Characterization of Organic Compounds

Abstract

HE accepted requirements for full characterization of an T organic compound include establishment of purity of sample, determination, of physical properties, determination of elementary composition, functional groups, and empirical formula, and elucidation of structural formula and spatial relationships. It is evident that identification of a known molecule will involve less extensive investigation than full characterization of a complex new compound. The characterization of simple or complex compounds may be accomplished by any of a Tide variety of techniques and methods, some of which are more effective than others. The choice of criteria and procedural steps is often dependent on availability of special equipment. Infrared absorption spectra and x-ray diffraction patterns alone, for example, are sufficient to identify many known substances; identification carried out by chemical methods, while sometimes more timeconsuming, is equally effective.A consequence of the recent increase in number and scope of chemical studies of naturally occurring organic substances is seen in the widely held view that thorough training in principles of characterization is of fundamental importance for students majoring in organic chemistry. A comprehensive treatise on detailed methods and techniques of characterization may some day be available. I t is probably true, however, that after successfully completing the characterization of a complex, new organic molecule the chemist enjoys a thrill of satisfaction derived in large part from the realization that the sequence of steps used was not given to him in a single reference work but was the result of his own experience, insight, and skill (and perhaps some luck).The present review of recent contributions in this realm of characterization is concerned with methods for determining purity of samples, procedures for establishing physical properties, and chemical methods of characterization. PURITYIt is essential for clear-cut determination of properties and for interpretable degradative work that the samples employed be substantially pure. Procedures which are now found most useful for establishment of degree of purity of samples were reviewed recently (64, 65). No fundamentally new methods of these types have been introduced during the past year, but there have appeared a number of papers in which extensions or new applications of method are described.The development by Craig (16, 64) of a machine for carrying out many-plate countercurrent distributions, and the recent introduction of a convenient glass apparatus for larger numbers of separation stages (19, 65) are now widely recognized. These methods have been introduced in many laboratories and have proved their worth. Continued studies by Craig and his coworkers have culminated in the development of an automatic control device for use with the glass apparatus (17). A strictly discontinuous extraction train containing 220 glass equilibration cells may now be operated automatically, so that 800 equilibration stages (about 150,000 ext...

Standardizing Nanomaterials

“…In an update on methods for organic compound characterization in 1952, Peck and Gale pointed out that "The accepted requirements for full characterization of an organic compound include establishment of purity of sample, determination, of physical properties, determination of elementary composition, functional groups, and empirical formula, and elucidation of structural formula and spatial relationships." 1 This thought was written well over half a century ago, but few papers on nanoscale materials today would meet these ideal requirements.…”

Preliminary Quality Criteria of Citrate-Protected Gold Nanoparticles for Medicinal Applications

“…Their advantages in biological inert, optical, and photothermal properties and shape-, size-, and surface chemistry-adjusted performance in vivo , made GNPs the promising material in the future as has been approved by the Food and Drug Administration (FDA). , However, there is no any business or national standards for the medicinal application of GNPs yet. As early as 1952, Peck and Gale suggested that the accepted requirements for full characterization of an organic compound place emphasis on the analysis of sample purity, physical properties, elementary composition, functional groups, and spatial relationships based on structural formula . On the contrary, the criteria of nanomaterials would focus on the analytical methods of main ingredients and limits of impurities as well as their possible influence on the biosafety.…”

“…As early as 1952, Peck and Gale suggested that the accepted requirements for full characterization of an organic compound place emphasis on the analysis of sample purity, physical properties, elementary composition, functional groups, and spatial relationships based on structural formula. 19 On the contrary, the criteria of nanomaterials would focus on the analytical methods of main ingredients and limits of impurities as well as their possible influence on the biosafety. Herein, to discuss the quality control of gold-based nanomaterials, we chose the simplest and most widely utilized citratereduced GNPs as a demonstration to establish the analytical methods for main ingredients and impurities.…”

Expert System for Fourier Transform Infrared Spectra Recognition Based on a Convolutional Neural Network With Multiclass Classification

“…11 Identification of many organic functional groups is carried out using FT-IR due to the unique oscillation frequencies of the corresponding bonds. 12 The analysis of any FT-IR spectrum takes a lot of time even for qualified scientists. Therefore, the interpretation of FT-IR spectra by using ML methods is a promising and interesting task.…”