Curve Resolution Of Spectral Analysis Applied To Self-Association System

Hydrogen bond self-association is the phenomenon that the molecules of the same substance aggregate to form molecule cluster, or called as multimer, due to inter-molecular hydrogen bonding. The substances which have hydrogen bond self-association have different physical properties from those non-self-assoication subtances. The state of self-association is essential to understand and explain the physical properties and phenomenons of self-association substances. The study of hydrogen bond self-association is always feazed by one problem. The pure self-association subtances always comprise monomers and multimers, which make them complicated complex. Such complex is called as self-association system. The components in self-association system are very difficult to separate in experiment. The experiment data is always blend of all the information of components, which brings big difficulties to analysis.Infrared spectroscopy (IR) can provide information of molecular structure, which makes it an important tool for studying hydrogen bond self-association system. However, intermixing of component spectra cripples the ability of IR to study self-association system. Curve resolution methods are promising to settle this problem. Curve resolution methods can determine the number of components in the system and resolve the spectral and concentration curves of pure components, without any knowledge of the system. However, it is not simple to apply curve resolution methods to self-association system. Most methods were developed under other backgrounds. Their applicability to self-association system needs more study. More important, the ability of curve resolution methods is not unlimited. Analysis oversteps limitation is uncertain. Some systems are easy to resolve, and others are not. But there is no systematic study to evaluate the ability of curve resolution of methods and systems. Without such knowledge, the availability and dependability of analysis are doubts. This is the key of rationality of applying curve resolution methods to self-association system.Our study focuses on curve resolution ability. First, the basic theory of curve resolution was systematically studied. Error theory of principal component analysis (PCA) was corrected. The criterion to judge the importance of principal component was determined, which succeeds in explaining the difference between the component number determined by curve resolution methods and the real value. The key factors to effect the curve resolution ability were studied and the limit of curve resolution ability in theory was determined. The regulation of curve resolution ability was analysed and summarized in the form of borderline map. Based on the regulation of curve resolution ability, the method of standard curve equivalent analysis was developed to analysis and evalute the curve resolution ability.Some widely used methods were analysed. Hypostases of SIMPLISMA and ITTFA were expounded. The ability of local curve resolution of EFA and FSMWEFA were analysed by using standard curve equivalent analysis.Then, a very important kind of self-association system, alcohol system, was used for instance to show how to study the regulation of resolving a specified kind of system. The regulation of resolving spectral data of alcohol systems was analysed on the basis of curve resolution theory. The properties of alcohol spectra and their effect on curve resolution were summarized. Alcohol system models were built to study the properties of concentration curves in alcohol systems and their effect on curve resolution. The resolution limits in theory of alcohol system models with type 1-2-3, 1-2-4, 1-3-4 and 1-2-3-4 were determined.Finally, the self-association system of diol containing HO(C)₃OH structure was detailed studied for the first time. IR spectroscopy, gradient concentration experiment and curve resolution methods were applied to (R)-1,3-butanediol system. Spectral and concentration curves of components in (R)-1,3-butanediol self-association system were resolved. The major part of multimers was determined to be trimer. The exsistance of dimer was revealed by alcohol system model. Structures of monomers, dimers and trimers were studied by density functional theory (DFT). The effect of HO(C)₃OH structure on diol self-association was summarized.