【作者】 张祥标；

【导师】 封继康；

【作者基本信息】 吉林大学 ， 物理化学， 2007， 博士

【摘要】 本论文利用密度泛函，半经验AM1和ZINDO等量子化学方法对一系列新型的有机和有机金属的双光子吸收材料进行了理论研究。理论计算结果详细地给出了以二茂铁为基础的偶极和四极矩金属化合物，有机和有机金属低聚物，八极矩有机和有机金属化合物以及三苯胺(硼，铝)为核的树枝状化合物的静电平衡结构，电子结构，单双光子吸收性质等信息。这为结构和双光子吸收性质间关系的建立奠定了理论基础，为实验研究提供了有价值的理论依据，为进一步探索具有大的双光子吸收截面的双光子吸收材料做出了贡献。研究了一系列带有2-二氰亚甲基-3-氰基-4-甲基-2，5-二氢呋喃(TCF)电子受体的二茂铁衍生物的电子结构，单双光子吸收性质。阐明了电子受体的强度，π-桥共轭链长以及二茂铁衍生物的结构对二茂铁衍生物的单光子吸收和双光子吸收的影响。阐明了在二茂铁衍生物的双光子激发过程中电荷转移的情况。研究了乙烯联接的对芳环低聚物的电子结构，单双光子吸收性质。阐明了低聚物的最高占据轨道和最低未占据轨道间能隙与分子长度间的关系以及双光子吸收截面和重复单元间的关系。比较性地研究了卟啉锌(Ⅱ)单体，中间-中间单联接，中间-β双联接和中间-中间，β-β，β-β三联接的卟啉锌(Ⅱ)二聚物和三聚物以及通过分子间氢键相互作用偶合的卟啉锌(Ⅱ)二聚物的电子结构，单双光子吸收性质。阐明了两卟啉环间夹角的大小和分子尺寸对卟啉锌(Ⅱ)衍生物的单双光子吸收性质的影响。比较性地研究了新颖的八极矩衍生物(Sumanene，Sumanene3O和苯并菲衍生物)的静电平衡结构，单双光子吸收性质。阐明了中心核对双光子吸收性质的影响。研究了一系列四取代的对芳环衍生物的单双光子吸收性质。阐明了分子的维数，给电子基团和受电子基团以及分子链长对对芳环衍生物双光子吸收性质的影响。研究了一系列以Cu(Ⅰ)，Zn(Ⅱ)和Al(Ⅲ)为中心，双肉桂基二亚胺为配体的八极矩金属络合物和一系列吡啶金属络合物的单双光子吸收性质。系统地阐明了中心金属离子的刘易斯酸酸性，配体性质和金属络合物的几何结构对金属络合物的单双光子吸收性质的影响。研究了三苯胺(硼、铝)为中心的树枝状化合物的电子结构，单双光子吸收性质。理论上给出了这些树枝状化合物的几何结构的特点，阐明了结构以及中心和节点原子对双光子吸性质的影响。更多还原

【Abstract】 Recently. two-photon absorption of organic and organometallic materials has received more and more attention due to the continuous improvement of the laser technique. Materials with large two-photon absorption response can be applied in the fields of chemistry, physics and biology. Two-photon absorption as one of nonlinear optical responses also plays a significant role in the national defense （such as laser protection）. Design and synthesis of materials with large two- photon absorption cross section is the important basis of its development. In this thesis, in order to design and select materials with large two-photon absorption response, we have performed systematic theoretical research of various organic and organometallic materials. The quantum chemical methods-density functional theory and AM1 have been applied to optimize the molecular equilibrium geometries. On the basis of the optimized structures. one- and two-photon absorption properties are obtained by ZINDO program combined with SOS equation. We have designed some unknown compounds using the same method so as to provide a theoretical basis of synthesizing novel materials with large two-photon absorption cross section. The following is the main results:1. The electronic structures, one-photon absorption and two-photon absorption properties of a series of ferrocene-based chromophores with TCF type acceptors （TCF=2-dicyanomethylene-3-cyano-4-methyl-2,5-dihydrofuran） have been studied. The results have revealed that the one-photon absorption and two-photon absorption of ferrocenyl derivative are affected by the strength of acceptor, especiallyπ-bridge conjugation length. Two-photon absorption cross section increases with increasing the strength of acceptor and theπ-bridge conjugation length. The TCF type acceptor with phenyl group can lead to larger two-photon absorption cross section. Quadrupole molecules have the largest two-photon absorption cross sections （2000 GM - 3000 GM） which are about 4 times as that of the corresponding dipolar molecules, indicating larger interactions between the top and bottom branches. During the two-photon excitations of ferrocenyl derivatives, the charges transfer from central metal to ligands.2. The electronic structures, the one-photon and two-photon absorption properties of two series of the olefin-linked paracyclophane （pCp） oligomers have been studied. Relationship between the two-photon absorption cross sections and the molecular chain length is obtained. The maximum two-photon absorption cross section increases in proportion to N^a （N denotes the number of the repeat units） and the values of a depend on different molecular structures. The olefin-linked pCp oligomers, which have good transparency and large two-photon absorption cross sections, are promising candidates for two-photon absorption materials.3. The electronic structures, one-photon and two-photon absorption properties of the meso-meso singly, the meso-βdoubly and the meso-mesoβ-ββ-βtriply linked Zn^Ⅱ-porphyrin dimers and trimers have been comparatively studied. The results show that on going from the dimers to the trimers, due to the increased conjugation chain, the maximum two-photon absorption positions are red-shifted and the maximum two-photon absorption cross sections produce a remarkable enhancement. The calculated maximum two-photon absorption cross sections of the studied molecules are in the range of 25.4-616.3×10^-48 cm⁴s/ photon. Compared with the meso-meso singly linked Zn^Ⅱ-porphyrin derivatives, the meso-p doubly and the meso-mesoβ-ββ-βtriply linked Zn^Ⅱ-porphyrin derivatives have larger two-photon absorption cross sections at 700-1000 nm.4. Electronic structures, one-photon and two-photon absorption properties of Zn（Ⅱ）-porphyrin compound （Z_h）, meso-meso singly-linked Zn（Ⅱ）-diporphyrin compound （Z2_H） and Zinc（Ⅱ） meso, meso-coupled porphyrin dimer （Z2_h-G） via intermolecular hydrogen bonding interactions have been comparatively studied. The results show that formation of hydrogen bondings between carboxyl groups and cyclic urea reduces the dihedral angle between the adjacent porphyrin planes in Z2_H-G, leading to increased electronic interactions between the two porphyrin planes and increased couplings between electronic states. Electronic spectrum of Z_h can be described with the four-orbital model, while the descriptions of the electronic spectra of Z2_H and Z2_h-G need eight frontier orbitals. Theoretical calculations reveal that two-photon absorption cross sections increase on going from Z_h to Z2_h to Z2_h-G due to increase of the couplings between electronic states through transition dipole moments.5. The two-photon absorption properties of sumanene and triphenylene derivatives have been comparatively studied. The results indicate that sumanene and triphenylene derivatives have relatively large two-photon absorption cross sections and the high transparency. And the two-photon absorption cross section increases as strength of donor/acceptor and conjugation length increase. In comparison with classical octupolar compounds, there exists stronger electron coupling between the branches of sumanene and triphenylene derivatives. Compared with triphenylene derivatives, the bowl-shaped structure of sumanene segment has an important effect on two-photon absorption of sumanene derivatives. It blocks electron transitions on the interior of sumanene segment and from the peripheric groups to molecular center.6. The two-photon absorption properties of a new octupolar compoundsumanene 30 derivative and relative molecules have been comparatively studied. The results indicate that the TPA cross sections of the octupolar compounds increase with the electron-accepting ability of the center. Sumanene 30 is a stronger electron-acceptor than 1,3,5-tri（nitro）benzene.7. The equilibrium geometries and one- and two-photon absorption properties of a series of tetra-paracyclophane derivatives have been determined. The results show that the tetra-paracyclophane derivatives have large tow-photon absorption cross sections, which are about two times larger than that of the corresponding linear counterparts. The introduction of donor/ acceptor groups has improved the two-photon absorption cross sections of paracyclophane derivatives. In particular, the increased molecular chain plays a crucial role in increasing two-photon absorption cross section. The calculated results also reveal that the dimers of D-π-A （D and A denote donor and acceptor, respectively） chromophore have relatively large two-photon absorption cross sections among studied compounds.8. The equilibrium geometries, electronic structures, one- and two-photon absorption properties of a series of octupolar complexes with the Cu（Ⅰ）, Zn（Ⅱ） and Al（Ⅲ） as coordinate centers and the bis-cinnamaldimine as ligands have been studied. Compared with the dipolar metal complexes, all the octupolar metal complexes （including tetrahedral and octahedral complexes） have relatively large two-photon absorption cross sections, indicating that building octupolar metal complex is an effective route to design of promising two-photon absorption material. Lewis acidity of metal center and molecular symmetry are two important factors for enhancement of two-photon absorption cross section of metal complex. Due to the stronger Lewis acidity of Zn（Ⅱ） than Cu（Ⅰ） as well as Al（Ⅲ） than Zn（Ⅱ）, the tetrahedral Zn（Ⅱ） complex exhibits a TPA cross section larger than that of the tetrahedral Cu（Ⅰ） complex, the maximum TPA position of the octahedral Al（Ⅲ） complex is red-shifted relative to the octahedral Zn（Ⅱ） complex, and at the same time, the octahedral Al（Ⅲ） complex has a large two-photon absorption cross section. Compared with the tetrahedral complexes, the two-photon absorption cross sections of the octahedral complexes are enhanced due to the increased number of ligands.9. The molecular equilibrium structures, electronic structures, one- and two-photon absorption properties of C_2v （Zn（Ⅱ）, Fe（Ⅱ） and Cu（Ⅰ）） dipolar, D_2d （Zn（Ⅱ） and Cu（Ⅰ）） and D₃ （Zn（Ⅱ）） octupolar metal complexes featuring different functionalized bipyridyl ligands have been studied. The calculated results show that one- and two-photon absorption properties of metal complexes are strongly influenced by the nature of the ligands （donor endgroups andπlinkers） and metal ions as well as by the symmetry of the complexes. Increase of the length of theπ-conjugated backbone and the Lewis acidity of the metal ions, and the increase of ligand-to-metal ratio result in a substantial enhancement of the two-photon absorption cross sections of metal complexes. Substitution of C=N and N=N for C=C plays an important role in altering the maximum two-photon absorption wavelengths and the maximum two-photon absorption cross sections of metal complexes. Of them, the C=N substituted metal complexes have relatively large two-photon absorption cross sections. Replacing styryl with thienylvinyl makes one-photon absorption wavelength red-shift, at the same time leads to great decrease of the maximum two-photon absorption cross sections of metal complexes. The possible reason is discussed. In the range of 500 nm - 1250 nm, octupolar metal complexes exhibit the intense two-photon absorptions, therefore are promising candidates for two-photon absorption materials.10. The electronic structures, one- and two-photon absorption properties of triphenylamine （boron, aluminum）-cored dendritic compounds have been studied. The dentritic structure- two-photon absorption property relationship has been discussed. These compounds exhibit large two-photon absorption cross sections and good transparency. They are promising two-photon absorption materials for optical power limiting.更多还原