具有相反电荷取代基的卟啉和酞菁异聚体荧光光谱的研究

用荧光光谱的方法研究了由水溶性的中位-四-[对-(N,N,N-三甲基苯基)铵基]卟啉的碘化物和2,6,9,15-四(4'-磺酸基)镓酞菁形成的超分子体系,在水溶液中阴离子酞菁与阳离子卟啉能形成杂聚集体。荧光光谱滴定的结果表明:聚集体为杂二聚体,形成平衡常数为1.17×10⁸L/mol。说明了卟啉-酞菁杂二聚体是非常稳定的。没有观察到聚集体的荧光发射。     

单冠醚取代酞菁形成的络合物中的荧光猝灭

在溶液中,单冠醚取代酞菁依靠冠醚的络合作用可以和含碱金属离子的受体分子形成络合物．这种络合物的形成有利于酞菁和受体分子间的光致电子转移反应,使得酞菁的荧光被强烈地猝灭．根据体系的化学平衡和酞菁荧光被受体分子猝灭的机制建立了数学模型,运用实验数据和最小二乘法曲线拟合得到了酞菁和受体分子形成的络合物的稳定常数．     

冠醚桥接苯并菲二聚体合成的新途径

本研究借鉴合成冠醚的Willianmson反应,通过缓慢滴加二氯乙醚合成了重要中间体乙氧基醚链接的苯并菲二聚体,且避免了2,3-二羟基四戊烷氧基苯并菲自身成环反应所导致单一冠醚苯并菲的生成.进一步以该中间体为原料,通过缩合反应,最终得到了冠醚桥接苯并菲二聚体,并用1H NMR,13C NMR和MALDI-TOF质谱对产物的结构和纯度进行了表征.     

二环己基18-冠-6异构体D与十五个稀土硝酸盐配合物的合成及其性质的研究

合成了二环己基18-冠-6-的异构体D与十五个稀土硝酸盐的配合物,系统研究了它们的FOURIER变换红外光谱的变化规律;测定了部分配合物的核磁共振氢谱和碳谱。结果均表明,在稀土系列内离子直径与冠醚穴大小的比例是否合适是影响配合稳定性的主要因素。文中还讨论了配合物中NO3[-]与稀土离子形成接触离子对对红外光谱及核磁共振谱的影响。在NO3[-]v6(B1)中观察到镧系"斜W"规律。基于红外光谱及核磁共振谱的结果,初步讨论了配合物的结构。     

卟啉衍生物π离子自由基二聚体的电子光谱研究

根据四甲基吡啶铜叶啉（CuTMPyP）的光谱电化学和部分质子化的5，10，15-三（4-羟基苯基）-20－（4-十六烷氧苯基）卟啉（P31）LB膜的荧光光谱，研究了卟琳衍生物离子自由基二聚体的电子光谱．电还原产生的CuTMPyP负离子自由基与基态分子通过SOMO’-LUMO作用形成面对面二聚体，在480nm处出现二聚体的Q带，在820nm处出现π*→π*带．质子化产生的P31正离子自由基与基态分子通过SOMO-HOMO作用形成面对面二聚体，在470～515nm处出现二聚体的Q带吸收，在710nm出现π→π带．与单体Q带相比这些Q带发生蓝移．     

碘阴离子桥联的金属镍大环二聚体[(NiL)_2I](I_3)_3

利用 Ni II- I- Ni II联接单元合成并表征了四氮大环镍 (II)配合物二聚体 [(Ni L) 2 I](I3) 3,这里 L=5 ,7,7,1 2 ,1 4,1 4-六甲基 - 1 ,4,8,1 1 -四氮杂环十四 - 4 ,1 1 -二烯。 X射线晶体结构及光谱数据显示 [(Ni L) 2 I](I3) 3是三明治结构 ,对称中心为碘离子 ,两个大环配合物平面相互平行 ,整个组装体的对称性为 D4d。结构数据还表明使 Ni II- I- Ni II单元起稳定作用的主要是碘离子与金属离子间的静电作用 ,还有较弱的共价相互作用。在这种二聚体中 ,金属离子不仅作为大环配合物的中心原子 ,而且在 Ni II- I- Ni II单元中还作为碘阴离子的受体。 [(Ni L ) 2 I](I3) 3的变温紫外可见吸收光谱表明其分解温度约为 375 K。因为这种四氮大环金属配合物二聚体含碘离子一价及三价碘阴离子 ,故有可能在将太阳能转变为电能的光电化学电池中作为电解质而获得应用。     

二乙胺合三(2-苯骈噻唑基)硼烷在电子电离质谱中的反应

在研究二乙胺合三(2-苯骈噻唑基)硼烷的EI质谱时,发现了在EI条件下三(2-苯骈噻唑基)硼烷的二聚作用,并用高分辨质谱、FAB质谱证实了二聚体的存在。用MIKE谱阐明了二聚体离子主要的裂解途径。提出了二聚体形成的一种机理及其可能的结构。     

冠醚配合物热力学性质的研究VI. 几种冠醚配合物的CNDO/2计算

本文用CNDO/2方法从理论上探讨了碱金属离子Na^+,K^+和Cs^+与2,3-苯并-8,11,15-三甲基-18-冠-6(简称BC3-18C6)在溶液中发生的配位反应,计算了配位反应中CNDO总能量的变化,再现了量热法所得出的碱金属离子Na^+,K^+和Cs^+与BC3-18C6在溶液中生成配合物的稳定性次序:K^+>Na^+>Cs^+。所计算的配位能和配合物的水化能表明,在水溶液中碱金属水合离子与冠醚配位,形成稳定的二水配位的碱金属离子冠醚配合物[M(BC3-18GC6)(H~2O)~2]^+。碱金属离子与冠醚中的氧形成的金属-氧键不如其水合物中的金属-氧键强,碱金属离子能与冠醚配位形成稳定的配合物主要是由于配体的大环效应和配合物的溶剂化作用。     

新型不对称镍酞菁的合成、表征及光电性质

通过改进传统的酞菁合成方法, 得到了一种新的不对称酞菁2-(4-异丙基苯氧基)-9(10),16(17), 23(24)-三(4-叔丁基苯氧基)酞菁镍(简称NiPc2), 并通过质谱、红外光谱及紫外-可见-近红外光谱对其进行了表征, 分析了其可能的形成机理以及循环伏安性质. 这种新的不对称酞菁在近红外光区有明显的吸收峰, 并且其固体紫外-可见光谱的Q带发生红移, 说明形成了J-聚集体.     

单冠醚取代不对称酞菁LB膜的制备和表征

酞菁化合物有序聚集体已成为材料化学中的研究热点［１,２］,在酞菁分子中引入冠醚会大大改善酞菁化合物的气敏性,在提高响应速度和重复性的同时,其响应温度可降到室温［３,４］．研究冠醚酞菁气敏性质的通常方法是将其制成浇铸膜［４］,这种膜是无序的．膜中分子的...     

Optical Properties and Dimer Formation in Copper Phthalocyanine-Doped Sol-Gel Matrices

Dimer formation in sol-gel matrices was studied using optical absorption spectroscopy of copper phthalocyanine tetrasulfonate dopants in silicate and aluminosilicate sol-gel matrices. Changes in the optical absorption spectra of dimers and monomers were correlated with various stages of the sol-gel process. Dimerization is strongly influenced by the chemistry of the pore liquid. The primary factors that control dimerization are the quantity of solvent remaining in the pores, pore solvent alcohol/water ratio, and presence of protons which can be either from the catalyst or from silanol groups on the silicate pore surfaces. Synthesis conditions which cause dye protonation invariably lead to dimerization during the latter stages of drying when the pore liquid becomes water-rich and there is a high dye concentration. These studies also identify chemical conditions which are able to avoid dye protonation and subsequently reduce dimer formation.     

EPR investigation of the origin of the magnetic field effect on the dimerization of aluminum(III) and gallium(III) phthalocyanine chlorides in film structures

The origin of the magnetic field effect on the dimerization of aluminum(III) and gallium(III) phthalocyanine chloride films is revealed. The EPR technique is employed to demonstrate that the dimerization of the above coordination compounds occurs via a free radical pathway with the formation of phthalocyanine and OH radicals, thus resulting in the appearance of the magnetic moment in the studied compounds.     

Self-association of sulfo derivatives of cobalt phthalocyanine in aqueous solution

Sulfo derivatives of cobalt phthalocyanine containing naphthalene fragments have been synthesized, and their self-association and molecular complexation with pyridine in aqueous solution have been studied by spectrophotometry. The dissociation constants of the dimeric associates have been determined. The effects of the number of functional groups in the peripheral substituents and of the axial ligand on the phthalocyanine dimerization process have been revealed.     

Iron-Catalyzed Biomimetic Dimerization of Tryptophan-Containing Peptides

Biomimetic oxidative dimerization of tryptophan derivatives in aqueous media with oxygen as a bulk oxidant catalyzed by an iron octacarboxy phthalocyanine complex was established. The discovery of the extremely active iron catalyst enables aerobic enzyme-mimetic oxidation to be performed in a flask. This method was applicable to the oxidative dimerization of a wide range of tryptophan derivatives, including various dipeptides and oligopeptides, with remarkable functional-group tolerance without the protection of the amino acid residues. Furthermore, oxidative dimerization of tryptophan derivatives bearing dioxopiperazine units enabled the convergent total synthesis of five natural pyrroloindole compounds and unnatural congeners. The established chemical method provides facile access to a broad range of dimerized peptides with a unique scaffold to link two turn structures, which will serve as a powerful tool to create new small- and medium-sized-molecules as drug candidates.     

ABSORPTION AND FLUORESCENCE SPECTROSCOPIC STUDIES ON DIMERIZATION OF CHLOROALUMINUM (III) PHTHALOCYANINE TETRASULFONATE IN AQUEOUS ALCOHOLIC SOLUTIONS

Dimerization of chloroaluminum (III) phthalocyanine tetrasulfonates (AIPCS) has been observed in different aqueous alcoholic solvents at room temperature by absorption and fluorescence spectroscopic methods. Both absorption and fluorescence spectral bands of the dimer are red shifted by ca 550 cm^-1 from the monomer Q bands in the corresponding spectra, suggesting that the interaction energy between the two monomer subunits is very weak. The fluorescence lifetime of the dimer is longer ( ca 9.5 ns) than that of the monomer ( ca 7–8 ns). These spectral behaviors of AIPCS dimer contrast with those of transition-metallaloid phthalocyanine dimers, which usually have a nonfluorescent face-to-face stacking conformation. The dimer fluorescence is interpreted to be due to the fact that the lowest excited singlet state of the dimer is lower in energy than a charge-resonance state, based on the excitoncoupling theory applied to the face-to-face slipping conformation. The dimerization constant determined spectrometrically decreases with an increase of water content in the aqueous alcoholic solution. Propanol and ethanol have been observed to be more effective than methanol in promoting dimerization. These results indicate that a specific interaction of water with AIPCS plays an important role in the inhibition of dimerization of AIPCS.     

Formation of bovine serum albumin associates with zinc tetra(4,4′-carboxy)phenylamino- and tetra-(4,4′-carboxy)phenoxy phthalocyanines in aqueous-organic solutions at 298 K

The states of water-soluble complexes of zinc phthalocyanine containing -O-C₆H₄-COONa and -NH-C₆H₄-COONa substituents in aqueous and organic media are studied. The type of dimerization is determined for each phthalocyanine. Phthalocyanine interaction with bovine serum albumin is studied with respect to the association equilibria. It is shown that phthalocyanines are localized in protein subdomains IB and IIA, and the interaction between protein and phthalocyanines is of a multicenter character.     

On the mechanism of mechanochemical dimerization of anthracene. Quantum-chemical calculation of the electronic structure of anthracene and its dimer

The electronic structure of anthracene, its dimer, and intermediate structures composed of two anthracene molecules were calculated in the density functional theory. The calculated potential barrier to anthracene dimerization is ～55 kcal/mol; the dissociation barrier is ～45 kcal/mol. The pressure required for the reaction to reach the transition state and acting on the anthracene crystal is ～60 kbar. Lower pressures, ～10 kbar, are required for molecules to approach each other to distances of ～3 Å, at which tunnel dimerization is possible for photoexcited molecules.     

亚甲蓝在分子有序组合体中的聚集行为

研究了生物染色剂亚甲蓝(MB)在分子有序组合体(胶束、O/W微乳液和层状液晶)介质中的聚集行为。根据MB特征峰处的吸收光谱值,计算了MB的二聚平衡常数和相应单体、二聚体的摩尔消光系数。并用稳态荧光法和无外加探针的循环伏安法进一步论证了计算结果。研究发现,当MB总浓度一定时,在胶束体系中MB单体量较少,在层状液晶体系中单体量较多,在O/W微乳液体系中则介于胶束和层状液晶之间。表明层状液晶体系是获取更多MB单体的理想介质。     

Spectroscopic behavior of cationic metallophthalocyanines in the presence of anionic quantum dots

The interactions and spectroscopic properties between cationic zinc phthalocyanine derivatives (peripherally and non-peripherally tetrasubstituted and peripherally octa substituted with 2-diethylmethylaminoethylsulfanyl (βTZnPc, αTZnPc and βOZnPc)) and CdTe core quantum dots (QDs) capped with mercaptopropionic acid or thioglycolic acid (represented as CdTe@MPA and CdTe@TGA, respectively) have been studied in methanol:water mixture. Strong coupling of MPcs was deduced from the interaction since the UV–vis spectroscopic studies of the ground state complex formed on mixing both components showed loss of the phthalocyanine monomeric band with the formation of a dimeric band (spectrum of aggregated species). The dimerization constants were of the order of 10⁴ M^?1.     

The effect of pH on the photophysics and photochemistry of disulphonated aluminum phthalocyanine

The results of a study of the effect of pH on the photophysics and photochemistry of di-sulphonated aluminum phthalocyanine (AlPcS₂) in aqueous solution are presented. The pH dependence of the triplet quantum yield, fluorescence quantum yield, singlet-oxygen quantum yield, triplet lifetime, fluorescence lifetime and apparent dimerization constants is investigated and the results interpreted in terms of the pH dependence of the nature of the axial ligands. Evidence that the aluminum–axial ligand bond strength, rather than dimer binding energy that determines the extent of dimerization is provided by semi-empirical and ab initio calculations. Possible dimer structures obtained using ab initio calculations are discussed.