The Mechanism Study Of Nonconventional Luminescent Materials System

Nonconventional luminescent materials belong to non-aromatic luminescent materials which don't contain any big ?-conjugated structures.In recent years,they have been attracting more and more attentions since they feature excellent biocompatibility,low toxicity,environmental friendliness and facile preparation.However,the luminescent mechanism is still obscure and under debate.Furthermore,some non-aromatic biomolecules show a phenomenon of auto-fluorescence.Thus,interpretation of nonconventional luminescence will help to understand the auto-fluorescence in living organisms and explore the nonconventional luminescent materials.In this thesis,we studied the nonconventional luminescent mechanism mainly based on the maleic anhydride polymers and small molecules: non-aromatic ?-amino acids.Firstly,we prepared three kinds of anhydride polymers including long-wavelength nonconventional fluorescent polymer and we concluded that they belong to the clusteroluminescence through comparing the absorption and emission spectra of different polymers and their different states as well as the study of concentration effect.Next,we synthesized a simpler system of maleic anhydride homopolymer and alternating copolymer.We further proved the “clusteroluminescence” mechanism by studying the structure-effect relationship of homopolymer and alternating copolymer and comparing the photo-physical properties of their solutions and aggregates and combining the theoretical simulation simultaneously.Then,we adopted the non-aromatic ?-amino acids which have well-defined structures as the study objectives.After comparing the absorption and emission of the crystals and dilute solutions,we concluded that the fluorescence of these non-aromatic ?-amino acids originated from “clusters” instead of single molecule.By analyzing their crystal structures,we found that there exists a great deal of strong hydrogen bonding interactions which contribute to the clusters' formation.Furthermore,preliminary theoretical calculations showed that the luminescence of amino acids are related to the size of clusters,which verified the “clusteroluminescence” mechanism.Therefore,the non-aromatic ?-amino acids system provides a more direct and accurate evidence for “clusteroluminescence”.Finally,in order to explore the universality of “clusteroluminescence” mechanism,we studied the nonconventional luminescent mechanism of other non-conjugated systems including polylactic acid,polymaleimide,the Aza-Michael addition reaction product of dimethyl 2-(butylamino)succinate and acetone.As a whole,most of the nonconventional systems belong to the “clusteroluminescence” mechanism,which means a good universality of “clusteroluminescence” mechanism.