【作者】 刘波；

【导师】 王惠钢；

【作者基本信息】 浙江理工大学 ， 有机化学， 2010， 硕士

【摘要】 近二十多年来,有机富硫分子如二硫纶（dithiolene）化合物dmit和四硫富瓦烯（TTF）衍生物作为有机光电磁的功能化合物,一直引起人们很大的兴趣。在二十多年时间里,TTF的化学研究主要围绕如何提高基于TTF衍生物电荷转移复合物的导电性能展开。随着超分子化学、分子电子学研究的发展和深入,TTF单元由于其特殊的电化学行为、组装特性、易衍生性等特殊物理化学性质,日益成为上述研究领域中重要的功能性结构单元。因此,1,3-二硫杂环类化合物作为合成四硫富瓦烯（TTF）衍生物的重要的前驱体,对其进行短时动力学研究具有很重要的意义。本文采用共振拉曼光谱技术研究了三硫代碳酸乙烯酯,1,3-二硫杂环戊烯-2-硫酮,2-硫代- 1 ,3 -二硫- 4 ,5 -二甲酸二甲酯和4 ,5-二亚乙基-2-硫代-1,3-二硫醇-2-硫酮化合物在适合溶剂中的光诱导反应在Franck-Condon区域的短时动力学特征,在以下几个方面做出了贡献。（1）测得三硫代碳酸乙烯酯在环己烷中的282.4nm、299.1nm、309.1nm和319.9nm激发光的共振拉曼光谱,研究结果揭示了三硫代碳酸乙烯酯的A与B两个吸收带的激发态动力学结构的差异。首先,三硫代碳酸乙烯酯A带的电子跃迁可归属为π（C=S）→π*（C=S）的跃迁,C=S伸缩振动ν₁₁为主要的振动模,而其泛频和组合频占据了共振拉曼光谱强度的主要部分,表明其在A带的光诱导短时动力学主要沿着这一个活性模展开。而S-C-S对称伸缩振动ν₁₈, H-C-C剪切振动及C-C伸缩振动ν₉,S-C-S剪切振动+C-S-C的面内弯曲振动ν₂₁,S=CS₂面外变形振动2ν₁₉四个活性模的同时存在也表明其在Franck-Condon区域的短时动力学具有多维性。B带的电子跃迁不同与A带,它的B吸收带可归属为n（C=S）→σ*（S-C-S）,其表明三硫代碳酸乙烯酯B带的光诱导短时动力学主要沿着C=S伸缩振动ν11,S-C-S对称伸缩振动ν₁₈, S-C-S反对称伸缩及H-C-H摇摆振动ν₁₄,S-C-S剪切振动+C-S-C面内弯曲振动ν₂₁,H-C-H摇摆振动ν₈,在S-C-C-S的C-S反对称伸缩振动ν₁₆,C=S面内摇摆振动ν₂₂、S–C–S反对称伸缩振动ν₁₅这八个活性模展开。而8个活性模的同时存在也表明其在Franck-Condon区域的短时动力学具有多维性。此外,就S=CS₂基团的局部对称性而言,A带和B带的共振拉曼光谱出现了不同的反对称振动模。B带（282.4nm）的共振拉曼光谱出现了S-C-S反对称伸缩及H-C-H摇摆振动ν₁₄与在S-C-C-S的C-S反对称伸缩振动ν₁₆,而A带（309.1和319.9nm）的共振拉曼光谱出现了S=CS₂面外变形振动的偶数倍频2ν₁₉、4ν₁₉,这说明分子在S₃态发生了官能团S=CS₂的碳原子的锥形化,而且B带的S-C-S反对称伸缩及H-C-H摇摆振动ν₁₄与在S-C-C-S的C-S反对称伸缩振动ν₁₆的出现也表明两个C-S键经历了不同的键长变化。（2）测得1,3-二硫杂环戊烯-2-硫酮在环己烷中的341.5nm、354.7nm和368.9nm激发光的共振拉曼光谱,研究结果表明1,3-二硫杂环戊烯-2-硫酮的共振拉曼光谱指认为7个Franck-Condon区域活性振动模:C=S伸缩振动+H-C=C-H剪切振动ν₄,H-C=C-H剪切振动ν₃,S-C（=S）-S对称伸缩振动ν₆,C=C伸缩振动ν₂,在S-CH=CH-S中C-S伸缩振动+ S–C–S剪切振动ν₅,S–C–S剪切振动ν₇属于A₁不可约表示,非完全对称性S=CS₂面外变形振动2ν₁₁的ν₁₁属于B₁不可约表示,这表明虽然大多数激发态结构动力学是沿着全对称性振动反应坐标进行,但它也可以沿着非完全对称性S=CS₂面外变形反应坐标展开,从而进一步说明A₁和B₁两态在Franck-Condon区域存在振动耦合。S=CS₂面外变形振动的2ν₁₁和4ν₁₁出现表明该分子在S₂激发态产生了几何结构变形与对称性打破,这与三硫代碳酸乙烯酯的S₃态与甲原磺酸根离子的S₃激发态类似。（3） 2-硫代- 1,3 -二硫- 4,5 -二甲酸二甲酯在环己烷溶液中的紫外最大吸收在355nm左右,采用341.5nm、354.7nm和368.9nm的激发光获得了其共振拉曼光谱,并进行强度分析。研究结果表明,2-硫代- 1,3 -二硫- 4,5 -二甲酸二甲酯在环己烷溶液中Franck-Condon区域短时动力学具有多维性,激发态初始反应坐标主要是沿着:C=S伸缩振动(ν₁₂,|△| =1.05)和在S-C-S中C-S对称伸缩振动(ν₁₈,|△|=0.93)展开,伴随着C=C伸缩振动（ν₂,|△|=0.23）,C=S伸缩振动+ C-C=C-C对称性收缩振动+ O-CH₃伸缩振动(ν₁₃,|△|=0.53)等振动模,它们共同对激发态分子几何结构重组作出贡献。总振动重组能为1081 cm-1,其中C=S伸缩振动ν₁₂（λ=597 cm-1）和在S-C-S中C-S对称伸缩振动ν₁₈（λ=212 cm-1）之和在总振动重组能中所占比例达到75%。（4） 4,5-二亚乙基-2-硫代-1,3-二硫醇-2-硫酮在氯仿溶液中的紫外最大吸收在400nm左右,采用397.9nm和416nm的激发光获得了其共振拉曼光谱,并进行分析。研究结果表明,4,5-二亚乙基-2-硫代-1,3-二硫醇-2-硫酮激发态初始反应坐标主要是沿着:C=C伸缩振动ν₃,C=C面外扭转振动ν₁₂展开,伴随着C=S伸缩振动ν₁₃,C7-C8伸缩振动ν₈,S-C-S反对称伸缩振动+环变形振动+ H-C-H摆动振动ν₂₅,H-C-H扭转振动ν₂₃等振动模,它们共同对激发态分子几何结构重组作出贡献,说明其短时动力学有多维性,沿着多重反应坐标展开。更多还原

【Abstract】 Over 20 years time, the organic sulfur-rich molecules such as dithiolene -Dmit and tetrathiafulvalenes derivatives are among the widely interesting developments, because they show a variety of properties in the preparation of organic optical and electrical materials. During this period , people have paid attention to tetrathiafulvalenes derivatives’ study on how to improve the conductive properties of the charge-transfer complexes based on tetrathiafulvalene .With the in-depth developments of the supramolecular chemistry and molecular electronics, the molecules will increasingly play an important role in the study on functional structural units because of their special physical and chemical properties of electrochemical behavior, assembly features, easy to derivatives and so on. Therefore we feel very interested in the study on the 1, 3-dithioles which are important precursors in the synthesis of a number of tetrathiafulvalenes derivatives .In this paper, the short-time photo-induced dynamics of the tetrathiafulvalenes derivatives’ precursors-ethylene trithiocarbonate, 1,3-dithiole-2-thione、dimethyl 1, 3-dithiole-2-thione -4,5-dicarboxylate and 4,5-Ethylenedithio-1,3-dithiole-2-thione in the appropriate solvent have been investigated by the Resonance Raman spectra in combination with DFT calculation. Main contributions of the present work are summarized as follows:（1） Resonance Raman spectra of ethylene trithiocarbonate were obtained with 282.4, 299.1, 309.1 and 319.9 nm excitation wavelengths that probe respectively the （n,σ*） and the 1（π,π*） potential energy surfaces. The results indicate that clearly the spectra obtained at different excitation wavelengths exhibit large variations in relative band intensity that reflects significant differences in the excited state structural dynamics. At first, we thus assign the A-band absoption of ethylene trithiocarbonate to theπ（C=S）→π* （C=S）electronic transition,and the resonance Raman spectra indicate that the short-time photo-induced dynamics in the Franck-Condon region occurs along the nominal C=S stretchυ₁₁ forms the largest overtone progressions and combination bands with the other four Franck–Condon active modes the nominal S–C–S symmetric stretchυ₁₈ , the nominal H-C-C scissor + C-C stretchυ₉, the nominal S-C-S scissor+ C-S-C in plane bendυ₂₁ , the overtone 2υ₁₉ of the nominal S=CS₂ out of plane deformation, the nominal H-C-C scissor + C-C stretchυ₉ . The B-band is different from the A-band, which is assigned to the n （C=S）→σ* （S-C-S） electronic transition. It appears that photoexcitation of ethylene trithiocarbonate in the B-band absorption causes larger motions among the C=S stretchυ₁₁, S-C-S symmetric stretchυ₁₈, the S-C-S asymmetric stretch + H-C-H rockυ₁₄, S-C-S scissor+C-S-C in plane bendυ₂₁, H-C-H wagυ₁₄, S=CS₂ out of plane deformationυ₁₉, C-S anti-symmetric stretch in S-C-C-Sυ₁₆,C=S in plane wagυ₂₂ and S–C–S symmetric stretchν₁₅、; Secondly the A- and B-band resonance Raman spectra also display very different kinds of anti-symmetry vibrational modes in terms of local symmetry of S=CS₂ functional group. The B-band resonance Raman spectrum （282.4 nm） shows the antisymmetric mode that are the nominal S–C–S asymmetric stretch + H-C-H rockυ₁₄ and the nominal C-S anti-symmetric stretch in S-C-C-Sυ₁₆, while the A-band resonance Raman spectrum （309.1 and 319.9 nm） shows even overtones 2υ₁₉ and 4υ₁₉ of a antisymmetric modes that is the nominal out of plane S=CS₂ deformationυ₁₉ . The appearance of the even overtones 2υ₁₉ and 4υ₁₉ in A-band resonance Raman spectra indicates that the molecule upon A-band absorption or in S₃ excited state undergoes pyramidalization of carbon atom in S=CS₂ group, while the presence of the antisymmetric modes of the nominal S–C–S asymmetric stretch + H-C-H rockυ₁₄ and the nominal C-S symmetric stretch in S-C-C-Sυ₁₆ indicates that the two C-S bonds undergo different bond length changes.（2） Resonance Raman spectra were acquired for 1,3-Dithiole-2-thione in cyclohexane solvent with 341.5, 354.7 and 368.9 nm excitation wavelengths. The resonance Raman spectra of these spectra indicate that most of the short-time photo-induced dynamics in the Franck-Condon region occurs mostly along the C=S stretch+ H-C=C-H scissorυ₄ , accompanied by the nominal H-C=C-H scissorυ₃ , the nominal S-C-S symmetric stretchυ₆ , the nominal C=C stretchυ₂ in A₁ irreducible representative, and one non-total symmetry S=C-SS out of plane deformation vibrational modeυ₁₁ in B₁ irreducible representative. This indicates that while most of the excited state structural dynamics are along the total symmetry vibrational reaction coordinates, it also moves along the non-total symmetry S=C-SS out of plane deformation reaction coordinate significantly, indicating the existence of the Franck-Condon region vibronic coupling between the A₁ and B₁ states. The appearance of the even overtones 2υ₁₁ and 4υ₁₁ of the nominal out of plane S=CS₂ deformationυ₁₁ suggests that geometry deformation or symmetry breaking occurs in the initial S2 excited state. This is very similar to the S3 state of ethylene or the S3 state of methyl xanthate anion.（3） We obtained the intensity absorption spectrum of dimethyl 1, 3-dithiole-2-thione -4,5-dicarboxylate in cyclohexane solvent which has a charge-transfer band near 355 nm. Resonance Raman spectra were acquired for dimethyl 1, 3-dithiole-2-thione -4,5-dicarboxylate in cyclohexane solvent with 341.5, 354.7 and 368.9 nm excitation wavelengths. The results indicate that the Franck-Condon region structural dynamics of dimethyl 1, 3-dithiole-2-thione -4,5-dicarboxylate have multidimensional character with motion predominantly in the C=S stretch (ν₁₂,|△| =1.05)and the C-S symmetric stretch modes in the S-C-S (ν₁₈,|△| =0.93), accompanied by moderate contributions from the C=C stretch（ν₂,|△| =0.23）,the C=S stretch+ S-C symmetric stretch in C-C=C-C + O-CH₃ stretch(ν₁₃,|△| =0.53)and so on. The 75% total vibrational organizational enery （1081cm-1） of dimethyl 1, 3-dithiole-2-thione -4,5-dicarboxylate -dicarboxylate which is distributed on the modes about C=S stretch (ν₁₂,λ=597 cm-1)and the C-S symmetric stretch modes in the S-C-S (ν₁₈,λ=212 cm-1).（4） We obtained the intensity absorption spectrum of 4,5-Ethylenedithio-1,3-dithiole -2-thione in chloroform solvent which has a charge-transfer band near 400 nm. Resonance Raman spectra were acquired for 4,5-Ethylenedithio-1,3-dithiole-2-thione in chloroform solvent with 397.5 and 416nm excitation wavelengths. The results indicate that the Franck-Condon region structural dynamics of 4,5-Ethylenedithio-1,3-dithiole-2-thione have multidimensional character with motion predominantly in the C=C stretchν₃ and the C=C twist out of planeν₁₂, accompanied by moderate contributions from the C=S stretchν₁₃, C7-C 8stretchν₈,S-C-S anti-symmetric stretch +Ring deformation +H-C-H rockν₂₅, H-C-H twistν₂₃.更多还原