Chloride complex spectra

Mesoionic 4-amino-l,2,3,5-thiatriazoles constitute the only class of mesoionic 1,2,3,5-thiatriazoles known. They are prepared by the reaction of l-amino-l-methyl-3-phenylguanidine with approximately 2 equivalents of thionyl chloride with pyridine as solvent (88ACS(B)63>. They are obtained as the yellow 1 1 pyridine complexes (17). The dark-violet mesoionic 1,2,3,5-thiatriazole (18) was liberated on treatment with aqueous potassium carbonate (Scheme 3). The structure is established on the basis of elemental analysis and spectroscopic data. In particular, the IR spectrum is devoid of NH absorptions. Compound (18) exhibits a long-wavelength absorption at 463 nm in methanol. When mixed with an equivalent amount of pyridinium chloride, complex (17) is formed and the absorption shifts to 350 mn. The mesoionic thiatriazoles are sensitive towards mineral acids and aqueous base and although reaction takes place with 1,3-dipolarophiles such as dimethyl acetylene-dicarboxylate, a mixture of products were obtained which were not identified. 

The nickel chloride complex(VIII) of N P (NHMe)g is paramagnetic (3.2 B.M.). The phosphorus NMR spectrum shows a single line which shifts upfield by 4.0 6 compared to the ligand. A tetrahedral structure is proposed for this complex in whioh the metal is coordinated to two antipodal nitrogen atoms of the ligand (Figure 2). 

Hirooka et al. (27, 29) recently reported that an equimolar mixture of acrylonitrile and ethylaluminum dichloride form a complex whose infrared spectrum is similar to that of the acrylonitrile-zinc chloride complex of Imoto et al. (33). The complex is a liquid above 0°C. and... 

Fig. 3. The infrared spectrum of the di-methylether-hydrogen chloride complex in the gas phase. From J. E. Bertie and D. J. Millen, J. Chem. Soc. 497 (1965). Reproduced by permission from the Chemical Society...

Commonly accepted mechanisms of the MMO reactions are based on the concept of the activation of dioxygen or the use of shunts such as H202. Nevertheless, the new mechanism of methane oxidation via an intermediate complex containing pentacoordinated carbon has been forwarded (Shilov, 1997, Karasevich et al 1998, 1999). This suggestion is based on experiments on the multiple H-D exchange and methane oxidation catalyzed by platinum (II) complexes, ([H2PtCl6], for instance). Formation of methyl platinum (IV) chloride complex in methane oxidation was confirmed by its NMR spectrum. 

Examples of this analysis mode are presented in Fig. 5. The slope of the log D versus log[L],i plots for the cobalt(II)-8 M HCl and the Fe(III)-6 M HCl systems indicate the formation of CoClj and FeClj, respectively, as the predominant complexes in the Dowex 1-X8 phase. These results are believed to prove the reliability of this approach, the presence of these complexes in concentrated hydrochloric acid being well documented. The chloride complex of uranium(IV), UClj, v 4iose unique absorption spectrum is shown in Fig. 6 [11], in the HCl, HCIO4 (I = 10 M)... 

The formation of platinum(III) [Pt(diAMsar)] + sarcophaginate by the y-radiolysis of [Pt(diAMsar)]X4 samples (where X = CF or CF3SO3I was detected by EPR spectroscopy [156], The strong split signals in the EPR spectra were observed at 4 and 77K and did not disappear even after storage of the samples at room temperature for several days. Since i Pt isotope with nuclear spin 1 - 1/2 is a dominant, the EPR spectrum must contain a triplet with the relative peak intensities equal to 1 4 1. Nearly the same spectrum (g = 2.01, the hyperfine interaction constant A 50G) was observed for [Pt(diAMsar)](CF3SO),3 sarcophaginate. For a chloride complex, the spectrum (g = 2.01, A 60G) is more diffuse, which may be due to the... 

NMR timescale in DMSO (dimethyl sulfoxide)-water solution (4 1 v/v), that is, resonances corresponding to the free ligand and the chloride complex appear separately in the spectrum. This allowed the receptor to be used to determine the concentration of chloride in a sports drink by comparing the intensity of resonances from the free ligand and complex using simple NMR methods. ... 

Available stability constants for the formation of various chloro complexes in anhydrous methanol are reported in table 3. Kozachenko and Batyaev (1971a) investigated the inner- and outer-sphere chloride complex formation in absolute and aqueous methanol for all the lanthanides which have absorption bands in the UV and visible parts of the spectrum. Stability constant data for absolute methanol reveal a slight increase in the degree of complex formation in the series Pr—Nd-Sm, followed by a decrease for the heavier lanthanide ions. Ho and Er. The stability constants are approximately three times larger than in 50% methanol and 8-9 times larger than in water. The estimated jSi s ( 0.1) amount to 0.71 (Nd), 0.82 (Nd), 1.24 (Sm), 0.50 (Ho), and 0.47 (Er). 

A differential technique is helpful in the analysis of organic compounds for traces of iron in the presence of interfering background absorption. The iron in the sample solution (solvent, 1+5 hydrochloric acid in methanol) is present as the strongly absorbing ferric chloride complex and exhibits an absorption band at 360 m/n. The reference liquid is equivalent to the sample solution except that phosphoric acid is substituted for hydrochloric. The iron phosphate complex is transparent. The phosphoric acid is presumed not to affect the spectrum of the organic background and the difference spectrum represents only the iron absorption. 

Fig. 149) (534). Attempts to make the analogous chloride complexes upon addition of chlorine to [Fe(NO)(S2CNR2)2], however, failed (1261). The v(NO) vibration in the IR spectrum lies between 1804 and 1829 cm being shifted some 100-120 cm to higher wavenumbers than in the iron(II) nitrosyls (see below). 

Perhaps the most convincing evidence for nucleophilic attack at an unexpected ring position comes from the direct observation of intermediate Meisenheimer complexes in the NMR spectrum. When 2-chloro-3,6-diphenylpyrazine is treated with KNH2 in liquid ammonia, the intermediate (29) was observed directly (Scheme 8). It was postulated that this initially formed complex rearranges to (30) which gives the observed product by elimination of a chloride ion (73RTC708). 

It gives the parent ion in the mass spectrum and has a simple IR spectrum (i (Ru=0) 1040 cm-1 and (i/(Ru—F) 720 cm-1) similar to that of the vapour (1060, 710, 675 cm-1), implying a monomeric structure. Chlorides RuOC12 and Ru2OC1x (x = 5,6) have been claimed various oxo complexes Ru2OX o are well defined. 

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