The Case for Bonds

This book is intended to help you understand more about the goings-on in the fixed-income marketplace, with a special emphasis on information and transactions carried out online. It will 

Most brokers tell investors that bonds are too difficult to understand—and that they must rely on their expert wisdom in order to properly invest in them. This way of thinking is on the way out. 

It is important to remember that bonds are not a replacement for stocks—they are a separate asset class with unique characteristics that provide a level of risk and return complementary to that of stocks and other securities. 

Any advisor will tell you that a portfolio should be allocated to bonds based on three characteristics  

The E-Z method of allocating bonds has always been this The older you are, the higher your allocation should be. The thinking is that risk is presumably reduced as bonds are added to the portfolio as one ages. This isn t a bad mle of thumb, but investing should never follow a cookie-cutter method. To avoid this pitfall, you can use the Internet to learn as much as you can about different portfolio strategies and asset allocation. 

---

Interestingly, calculations with large uncontracted spdf basis sets yield bond distances of nearly the same quality as the cc-pVQZ basis sets, while this is not the case for bond angles. This does suggest that the main contribution of the g function is to the bond angle part of the potential, which stands to reason.)... 

Hydricity involves production of charged species, so the energy needed will strongly depend on the polarity of the solvent, unlike the case for bond dissociation energy where neutral fragments are formed. 

However, most impurities and defects are Jalm-Teller unstable at high-symmetry sites or/and react covalently with the host crystal much more strongly than interstitial copper. The latter is obviously the case for substitutional impurities, but also for interstitials such as O (which sits at a relaxed, puckered bond-centred site in Si), H (which bridges a host atom-host atom bond in many semiconductors) or the self-interstitial (which often fonns more exotic stmctures such as the split-(l lO) configuration). Such point defects migrate by breaking and re-fonning bonds with their host, and phonons play an important role in such processes. 

In addition to diamond and amorphous films, nanostructural forms of carbon may also be formed from the vapour phase. Here, stabilisation is achieved by the formation of closed shell structures that obviate the need for surface heteroatoms to stabilise danghng bonds, as is the case for bulk crystals of diamond and graphite. The now-classical example of closed-shell stabilisation of carbon nanostructures is the formation of C o molecules and other Fullerenes by electric arc evaporation of graphite [38] (Section 2.4). 

When the combination X,Yor X, Y is of the capto-dative type, as is the case for an alkoxy and an ester group, the enthalpy of bond dissociation is 10-15 kcal lower than when all four groups are electron-attracting. When the capto-dative combination CN/NR2 occupies both the X, Y and the X, Y positions, the enthalpy for dissociation of the C(3)—C(4) bond is less than lOkcal/mol. ... 

Pantothenic acid, sometimes called vitamin B3, is a vitamin that makes up one part of a complex coenzyme called coenzyme A (CoA) (Figure 18.23). Pantothenic acid is also a constituent of acyl carrier proteins. Coenzyme A consists of 3, 5 -adenosine bisphosphate joined to 4-phosphopantetheine in a phosphoric anhydride linkage. Phosphopantetheine in turn consists of three parts /3-mercaptoethylamine linked to /3-alanine, which makes an amide bond with a branched-chain dihydroxy acid. As was the case for the nicotinamide and flavin coenzymes, the adenine nucleotide moiety of CoA acts as a recognition site, increasing the affinity and specificity of CoA binding to its enzymes. 

Any doubt about the existence of individual tautomers is now long past some tautomers can be crystallized separately (desmotropy), and others can be observed simultaneously in the same crystal (Section V,D,2) in summary, tautomers are not intrinsically different from isomers. Maybe it is worth mentioning that even two identical tautomers can differ. This is the case for the two intramolecular hydrogen-bonded (IMHB) enol tautomers of acetylacetone and for many NH-azoles they correspond to a doublewell profile for the proton transfer with both wells having the same energy (autotrope). 

The twofold dehydrohalogenation takes place through a vinylic halide intermediate, which suggests that vinylic halides themselves should give alkynes when treated with strong base. (Recall A vinylic substituent is one that is attached to a double-bond carbon.) This is indeed the case. For example ... 

A disulfide bond between cysteine residues in different peptide chains links the otherwise separate chains together, while a disulfide bond between cysteine residues in the same chain forms a loop. Such is the case, for instance, with vasopressin, an antidiuretic hormone found in the pituitary gland. Note that the C-terminal end of vasopressin occurs as the primary amide, -CONHz, rather than as the free acid. 

One of the most striking results is that of C2H4 oxidation on Pt5 where (xads,o ctact = -1, i.e. the decreases in reaction activation energy and in the chemisorptive bond strength of oxygen induced by increasing work function ethylene epoxidation and deep oxidation on Ag.5... 

Sometimes the atomic arrangement of a crystal is such as not to permit the formulation of a covalent structure. This is the case for the sodium chloride arrangement, as the alkali halides do not contain enough electrons to form bonds between each atom and its six equivalent nearest neighbors. This criterion must be applied with caution, however, for in some cases electron pairs may jump around in the crystal, giving more bonds than there are electron pairs, each bond being of an intermediate type. It must also be mentioned that determinations of the atomic arrangement are sometimes not sufficiently accurate to provide evidence on this point an atom reported equidistant from six others may be somewhat closer to three, say, than to the other three. 

---