Platinum complexes pyridine

Pyridine complexes of Pd- and Pt-pincer ligands are also suitable substrates for olefin metathesis [116]. The first-generation catalyst 9 efficiently mediates the RCM of diallylphosphines and diallyl sulfide when the heteroatom is com-plexed by a cationic [C5H5(NO)(PPh3)Re] moiety [117]. This principle has been exploited in the same study for tungsten, rhodium, and platinum complexes. 

Aresta (54) has investigated the platinum complexes formed with o-allylphenol and o-allylthiophenol. The phenolic ligand reacts with the PtCl4 ion (in a suitable acetate buffer) to form the chelate complex shown in Fig. 40. The coordinated double bonds of this compound are successively replaced by two equivalents of pyridine. 

For example, in 1963 the photochemistry of magnesium phthalocyanine with coordinated uranium cations was studied in pyridine and ethanol and indicated the occurrence of PET to the uranium complex . A rapid photoinduced electron transfer (2-20 ps) followed by an ultrafast charge recombination was shown for various zinc and magnesium porphyrins linked to a platinum terpyridine acetylide complex . The results indicated the electronic interactions between the porphyrin subunit and the platinum complex, and underscored the potential of the linking para-phenylene bisacetylene bridge to mediate a rapid electron transfer over a long donor-acceptor distance. 

CsHuN, Ethanamine, A-ethyl-A-methyl-tungsten complex, 26 40, 42 C6HF5, Benzene, pentafluoro-gold complexes, 26 86-90 C H4I2, Benzene, 1,2-diido-iridium complex, 26 125 CJT, Phenyl platinum complex, 26 136 C,H,N, Pyridine osmium complex, 26 291 OHtS, Benzenethiol osmium complex, 26 304 QH7P, Phosphine, phenyl-cobalt-iron complex, 26 353 QH 1-Butyne, 3,3-dimethyl-mercury-molybdenum-ruthenium complex, 26 329-335 C6H 4P, Phosphine, triethyl-platinum complex, 26 126 platinum complexes, 26 135-140 CsHisPO, Triethyl phosphite iron complex, 26 61... 

Rate constants for chelate ring-opening in four-coordinated square-planar cf-platinum complexes [ 1,2-bis(phenylsulfinyl)ethane]dichloroplatinum(II) by a series of pyridines show from a negative deviation in a Bronsted plot (a = 0.53) an estimated rate decrease of steric origin of 200 for the 2-picoline (81IC71) (Scheme 33). 

Acyl-platinum complexes are prepared from o-hydroxybenzaldehyde (salicylalde-hyde) and KjPtCl Heating salicylaldehyde, KjPtCl and KjCOj in DMSO at 140°C for 40 min, followed by partial cooling and addition of ligands such as phosphines, arsines or substituted pyridines, gives the yellow chelated acyl complexes... 

Orchin and colleagues have studied (239, 325, 326, 514, 543-545) extensively the platinum complexes traws-(olefin)(4-ZC5H4NO)PtCl2 (212) in which the 4-substituent, Z, on pyridine-iV-oxide is OCH3, CH3, H, Cl, CO2CH3, CN, or NO2. The olefins have included ethylene (239), styrene, and 3- or 4-substituted styrenes (239, 544), 1-dodecene (544),... 

The addition of methyldichlorosilane to styrene has been carried out homogeneously in the presence of [PtCl2(CgH8)]2 246). This reaction is first-order with respect to the styrene and the silane, and first-order with respect to the platinum complex. In aromatic solvents, an induction period was observed which was attributed to coordination of the aromatic or a second molecule of styrene to the platinum. This necessity of a vacant site was further emphasized by the finding that addition did not occur in donor solvents such as tetrahydrofuran, ether, or pyridine. 

Phenyl, platinum complex, 26 136 QH,N, Pyridine, osmium complex, 26 291 OH,NO, 4-Pyridinecarboxylic acid, rhodium complex, 27 292... 

The isomerization of this Dewar pyridine to the aromatic pyridine is catalyzed by acids and some heavy metals. Palladium and platinum complexes of this Dewar pyridine have been isolated and analyzed by X-ray analysis152). The kinetics of this isomerization was studied using the complexes 1S4). 

Conversion of norbornadiene to nortricyclenes can also be achieved with organomercurials. This reaction proceeds via transmetalation to form a c-bonded organopalladium system which inserts norbornadiene. Thus an enrfo-cw-addition is observed. Conversions of this type were observed in the phenylation of dichloro(t -norbornadiene)palladium either with diphenyl-mercury or, more conveniently, with sodium tetraphenylborate to give di-/r-chlorobis(2 5,6-t -c ffo-3-phenylbicyclo[2.2.1]hept-e /o-2-yl)palladium (30) via cis addition.By contrast, the analogous platinum complex did not give a phenylation product. The palladium complex 30 underwent reversible ring closure to a nortricyclenyl complex 31 with pyridine. ... 

Another example of this type starts from exo,< xo-tetracyclo[3.3.1.0. 0 ]nonane, which reacted with Zeise s dimer, [(C2H4)PtCl2]2, to form an insoluble platinum complex. This product is solubilized with pyridine and was shown to be a metallacyclobutane complex 4. Synthesis of cxo-tricyclo[3.3.1.0 ]non-6-ene was achieved in 45-55% yield if 4 was treated with dimethyl sulfoxide. ... 

The spectroscopic properties of platinum complexes containing bidentate C-deprotonated 2-phenylpyridine or 2-(2 -thienyl)pyridine ligands was previously studied by von Zelewsky [14] and others [15]. These complexes typical-... 

On the other hand, the palladium and platinum complexes of pyridine-2-aldoxime, when treated with acetyl chloride in hot chloroform, gave stable chelates containing the acylated ligand. A monoacetylated palladium chelate was isolated in which 1 mole of pyridine-2-aldoxime was replaced by two chloride ions (see reaction XXIV). This compound was identified by its infrared spectrum, which had a strong carbonyl absorption band near 1790 cm-1. The platinum complex of pyridine-2-aldoxime gave a... 

Magnanini studied the absorption spectrum and A. Speransky found that the electrical conductivity of aq. soln. shows that only a small proportion of the salt is ionized. The soln. of the violet modification conducts electricity three times better than that of the green. G. Gore electrolyzed a cone. soln. of chromic fluoride acidified with hydrofluoric and hydrochloric acids, and found that the liquid became hot no gas was liberated at the cathode, but chlorine and ozone were liberated at the platinum anode which was not corroded. C. Poulenc showed that the salt is reduced by hydrogen at dull redness. The heat of formation is 230-95 Cals, per mol—vide infra, the dichloride. Steam transforms chromic fluoride into chromic oxide. Chromic fluoride is insoluble in water, and alcohol hydrogen chloride transforms it into chromic chloride hot hydrochloric, sulphuric, and nitric acids attack chromic fluoride only a little hydrogen sulphide converts it into black sulphide and molten alkali nitrate or carbonate converts it into chromate. A. Costachescu prepared complex pyridine salts. 

---