环状聚茚并茚及其取代衍生物电子结构和磁性研究

采用半经验的AM1法，对环状聚茚并茚及其取代物的电子结构进行了计算研究 ，探讨了其磁性和取代基效应．计算得到，环状聚茚并茚及其取代物皆表现半导体 性质且发现其中一种异构体可能具有磁性．取代基效应表明，吸电子基团的取代使 聚合物的电子亲合势增大，而给电子基团的取代则导致电离势减少，但取代基效应 不能改变聚合物的半导体性质．此外，无论吸电子基团还是给电子基团的取代都不 能改变聚合物的磁性特征．     

聚磷氮烯及其衍生物电子结构的理论研究

用分子轨道和晶体轨道方法,对聚磷氮烯及其衍生物的电子结构进行了研究,以期更深入地了解聚磷氮烯的结构和性能.研究发现,链状聚磷氮烯和环状三聚磷氮烯为平面结构,其它的环状聚磷氮烯则为巢式结构,吸电子基团取代有使环状聚磷氮烯主链环取平面结构的倾向.研究还发现,无论是链状还是环状聚磷氮烯,都表现为半导体.取代基效应表明,吸电子基团-F和-CN的取代,使聚合物的电子亲和势(EA)和电离能(IP)均增大,能隙减小,给电子基团-CH₃和-OCH₃的取代,使聚合物的IP减少;吸电子基团取代有利于n-型掺杂,给电子基团取代有利于p-型掺杂,但都不改变其半导体的特性.     

聚(茚并芴-三苯胺)的合成及性能

设计并合成了一类新的可用于有机场效应晶体管(OFET)的聚合物半导体材料聚(茚并芴-三苯胺)(pIFTPA1~4), 通过核磁共振谱和凝胶渗透色谱等对聚合物进行了表征, 同时对其场效应薄膜晶体管性能进行了测试. 结果表明, 这些聚合物形成了无定形半导体膜, 在空气中稳定, 其载流子迁移率远高于聚三苯胺(pTPA)类材料, 其中pIFTPA1载流子迁移率高达4×10^-2 cm²/(V·s), 开关比为10⁶.     

七甲茚基稀土络合物和碱金属盐的化学反应

本文用核磁共振等方法研究了稀土络合物和碱金属盐中的七甲茚基的质子化或氘化反应、亲核取代反应及络合物中稀土离子的还原反应。七甲茚基络合物比相应的茂基或茚基化合物更易与盐进行上述反应。三氘代七甲茚基在氘化反应中显示了同位素效应。     

茚及其衍生物的催化不对称合成

茚及其衍生物广泛存在于自然界中,其中多官能团化的茚类化合物大多具有重要的生物活性,因而非常具有成为药物的先导化合物的潜力。特别是茚类化合物的不对称合成吸引了有机化学家们的广泛关注,最近有许多相应的合成方法研究被报道,包括外消旋体拆分、手性辅基及底物诱导的合成和手性催化合成等。本文总结了茚及其衍生物的催化不对称合成研究进展,重点介绍过渡金属及有机小分子不对称催化反应,并对该领域的研究前景进行了展望。     

新型二茂铁茚基化合物的设计、合成及电化学性质研究

利用Sonogashira偶联反应,以1,1¢-二碘二茂铁(I-C₅H₄FeC₅H₄-I),1,1¢-二碘联二茂铁(I-C₅H₄FeC₅H₄-C₅H₄FeC₅H₄-I)和2-乙炔茚(Ind-C≡CH)为原料,设计合成了6种新型二茂铁茚基化合物I-C₅H₄FeC₅H₄-C≡C-Ind(1,Ind为茚基), Ind-C≡C-C₅H₄FeC₅H₄-C≡C-Ind(2), I-C₅H₄FeC₅H₄-C₅H₄FeC₅H₄-C≡C-Ind(3), Ind-C≡C-C₅H₄FeC₅H₄-C₅H₄FeC₅H₄-C≡C-Ind(4), C₅H₅FeC₅H₄-C≡C-C₅H₄FeC₅H₄-C≡C-Ind(5), Fc-C≡C-C₅H₄FeC₅H₄-C₅H₄FeC₅H₄-C≡C-Ind(6,Fc为二茂铁基),其结构经¹H NMR, ¹³C NMR, MS(ESI)和X-射线单晶衍射表征,其中化合物1~3的晶体结构为首次报道。采用循环伏安法研究了化合物1~6的电化学性质。结果表明：取代基对调控二茂铁茚基衍生物二茂铁基之间的电子交互作用显著。单二茂铁茚基衍生物1和2中分别引入不对称和对称的共轭取代基团后,二茂铁基的氧化电位值升高。联二茂铁茚基衍生物3和4二茂铁基之间的电子交互作用基本不受取代基的影响。在乙炔桥相连接的取代二茂铁茚基衍生物5中,受金属-金属间距增加的影响,两个二茂铁基之间的电子交互作用减弱。不对称地引入二茂铁乙炔和乙炔茚取代基后,联二茂铁茚基衍生物6的两个二茂铁基之间的电子交互作用明显减弱。      

茚环3-位手性基团取代的桥联二茚锆络合物合成及表征

将(+)-新孟基和(+)-异莰基引入茚环结构中,合成得到三个茚环3-位手性基团取代的桥联二茚配体化合物1a~3a.利用这些配体化合物的二锂盐与四氯化锆反应,最终分离得到两个C2-对称的亚乙基桥联取代二茚锆络合物2b和3b,相应具类内消旋结构、C1-对称的锆络合物2c和3c未能分离得到纯品.所有配体化合物和络合物均通过1H NMR、13C NMR、元素分析(或HRMS)的鉴定.对络合物2c进一步用X射线单晶衍射测定了晶体结构.2c属正交晶系,其空间群为P2(1)2(1)2(1),晶胞参数a=10.946(4),b=13.377(4),c=24.294(8),α=β=γ=90°,Mr=694.94,V=3557(2)3,Dc=1.298 g/cm3,Z=4,F(000)=1464,μ=0.486 mm-1,R=0.0296,wR=0.0683[I2σ(I)].     

利用二维核磁共振方法研究取代茚基金属钛、锆配合物 的空间结构

通过^1H-^1HTOCSY和^1H-^1HNOESY谱对一系列新型结构的取代茚基钛、锆配合物进行了结构上的解析，并由此发现夹心结构的锆配合物中，两个茚环(或茚环和茂环)以及茚环上的取代基之间存在核的Overhauser效应，这对于茚环相对空间结构的判断提供了有效的证据。     

以三聚茚为核的星型电子受体材料的合成、 表征与光伏性能

以高度平面共轭的烷基取代三聚茚为中心核, 以噻吩基团桥联, 在末端连接氰基茚酮作为拉电子基团, 设计合成了一类星型受体分子2,2',2″-{[(5,5,10,10,15,15-己基-10,15-二氢-5H-二茚[1,2-a：1',2'-c]芴-2,7,12-三基)三(噻吩-5,2-二基)]三(亚甲基)}三(3-氧杂-2,3-二氢-1H-茚-2,1-二叉)三丙二腈(NFT-C6)和2,2',2″-{[(5,5,10,10,15,15-癸基-10,15-二氢-5H-二茚[1,2-a：1',2'-c]芴-2,7,12-三基)三(噻吩-5,2-二基)]三(亚甲基)}三(3-氧杂-2,3-二氢-1H-茚-2,1-二叉)三丙二腈(NFT-C10). NFT-C6和NFT-C10的最高占据轨道(HOMO)和最低未占轨道(LUMO)分别位于-5.66和-3.75 eV. 其薄膜在400~700 nm范围内具有较大的吸收强度, 最大吸收峰分别位于606和586 nm. 以聚[(2,6-{4,8-二[5-(2-乙基己基)噻吩-2-基]-苯并[1,2-b：4,5-b']二噻吩})-{5,5-(1',3'-二-2-噻吩基-5',7'-二(2-乙基己基)苯并[1',2'-c：4',5'-c']二噻吩-4,8-二酮)}](PBDB-T)为给体材料, 以NFT-C6或NFT-C10为受体材料制备了太阳能电池器件, 器件在300~700 nm之间具有较宽的响应光谱, 其光电转换效率(PCE)分别达到1.09%和5.23%. 原子力显微镜(AFM)结果表明, PBDB-T和NFT-C10共混制备的光伏器件活性层具有合适的相分离尺寸, 有利于激子的有效解离, 而PBDB-T: NFT-C6器件的活性层相分离尺寸过大, 增加了激子复合的几率, 使器件的短路电流、 填充因子和PCE降低. 研究结果表明, 基于三聚茚的星型光伏材料具有一定的应用前景.     

给/吸电子基团取代对PPV类电致发光聚合物光电特性的影响

用量子化学的AM1和EHMACC/CO方法计算PPV,MEH-PPV和CN-PPV的电子和能带结构,讨论了烷氧基(-OR)和氰基(-CN)侧基取代对PPV类电致发光聚合物光电特性的影响.计算结果表明:给电子基团(-OR)取代使聚合物的HOCO(最高占据晶体轨道)能级升高,电离势减小,而吸电子基团(-CN)取代使LUCO(最低未占据晶体轨道)能级降低,电子亲和势增大,两者都使聚合物能隙降低,同时使聚合物的导电类型由PPV的p型转变成CN-PPV的n和p兼容型.该结果解释了MEH-PPV和CN-PPV光谱的红移及CN-PPV高的电致发光效率,为设计新型高效的PPV类电致发光聚合物提供了理论基础.     

Structural and spectral properties of 3-substitutedphenyl-1,5-diphenylformazans: A quantum chemical study

The structural and optical properties of 3-substitutedphenyl-1,5-diphenylformazans are studied by quantum chemical methods. The density functional theory (DFT) is employed to optimize the ground state geometries of formazans substituted with different electron donating and withdrawing groups in both gas and solvent phases. The absorption spectra of formazan derivatives are calculated using time dependent density functional theory (TD-DFT). The polarizable continuum model (PCM) calculations of 3-substitutedphenyl-1,5-diphenylformazans are performed for bulk solvent effects. The geometrical parameters, vibrational frequencies, and relative stabilities of isomers of 3-substitutedphenyl-1,5-diphenylformazans are studied. The results obtained by TD-DFT calculations reveal that the substitution of electron withdrawing and donating substituents affects the absorption spectra of 3-substitutedphenyl-1,5-diphenylformazans. The calculated maximum absorption wavelengths (λ_max) are highly consistent with the experimental values as found from UV-vis spectra.     

Push–pull effect on the geometries,electronic and optical properties of thiophene based dye-sensitized solar cell materials

Geometries, electronic structure and electronic absorption spectra of thiophene based dye-sensitized solar cells were performed using Density Functional Theory (DFT) and time dependent density functional theory (TD-DFT). Different electron donating and electron withdrawing groups have been substituted. Geometries and electronic properties have been computed at B3LYP/6-31G⁷ and absorption spectra at TD-B3LYP/6-31G⁷ level of theory. Major change in bond lengths and bond angles occurs in the system where there is electron withdrawing or electron donating groups have been substituted. In SYSTEM-2 and SYSTEM-3 intra charge transfer has been observed. HOMO of SYSTEM-2 and SYSTEM-3 is delocalized on left side while LUMO on right side of the molecule. In SYSTEM-1, HOMO is on left side while LUMO is in the center. The designed systems show two absorption peaks for each of the system. In short, choice of appropriate electron withdrawing and donating groups is very important for improving the performance of dye-sensitized solar cells.     

DFT/TD-DFT study on halogen doping and solvent contributions to the structural and optoelectronic properties of poly[3,6-carbazole] and poly[indolo(3,2-b)-carbazole]

The polycarbazoles have been proved to be a good organic semiconductor. These are investigated by quantum chemical studies using B3LYP density functional theory (DFT), and the studies have given a detailed understanding on the impact of carbazole units and an introduction to the electron donating on the optoelectronic properties. The electron withdrawing groups of halogen atoms (chlorine, bromine and iodine) have been substituted into the side chain of the poly[3,6-carbazoles] (PCs) and poly[indolo(3,2-b)-carbazoles] (PICs) and analysed. The band was assigned in the gas phase at 354.8 and 365.1 nm for PCs and PICs which are in good agreement with experimental values of 350 and 390 nm. The calculated results show that the selected three halogen derivatives exhibit a strong blue shift in the toluene solvent medium, with high electronic transition. It is found that PCs, PICs and their derivatives have a narrow band derived in the conduction band, and it is composed of 3p, 4p and 5p states; thus, the energy gap of PCs and PICs increased between the highest occupied molecular orbital and lowest unoccupied molecular orbital energy level by the addition of electron acceptor group atoms. The doped PC and PIC electronegativities are well plotted by an electrostatic potential map, and the plot reveals that chlorine-doped PCs and PICs have less electronegativity and bromine-doped polymer has high electronegativity than that of the chlorine-doped polymers. The results obtained from these studies will expose the affairs between the molecular geometry and electronic and optical properties of the investigated polymers.     

胶束催化体系中的对映选择性环醚化反应

The enantioselective cycloetherification of substituted keto phenols into their corresponding dihydrobenzofuran derivatives was carried out using hydrogen peroxide and chiral quaternary ammonium iodide in micellar media. This approach increased the conversion rate of cycloetherification and also widened the scope of this particular reaction for various substituted keto phenols with electron withdrawing as well as electron donating functionalities. The use of a surfactant in the cycloetherification reaction ...     

Structural and spectral properties of 4-bromo-1-naphthyl chalcones: a quantum chemical study

The structural and optical properties of 4-bromo-1-naphthyl chalcones (BNC) have been studied by using quantum chemical methods. The density functional theory (DFT) and the singly excited configuration interaction (CIS) methods were employed to optimize the ground and excited state geometries of unsubstituted and substituted BNC with different electron withdrawing and donating groups in both gas and solvent phases. Based on the ground and excited state geometries, the absorption and emission spectra of BNC molecules were calculated using the time-dependent density functional theory (TDDFT) method. The solvent phase calculations were performed using the polarizable continuum model (PCM). The geometrical parameters, vibrational frequencies, and relative stability of cis- and trans-isomers of unsubstituted and substituted BNC molecules have been studied. The results from the TDDFT calculations reveal that the substitution of electron withdrawing and electron donating groups affects the absorption and emission spectra of BNC.     

Effect of aromatic substitution in aniline on the properties of polyaniline

Substitution in aniline has tremendous effect in the synthesis of poly(substituted anilines) as well as in their properties. In this investigation polyaniline (PANI), poly(m-nitro aniline) (PMNA), poly(m-amino phenol) (PMAP) and poly(o-ethyl aniline) (POEA) were synthesized by oxidative polymerization under identical conditions. Different properties were measured and compared with PANI to find out the presence of electron donating -OH group, electron withdrawing -NO₂ group and less effecting ethyl group on the properties of poly(substituted anilines). It was found that presence of any type of substitution in the benzene ring of aniline increases the solubility of the resulted polymer but reduces the yield, degree of polymerization, thermal stability, electrical and thermal conductivity. The colors, bulk density, particle size, percentage of crystallinity vary considerably depending on the nature of substitution.     

Photo‐physical Properties of N‐methyl‐3,4‐fulleropyrrolidine and Its Derivatives: A DFT and TD‐DFT Investigation

A series of N‐methyl‐3,4‐fulleropyrrolidine (NMFP) derivatives were designed by selecting different π‐conjugated linkers and electron‐donating groups as D‐π‐A and D‐A systems. The optimised structures and photo‐physical properties of NMFP and its derivatives have been determined using density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) methods with the B3LYP functional and the 6‐31G basis set. According to the computation analysis, both the π‐conjugated linkers and the electron‐donating groups can influence the electronic and photo‐physical properties of the NMFP derivatives. Our calculated results demonstrated that the electron‐donating groups, with significant electron‐donating ability, had the tendency to increase the highest occupied molecular orbital (HOMO) energy. The π‐conjugated linkers with lower resonance energy decreased the lowest occupied molecular orbital (LUMO) energy and caused a significant decrease in the energy gap (E_g) between the E_HOMO and E_LUMO. A Natural Bond Orbital (NBO) analysis examines the effect of the electron‐donating group, π conjugated linker, and electron‐withdrawing group for these NMFP derivatives. For the NMFP derivatives, a projected density of state (PDOS) analysis demonstrated that the electron density of HOMO and LUMO are concentrated on the electron‐donating group and the π‐conjugated linker, respectively. A TD‐DFT/B3LYP calculation was performed to calculate the electronic absorption spectra of these NMFP derivatives. Both the electron‐donating group and the π‐conjugated linker contribute to the major absorption peaks, which are assigned as HOMO to LUMO transitions and are red‐shifted relative to those of non‐substituted NMFP.     

Boron trifluoride-induced, new stereospecific rearrangements of chiral epoxy ethers. Ready access to enantiopure 4-(diarylmethyl)-1,3-dioxolanes and 4,5-disubstituted tetrahydrobenzo[c]oxepin-4-ols

Upon treatment with BF3.Et2O at low temperature, enantiopure benzyl-type ethers of arylglycidols with electron withdrawing substituents at the skeletal aryl group and electron donating substituents at the benzyl group undergo stereospecific rearrangements of Friedel-Crafts type, leading to enantiopure 4-diarylmethyl-1,3-dioxolanes (2) or to enantiopure trans-4,5 disubstituted tetrahydrobenzo[c]oxepin-4-ols (5). The course of the reactions is controlled by the substitution pattern at the benzyl ether: While benzylic systems activated toward ipso substitution afford diarylmethanes 2 through a Friedel-Crafts reaction followed by fragmentation, benzylic systems activated toward ortho attack lead to enantiopure oxepinols 5 through a 7-endo-tet ring closure of Friedel-Crafts type.