Design, Synthesis And Relationship Between Structure And Optical Properties Of Novel Photoelectric Functional Materials Of Pyridine Derivatives

Molecular and crystal engineering are playing a more and more important role in designing and investigating the photoelectric functional materials.By means of crystallography and the basic principle of crystal engineering,a strategy for designing new photoelectric functional materials has been reported and some new crystal materials were obtained.Based on the research works the following conclusions are got.1.First of all,two kinds of organic crystal materials with largeÏ€-conjugated system were designed and synthesized.Both molecular crystal structures were characterized by X-ray single-crystal diffraction analysis.And the molecular conformation,molecule stacking and intermolecular interactions in the aggregation state were studied in detail.In addition,their effects on the linear optical properties of the materials were also investigated.It is found that adjusting the range and degree of theÏ€-conjugated system can reduce the intermolecular interaction.The optical properties of the molecules in the aggregation state could be improved.Following this, a new kind of small-molecule organic crystal material was synthesized.For reducing the length of the conjugated backbone and the degree of the conjugation,the weak intermolecular interaction in the crystal structure is reduced,particularly,the interaction betweenÏ€-conjugated backbones nearly disappeared.As a result,the new molecule shows very strong fluorescence in the aggregation state.Furthermore,an electroluminescence device using the strong fluorescence crystal material as emitting layer was made.The results show that it has potential application for electroluminescent devices.2.The skeleton of indolo[3,2-b]carbazole is a planar structure possessing abundantÏ€-electrons and also in an optimized delocalization environment.Its derivatives exhibit different properties,but have seldom been mentioned as luminescent materials.On the other hand,Cd(â…¡)-containing coordination polymers have attracted considerable interest owing to the variability in forming bonds with different donors,various coordination modes,and special physical properties of Cd(â…¡) ion.By combining a new,large,Ï€-conjugated bidentate ligand,2,8-Bis[2-(2-pyridyl) vinyl]-5,11-di(2-ethylhexyl)-indolo[3,2-b]carbazole(BPVIC)with a[Cd(NCS)₂]_∞, polymer chain,a novel supramolecular coordination polymer,[Cd₂(BPVIC)₂(SCN)₄]_∞, with network structure has been prepared.The crystal structures of the free ligand and the coordination polymer were determined by X-ray single-crystal diffraction analysis and their solid state luminescence was investigated.The experimental results indicated that the luminescence maximum of the coordination polymer is obvious red-shifted compared to that of the free ligand and the luminescence intensity is enhanced significantly.The strong interaction between the ligand and metal in the coordination polymer is one of the important factors for the strong luminescence of the polymer.The other factor is that in the coordination polymer,theÏ€-Ï€and C-H…πinteractions are eliminated due to the infinite[Cd(NCS)₂]_∞zigzag chain,which acts as a spacer and a controller for the arrangement and alignment of the largeÏ€-conjugated system.The results indicated that supramolecular assembly is a suitable way to design strongly luminescent materials.3.The styrene-conjugated system has been introduced into the A-shape backbone molecules,and the effects of conformation on the structure and property of the A-shape molecules has been studied.An important intermediate compound and its crystal structure were successfully been obtained and a potential synthesized method for asymmetric molecules was found.Some meaningful developments for the A-shape organic crystal materials have been obtained.4.Crystalline nanoporous materials have received extensive attention due to their potential applications in catalysis,separation,sensors,lasers,gas storage,biological simulation,and so forth.Nano-channels exist widely in inorganic and special metal-organic-framework(MOF)materials.However,purely organic structures with nanometer dimensions are rare,especially,formed with organic rigid molecules. Herein,we report a novel organic nanoporous crystal with unidirectional helical channels of diameter about 1 nm.The novel nanoporous organic crystal is self-assemblied mainly through C-H…πinteractions with a new class of∧-shaped Troger's base analogues.The results indicate that intermolecular electrostatic interactions can play an important role in the formation of this special crystal although many other factors could influence the crystallization process.The crystal belongs to rhombohedral space group R-₃^-.The internal surfaces of the helical hexagram nano-channels possess a diameter ranging from 9.442 to 16.755(?).The nano-channels are co-directed and large enough to accommodate some small organic molecules to form new host-guest complexes.The results are useful for the design and synthesis of other new nanoporous organic crystal materials.