钌多吡啶配合物的合成及插入配体的位阻效应对键合DNA的影响

合成了2,3-二甲基-1,4,8,9-四氮三联苯(dmtatp)和2,3-二苯基-1,4,8,9-四氮三联苯(dptatp)两种新配体及它们与2,2′-联吡啶和钌(Ⅱ)的混配物[Ru(bpy)₂dmtatp]²⁺(1)和[Ru(bpy)₂dptatp]²⁺(2),用电子吸收光谱、稳态荧光、粘度测定和圆二色谱研究了配合物与小牛胸腺DNA的相互作用。结合我们以前对配合物[Ru(bpy)₂tatp]²⁺(3)(tatp为1,4,8,9-四氮三联苯)与小牛胸腺DNA的作用研究,得出配合物与DNA的键合强度顺序为:[Ru(bpy)₂tatp]²⁺>[Ru(bpy)₂dptatp]²⁺>[Ru(bpy)₂dmtatp]²⁺,这与插入配体的位阻效应的减少趋势相一致。同时,还测定了配合物与DNA的键合常数。     

手性三元铜(Ⅱ)配合物的制备及其在菊酸不对称合成中的应用

手性金属配合物催化剂在不对称合成中占有重要地位^[1-3]。在该类催化剂参与的不对称催化反应中,配合物中手性配体是催化反应立体选择性优劣的关键^[4,5]。为了改进该类催化剂的性能,主要对手性配体进行过化学修饰。目前合成的手性催化剂几乎都是由同一种手性配体和一种金属离子组成的二元配合物,且高效者并不多.文献[6]曾提到有关手性三元配合物(亦称手性混合配体配合物)。在不对称催化中应用的可能性,但未见具体报道。本文以中性含氮配体和含氧酸与铜(Ⅱ)配位合成了一类手性三元铜(Ⅱ)配合物及其在不对称合成菊酸中的催化性能。     

硝酸钪、钇与缩二脲的固体配合物的合成及性质

六十年代后,缩二脲(以下简称配体B)与过渡金属等配合物的制备及物性测试已相继报道^[1]。但与稀土形成配合物的报道很少,A.Seminara^[2]等合成过镨、钕等氯化物与缩二脲的配合物。钪、钇的硝酸盐与缩二脲固体配合物的合成及其性质的研究尚未见报道。我们在无水乙醇介质中合成出ScB₄(NO₃)₃和YB₄(NO₃)₃固体配合物,并研究了它们的差热、红外光谱、摩尔电导及X-射线粉末衍射等性质。     

气液色谱法研究双-(O,0′-二正辛基二硫代磷酸酯)合镍(Ⅱ)与酮类加合反应的热力学性质

二烷基二硫代磷酸酯及其过渡金属配合物具有强杀菌性能及抑制酶水解作用,可以用作石油添加剂和高聚物防老剂,又是一类优良的萃取剂,用于钴镍、钴锰等的萃取分离^[1-2]。二硫代磷酸酯的金属盐与含氮、含氧的有机碱形成的加合物在液-液萃取中起着重要作用^[3],因此这类配物合的加合作用受到了广泛的注意。     

取代基对咪唑[4,5-f]-1,10-邻菲罗啉Ru(Ⅱ)配合物的温敏性能影响

合成了3种具有不同取代基的咪唑[4, 5-f]-1,10-邻菲罗啉配体L¹~L³及其Ru(Ⅱ)配合物[Ru(L¹)₃]、[Ru(L²)₃]和[Ru(L³)₃],并进行了表征。这些Ru(Ⅱ)配合物在溶液中具有π→π^*跃迁吸收峰和金属到配体的电荷转移跃迁(MLCT)吸收峰,其发光峰位约为590 nm左右。将Ru(Ⅱ)配合物掺杂到聚甲基丙烯酸甲酯(PMMA)中得到相应的温敏漆。Ru(Ⅱ)配合物在PMMA膜中的吸收峰精细结构消失,且在长波方向663 nm附近有新的发射峰,表明Ru(Ⅱ)配合物在PMMA膜中有聚集。温度升高后,Ru(Ⅱ)配合物在PMMA膜中的发射峰强度逐渐减弱。分别计算了在30~60 ℃和60~90 ℃区间内非辐射活化能E_nr和温度灵敏度S_T。结果表明,具有苯基取代的咪唑[4, 5-f]-1,10-邻菲罗啉配体的[Ru(L¹)₃]配合物,比咪唑[4, 5-f]-1,10-邻菲罗啉Ru(Ⅱ)配合物[Ru(L²)₃]及烷基取代基的咪唑[4, 5-f]-1,10-邻菲罗啉Ru(Ⅱ)配合物[Ru(L³)₃]具有更高的温度灵敏度。     

一系列Ru(II)配合物电致化学发光性质的比较研究

比较研究了以C₂O₄^2－为共反应物时5个结构相关的Ru(II)配合物[Ru(bpy)₂L¹]^2＋, [Ru(bpy)₂L²]^2＋, [Ru(bpy)₂L³]^2＋, [Ru(phen)₂L¹]^2＋和[Ru(phen)₂L²]^2＋(其中bpy＝2,2′-联吡啶, phen＝1,10-邻菲啰啉, L¹＝4-羧基苯基咪唑[4,5-f][1,10]邻菲啰啉, L²＝3-羧基-4-羟基苯基咪唑[4,5-f][1,10]邻菲啰啉, L³＝3,4-二羟基苯基咪唑[4,5-f][1,10]邻菲啰啉)的电致化学发光(ECL)性质. 结果表明, 酚羟基的存在能有效地淬灭Ru(II)配合物[Ru(bpy)₂L²]^2＋, [Ru(bpy)₂L³]^2＋和[Ru(phen)₂L²]^2＋的ECL, 其它Ru(II)配合物的ECL量子效率与[Ru(bpy)₃]^2＋相差不大.     

镧系离子(Nd3+、Ho3+、Er3+)与PMHFP和DAM三元配合物的制备及超灵敏跃迁的研究

镧系离子(Ln³⁺)同二安替吡啉甲烷(DAM)和1-苯基-3-甲基-4-苯甲酰基吡唑酮-5等β-二酮形成的三元配合物的超灵敏跃迁现象已有研究^[1-3]。Ln³⁺同1-苯基-3-甲基-4-七氟丁酰基吡唑酮-5(PMHFP)的二元配合物已经合成^[4]。本文研究Ln³⁺)-PMHFP-DAM体系中的超灵敏跃迁现象及其三元配合物的组成、结构和性质。     

季胺基修饰的Salen配合物的合成及性质

采用季胺基取代的水杨醛(由2,4-二羟基水杨醛、1,2-二溴乙烷、高氯酸钠等为原料合成)合成了两个新型Salen配体N,N'-二{4-[[2-(三甲胺基)乙基]氧化]水杨醛}-邻苯二胺二高氯酸盐(L¹), N-(2-羟基-5-甲基二苯甲基)-N'-{4-[[2-(三甲胺基)乙基]氧化]水杨醛}-邻苯二胺高氯酸盐(L²), 并进一步合成了8个新型Salen金属配合物[ZnL¹, NiL¹, CuL¹, ZnL², NiL², CuL², MnL², CoL²]. 用¹H NMR, ¹³C NMR, FT-IR, UV-vis, MS对配体和配合物进行了表征, 测定了金属配合物的水溶性及在水中的摩尔电导率. 结果表明, 与相应母体配合物的水溶性比较, 含有季胺基修饰的Salen金属配合物的水溶性有了较大提高.     

香豆素晶体的光二聚——基态非局部化学控制反应的首例

香豆素及其衍生物有重要的生理活性,对此早期已开展了详尽的研究^[1],对它的光化学性能也有些报道^[2-3]。随着实验手段及检测仪器的进步,不断发现有关香豆素光化学的一些新现象和实验结果,并不断修正过去的报道。Hammond等^[4]报道香豆素在极性溶剂中(乙醇等),直接光解,生成syn-cis二聚体,在非极性溶剂中,未发现二聚体。     

几种过渡金属离子与苏丹Ⅰ(1-苯基偶氮基-2-萘酚)形成配合物的13C核磁共振研究

目前用核磁共振测定配合物结构的报道很多,J。Blackburn等人曾用NMR做为研究电子施主-受主配合物结构的探针^[1],也有人曾用弛豫速率研究胰朊酶的钙键位置^[2]。但随过渡金属离子的逐渐加入形成配合物的NMR研究报道尚不多,本文利用苏丹Ⅰ与一些过渡金属离子形成配合物后¹³C化学位移的变化,并以红外光谱、紫外-可见光谱为佐证研究了这些配合物的结构,并用多种方法对苏丹Ⅰ骨架的¹³CNMR谱进行了归属,初步探讨了,苏丹Ⅰ分子¹³C屏蔽机理及化学位移与分子电子结构间的关系。     

Er2O3的光致发光光谱,吸收光谱和Raman光谱

在可见激光的激发下,Ｅｒ２Ｏ３粉晶样品的Ｒａｍａｎ光谱易受Ｅｒ＾３＋光致发光光谱的干扰。本文利用同一Ｒａｍａｎ光谱仪测得Ｅｒ２Ｏ３的高分辨可见光吸收光谱和激发光谱。     

Preparation and absorption spectrum studies of aromatic and alicyclic poly(amide acid) ammonium salts in water and DMF and in films

A series of ammonium salts of poly(amide acid)s (PAS) were prepared from various poly(amide acid)s (PAA) with tertiary amines. The solubility of poly(amide acid) ammonium salts prepared from PAA(PMDA/ODA) in water is related to the ion concentration of tertiary amines. In order to elucidate the influence of the chemical structures of poly(amide acid)s and poly(amide acid) ammonium salts on their absorption spectra, pyromellitic dianhydride (PMDA), 3,3′,4,4 ′-biphenyltetracarboxylic dianhydride (BPDA), and 3,3′,4,4 ′-benzophenonetetracarboxylic dianhydride (BTDA) were chosen to react with p-phenylenediamine (PDA) and (4,4′-diaminodicyclohexyl)methane (DCHM) to give three kinds of aromatic PAAs and three kinds of alicyclic PAAs. The corresponding PASs were prepared by the reaction of PAAs with triethanolamine (TEA). Their ultraviolet–visible (UV–vis) absorption spectra were investigated compared to those of model compounds. A transparent film without absorption above 320 nm was obtained for PAS(PMDA/DCHM). The difference in absorption spectra of PAS(PMDA/PDA) from that of PAS(PMDA/DCHM) can be related to the existence of intra- and intermolecular charge transfer (CT) for PAS(PMDA/PDA). The absorption spectra of PASs with PDA in films are red shifted compared to those of corresponding PAAs in films, while the absorption spectra of PASs in water are blue shifted compared to those of corresponding PAAs in DMF. No differences in the absorption spectra of PAAs and PASs were found in DMF/H₂O (9/1) mixed solvent. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1329–1340, 1998     

Isolation, Purification and Spectral Characteristics of Soluble Guanylate Cyclase from Bovine Lung *

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Vibronic intensity borrowing. Deuterium effect and emission—absorption asymmetry of the S1---S0 transition in pyrene

The intensities of the vibrationally induced bands in the S₁---S₀ emission and absorption spectra of pyrene-h₁₀ and -d₁₀ are measured and analysed. Several new expressions are reported which relate the deuterium effect and emission—absorption asymmetry of induced spectra to the vibronic coupling mechanism.     

FLUORESCENT TAUTOMERS AND THE APPARENT PHOTOPHYSICS OF ADENINE AND GUANINE

Abstract— Fluorescence, absorption and fluorescence excitation spectra, and quantum yields of 0.02 mM solutions of adenine, 7-methyladenine (7-MA), guanine and 7-melhylguanine (7-MG) are presented for excitation with240–300 nm light. The solvent is neutral ethylene glycol-water (70:30 v/v) in the temperature range140–165 K. Phosphorescence spectra of adenine and 7-MA at 140 K are also presented. The excitation spectrum of adenine shows vibrational structure, whereas the absorption does not. However, the fluorescence of adenine shows the vibrational structure, as do the absorption, fluorescence and excitation spectra of 7-MA. The results confirm (and reinforce) the notion that luminescence from adenine under these conditions is from the N₇–H tautomer, instead of the more abundant N₉–H form. In a similar fashion, the data from guanine and 7-MG strongly suggest that the luminescence from guanine is also mostly from the N₇–H tautomer.     

硫化铅超微粒的制备及量子尺寸效应研究

通常表现明显能级量子化的超微粒结构被称作量子点,由于大而快的三阶非线性光学响应,这种材料很可能用于光计算机的开关、信号转换、信息存贮、运算等功能元件,实验表明,PbS超微粒表现出很强的三阶光学非线性响应。 我们用两种方法合成了3种PbS超微粒溶胶,测定了3种胶体粒子的粒度及紫外-可见     

N,N'-二-[3-羟基-4-(2-苯并噻唑)苯基]脲的光谱实验与密度泛函理论研究

利用实验观测与密度泛函理论(DFT)计算方法考察了新化合物N, N'-二-[3-羟基-4-(2-苯并噻唑)苯基]脲(4-DHBTU)的红外、核磁与紫外吸收光谱性质.与单体2-(4-氨基-2-羟苯基)苯并噻唑(4-AHBT)相比, 4-DHBTU的实验紫外吸收强度显著增强,最大吸收峰发生了明显红移,并呈现出双吸收峰特征.结合实验光谱数据与密度泛函理论计算分析表明, 4-DHBTU分子最稳定的基态异构体为cis-C₁₁和trans-C₁₁,而导致上述紫外光谱差异的主要原因是4-DHBTU样品中cis-C₁₁, trans-C₁₁, cis-C₂₂, trans-C₂₂等多种异构体共存.此外, 4-DHBTU与溶剂二甲基亚砜(DMSO)间氢键作用使得核磁实验中4-DHBTU的15H、16H氢谱化学位移显著增大.     

PROTONATION AND DEPROTONATION EQUILIBRIA OF LUMICHROME

Abstract— In order to investigate the possibility of the tautomerization of alloxazine to isolloxazine in its ground state, the parameters affecting the redistribution of charges in the lumichrome molecule were studied. The absorption and emission spectra of lumichrome as a function of pH in the range H₀ = - 6 to pH = 12 were recorded. At extreme pH conditions the spectra of lumichrome are similar to those of the isoalloxazine system. At high acid concentration ( H ₀ < - 3.0) the absorption spectrum of lumichrome protonated at N₁₀, is practically identical to that of lumiflavin. The fluorescence quantum yield of the two cations is negligible at room temperature.
At pH = 10.5 lumichrome is deprotonated at positions N₁ or N₃, The two monoanions have different excitation spectra. Except for slight differences in the extinction coefficients, the absorption of the anion deprotonated at N₃ is very similar to the lumichrome spectrum. The absorption spectra of the N₁ monoanion and of the di-anion are similar to the spectrum of lumiflavin except for a blue shift of about 20 nm. Furthermore, the emission spectrum of the N₁ -monoanion is identical to that of the isoalloxazine system. These results indicate that the charge distribution in the lumichrome molecule depends on the protonation and deprotonation of the nitrogen atoms at positions 10 and l. Both processes cause a redistribution of charges so that an isoalloxazine ring system is formed.     

Simulation of X-ray absorption near edge spectra of organometallic compounds in the ground and optically excited states

The Mg K-edge and Zn K- and L3-edge X-ray absorption near edge spectra of Mg and Zn porphyrins in the ground state and low-lying optically excited states are calculated. Also computed are X-ray absorption near edge spectra of Fe(II) spin crossover compound in its ground and low-lying optically excited states, motivated by a recent experiment (J. Phys. Chem. A 2006, 110, 38). The calculated absorption spectra of optically excited states can be used to simulate ultrafast optical pump/X-ray probe experiments.     

Electronic absorption spectrum of radiation-produced pentane and hexane radical cations in saturated chlorofluorocarbon and perfluorocarbon matrices at 77 K.

Pentane and hexane radical cations are produced by irradiation, stabilized in saturated chlorofluorocarbon and perfluorocarbon matrices at 77 K and studied by electronic spectrometry. Special emphasis is laid on the obtainment of pure spectra by suitable deconvolution techniques. Electronic absorption spectra of these cations consist of a broad structureless absorption band with maximum at respectively 400 nm (pentane) and 480 nm (hexane). The absorption is intrinsic and is not to a considerable extent affected by the matrix. It is due to transitions from fully-occupied orbitals to the half occupied molecular orbital where the unpaired electron resides. A comparison is made of the electronic absorption spectra with photodissociation spectra obtained by ICR techniques and with theoretical spectra obtained by a conformationally-averaged MINDO/3 approach that includes transition-moment weighting.