XXVIII

EXPLANATIONS AND REFERENCES TO TABLES XXVII, XXVIII AND XXIX 

The dissociation of an organic carboxylic acid, phenol or the conjugate acid of an amine in aqueous solution IS expressed by the equation 

The dissociation constants in the Tables are given in the more convenient pKa notation, where 

For dicarboxylic acids both pK and DK2 are given, pK is defined above, and pK2 is the analogous disso- 

For a comprehensive compilation of the dissociation constants of organic acids (including phenols) in aqueous solution, as well as summary of the methods for pK determinations, see G Kortum, W Vogel and K Andrussow, m Pure and Applied Chemistry, Vo 1, Butterworths, London, 1961, pp 190-536 

For dicarboxylic acids both pK and pKi are given, pK is defined above, and pKi is the analogous dissociation constant of the monoanion, A , obtained on the first dissociation For other dibasic acids such as the conjugate acids of ammo acids, or diamines, pK is as defined above, and pKi is the dissociation constant for the species obtained after the first protonation 

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Calculations for CHON Species. Journal of the American Chemical Society 97 1302-1306. i iiigliam R C, M J S Dewar and D H Lo 1975d. Ground States of Molecules. XXVIII. MINDO/3. -alculahons for Compounds Containing Carbon, Hydrogen, Fluorine and Chlorine. Journal of the -American Chemical Society 97 1307-1310. 

Tables IV-XXVIII (pp. 560—561) record the m.ps. of crystalline derivatives of a much wider range of compounds, and are intended primarily for the more advanced student.

N—C(CHO) This is taken to imply that the unsaturation in the wco-bases lies between C and C (XXVII), i.e., in the change from strychnine to neostrychnine (XXVIII) the ethylenic linkage moves one step nearer Nfi). 

Exhaustive Methylation. (Parts I, XXII, XXVIII>) This process applied to vomicine has developed difficulties like those met with in the case of strychnine (p. 575). The Emde process used with vomicine metlio-sulphate, C22H24O4N2. MeHS04, m.p. 272° (dec.), produced two methyl-vomicihes, I and II, C23H28O4N2. 

All of these rate equations can be succinctly expressed in the form of Scheme XXVIII. 

In conditions of base catalysis, the acetylenylpyrazolecarboxylic acid hydrazides, as opposed to benzene derivatives, are more difficult to cyclize compared with the benzoic acid derivatives and are isomerized only after heating in alcohol in the presence of KOH, forming not five- but six-membered lactams. The yields of pyri-dopyrazoles were 80-90% (Scheme 133 Table XXVIII) (85IZV1367 85MI2). 

TABLE XXVIII. 6-Amino- 1-methyl-1,6-dihydropyrazolo[3,4-c]pyiidm-7-ones Prepared by Cyclization of 4-(Alkyn-l-yl)pyrazole-5-carboxylic Acid Hy-drazides [85IZV1367 85MI2]. 

The crystallographic data are summarized in Table XXVIII. The best known structure is that of the compounds belonging to the so-called SbSI type (see Table XXVIII), which was proposed by Donges 106,107), and confirmed for SbSBr 84), SbSI 153,174,184,258), and BiSI 153). 

The semiconducting properties of the compounds of the SbSI type (see Table XXVIII) were predicted by Mooser and Pearson in 1958 228). They were first confirmed for SbSI, for which photoconductivity was found in 1960 243). The breakthrough was the observation of fer-roelectricity in this material 117) and other SbSI type compounds 244 see Table XXIX), in addition to phase transitions 184), nonlinear optical behavior 156), piezoelectric behavior 44), and electromechanical 183) and other properties. These photoconductors exhibit abnormally large temperature-coefficients for their band gaps they are strongly piezoelectric. Some are ferroelectric (see Table XXIX). They have anomalous electrooptic and optomechanical properties, namely, elongation or contraction under illumination. As already mentioned, these fields cannot be treated in any detail in this review for those interested in ferroelectricity, review articles 224, 352) are mentioned. The heat capacity of SbSI has been measured from - 180 to -l- 40°C and, from these data, the excess entropy of the ferro-paraelectric transition... 

Additional ionization equilibria involving ortho substituents have been reported by Charton (34) to follow eq. (1). The results of our analysis of the data for aqueous ionization of 2-substituted pyridinium ions, -substituted anilinium ions, and -substituted phenols are given in Table XXVIII. Comparison with the corresponding meta and para data set results is also included. 

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