Planar compounds

Details of some inducible P450 forms that play key roles in the metabolism of xenobiotics are shown in Table 2.4. P450s belonging to family lA are induced by various lipophilic planar compounds including PAHs, coplanar PCBs, TCDD and other dioxins, and beta naphthoflavone (Monod 1997). As noted earlier, such planar compounds are also substrates for P450 lA. In many cases, the compounds induce the enzymes that will catalyze their own metabolism. Exceptions are refractory compounds such as 2,3,7,8-TCDD, which is a powerful inducer for P450 lA but a poor substrate. 

They require some form of adsorption chromatography (usually with carbon) to isolate planar compounds. 

Incorporation of tricoordinate phosphorus to three delocalized systems resulted in 30, a planar compound (B3LYP/6-31 H-G(d,p)) exhibiting equalized... 

The relation between UV- and PES-spectra is quite similar as found for planar aromatic compounds. All chemical shifts in NMR-spectra can well be explained by normal ring-current effects and Van der Waals interactions. Polarographic data do not deviate from those for planar compounds. 

Neglecting the contribution of adsorption, especially for planar compounds and at low concentrations, may cause substantial underestimation of Kid. This is shown in Illustrative Example 9.2 for phenanthrene sorption to various soils and sediments (Huang et al., 1997). 

For this nonionic, planar compound, you have to take into account both absorption to POM and adsorption to a high-affinity sorbent (e.g., black carbon). For Chelsea I soil, was measured as 0.056 kg oc-kg1 solid. The /bc was not measured, but in sediment samples it is typically between 1 and 10% of they. (Gustafsson and Gsch-wend, 1998). Use the full range of 1 to 10% to see the possible impact of adsorption to black carbon (i.e., fhc = 0.00056 to 0.0056 kg bc-kg1 solid). Assume nt 0.7 and use Eq. 9-28 to estimate K ... 

Boiling points and melting points are considered from the point of view of intermolecular forces between the molecules, together with solubilities and chromatographic behavior, both gas and liquid chromatography. The topic of aromaticity and stability in general is covered as befits its importance. Conformations, particularly of the cyclic non-planar compounds, are dealt with. A section on tautomerism covers both prototropic tautomerism (annular and of substituents) and ring-chain tautomerism. 

The organometallic complexes of nickel(II) of general formula [NiX(R)(PR3)2] and [NiR2(PR3)2] are invariably diamagnetic square planar compounds like (156)1196 and (157).1200 The cationic complex [Ni(Me)(PMe3)4]BPh4, on the other hand, is five-coordinate.1199... 

Recently, stable organometallic compounds derived from Ni(acac)2 have been described. The square planar compounds [Ni(acac)(PR3)L] (R = Ph, Cy L = Me, Et) were obtained by reacting Ni(acac)2 and PR3 in ether at -20 °C with either diethyl- or dimethyl-aluminum monoethoxide.1546,1547,1577 [Ni(acac)(Me)PPh3] reacts with diphenylacetylene at room temperature, according to equation (183).1578... 

Some square-planar compounds of the type [Ni(AA)2]X2 are reported to undergo reversible thermochroic behavior when heated beyond the temperature range for dehydration. This behavior has been attributed to reversible square-planar to octahedral conversion.87 88 However, the thermochroic behavior of the similar copper compound, [Cu(AA)2](C104)2 (where AA is N,N-di-ethylethylenediamine), does not involve a change in coordination number rather, a change in the in-plane field strength appears to be the cause.89... 

Halides. The four teirahalides of carbon are symmetrical, planar compounds, with the general property of marked stability to chemical reactions, although die tetraiodide utideigocs slow hydrolysis in contact with water to form iodoform and iodine. It also decomposes under the... 

Draw atomic-orbital models for thiophene and imidazole that are consistent with their being planar compounds with six 77-electron systems associated with five atomic nuclei. 

In 1931, Erich Htickel postulated that monocyclic (single ring) planar compounds that contained carbon atoms with unhybridized atomic p orbitals would possess a closed bond shell of delocalized n electrons if the number of n electrons in the molecule fit a value of 4 + 2 where n equaled any whole number. Because a closed bond shell of n electrons defines an aromatic system, you can use Hiickel s Rule to predict the aromaticity of a compound. For example, the benzene molecule, which has 3 n bonds or 6 n electrons, is aromatic. 

The crystal and molecular structures of 2-substituted 8-azahypoxanthine derivatives 63 have been determined from X-ray data using MoXa radiation. The propoxy group has a strong intramolecular hydrogen bond to N-l of the purine, and that in turn led to a planar compound. The 2-propoxyphenyl and N-methyl-iV-isopropylsulfonyl derivatives are present as the N-9-H tautomers, but the propylsulfonyl compound exists as the... 

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