Physical data

Gas chromatography over optically active metal chelates permits analytical separation of the enantiomers of optically active diols as their n-butyIboronate esters. 

Several X-ray structures have been reported including tris(Z trimethylsilylprop-l-enyl)borane, [tris(trimethylsilyl)- 

1 Organoboron Compounds In Organic Synthesis, B.M.Mikhailov and Yu.N.Bubnov, Harwood Acad, N.York, N.Y., 1984. 

Hoffmann, Sel. Goal Synth. Effic., Proc. Workshop Conf. Hoechst, (14th), 1983, 87. eda. W.Bartmann and B.M.Trost, Verlag. Chem., Weinheim Fed. Rep. Ger. 

Chandrasekharan and K.K.Wang, Pure Appl Chem.. 1983, M, 1387. 

Measurement of KE and knowledge of hv thus lead to the ionization energy, which, by Koopman s theorem, is equated to the energy level in which the electron resided. PES Therefore gives fundamental information of the energy levels of the various molecular orbitals. 

Vertical IEs of a variety of stannanes are given in Table 2-11,70 and their use in analysing the hyperconjugative effect in allylstannanes is given in Section 3.1.2.3. For comparison, IE values for simple organic compounds are MeH 12.61, BuH 10.53, CH2=CH210.51, MeCH=CH2 9.69, HOCH 11.4, MeOCH 10.4, PI14C 8.41 eV. 

Selected physical data which are relevant to the synthesis, structure, stability, and spectroscopic properties of organotin compounds are listed here. Further details are given in the appropriate chapters. 

Atomic number 50. Relative atomic mass 118.710. The abundance of the ten naturally occurring isotopes is given in Table 2-5, and the properties of the spin-active isotopes are given in Table 2-6. 

Electronegativity values of the Group 14 elements (Table 2-12) are of limited value as there are disagreements between the various scales,6 76 and in polyatomic compounds the values vary with the ligands. 

Most pyrazaboles are well crystallized solids, a notable exception being the liquid 4,4,8,8-tetra(n-butyl)pyrazabole 

The first X-ray crystal and molecular structure study of a pyrazabole was reported for the species H(pz )B(pz )2BH(pz ) (pz = 3,5-dimethylpyrazolyl) The compound 

The structure of (pz)2B(pz)2BH2 has also been determined . As expected, the central B2N4, ring exists in boat conformation and the two fragments (pz)2B(p-pz)2 and (p-pz)2BH2, respectively, are quite similar to those of the corresponding symmet- 

Crystal structures have been reported for (MeaPhSi) 3CBF(0H), pyridine-borabenzene and pyridine-2-boranaphthalene and for the chiral borane (21). 

Spectroscopic and theoretical studies have been carried out on l-aza-5-boratatricycle[3.3.3.0 ]undecane (22) and related compounds and the radicals R2C-OBPh2 and Bu N-9-BBN observed. 

1 Houben-Weyl Methods of Organic Chemistry, Part 3 Organoboron Compounds 4th Ed., Ed. R. Koester, Stuttgart, 1984. 

Suzuki and S. Hara, Yukl, Gosel Kagaku Kyokalshl, 1985, 100. 

Koester, S. Penades-Ullate and W. V. Oahlhoff, Angew. Chem. Int. Ed. 

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JCAMP. jdx,. dx,. cs Joint Committee on Atomic and Molecular Physical Data structure and spectroscopic format nmm.jcamp. org/ 56... 

M. C. Ball and A. A. Norbury, Physical Data for Inorganic Chemicals Longman, Inc., New York, 1974. 

Megestrol acetate can be recrystakhed from aqueous methanol (108). It is soluble in acetone, chloroform, and ethanol slightly soluble in ether and fixed oils and insoluble in water (107). Additional spectral and physical data have been pubHshed (62). 

A computer file of about 19,000 peak wavenumbers and intensities, along with search software, is distributed by the Infrared Data Committee of Japan (IRDC). Donated spectra, which are evaluated by the Coblentz Society in coUaboration with the Joint Committee on Atomic and Molecular Physical Data (JCAMP), are digitized and made avaUable (64). Almost 25,000 ir spectra are avaUable on the SDBS system developed by the NCLl as described. A project was initiated at the University of California, Riverside, in 1986 for the constmction of a database of digitized ftir spectra. The team involved also developed algorithms for spectra evaluation (75). Other sources of spectral Hbraries include Sprouse Scientific, Aston Scientific, and the American Society for Testing and Materials (ASTM). 

Data Analysis. The computerization of spectrometers and the concomitant digitization of spectra have caused an explosive increase in the use of advanced spectmm analysis techniques. Data analysis in infrared spectrometry is a very active research area and software producers are constantly releasing more sophisticated algorithms. Each instmment maker has adopted an independent format for spectmm files, which has created difficulties in transferring data. The Joint Committee on Atomic and Molecular Physical Data has developed a universal format for infrared spectmm files called JCAMP-DX (52). Most instmment makers incorporate in thek software a routine for translating thek spectmm files to JCAMP-DX format. 

Physical Properties. Both (1) and (2) are weak bases, showing 4.94 and 5.40, respectively. Their facile formation of crystalline salts with either inorganic or organic acids and complexes with Lewis acids is in each case of considerable interest. Selected physical data for quinoline and isoquinoline are given in Table 1. Reference 4 greatly expands the range of data treated and adds to them substantially. 

Selected physical data for various quiaones are given ia Table 2 Table 3 gives uv spectral data and redox potentials (Fig. 2). References 19 and 20 greatiy expand the range of data treated. 

Carbonylation, or the Koch reaction, can be represented by the same equation as for hydrocarboxylation. The catalyst is H2SO4. A mixture of C-19 dicarboxyhc acids results due to extensive isomerization of the double bond. Methyl-branched isomers are formed by rearrangement of the intermediate carbonium ions. Reaction of oleic acid with carbon monoxide at 4.6 MPa (45 atm) using 97% sulfuric acid gives an 83% yield of the C-19 dicarboxyhc acid (82). Further optimization of the reaction has been reported along with physical data of the various C-19 dibasic acids produced. The mixture of C-19 acids was found to contain approximately 25% secondary carboxyl and 75% tertiary carboxyl groups. As expected, the tertiary carboxyl was found to be very difficult to esterify (80,83). 

Table 2 Physical Data for Aminopteridines and Ring and Af-Methylated Derivatives...

Table 5 Physical Data for 8-Substituted Lumazines and Pterins...

The parent 1-azetine is a colourless liquid, stable at -70 °C, which undergoes polymerization within a few seconds at 20 °C (81JA468). Substituted 1-azetines possess greater stability, and physical data for representative derivatives of 1-azetine are shown in Table 6. 

Physical Data Index 4H-Azepine-2-carboxylic acid... 

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