Chloride complex susceptibility

The mechanism of the Etard reaction is not completely known.291 An insoluble complex is formed on addition of the reagents, which is hydrolyzed to the aldehyde. The complex is probably a kind of acylal, but what the structure is is not fully settled, though many proposals have been made as to its structure and as to how it is hydrolyzed. It is known that ArCH2CI is not an intermediate (see 9-20), since it reacts only very slowly with chromyl chloride. Magnetic susceptibility measurements292 indicate that the complex from toluene is 27, a structure first proposed by Etard. According to this proposal the reaction stops after... 

The pharmaceutical interest in the tricyclic structure of dibenz[6,/]oxepins with various side chains in position 10(11) stimulated a search for a convenient method for the introduction of functional groups into this position. It has been shown that nucleophilic attack at the carbonyl group in the 10-position of the dibenzoxepin structure renders the system susceptible to water elimination. Formally, the hydroxy group in the enol form is replaced by nucleophiles such as amines or thiols. The Lewis acids boron trifluoride-diethyl ether complex and titanium(IV) chloride have been used as catalysts. 

Copper(II) complexes of 2,6-lutidylphenylketone thiosemicarbazone, 38, have been prepared from copper(II) chloride and copper(II) bromide [186]. Similar to 2-pyridyl thiosemicarbazones, 38-H coordinates via the ring nitrogen, the azomethine nitrogen and the thiol sulfur based on infrared spectral assignments. Magnetic susceptibilities and electron spin resonance spectra indicate dimeric complexes and both are formulated as [Cu(38-H)A]2 with bridging sulfur atoms. The electronic spectra of both halide complexes show band maxima at 14500-14200 cm with shoulders at 12100 cm S which is consistent with a square pyramidal stereochemistry for a dimeric copper(II) center. 

In this study, we extend the range of inorganic materials produced from polymeric precursors to include copper composites. Soluble complexes between poly(2-vinylpyridine) (P2VPy) and cupric chloride were prepared in a mixed solvent of 95% methanol 5% water. Pyrolysis of the isolated complexes results in the formation of carbonaceous composites of copper. The decomposition mechanism of the complexes was studied by optical, infrared, x-ray photoelectron and pyrolysis mass spectroscopy as well as thermogravimetric analysis and magnetic susceptibility measurements. 

Aten, J. et al., Susceptibility to the induction of either autoimmunity or immunosuppression by mercuric chloride is related to the major histocompatibility complex class II haplotype. Eur. J. Immunol., 21, 611, 1991. 

Type III (immune complex related disease) reactions have been demonstrated by the presence of proteinuria and immune complex deposits in the kidneys of the Brown-Norway, Lewis, and PVG/C rat strains. However, susceptibility to the deposition and the subsequent lesions (glomerulamephritis) are often variable and dependent on the strain (Bigazzi, 1985). For example, despite the appearance of clinical signs and proteinuria, after two-months administration of mercuric chloride, detectable levels of circulating antinuclear autoantibodies can no longer be observed in the Brown-Norway strain (Bellon et al., 1982). By contrast, in PVG/C rats administered mercuric chloride, immune complex deposition and antinuclear autoantibodies are present for longer periods of time however, proteinurea is not observed (Weeping et al., 1978). 

In general, the effects of complexing on the reactivities of the mercuric (Korinek and Halpern, 26) and silver (Webster and Halpern, 12) ions are susceptible to similar interpretations, although it should be noted that the order of activity of the various complexes differs for the three metals. Thus, the chloride and acetate complexes of the mercuric ion (which are much more stable than the corresponding cupric complexes) are less reactive than the aquo complex, while the relatively unstable sulfate complex is more reactive. In the case of silver, the acetate and ethylenediamine complexes are more reactive than the uncomplexed ion, while the very stable cyanide complex is inactive. 

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