4-(9-蒽基)-6-十六烷氧基-2-氨基-1,3,5-三嗪的合成及光谱行为的研究

从三氯均三嗪出发通过三步反应合成了4-(9-蒽基)-6-十六烷氧基-2-氨基-1,3,5-三嗪(AHTA),并通过红外、核磁、质谱、高分辨质谱对目标产物进行了表征.研究表明AHTA分子在基态下分子的蒽环与三嗪环不共平面,激发态下表现为ICT的荧光发射.由于分子间氢键作用的存在,AHTA在自组装膜和LB膜中均形成H-聚集体.     

2,4,6-三萘基-1,3,5-三嗪的合成与光谱行为

本文通过Suzuki偶联反应高效合成了两种三萘基三嗪化合物,即2,4,6-三(1-萘基)-1,3,5-三嗪(T1NT)和2,4,6-三(2-萘基)-1,3,5-三嗪(T2NT). 考察了介质的极性、温度以及THF-H₂O二元溶剂体系中的溶解性等因素对它们吸收和发射光谱行为的影响.研究发现, 由于T1NT比T2NT具有更好的分子平面性,其激发态下分子内电荷转移的程度较大,导致其在溶液中吸收光谱、发射光谱比T2NT呈现显著红移.冻结态下,分子平面性较差的T2NT显示出较短波长的发光.     

2,6-萘二甲酸二甲酯质子化机理的研究

本文通过对含有不同硫酸浓度的2,6-萘二甲酸二甲酯溶液的吸收光谱、室温和低温下的荧光光谱及荧光寿命的研究,观察到了2,6-萘二甲酸二甲酯与硫酸分子之间各种不同的相互作用:即基态下的电荷转移复合物吸收谱,激基复合物的发射谱,氢键作用吸收谱,质子转移后的吸收谱和发射谱以及质子化前后不同的荧光寿命。提出了2,6-萘二甲酸二甲酯与硫酸分子之间的相互作用是通过激基复合物过渡到氢键,然后由氢键过渡到质子转移的过程。     

氮杂杯[2]-间/对-芳烃[2]三嗪与RDX氢键作用理论研究

利用MP2和mPWPW91方法,在6-311G**和6-311++G**基组水平上研究了RDX分别与硝基、氨基和迭氮基取代的氮杂杯[2]-间-芳烃[2]三嗪和氮杂杯[2]-对-芳烃[2]三嗪形成的分子间氢键相互作用,并借助自然键轨道(NBO)和分子中的原子(AIM)理论揭示了氢键的本质.结果表明,氮杂杯[2]-间-芳烃[2]三嗪复合物中氢键主要发生在RDX与三嗪环及其取代基之间;氮杂杯[2]-对-芳烃[2]三嗪复合物中氢键主要发生在RDX与杯芳烃环及其取代基之间.分子间相互作用能在-18.82~-40.62kJ/mol之间;经基组叠加误差(BSSE)校正后,相互作用能顺序为e>f≈b>a>c>d和e′>b′>f′>a′>d′>c′.两类复合物中,氨基取代的复合物分子间氢键强于硝基或叠氮基复合物分子间氢键,氨基氮杂杯[2]-对-芳烃[2]三嗪与RDX形成的氢键最强,有望作为降低火炸药感度、进行火炸药废水处理的候选物.为获得稳定性较强的RDX-氨基氮杂杯芳烃超分子炸药,应该选取介电常数较大的溶剂.     

2-(2′-羟基苯基)苯并咪唑的质子转移反应和光谱性质的理论研究

用AM1和INDO/S-CI方法对2-(2’-羟基苯基)苯并咪唑的基态和激发态分子内质子转移反应进行了理论研究,求得基态和激发态反应的势能曲线、势垒和过渡态,并研究了此分子的一些异构体、阴离子的相对稳定性,估算了氢键能.进行了实验光谱的理论指认,所得结果与实验值符合较好,在此基础上对光化学反应机理和光谱性质进行了探讨.     

1-苯基-3-(4-硝基苯基)-5-(9-蒽基)-2-吡唑啉分子内高位共轭

通过对1 苯基 3 (4 硝基苯基) 5 (9 蒽基) 2 吡唑啉及其相关化合物的吸收光谱进行比较研究,发现该分子的吸收不同于分子内"Ar—N—N=C—Ar"发色团与蒽发色团的叠加.其中"Ar—N—N=C—Ar"发色团的吸收系数增强了12倍,存在极大的增色效应,蒽的精细吸收峰也均红移了20nm左右.说明两者存在基态下的相互作用.优势构象理论分析表明这是由于基态π电子轨道重叠的高位共轭效应引起的.该发现将有助于解释该类分子激发态下发色团间的非共轭电荷转移以及能量转移,并为寻找更大吸收系数的该类化合物提供了较好的方法.     

“马鞍型”环八四噻吩-三嗪体系的合成与聚集诱导发光(AIE)性质研究

以"马鞍型"环八四噻吩(COTh)与1,3,5-三嗪为构筑模块,通过Kumada类型反应有效地制备了三种分别含有1~3个COTh结构单元的环八四噻吩-三嗪衍生物,即2,4-二甲氧基-6-(5,8,11-三甲基硅基)-环八[1,2-b:4,3-b':5,6-b':8,7-b'']四噻吩-1,3,5-三嗪(1),2-甲氧基-4,6-二{(5,8,11-三甲基硅基)-环八[1,2-b:4,3-b':5,6-b':8,7-b'']四噻吩}-1,3,5-三嗪(2)和2,4,6-三{(5,8,11-三甲基硅基)-环八[1,2-b:4,3-b':5,6-b':8,7-b'']四噻吩}-1,3,5-三嗪(3).理论计算表明了该类化合物的长波长的两个吸收峰来自于分子内的电荷转移(CT)吸收.在溶液相它们发射分子内电荷转移(ICT)态荧光,峰位在560~570nm.而在冻结态下呈双荧光发射,即短波长的环八四噻吩本征态发光(400 nm)与长波长的ICT发光(480~500 nm).在四氢呋喃(THF)-H2O二元溶剂体系中,该类化合物产生聚集诱导发光(AIE)现象,可能与化合物分子同时受分子内旋转受阻(RIR)与分子内振动受阻(RIV)机制控制有关.单晶数据表明,化合物1分子内噻吩环与三嗪环之间呈现近平面构象.相邻分子之间噻吩环上的碳原子与三嗪环上的碳原子存在C-C相互作用,制约着连接分子内噻吩环与三嗪环之间单键的自由旋转,从而一定程度上制约了非辐射失活过程,有利于AIE现象的产生.     

2-(2′-羟基-5′-甲基苯基)苯并三氮唑质子转移的光谱和反应机理

用AMI和INDO/CI方法研究了2-(2’-羟基-5’-甲基苯基)苯并三氮唑的激发态质子转移反应,求得基态和激发态反应的位能面、势垒和过渡态;研究了异构体的稳定性、氢键强度及光谱的指认,计算结果均与实验结果符合.讨论了对光诱导质子转移的机理和应用前景.     

硝基苯乙烯基芳香化合物光谱性质的研究

本文通过9-对-硝基苯乙烯基蒽和1-对-硝基苯乙烯基芘在不同溶剂中的光谱数据,利用Lippert-Mataga公式估算了它们在激发态与基态时偶极矩的差值,计算了1-对-硝基苯乙烯基芘在不同溶剂中的辐射与非辐射速率常数,讨论了溶剂极性和温度对分子内光致电子转移和电荷分离的影响。文中还初步探讨了光诱导顺反异构化反应与分子内电荷转移的关系。     

末端含香兰醛亚胺Schiff碱的1,3,5-三嗪核-聚酰胺树枝状化合物的合成

2,4,6-三氯-1,3,5-三嗪与亚胺基二(乙酸乙酯)进行亲核取代反应制得1,3,5-三嗪核-六酯基树枝状化合物(1);1经乙二胺酰胺化制得1,3,5-三嗪核-六乙二胺基树枝状化合物(2);2与丙烯酸甲酯进行Michael加成反应制得1,3,5-三嗪核-六胺基-十二酯基树枝状化合物(3);3再经乙二胺酰胺化制得1,3,5-三嗪核-六胺基-十二胺基树枝状化合物(4);4与香兰醛在乙醇中反应合成了末端含香兰醛亚胺Schiff碱的1,3,5-三嗪核-聚酰胺树枝状化合物,其结构经NMR和IR表征.     

氮化锇配合物离子[OsN(mnt)2]-的电子结构和光谱性质的理论研究

理论研究了离子型配合物[OsN(mnt)2]-[mnt=S2C2(CN)2)]的电子结构和光谱性质, 考察不同配体三价N、二硫氰烯S2C2(CN)2和金属Os的相互作用对光化学性质的影响. 分别在B3LYP/LANL2DZ和CIS/LANL2DZ水平上优化了配合物的基态和激发态结构. 与基态(1A1)相比, 激发态(3A2)的Os≡N 的键长缩短了0.0066 nm, 这与计算得到的频率增大一致, 使用TD-DFT方法计算得到了配合物的吸收和发射光谱. 计算得到的位于300 nm(f=0.1497)和262 nm(f=0.2890)的强吸收都来自1A1→1B1跃迁, 分别指认为SC→Os≡N+CN 和N+SC→Os≡N+CN的电子跃迁. 最低能量的吸收位于446 nm(f=0.0206) 处, 来自1A1→1B2的电子跃迁, 指认为N→Os和 N+SC→CN. 计算得到配合物在气态的磷光发射位于678 nm(A3A2→X1A1)处, 而在丙酮溶液中则蓝移到了625 nm处, 跃迁属性不变, 都是N→Os和S→Os的跃迁.     

Thermodynamic stability of 2,4,6-tris(nitromethyl)-1,3,5-triazine: an experimental and theoretical study

The molecular geometries and electronic structures of 2,4,6-tris(nitromethyl)-1,3,5-triazine isomers were investigated by the density functional method DFT/B3LYP/6-311++G** to elucidate the structural factors responsible for the stability of these systems. It was shown that a characteristic feature of the nitromethyl tautomer (1) of 2,4,6-tris (nitromethyl)-1,3,5-triazine consists in nonvalence interactions between an oxygen atom of nitro group and a carbon atom of triazine ring, which are probably due to Coulomb attraction between them. The tautomer with the 2,4,6-tris (nitromethylene)-hexahyrdo-1,3,5-triazine structure (2) is stabilized trough direct polar conjugation between the amino and nitro groups at the double bond. Structural strain of the molecule with the 2,4,6-tris(aci-nitromethyl)-1,3,5-triazine structure (3) is the reason for its thermodynamic instability. X-ray data indicate that the compound under study exists in the triazine tautomeric form 1 and the distances between oxygen atoms of nitro group and carbon atom of the triazine ring are shortened. NMR data suggest the existence of triazine in the nitromethyl form 1 in acetonitrile and acetone and a tautomeric equilibrium between the nitromethyl and nitromethylene forms in a more polar solvent (DMSO). The results obtained suggest a Coulomb-type stabilization of the 2,4,6-tris(nitromethyl)-1,3,5-triazine molecule in the gas phase, in the crystal, and in nonpolar solvents.     

顺-8-三甲基锡烷基-6-辛烯醛分子内环化反应立体选择性的理论研究

用密度泛函方法在B3LYP/6-31G^*水平上研究了顺-8-三甲基锡烷基-6-辛烯醛分子内环化反应的机理,通过振动分析和内禀反应坐标对过渡态进行了确认,解析了三种反应途径.结果表明,反应具有很强的立体选择性,虽然-OSn(CH₃)₃和-C₂H₃基团均处于环的平伏位,是最稳定的产物构型,但是主要产物是经过活化能最低,且具有两个六元环椅式构象的过渡态形成的,主要产物中-OSn(CH₃)₃基团处于环的直立位.该结果与实验事实一致.     

Time-dependent density functional theory study on hydrogen-bonded intramolecular charge-transfer excited state of 4-dimethylamino-benzonitrile in methanol

The time-dependent density functional theory (TDDFT) method was carried out to investigate the hydrogen-bonded intramolecular charge-transfer (ICT) excited state of 4-dimethylaminobenzonitrile (DMABN) in methanol (MeOH) solvent. We demonstrated that the intermolecular hydrogen bond C[triple bond]N...H-O formed between DMABN and MeOH can induce the C[triple bond]N stretching mode shift to the blue in both the ground state and the twisted intramolecular charge-transfer (TICT) state of DMABN. Therefore, the two components at 2091 and 2109 cm(-1) observed in the time-resolved infrared (TRIR) absorption spectra of DMABN in MeOH solvent were reassigned in this work. The hydrogen-bonded TICT state should correspond to the blue-side component at 2109 cm(-1), whereas not the red-side component at 2091 cm(-1) designated in the previous study. It was also demonstrated that the intermolecular hydrogen bond C[triple bond]N...H-O is significantly strengthened in the TICT state. The intermolecular hydrogen bond strengthening in the TICT state can facilitate the deactivation of the excited state via internal conversion (IC), and thus account for the fluorescence quenching of DMABN in protic solvents. Furthermore, the dynamic equilibrium of these electronically excited states is explained by the hydrogen bond strengthening in the TICT state.     

Time-dependent density functional theory study on electronically excited States of coumarin 102 chromophore in aniline solvent: reconsideration of the electronic excited-state hydrogen-bonding dynamics

The time-dependent density functional theory method was performed to investigate the electronically excited states of the hydrogen-bonded complex formed by coumarin 102 (C102) chromophore and the hydrogen-donating aniline solvent. At the same time, the electronic excited-state hydrogen-bonding dynamics for the photoexcited C102 chromophore in solution was also reconsidered. We demonstrated that the intermolecular hydrogen bond CO...H-N between C102 and aniline molecules is significantly strengthened in the electronically excited-state upon photoexcitation, since the calculated hydrogen bond energy increases from 25.96 kJ/mol in the ground state to 37.27 kJ/mol in the electronically excited state. Furthermore, the infrared spectra of the hydrogen-bonded C102-aniline complex in both the ground state and the electronically excited state were also calculated. The hydrogen bond strengthening in the electronically excited-state was confirmed for the first time by monitoring the spectral shift of the stretching vibrational mode of the hydrogen-bonded N-H group in different electronic states. Therefore, we believed that the dispute about the intermolecular hydrogen bond cleavage or strengthening in the electronically excited-state of coumarin 102 chromophore in hydrogen donating solvents has been clarified by our studies.     

Electronic Structure and Photophysical Properties of 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine

Electronic structure and photophysical properties of 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine are studied theoretically with quantum chemical methods as well as 2D site and 3D cube representations. The theoretical results reveal that the first excited state is an intramolecular charge transfer excited state. The change in dipole moment for the first excited state of the excitation is fitted, and the calculated result the change in dipole moment ￠1=6.40 D is consistent with the experimental result ￠1=6.90 D. The polarizability is also fitted. The large changes in dipole moment and the polarizability of the excitation show that S1 is of large nonlinear optical (NLO) effect. The NLO will promote efficient two-photon-absorption cross sections. The excited state properties of dpbt with different external electronic fields are also discussed theoretically.     

Nucleophilic substitution reactions of 2,4,6-tris(trinitromethyl)-1,3,5-triazine. 2. interaction of 2,4,6-tris(trinitromethyl)-1,3,5-triazine with primary amines and hexamethyldisilazane

2-R-amino-4,6-bis (trinitromethyl)-1,3,5-triazines have been synthesized, and their structures have been established. Dynamic¹³C NMR spectroscopy has been used to measure the rotational barriers of the tertbutylamino group around the C₍₂₎-NHBu-t bond in 2-(tert-butylamino)-4,6-dichloro-1, 3, 5-triazine and 2-(tertbutylamino)-4,6-dimethoxy-1,3,5-triazine. X-ray diffraction was used to investigate the structure of 2-(tertbutylamino)-4,6-bis (trinitromethyl)-1,3,5-triazine. From the results obtained in this work it has been concluded that the bond between the NHBu-t group and the triazine ring has a partial double-bond character.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from ] Khimiya Geterotsikiicheskikh Soedinenii, No. 5, pp. 679–688 May, 1995. Original article submitted March 7, 1995.     

Hydrogen-bonded supramolecular poly(ether ketone)s

The preparation of 2,4-diamino-1,3,5-triazine telechelic poly(ether ketone)s (triazine PEKs) and the formation of supramolecular polymers with dodecyl-(α-ω)-bis(5-methyl-1,3-pyrimidine-2,4-dione) were investigated. Both structures interacted by complementing hydrogen-bonding units present at their respective chain ends, this being reminiscent of triple hydrogen bonding in DNA. The preparation of the triazine PEKs started from hydroxyl-terminated poly(ether ketone)s by a nucleophilic displacement reaction with 2,4-diamino-6-(4-fluorophenyl)-1,3,5-triazine. With this method and molecular weight control via the Carothers equation, a series of triazine PEKs with a complete degree of end-group functionalization were prepared. The structure of the polymers was proven by ¹³C NMR spectroscopy and matrix-assisted laser desorption/ionization spectroscopy. When mixed as a 1:1 complex in solution with dodecyl-(α-ω)-bis(5-methyl-1,3-pyrimidine-2,4-dione), short triazine PEKs (molecular weight = 5700 or 10,000) showed a temperature-dependent association behavior visible via dynamic NMR spectroscopy. Additional proof of the formation of a supramolecular, hydrogen-bonded network was derived from solid-state NMR spectroscopy, differential scanning calorimetry, and rheological investigations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 661–674, 2004     

Studies on Mechanism of Chemiluminescence Reaction of 2, 6, 7-Trihydroxyl-9-(4'-chlorophenyl )-3-fluorone

1INTRoDUCTIONPhenylfluoroneisanimportanttypeofreagentinanalytica1chemistry"~'>.Themoleculesofthisreagenthavearigidplanarstructuret5'6i,sotheenergyofmolecularorbitsofthereagentscanbecalculatedbyHuckelmolecularorbitalmethod(HMO).WehadtriedtoassigndissociationconstantsforsomesuchreagentsbyacombinedspectrophotometricandHMOmethodt7'8i.Them.thodissimpleandtheresultsaresatisfactory.Inthispaper,apossiblemechanismforcatalyticchemiluminescencere-actionofCl-PFisproposedonthebasisofstudyingchemil…