Compounds Containing Heteroatoms

While nitrogen, sulfur, silicon, and phosphorus are important heteroatoms, we will look briefly only at nitrogen and sulfur compounds. In generak when the heteroatom is incorporated into an aromatic ring, strong molecular ions are seen. Table 10.4 should be reviewed to remind you of the isotope ratios for these heteroatoms to help in interpreting spectra. 

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This chapter will not cover compounds containing heteroatoms hnked to the P and/or N atom of the P-N unit, with the notorious exception of those with N-Si bonds (A/-silyl phosphinous amides) due to its particular relevance in terms of chemical reactivity. 

Catalyst Inhibition Caused by Compounds Containing Heteroatoms... 

The introduction of silyl substituents also causes significant effects on the redox properties of compounds containing heteroatoms such as oxygen, nitrogen, and sulfur. 

The electrooxidation of organosilicon compounds containing heteroatoms has been investigated extensively and various synthetic applications have been developed. Cooper and Owen studied the oxidation potentials of a series of silyl-substituted amines, phosphines, and sulfides, and observed that silyl substitution at the carbon adjacent to the heteroatom caused a significant decrease in the oxidation potentials (Table 4) [35]. 

After a plate has been exposed to the mobile-phase solvent for the required time, the compounds present can be viewed by several methods. Polynuclear aromatic hydrocarbons, other compounds with conjugated systems, and compounds containing heteroatoms (nitrogen, oxygen, or sulfur) can be viewed with long-and short-wave ultraviolet light. The unaided eye can see other material, or the plates can be developed in iodine. Iodine has an affinity for most petroleum compounds, including the saturated hydrocarbons, and stains the compounds a reddish-brown color. 

Other compounds containing heteroatom-heteroatom bonds have been reported as 5-LO inhibitors. Diphenyldisulphides and substituted analogues, as well as disulphiram (108), inhibited cRBL and LT release from zymosan-stimulated mouse macrophages (0.3-20 / M) [277, 278]. A number of thiosulphinate esters such as (109) and related compounds, isolated from onion and garlic, were likewise active in cells and cell-free enzymes over the... 

Two additional examples of aromatic compounds containing heteroatoms eire shown in Figure 6-14. In both compounds, the heteroatom has two lone pairs. However, only one of the pairs is in a p-orbital perpendiculcir to the plane of the ring. The other electron pair is in the plane of the ring. 

Alkaline earth metal oxides are active catalysts for double bond isomerization. For example, SrO exhibits high activity and selectivity for the isomerization of a-pinene to /1-pinene 110). MgO and CaO have excellent activities for isomerization of 1-butene and 1,4-pentadiene and, particularly, for isomerization of compounds containing heteroatoms, such as allylamine or 2-propenyl ethers 111-115). Recently... 

The VUV absorption spectra of alkanes are rather featureless, usually without marked peaks (as shown in Fig. 1 for -hexane) in contrast to the spectra of aromatics or to the spectra of compounds containing heteroatoms. Earlier works usually assumed that at low energies in alkanes the excitation results in o- o -type valence-electron transitions, but later works concluded that the excitations, at least partly, result in Rydberg states [20-23]. 

There is much current interest in four-membered ring compounds containing heteroatoms that are isoelectronic with a cyclobuta-l, 3-dienediide. The first thermally robust parent homocyclic dianion [ CfSiMe,), " was only reported in 2000 the first neutral heterocyclic analogue [P(C6H2Bu 3-2,4,6) p-C( Cl) ]2, containing a Group 14 element (C) dates from 1995 Extensions to the 4" and 5" quantum group elements Ge and Sn respectively, were published in 2004. 

Organic Aspects of Photochemistry Photoreactions of Compounds Containing Heteroatoms Other Than Oxygen , A. Gilbert, in Photochemistry , ed. D. Bryce-Smith, Royal Society of Chemistry, London, 1970, vol. 1, pp. 351-391. 

Densities of various hydrocarbon compounds have been reported at 20, 25, and 30 °C [35-39] including temperature coefficients of density at 25°C. For 1-alkenes, for example, the coefficients decrease with increasing Nq in the range from 0.001034gem-3 °C I for 1-pentene to 0.000733gcm 3 °C 1 for 1-dodecene. For hydrocarbons and various compounds containing heteroatoms, density/temperature correlations have been presented as a polynomial function of the type... 

Bicyclo[2.2.1 ] compounds containing heteroatoms in the ring system... 

Compounds Hydrocarbons, organic compounds containing heteroatoms (O, N)... 

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