Infrared data correlations with chemical structure

Spectral and X-ray crystallographic data are described in Ref. 1 and in Infrared Data Correlations with Chemical Structure NMR Data Correlation with Chemical Structure and NMR Refinement. For toxicology and biological properties or environmental and hazard or reaction data refer to Chemical Safety Information Databases or Environmental Information Databases. Chemical and physical properties databases will be presented in this article. 

Chemical Safety Information Databases Environmental Information Databases Infrared Data Correlations with Chemical Structure NMR Data Correlation with Chemical Structure NMR Refinement Online Databases in Chemistry Reaction Databases. 

When the structure of a newly synthesized compound has to be established, first the probable molecular fragments are detected using their characteristic features in spectra of different nature (IR, NMR, MS, etc.) and then an attempt to build all feasible structures is made. For this purpose, currently available expert systems are used (see Infrared Data Correlations with Chemical Structure NMR Data Correlation with Chemical Structure and Structure Determination by Computer-based Spectrum Interpretation). 

Exploratory analysis of spectral data by PCA, PLS, cluster analysis, or Kohonen mapping tries to get an insight into the spectral data structure and into hidden factors, as well as to find clusters of similar spectra that can be interpreted in terms of similar chemical structures. Classification methods, such as LDA. PLS, SIMCA, KNN classification, and neural networks, have been used to generate spectral classifiers for an automatic recognition of structural properties from spectral data. The multivariate methods mostly used for spectra prediction (mainly NMR. rarely IR) are neural networks. Table 6 contains a summary of recent works in this field (see Infrared Data Correlations with Chemical Structure). 

Circular Dichroism Electronic Configuration Interaction Density Functional Theory (DFT), Hartree-Fock (HF), and the Self-consistent Field Force Fields A Brief Introduction Force Fields A General Discussion Geometry Optimization I Geometry Optimization 2 Infrared Data Correlations with Chemical Structure Intensities of Infrared and Raman Bands Magnetic Circular Dichroism of it Systems Molecular Magnetic Properties. 

Algorithms Infrared Data Correlations with Chemical Structure Infrared Spectra Interpretation by the Characteristic Frequency Approach Machine Learning Techniques in Chemistry Molecular Models Visualization Neural Networks in Chemistry NMR Data Correlation with Chemical Structure Partial Least Squares Projections to Latent Structures (PLS) in Chemistry Shape Analysis Spectroscopic Databases Spectroscopy Computational Methods Structure Determination by Computer-based Spectrum Interpretation Zeolites Applications of Computational Methods. 

INFRARED DATA CORRELATIONS WITH CHEMICAL STRUCTURE... 

Chemometrics Multivariate View on Chemical Problems Combined Quantum Mechanics and Molecular Mechanics Approaches to Chemical and Biochemical Reactivity Environmental Chemistry QSAR Infrared Data Correlations with Chemical Structure Quantitative Structure-Activity Relationships in Drug Design Quantitative Structure-Property Relationships (QSPR). 

Infrared Data Correlations with Chemical Structure Infrared Spectra Interpretation by the Characteristic Frequency Approach Neural Networks in Chemistry NMR Chemical Shift Computation Ab Initio NMR Chemical Shift... 

Infrared Data Correlations with Chemical Structure 2 1299... 

In the case of an unknown chemical, or where resonance overlap occurs, it may be necessary to call upon the full arsenal of NMR methods. To confirm a heteronuclear coupling, the normal H NMR spectrum is compared with 1H 19F and/or XH 31 P NMR spectra. After this, and, in particular, where a strong background is present, the various 2-D NMR spectra are recorded. Homonuclear chemical shift correlation experiments such as COSY and TOCSY (or some of their variants) provide information on coupled protons, even networks of protons (1), while the inverse detected heteronuclear correlation experiments such as HMQC and HMQC/TOCSY provide similar information but only for protons coupling to heteronuclei, for example, the pairs 1H-31P and - C. Although interpretation of these data provides abundant information on the molecular structure, the results obtained with other analytical or spectrometric techniques must be taken into account as well. The various methods of MS and gas chromatography/Fourier transform infrared (GC/FTIR) spectroscopy supply complementary information to fully resolve or confirm the structure. Unambiguous identification of an unknown chemical requires consistent results from all spectrometric techniques employed. 

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