Substitution effect

Physicochemical studies on aminothiazoles are mainly centered on two problems the position of imino-amino protomeric equilibrium and IsRR substitution effects on the thiazole nucleus. 

TABLE MI. SUBSTITUTION EFFECTS QUALITATIVE VARIATIONS OF NET CHARGES INDUCED BY A METHYL SUBSTITUTION... 

Another example is the acidities of a series of carboxylic acids. It is known that the substitution effect on these compounds also depends on the environment. The behavior of the halo-substituted acetic acids is one of the prototype problems for the solvent effect on acidity The order in strength of the haloacetic acids in the gas phase is... 

The effect of pH is rarely of use for pK measurement it is more often of use in identifying the site of protonation/deprotonation when several basic or acidic sites are present. Knowing the incremental substitutent effects Z of amino and ammonium groups on benzene ring shifts in aniline and in the anilinium ion (40), one can decide which of the nitrogen atoms is protonated in procaine hydrochloride (problem 24). 

With the method applied it is possible to take into account substitution effects both in the A and C monomers, as explained elsewhere (12). The substitution effect factor Kjj indicates the factor by wKTch the reaction rate between monomer I and any other monomer L is multiplied for each previous bond formed between monomers I and J (i.e. first-shell substitution effects (7)). For positive substitution effects Kjj is larger than 1, for negative effects it is smaller than 1. 

The last topic to be treated is unequal reactivity by substitution effects. As a first example, the effect of an infinitely negative substitution effect in C due to a reaction with an h group (so I CD Kqj = 0) is compared with the case of equal (random) reactivity of the two functional groups in C for formulation F40. This is suggested as an example of polyesterification with an anhydride and a carboxylic acid, respectively. Figure 15 gives the dramatic effect on... 

Figure 15. Variaton of with the conversion in stage 3 for formulation F40 1 means no substitution effects, 0 means KcD = Kct = 0.

These composite BDE values increase strongly on substituting the phosphorus atom with n-electron donating groups. However, this substitution effect does not relate to strengthening of the M=P bond,but rather reflects a reduction in the AEji of tho froo phosphinidene or conversely an increase in the AEji for the complexed phosphinidene. Still, as a point of reference, it is noted that similar CASPT2 and BP values of 41.1 and 40.5 kcal/mol, respectively, have been deduced for the dissociation of the parent Cr complex (OC)5Cr=PH into CrfCO) and PH. 

Reactions suggest that Ca3(BN2)N can be viewed as an intermediate in the reaction (4). The substitutional effect of nitride by nitridoborate ions reflects that the linear [N=B=N] ion (with a typical B-N distance around 135 pm) can be viewed as a pseudo-nitride. 

PECD in Camphor Convergence of the Partial Wave Expansion 1. Data Acquisition and Analysis Molecular Conformation and Substitution Effects 1. Data Acquisition and Treatment... 

JusysZ. 1994. H/D substitution effect on formaldehyde oxidation rate at a copper anode in alkaline medium studied by differential electrochemical mass spectrometry. J Electroanal Chem 375 257-262. 

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