadienyl titanium complexes Xl.IVXLVlll wherein the titanium-containing unit may either form the cationic or the anionic moiety. Because of... 

Another polymerization that proceeds under the influence of a photogenerated catalyst is the hydrosilylation reaction. In a patent, Drahnak described the photoinduced addition of Si-H functional silanes to poly(dimethylsiloxane)s containing pendant and terminal vinyl double bonds. This reaction is catalyzed by the in situ generation of a colloidal platinum hydrosilylation catalyst, [Pt(0)] c/ by the photolysis of T -cyclopentadienyl(trimethyl)platinum complex, 7. The proposed mechanism is shown in eqns [11] and [12] of Scheme 4. Reportedly, this chemistry has been used to generate crosslinked silicone elastomers. ... 

The general methodology outlined above for the synthesis of platinum(II) cyclopentadienyls from platinum halide complexes and either TlCpl l or [HgCp2]2 has been utilized in a number of synthetic schemes. 

Allyl Complexes. Allyl complexes of thorium have been known since the 1960s and are usually stabilized by cyclopentadienyl ligands. AEyl complexes can be accessed via the interaction of a thorium haUde and an aHyl grignard. This synthetic method was utilized to obtain a rare example of a naked aHyl complex, Th(Tj -C2H )4 [144564-74-9] which decomposes at 0°C. This complex, when supported on dehydroxylated y-alumina, is an outstanding heterogeneous catalyst for arene hydrogenation and rivals the most active platinum metal catalysts in activity (17,18). 

The first metal-olefin complex was reported in 1827 by Zeise, but, until a few years ago, only palladium(II), platinum(Il), copper(I), silver(I), and mercury(II) were known to form such complexes (67, 188) and the nature of the bonding was not satisfactorily explained until 1951. However, recent work has shown that complexes of unsaturated hydrocarbons with metals of the vanadium, chromium, manganese, iron, and cobalt subgroups can be prepared when the metals are stabilized in a low-valent state by ligands such as carbon monoxide and the cyclopentadienyl anion. The wide variety of hydrocarbons which form complexes includes olefins, conjugated and nonconjugated polyolefins, cyclic polyolefins, and acetylenes. 

C,Hj, Acetic acid palladium complex, 26 208 tungsten complex, 26 224 02CiH(, 2-Propenoic acid, methyl ester platinum ester, 26 138 02C4Hu, Ethane, 1,2-dimethoxy-solvates of chromium, molybdenum, and tungsten carbonyl cyclopentadienyl complexes, 26 343 tungsten complex, 26 50 ytterbium complex, 26 22 02C4Hi, -NaCsHs, Ethane, 1,2-dimethoxy-compd with cyclopentadienylsodium(l l), 26 341... 

Cyclopentadienyl complexes of platinum are known for both the divalent and tetravalent oxidation states. Examples of both rfs and rj1 complexes are shown in equations (290) and... 

The complex (197) with a dithiocarboxylate ligand coordinated to platinum(II) bonded through both monodentate carbon and die chelating dithiocarboxylate ligand has been prepared from either the thiocarbonyl platinum(II) precursor or the carbon disulfide adduct of platinum(O).1796,1797 A cyclopentadienyl-substituted dithiocarboxylate ligand (198) can be used to prepared S,S-bonded platinum(II) and (IV) complexes Pt(C5H4CS2)2 and PtfCsKtCS 2-. The complexes show v(PtS) at 340 cm-1, and in each case electronic absorption bands of the Pt— L type are at 19 500 cm-1 and 29 500 cm-1.1798... 

The types of compounds formed by gold(I) and gold(III) often differ from those of other metals due to the constraints imposed by coordination number and electron count at the metal. Thus, for example, whereas 7r-bonded cyclopentadienyl complexes of palladium and platinum are numerous (336), and a copper(I) species of this type is known (337), cyclopentadienyl complexes of univalent (94, 96, 97) and trivalent (228) gold have invariably been found to be fluxional behavior, similar to that in dicyclopentadienylmercury, was involved (228). 

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