The “IR EXPERT” Information System for Solving Spectral and Structural Problems

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The algorithms and characteristic features of realization of a new IR spectroscopy system “IR EXPERT” are considered. The special features of the system for solving problems in predicting the structure of compounds by its spectral parameters, verification of the proposed hypothesis, and construction of IR spectra models according to the structure of a compound on the basis of structural similarity and theoretical calculations are discussed.

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... In the early 2000s, a new computer system for working with IR spectra of complex molecules was proposed in Novosibirsk (Piottukh-Peletsky et al. 2000;Piottukh-Peletskii et al. 1999Derendyaev et al. 2003). It was called the BIR EXPERT^and was originally used only to work with the spectra of individual organic compounds. ...
... The IR EXPERT information-analytical system was developed at the Chemical Informatics Centre of N.N.Vorozhtsov Institute of Organic Chemistry, SB RAS (Derendyaev et al. 2003). This is a combination of the Database (more than 50,000 correlation records of BIR spectrum-structure-structural fragments-accompanying information^and software modules that allow solving various spectral-structural tasks (i.e., search for spectral and structural analogs, determination of spectral features of a structural fragment, creation of model spectra, determination of the difference degree or the similarity of spectral curves, etc.). ...
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PurposeThe purpose of this work is to identify the most probable structural fragments of the tundra and the taiga soil humic acids on the basis of computer analysis of their IR spectra. Materials and methodsHumic acid (HA) samples were isolated from 11 northern soils of the Komi Republic, Russia. IR spectra were registered in KBr by Bruker FTIR spectrometer Vector-22. IR EXPERT information-analytical system was used for analysis of these spectra. This system is a combination of an extensive database (more than 50,000 correlation records of “IR spectrum–structure–structural fragments–accompanying information”) and software modules that allow solving various spectral-structural tasks. Results and discussionThe procedure of working with new IR spectra of humic acid involved two stages. Comparison of the sample IR spectrum with all spectra in IR-EXPERT databases was followed by decomposition of the closest spectral analogs into the set of fragments which is individual for each HA. This unique representation makes it possible to associate a spectrum with a combination of structural fragments rather than with the exact structure. That is what we need for HA. The analysis of the obtained ten-vertex fragments shows that all HA samples contain linear, slightly branched, conjugated chains of double C–C bonds, as well as the fragments of aromatic amines and amides. Conclusions Using only IR spectroscopy data and the IR EXPERT system, we were able to show that humic acids of these northern soils are predominantly aliphatic and contain a large number of oxygen-containing groups, which allows one to predict their high reactivity when interacting with ecotoxicants.
Today’s modern society produces a large amount of wastewaters rich in toxic compounds that, if not properly treated, will have deleterious environmental impact. Considering that conventional treatment methods have limitations in the complete removal of some of the most recalcitrant compounds, the need for more efficient treatments becomes imperative. Over the past decades, electrochemical oxidation as proved to be a powerful remediation process due to its high oxidizing nature and ease of operation. However, in recent years, concern for the toxicity evolution of wastewaters, treated by this method, has increased. Therefore, ecotoxicity tests, performed with organisms from different trophic levels, are nowadays an important parameter included in degradation and remediation studies. The present work seeks to increase the knowledge on the efficiency of the electrochemical oxidation method in toxicity removal of synthetic and real wastewaters. Electrochemical oxidation processes will be characterized from an ecotoxicological perspective. This approach will allow to evaluate the influence of the electrochemical degradation parameters, such as electrode material or type of electrolyte, in the modulation of toxicity under different scenarios. This chapter aims to provide a comprehensive review on the available literature published since its origin, in the 1990s up to the present.
Methods for automating spectral interpretation include library searching for matching an unknown spectrum against spectra stored in a database; artificial intelligence and pattern recognition techniques used to link features in spectra with the chemical substructures that give rise to them; and spectral simulation, in which the computer predicts the spectrum that might be expected for a given chemical structure. Part 1 of this two-part series examines library search methods and spectral data collections. Part 2, which will appear in the December 15 issue, will describe artificial intelligence and pattern recognition as well as spectral simulation.
A theoretical study of the IR spectra of cis- and trans-isomers of biuret, based on coupled calculations of vibrational frequencies as a valence force field approximation and of absorption band intensities by the CNDO/2 method, is reported. Calculated thermodynamic functions for biuret agreed with experimental thermochemical data. For calculating the vibrations of an isolated biuret molecule, the experimental vapour-phase IR absorption spectra were used.
Coupled calculations have been carried out of normal vibration frequencies from the point of view of the valence-force field scheme and of absolute IR band intensities by the CNDO/2 method for the 2,3-di-O-nitro-methyl-β-d-glucopyranoside and 2,3,6-tri-O-nitro-methyl-β-d-glucopyranoside molecules. A good agreement with experiment has been achieved. A detailed interpretation of the observable IR spectra of both the nitro-glucopyranosides compounds considered is given. Regularities of formation of complex absorption bands of characteristic vibrations of nitro-groups have been established.
A method for comparison of spectral search algorithms is proposed. It is based on the evaluation of spectral distance and structural similarity selected from database compounds relative to query compound. Model examples are discussed.
The capability of the ‘Self-Training Interpretive and Retrieval System’ has been extended so that the compounds selected as providing the best match in each data class to the unknown mass spectrum are examined by the computer for the presence of each of 179 common substructural fragments. Stastical methods were used to evaluate the selectivity for identification of each substructure by each data class using a reference file of 18 806 spectra of different compounds. In tests using at least 373 unknown spectra for each of the substructures, with criteria that gave a mean reliability of 98.1%, the method averaged 49% recall, which corresponds to the identification of 2.55 substructures per unknown spectrum, as well as the normal “Self-Training Interpretative and Retrieval System” match-factor results, requires 68 s on a laboratory computer. The method is also available to outside users on an international computer network.
A procedure for the objective evaluation of infrared library search systems is proposed. Results for 41 different search systems are discussed.
The prediction of IR spectra of organic compounds in the range between 2250 and 550 cm−1 containing carbon, nitrogen, oxygen and halogen atoms based on a spectroscopic database is outlined. Structure similarity searches are performed to determine appropriate reference molecules whose spectra are then used for the prediction of the spectrum of the query molecule. The performance and reliability of the prediction system was extensively tested by a ‘leave one out’ procedure.
An IR database containing spectra, molecular graphs and exhaustive sets of k-node (k = 2 ÷ 7) structure fragments used for structure elucidation of ‘unknown’ by its IR spectrum. The type of recognizable fragments, correct and false fragments ratio and the method of most probable structure construction are discussed.
Comparing the infrared spectrum of a compound whose chemical structure is unknown with the spectra of a library is a routinely used method to obtain information about the unknown structure. The resulting hitlist contains compounds exhibiting the most similar spectra. If the unknown is not contained in the library, a method based on the maximum common substructure concept can be applied to extract common structural features from the hitlist structures. The result is a set of substructures that are characteristic for the query structure. This approach has been applied to infrared spectra from a series of model compounds and has been compared with information obtained from mass spectra by the same procedure. A complementary chemometric method for evaluating spectral hitlists is principal component analysis of spectral and structural data.
La 1ª ed. fue publicada bajo el título: Advances in infrared group frequencies Incluye índice
El'yashevich, and B. I. Stepanov, Vibrations of Molecules
  • L M V A Kenshtein
  • M A Gribov
Dement'ev, Computer Modeling of Spectra of Complex Compounds
  • V L A A Gribov
Zelentsov, Elektronic-Vibrational Spectra of Multiatomic Molecules: Theory and Methods of Calculation
  • V L A I Gribov
  • D Baranov
  • Yu
Artificial Intelligence: Applications in Chemistry [Russian translation
  • S T Woodruff
  • G Tomellini
  • Smith
Calculation and Analysis of Intensities of Absorption Bands in the IR Spectra of Some Types of Carbohydrates
  • M V Korolevich