Pyridines complexes with

In the context of copper catalysis in important synthetic dediazoniations of arene-diazonium ions, Starkey s group (Bolth et al., 1943, Whaley and Starkey, 1946) isolated blue pyridine complexes with the constitution ArCu(C5H5N)3 by adding copper powder to pyridine solutions of ArNjBF4. However, it is unlikely that arylcopper is a relevant intermediate in these reactions (see Sec. 8.6). 

Kenausis G, Taylor C, Katakis I, Heller A. 1996. Wiring of glucose oxidase and lactate oxidase within a hydrogel made with poly(vinyl pyridine) complexed with [Os(4,4 -dimethoxy-2,2 -bipyridine)2Cl]. J Chem Soc Faraday Trans 92 4131-4136. 

Electrophilic iodine reagents are extensively employed in iodocyclization (see Section 4.2.1). Several salts of pyridine complexes with 1+ such as bis-(pyridinium)iodonium tetrafluoroborate and b/.s-(collidine)iodonium hexafluorophos-... 

Electrophilic iodine reagents have also been employed in iodocyclization. Several salts of pyridine complexes with I+ such as bis(pyiidinium)iodonium tetrafluoroborate and bis(collidine)iodonium hexafluorophosphate have proven especially effective.61 y-Hydroxy- and d-hydroxyalkcncs can be cyclized to tetrahydrofuran and tetrahydropyran derivatives, respectively, by positive halogen reagents.62 (see entries 6 and 8 in Scheme... 

Yam VW-W, Chan KH-Y, Wong KM-C, Chu BW-K. Luminescent dinuclear platinum(II) ter-pyridine complexes with a flexible bridge and sticky ends. Angew Chem Int Ed 2006 45 6169-6173. 

The carbonyl complexes listed in Table V are of two types tricarbonyl-chromium rj6-arene 77-complexes, and pentacarbonyltungsten <7-pyridine complexes, with both complex types having relatively low y. Nonlinearities increase on arene or pyridine 77-system lengthening, and on proceeding from acceptor to donor substituent on the tricarbonylchromium-coordinated arene ring. Relative magnitudes and trends thus mirror those observed with quadratic nonlinearities of these complexes (see Ref. 1)... 

In the presence of critically controlled concentrations of isonitriles and pyridines various heme spectra have been obtained with Soret maxima close to 450 nm (60). Moreover the effects of detergents and ptL on these spectra are somewhat similar to those seen with P-450 — there is a shift in the absorbtion towards 420 nm. It is clear that these unusual spectra are due to polymerisation and this has led many authors to suppose that the heme in P-450 is polymerised. (In the polymerised systems a carbon-monoxide pyridine complex with an absorption at 450 nm can even be produced.)... 

X-Ray studies of crystals of pyridine complexes with trimethylsilyl bromide and iodide (264) and of N-methylimidazole adducts to trimethyl-chlorosilane (265) were performed. The tetracoordinate silicon structure of these complexes was proved. The distances between the halogen and silicon atoms in pyridine adducts are 4.359 and 4.559 A for bromine and iodine, respectively, which is approximately 2 A greater than the sum of the covalent radii and significantly longer (0.5 A) than the sum of the van der Waals radii. This result is consistent with the ionic structures of the complexes in the solid state. The distance from silicon to nitrogen (1.86 A) is evidently larger than the length of typical Si—N bonds (1.75 A), which... 

A different behavior is found when strong nucleophiles are added to a polymerization of isobutene coinitiated with Lewis acids. When the concentration of nucleophile reaches that of Lewis acid, no polymerization is observed [5,91,268]. Quite often a precipitate, identified as a complex between Lewis acid and the nucleophile, is detected. This indicates that the complexed Lewis acid is no longer capable of ionization of the covalent species. A fractional negative order (-0.3) was reported in the polymerization of isobutene initiated by alkyl chloride/TiCL with added pyridines [268]. It is possible that a small amount of pyridine complexes with the Lewis acid, reduces its concentration, and thereby additionally shifts the equilibria from the more reactive dimeric to the less reactive monomeric TiCI4. Nevertheless, a small amount of nucleophile apparently has a beneficial effect, because polymers with lower polydispersities are formed. The plausible explanation of the role of nucleophiles in these systems will be offered in Section VILE.4. 

In several papers silver-containing complexes were used as active components of selective stationary phases. Cook and Givand [60], for example, used silver ion complexes with different compounds as stationary phases. The best separation was obtained with the silver complex with pyridine. Complexes with 2,6-dimethylpyridine, quinoline, isoquinoline, 2,2-bipyrryl, etc., did not interact with olefins, which can probably be explained by steric factors [60]. 

However, the behavior or function of spilt-over hydrogen on zeolite is not clear yet. Pyridine, which is a typical organic base, is chemisorbed on either Brpnsted (B) acid site or Lewis (L) acid site to form pyridinium ion or coordinately bonded pyridine complexes with B or L acid sites, respectively, and giving different IR-adsorption bands [7]. Therefore, the change in the IR band of adsorbed pyridine on B or L acid sites could be attributed to the change in the adsorbed pyridine on acid site. 

Preparation of Polythioesters by the Reaction of Adipoyl Chloride-Pyridine Complex with Hexanedithiol [5]... 

Based on the potential isolobal relationship between [Fe(CO)3] and [C PDI)Fe], we sought to prepare a formally iron(O) bis(itriino)pyridine complex with a thermally labile ligand. Dinitrogen seemed an ideal target ligand that could readily be... 

The further coordination of copper pyridine complexes with other ligands in methanol has been studied by investigation the absorption spectra and by studying equilibria of cupric nitrate and pyridine in methanol in the presence of solid Cu(F r) (NOj)j. If addition of a ligand X to such a system leads to... 

The same series of reductants has been used to compare rates of reduction of the complexes c/j-[Co(en)2(A)Cl] + where A = py or PVP, the polymer poly-4-vinyl-pyridine. Complexes with degrees of polymerization (P/i) of 19 and 98 and degrees of co-ordination (x) = 0.3—0.7 were used. For the series, the rates were fairly well defined by the rate law (3)... 

Figure 2.29. Binuclear Ru" poly(pyridine) complexes with elongated bridges.

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