Parent function

In each case, the N atom is sp hybridized, with one lone pair of electrons and three o-bonds. A quaternary ammonium ion is a tetrahedral ion of the form R4N, where as many as three of the R groups (which may all be different) can be replaced by H atoms. For example, the tetramethylammonium ion, (CH3)4N+, and the trimethylammonium ion, (CH3)3NH+, are quaternary ammonium ions. The amino group, the parent functional group of amines, is —NH2. 

Numerous aromatic nitro compounds have explosive properties, and thus it is important to understand the role that enthalpy of formation has on the sensitivity and long-term stability of these compounds. We will examine three nitro-substituted aromatic families for which thermochemical data can be found in the literature2,84 derivatives of nitrobenzene, aniline and toluene. The choice of these three families allows us to compare the various electronic effects exerted by the parent functional group. The parent compounds differ electronically with respect to the aromatic ring in that ... 

Most of the functional groups obtained in this work have very high absorption coefficients comparatively with the parent functions and this technique can also be usefull to improve their detection in polymer matrix. From this point of view, reactions as saturation of double bonds or oxidation of NH group into nitroxyl radical can allow to follow these groups in situ along typical reactions as the ageing. 

Acetal and ketal carbon nuclei are shielded relative to the parent functions. Their shifts occur at 105 + 5 ppm, reflecting the change from sp2 carbonyl to sp3 dialkoxy carbons. Increasing the number of alkoxy groups successively enhances the associated carbon shift. But the effects are not additive when comparing the data of formaldehyde dimethyl-acetal, triethyl orthoformate and tetramethyl orthocarbonate. 

An interesting selectivity, that appears to be fairly general, is observed in the catalytic hydrogenation of 2-fluoro-2-nitroalkanoates and -alkanamides 15 and 17, respectively. Both substituents are reduced in the esters, while in the amides only fluorine is replaced, despite using various catalysts. The parent functional group remains untouched in all of the reductions. 140... 

You first should decide what type of compound it is. The decision usually is straightforward for hydrocarbons, which will fall in one or the other of the categories alkanes, alkenes, alkynes, arenes, cycloalkanes, and so on. But when the compound has more than one functional group it is not always obvious which is the parent function. For example, Compound 1 could be named as an alkene (because of the double-bond function) or as an alcohol (because of the OH function) ... 

There are no simple rules to follow that dictate which is the parent function, and we suggest that the order of precedence of functional groups set by Chemical Abstracts be used whenever possible (see Table 7-1). By this system, the OH group takes precedence over hydrocarbons, and Compound 1 therefore is named as an alcohol, not as an alkene. 

The first step is to identify the parent function, which usually is determined from the suffix or word at the end of the name. Suppose, for example, that a structure is to be written for a compound having the name 3-methoxy-butanal. The suffix -al is the IUPAC suffix for aldehyde therefore the compound is an aldehyde and the function is —CHO. 

The substituent name for the OH group is hydroxy and should be used whenever the OH group is not the parent function (see Table 7-1). Notice how the precedence rules apply — hydroxy below carboxylic acid and hydroxy below ketone ... 

A troublesome point in naming chemical compounds concerns the rules governing when a compound is to be written as a single word (as methylamine) or as two or more words (as methyl chloride). To solve this problem, you must determine whether the principal or parent function is an element or a compound in its own right if it is either one, then the name is written as a single word. 

However, if the parent function cannot be construed as being a real compound, the name is correctly written as two or more words. For example, CH3CI could be named as a chloride, in which case we use two words, methyl chloride, to describe it. A chloride, or any halide, is a class of compound, not a specific compound. To identify a specific halide, the adjective that describes the halide is written as a separate word preceding the class name. Examples follow in which the class name is italicized 3... 

From the known values of the Clebsch-Gordan coefficients, determinantal wavefunctions with selected angular momenta can easily be evaluated by adding to the parent function the new non-equivalent electron orbital and taking into account the Clebsch-Gordan coefficient ... 

Such a distinction is made here for two reasons a) In the cases where the theoretical considerations lead to a given vxc directly, the parent functional is not known, b) In the process of developing approximations to the exchange-correlation functional, it is frequently the case that the functional is tested on electron densities obtained with a potential corresponding to another exchange-correlation potential i.e. not self-consistently. 

The empirical mPBE functional39 discussed in the previous section leads to slightly better equilibrium interatomic distances for the He2, Ne2, and Ar2 dimers without, however, affecting the interaction energies compared to the parent functional (PBE). 

In this case the eigenfunction must hence belong to the complement C(U ) and the parent function F must then be situated in the set A U l) outside the L2 Hilbert space. Substituting the relation = UF into the second relation of Eq. (2.36) and multiplying the left by U one obtains... 

Fig. 9.2. Schematic illustration of the (Pa)g-barrel structure. The highly symmetrical structure presumably arose by multiple gene duplication events from a Pa-fragment. This hypothesis was tested using reverse engineering. Bisection of the barrel into two halves yielded correctly folded fragments which, upon heterodimerization, regained parental function. However, further fragmentation awaits experimental exploration.

The extended Lagrangian method is the base for the development of two modified version of SPC and TIP4P, named SPCfq and TIP4Pfq, where the charge itself instead of the induced dipole, is treated as a dynamical variable [100], while the molecular geometry and the number of sites is the same as in the parent functions. 

How people plan and conduct their life and what attitude to life they adopt, are important indicators as to whether someone will ultimately develop adiposity. Hence, parents function as role models as well, and can have a decisive influence on the eating habits of their children (Fig. 5.104). 

The contributions of the correlated and uncorrelated components of the electron-pair density to atomic and molecular intracule I and extracule E densities and their Laplacian functions were analysed at the HF and Cl level. The correlated components of the / and E densities, and their associated Laplacian functions, reveal the short-ranged nature and high isotropy of Fermi and Coulomb correlation in atoms and molecules. In general, it has been found that the uncorrelated / and E have the same topological structure as the parent functions I and E functions. 

The final tool is the second derivative of the electron density, also known as the Laplacian. Second derivative functions act in some sense as a magnifying glass for small changes in the curvature of the parent function, which may itself be monotonically deseending. This has been widely applied in so-called derivative spectroscopy to detect small contributions that would otherwise be overwhelmed by the main component signal. Figure 10.52 illustrates this point with a simple one-dimensional function. 

---