Other Physical Data

Compound Preparation Crystallo- graphic data Optical properties Magnetic data Other physical data... 

More recently 233) it has been reported that cross-linked polystyrene containing imidazole ligands did not provide a support rigid enough to prevent dimerization, and that the p-oxo dimer was benzene extracted from oxygenated tetraphenyl porphyrin iron(ll), Fe(TPP), which had been attached to the modified polystyrene. A discussion of model synthetic porphyrins, from which definitive structural and other physical data are obtained, is given in section V.C. 

The qualitative investigation of copolymers is considerably more difficult when the homopolymers cannot be distinguished by their solubility. In this case other physical data of the supposed copolymer can be compared with the corresponding data for various physical mixtures of homopolymers, for example, softening point and melting range, density, and crystallinity. Copolymers can frequently be distinguished from physical mixtures of homopolymers by the qualitative and quantitative composition of their pyrolysis products. 

Chromatographic behavior Aromaticity Other Physical Data Tautomerism... 

Other X-ray analyses (78JOC3513) together with H and 13C NMR spectroscopic data have given a firm basis for the stereochemistry of this class of ring compounds. The information has helped to clarify steric problems of other phosphorus heterocycles, e.g. (117)-(120), where the difficulties of interpretation of NMR or other physical data are greater. 

The specific heat of coal (Table 7.2) usually increases with its moisture content (Figure 7.1), decreases with carbon content (Figure 7.2), and increases with volatile matter content (Figure 7.3), with mineral matter content exerting somewhat less influence. The values for the specific heats of various coals fall into the general range 0.25 to 0.37, but as with other physical data, comparisons should be made only on an equal (e.g., moisture content, mineral matter content) basis. 

Once the unknown is determined to be a ketone or an aldehyde. the melting point of the imine derivative is determined. The melting point and other physical characteristics (i.e.. solubility of unknown and boiling point or melting point of the unknown) are used to determine the unknown s identity. The information is compared to tables in books which contain the melting points of derivatives and other physical data for organic compounds. 

These data were used to good advantage in the structural elucidation of 10-oxocancentrine (44). Other physical data had suggested that the new alkaloid differed from cancentrine only at C-10. To provide additional support for these observations the 13C spectrum of 10-oxocancentrine and the model compounds, codeinone (45) and 10-oxocodeinone (46), were recorded. In the latter the carbonyl group at C-10 appears at 190.4 ppm. This change in functionality caused a deshielding of carbons C-9, C-14, C-3, and C-12 relative to codeinone. 

Using the mass transfer coefficients and other physical data, Schmidt and Nusselt numbers were calculated for each experiment. ... 

Alkaloids. 1000 spectra with other physical data J. HolubekandO. Strouf, Spectral Data andPhysical Constants of Alkaloids, London, Heyden and Sons Ltd,1965-1973. 

Magnetic measurements indicate that the previously discussed [Re2(NCS)8] has a dinuclear structure with a metal-metal bond (214). The reaction of NCS with RegCle in the presence of PhgP results in the formation of [Re2(NCS)B(PPh3)2], but here the magnetic data indicate no metal-metal bonding. The infrared spectra and other physical data are consistent with a dimeric anion in which the two... 

In spite of these caveats, there is intense activity in the application of these methods to polymorphic systems and considerable progress has been made. Two general approaches to the use of these methods in the study of polymorphism may be distinguished. In the first, the methods are utilized to compute the energies of the known crystal structures of polymorphs to evaluate lattice energies and determine the relative stabilities of different modifications. By comparison with experimental thermodynamic data, this approach can be used to evaluate the methods and force fields employed. The ofher principal application has been in fhe generation of possible crystal structures for a substance whose crystal structure is not known, or which for experimental reasons has resisted determination. Such a process implies a certain ability to predict the crystal structure of a system. However, the intrinsically approximate energies of different polymorphs, the nature of force fields, and the inherent imprecision and inaccuracy of the computational method still limit the efificacy of such an approach (Lommerse et al. 2000). Nevertheless, in combination with other physical data, in particular the experimental X-ray powder diffraction pattern, these computational methods provide a potentially powerful approach to structure determination. The first approach is the one applicable to the study of conformational polymorphs. The second is discussed in more detail at the end of this chapter. 

Conformations of the five-membered ring D are not clear-cut. Two envelope forms (10) and (ii), and a half-chair conformation (12) [32,33] have been proposed, each for a specific group of compounds. Experimental evidence (spectroscopic and other physical data [34,35,36]), supported by cal-... 

The tables in the Appendix provide access to the literature, melting points, and some other physical data for most known simple pyrazines and pyrazine A -oxides. 

Other physical data of phenol follow below ... 

Spectral and Other Physical Data.—13C N.m.r. studies on hydroxy- and chloro-menthanes have revealed that certain shifts are very sensitive and reliable probes... 

Other physical data or theoretical calculations will be quoted in the appropriate places in the following sections. 

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