Structural Design And Demonstration On Antipyrine Derivatives For Organic Photovoltaic Conversion Molecular Devices

This dissertation is based on the need for new energies and photovoltaic (PV) materials of current social energy requirements. In this research, a photoelectric molecular device was designed according to interactions of adjacent natural bond orbitals andÏ€-conjugated organic material characteristics, and series of antipyrine derivatives were chosen to demonstrate the feasibility of the organic PV device by consulting lots of related organic functional materials references. A combined experimental and theoretical investigation was used to characterize and predict the structures and photophysicial properties for the studied compounds. The research results are as follws.1. An organic photovoltaic conversion molecular device was designedAn organic photovoltaic conversion molecular device (OPVCMD) was designed according to the atomic potential differences of electron affinities or ionization and the enlightenment ofÏ€-electron conjugated organic studies.2. Antipyrine derivatives were selected to demonstrate OPVCMD feasibilitySchiff based imines-antipyrine derivatives (APD-linked aromatic groups by Schiff base imines, APDs) were selected as optoelectronic functional materials in order to demonstrate the OPVCMD feasibility. This was validated by applying modern experimental and theoretical approaches to investigate on the respective structural properties and photophysical behaviors for APDs.3. Series of APDs were prepared purposelySeries of antipyrine derivatives (APDs), viz, FAP, BAP, CAP, OH-s-BAPs, F-s-BAPs, Cl-s-BAPs, Br-s-BAPs, CH3-s-BAPs, CNBAP, NO₂-s-BAPs and OH-s-NAPs, were purposely synthesized by classical condensation reactions of aldehydes with ammonia in one step, and their single-crystal samples were prepared by slow solvent evaporation methods. Elemental analysis was firstly used to test these products, which on the overall gave the same results as calculations.4. Three-dimension structures of APDs were deteriminedThree-dimension structures of the present APDs were determined by an X-ray single diffraction technique and used as initial configuration parameters to for theoretical calculations. The optimized structures of APDs shows good agreement with their XRCD parameters, which indicates that these theoretically optimized geometrics can be used as theoretically calculated foundation to predict molecular properties.As expected, all these molecules adopt trans configurations around central Schiff base imine C=N bonds in order to decrease space hindrances, and form effective dihedral angles (range from 43.7(2) to 65.2(2)°) between benzene and pyrazole rings of antipyrine moieties due to methyl steric effects, and approximate coplanar structures (range from 5.1(2) to 38.3(6)°) in the benzene-pyrazole moieties linked by Schiff based imines. In their molecular packing, a kind of intramolecular hydrogen bonding of C—H…O formed by imine C-H and carbonyl group O atoms and some ortho-positional hydroxyl substituents are helpful to strengthen the stability of these molecules. The neighbouring molecular packings are usually connected by some intermolecular hydrogen bonding and inter-ringÏ€-Ï€packing.5. Vibrational spectra of APDs were assigned in detailsVibrational spectra of FT-IR and FT-Raman for these compounds were assigned with the aid of theoretical calculations by GaussView program. The vibrational mode assignments of Raman spectra reveal that their strong Raman scattering activites are closely related to theirÏ€-conjugated moieties linked by imines.6. Intramolecular electron migrations of APDs were obtained by NBO analysisIntramolecular electron migrations of APDs were obtained theoretically by the NBO analysis approach and their photovoltaic conversion illustraions were shown respectively according to interactions of adjacent bonds with light perturbations. These molecules can perform theoretically photovoltaic conversion functions under the actions of intramolecular electron transfer pumps with light absorption and electron output.7. NLO properties of APDs were obtained by theoretical calculationsMolecular polarization behaviors of these compounds have been calculated by B3LYP/6-31G(d) method. Their polarizabilities and hyperpolarizabilitis are much more than the ones of urea by comparing with the results obtained by the same theoretically calculated method, which indicates that these compounds are good candidates of nonlinear optical materials. Theoretical calculations reveal that their FMOs composed of atomic p-electrons are responsible for their NLO properties.8. Electron transitions by photoinduction were analyized theoreticallyUV-vis and fluorescence techniques as well as theoretical calculations have been adopted to reveal electron transition behaviors induced by light. These experimentally recorded bands have been ascribed to corresponding orbital transitions based on the combined investigation. Effective photoinduction wavelengths, which are helpful to perform molecular photovolotaic conversions, have been pointed out by the analysis of UV-vis and fluorescence spectra for the studied compounds. These photoinduction electron behaviors propose that these antipyrine derivatives will be promising candidates of photovoltaic materials.In general, the research on series of antipyrine derivatives indicates that the theoretically designed organic molecular device can perform photovoltaic conversion, and different subsitituents of APDs have effects on material molecular structures and physical functions.