Chiral Self-Assembling And Upconverted Luminescence Of Glutamide Derivatives

Chirality is a very important factor for the self-assembled supramolecule in the process of the suppromolecular construction.With more detailed studies have been carried out,the understanding of the role of chirality in the process of constructing supramolecular self-assembling has been more clear,which had produced a better understanding of the life processes and the nature.This paper is mainly focused on the self-assembly behavior of gelators with two chiral centers.In which the self-assembly process,mechanism of the self-assembly,and the application of the self-assemblies in the field of upconversion luminescence had been studied.The detailed work were introduced by the following two parts:Firstly,the gelators with two chiral centers were designed and synthesized.According to the work of predecessors,we know that there are three kind of rotamers for the dihydroxysuccinic acid.In which,the two chiral centers in the molecule are connected by a single bond of sp~3 type,which made the chiral groups could rotate freely along the single bond in solution and resulting in the non-optical activity of the meso-tartaric acid molecule.However,the optical activity would appear if the chiral centors were fixed in special type.In this work,we synthesized the BDCA(4,4’-(Anthracene-9,10-diylbis(ethyne-2,1-diyl))dibenzoic acid)by the Sonogashira reaction,which is the derivative of the BPEA(9,10-Bis(phenylethynyl)anthracene).Then,the different chiral groups(L-GAm and D-GAm)were synthesized through the amide condensation reaction.In which,the chiral group was derived from the glutamate with two flexible hydrophobic alkyl chains.Finally,by EDC condensation,two different chiral central groups were connected to the each ends of BDCA molecule forming three chiral gelators(LBL,DBD and LBD).Through the process of supramolecular self-assemble,one kind of novel helical junction assemblies have be obtained by the self-assembled process with mesomer molecule LBD.For the helical junction assemblies,there were some helical inversion on the same fiber,which is one extremely different phenominen compared with the conventional helix.We have made in-depth speculation,discussion and simulation from the perspective of of instantaneous fixity to study the formation of supramolecular chiral junction assemblies,and the models were also made to simulate the process of the formation.Secondly,we further studied the effects of chiral recognition on triplet-triplet annihilation(TTA)based photon upconverted(UC)luminescence.In which,the chiral molecules(LBL and DBD)used were synthesized in the above experiment.The TTA-UC system were constructed by mixing the photosensitizers(Platinum(II)tetraphenyltetra-benzoporphyrin,PtTPBP)with the three assemblies,respectively.Then,the efficient of the triplet energy migration between the donor and acceptor and the triplet-triplet annihilation in the assemblies(LBL,DBD and racemate(LBL:DBD=1:1))were studied and calculated.Then,The luminescent efficiency and factors of these three TTA-UC luminescent systems have been calculated and evaluated,respectively.Surprisingly,through this study,we found that the efficiency of the TTA-UC photoluminescence was higher in the racemic mixture system than that in the homochiral systems.The research of this thesis not only found a link between chirality and triplet energy transfer,but also pointed out one design route for how to obtain higher TTA-UC photoluminescence materals.