吡嗪-2-羧酸在γ-改性磷酸锆中的插层组装及发光性能

采用直接沉淀法制备了层状框架γ-磷酸锆（γ-ZrP）及改性磷酸锆（γ-DDZrP）,通过插层化学法将吡嗪-2-羧酸生色团与改性磷酸锆进行杂化组装。X射线衍射结果显示,γ-DDZrP的层间距（3.70 nm）远远大于γ-ZrP（1.11 nm）,这有利于吡嗪-2-羧酸生色团的插入。组装后层状框架的层间距由3.70 nm减小为3.33~3.29 nm。 荧光光谱表明,最大发射峰位置发生了明显蓝移,由溶液中的373 nm蓝移至悬浮液的366 nm。研究发现,吡嗪-2-羧酸在水溶液中的荧光强度很低,但形成插层组装后,悬浮液的荧光强度有了很大程度的提高,当浓度为15 μmol/L时,荧光强度增大了6倍。这说明γ-DDZrP能够改善吡嗪-2-羧酸的荧光性能,有利于其在分子识别和荧光探针等领域的应用。     

一种新型尾式卟啉的合成及其光电性质研究

合成了新型尾式5-(2-(α-咪唑基间甲基苯甲酰胺基)苯基)-10,15,20-三苯基卟啉(H2TPP-Bz Im)及其Fe、Co、Zn配合物,并用核磁、质谱、红外光谱、紫外-可见光谱等对其化合物进行了表征,通过紫外吸收、荧光分析、循环伏安法研究了化合物的光电性质。结果表明,与四苯基卟啉(H2TPP)相比,该尾式卟啉及其配合物的紫外和荧光光谱均出现较明显红移。Fe和Co卟啉的循环伏安曲线表明不仅发生了卟啉环上的氧化还原反应,还发生了金属离子的氧化还原反应。     

脱氧核糖核酸与3-氨基-6-二甲氨基-2-甲基吩嗪盐酸盐反应机理的研究

采用UV光谱法 ,发现在pH 7～ 8的缓冲溶液中 ,脱氧核糖核酸 (DNA)与 3 氨基 6 二甲氨基 2 甲基吩嗪盐酸盐 (ZR)相互作用 ,生成红色配合物 ,此配合物的最大吸收峰为 5 2 0nm。反应前后的吸收光谱变化明显 ,配合物的吸收峰值红移 70nm。测得该配合物的表观摩尔吸光系数ε =1 5× 10 6mol-1·L·cm-1;最大结合数n =30 3。研究了体系的酸度、温度、时间等基本反应条件。离子强度的改变对体系的吸光度有明显的影响。实验研究了生物大分子与小分子探针的结合模式 ,认为该反应基本符合Scatchard模型。     

2,9-二正丁基-1,10-菲咯啉双核铜(Ⅰ)配合物的合成、晶体结构及光学性质

以2,9-二正丁基-1,10-菲咯啉(dnbp)和碘化亚铜为原料,在四氢呋喃溶液中反应合成了一种新型中性双核铜(Ⅰ)配合物[CuI(dnbp)]2。采用X射线单晶衍射、核磁共振氢谱、紫外-可见吸收光谱表征其结构,荧光光谱测定其发光性能。结果表明:该配合物分子由两个Cu(Ⅰ)离子通过两个碘离子桥联形成畸变的菱形Cu2I2核心和dnbp螯合配体构成,配合物中I—Cu—I的夹角较小(106.08°),两个Cu(Ⅰ)离子的距离很长(0.319 4 nm),表明它们的相互作用可以忽略。上述结构的特征主要由dnbp配体大的空间位阻造成。配合物晶体属于三方晶系,空间群为R-3,晶胞参数a=4.404 14(11)nm,b=4.404 14(11)nm,c=1.085 92(4)nm,γ=120°,V=18.241 1(9)nm3。配合物在二氯甲烷溶液中出现350～500 nm的吸收峰,归属于金属离子到配体的电荷转移跃迁(MLCT)。室温下,当激发波长为365 nm时,其最大发射波长为653 nm,发光寿命为3.1μs,光致发光量子产率为0.013。发光机制属于金属离子和卤素到配体电荷转移激发态的磷光发射。低温下,配合物最大发射波长蓝移至645 nm,发射峰变窄。     

含氮配体构筑的单核锌Zn(Ⅱ)/双核Cu(Ⅰ)配合物蓝光材料的结构和荧光性能研究

采用溶剂热法合成出单核Zn(Ⅱ)配合物[Zn(2,6-PDA)(phen)H₂O]·H₂O (1)和双核Cu(Ⅰ)配合物{[Cu(μ-Ⅰ)(phen)H₂O]·H₂O}₂ (2) (2,6-H₂PDA=2,6吡啶二甲酸,phen=1,10-邻菲罗啉),通过单晶结构测试、元素分析和红外吸收光谱对结构进行表征,并研究了两种配合物在二甲基亚砜(DMSO)中及固态时的荧光光谱及DMSO溶液中紫外可见吸收光谱。配合物1和2的最大吸收峰分别出现在253和242 nm附近,相比于配体吸收峰均发生红移,在1和2中,主要呈现出中心金属离子微扰的phen的π→π*的跃迁,且吸收强度强于phen,说明中心金属离子与phen配位后,增加了有机配体在紫外区的吸收,利于配体对能量的吸收。1在DMSO溶液中的荧光发射峰位于361,379和392 nm,在固态时的荧光发射峰为407,434和467 nm,2在DMSO溶液中的荧光发射峰出现在422,443和461 nm,固态时荧光发射峰在442,469,501 nm,均呈现蓝光发射。配合物1和2的固态荧光发射光谱与相应的DMSO溶液中的发射峰相比分别红移55和23 nm,这是由于在固态时配合物1和2的分子中的π—π堆积相互作用和分子间的相互作用,特别是配合物2中存在强烈的Cu(Ⅰ)…Cu(Ⅰ)相互作用,降低了体系前线轨道之间的能量差。     

一种新型金属铱(Ⅲ)有机配合物的光谱特性研究

针对一种合成的新型金属铱(Ⅲ)有机配合物的光谱特性进行了研究.实验中,该配合物的配体为苯基喹啉和异丁基酰苯胺.紫外-可见吸收光谱研究表明,该配合物分别在225 nm,267 nm、339 nm以及460 nm附近出现较强吸收峰,其中在320 nm～580 nm范围内,存在着单线态和三线态的金属铱到配体的电荷跃迁.发光光谱测试表明,随着溶液中(二氯甲烷作为溶剂)该新型金属铱(Ⅲ)有机配合物浓度的增加.溶液的发光光谱峰值位置不断发生红移.当处在460 nm激发波长下,溶剂二氯甲烷发光光谱没有出现明显的峰值强度,排除了溶剂对发光光谱测量的影响,直接测量出该配合物在606 nm附近有强的金属二线态磷光发射.因此,该配合物有望成为一种可用于有机电致发光领域的新型磷光材料.     

四-(二甲氨基苯基)卟啉及其金属配合物的合成及光谱性能研究

以丙酸、乙酸、硝基苯为溶剂一步法合成了四-(二甲氨基苯基)卟啉(T(DMAP)P),并采用氯仿-N,N二甲基甲酰胺为溶剂合成了其与Zn2+,Mn2+,Tb3+三种离子的配合物,考察了溶剂种类、温度、时间对反应的影响,探讨了卟啉与金属盐反应两者用量的最佳比例,在较温和条件下合成了卟啉金属配合物,避免了高温合成金属卟啉不稳定现象。利用元素分析,IR,UV-Vis等方法确定了目标化合物的组成和结构。考察了不同浓度及温度下卟啉配合物的电导率并计算了其摩尔电导率。实验结果发现,卟啉与铽离子配合物摩尔电导率远大于锌、锰配合物。实验研究了不同金属离子对反应的影响,重点考察了卟啉及其金属配合物的分子光谱性能的差异。与四苯基卟啉相比,T(DMAP)P及其金属配合物UV-Vis光谱均发生红移,探讨了该现象产生的原因。     

新型卟啉吡啶季铵盐对铜(Ⅱ)显色反应的研究

研究了在不使用表面活性剂的情况下,新型卟啉吡啶季铵盐溴化5-[4-N-(甲氧基)苄铵基吡啶基]-10,15,20-三(4-N-吡啶基)卟啉对铜(I)的显色反应.结果表明,在pH=1.2时卟啉与Cu2 形成了稳定的配合物,其最大吸收波长为423nm,试剂与Cu2 络合比为1:1,表观摩尔吸光系数为3.24×105L·mol-1·cm-1,铜含量在0-0.8μg/10mL范围内符合比耳定律,该方法应用于环境水样中铜的测定,结果令人满意.     

卟啉和钌二元体的超快能量转移

采用超快时间分辨的荧光光谱技术测量了一种由柔性链连接的卟啉-钌二元体分子内的能量转移动力学过程.通过在钌的吸收峰(～453nm)对二元体进行光激发,实验上观测到了从钌基团到卟啉基团的超快能量转移过程(～400ps).而在卟啉的吸收峰(～400nm)对二元体进行光激发,实验上没有观测到从卟啉基团到钌基团的能量转移.采用Frster理论对二元体系能量转移过程的产生机理进行了分析,结果表明,钌和卟啉之间的能量转移来源于基于光谱重叠的偶极-偶极相互作用. 关键词： 卟啉-钌二元体 能量转移 超快激光光谱技术     

H3 PAuPh与(H3PAu)2(1,4-C6H4)2光谱性质的密度泛函研究

用密度泛函(DFT)方法优化了配合物H3 PAuPh(a),(H3 Pau)2(1,4-C6 H4)2(b)的基态的几何结构,并用含时密度泛函方法计算了它们的吸收光谱.结果表明配合物a与b的最低能量吸收谱线的波长分别为257.5 nm和307.6nm,皆具有C(2p)→Au(6p)电荷转移参与下的Px(芳环)→px>(芳环)跃迁本质,并伴有Au(5d)→Au(6p)的金属中心电荷转移性质.配合物b是由两个配合物a相连接而成,配合物b的分子轨道也是由配合物a的分子轨道组合而成.由于轨道组合中存在px或Px相互作用,配合物b的最低能量吸收谱线的波长大于配合物a的相应值.     

Encapsulation of highly confined CdSe quantum dots for defect free luminescence and improved stability

This is the first report on the generation of trap states and their effective elimination in highly confined CdSe quantum dots in order to obtain enhanced and stable optical properties prepared by aqueous route. Surface plays an important role in optical properties of quantum dots (QDs) and surface modification of quantum dots can improve optical properties. In present work luminescent CdSe QDs were prepared using 2-Mercaptoethanol (2-ME) as stabilizing agent and encapsulated by polymer. Different concentrations of 2-ME were used to tune the emission spectra with respect to their reduced size. Addition of 2-ME to CdSe QDs enhances the trap emission and quenching band edge emission due to (i) increased surface to volume ratio and; (ii) presence of high concentration of sulfide ions as confirmed from EDX analysis as sulfide ions possesses the hole scavenging characteristics. Polymer encapsulation of QDs was carried out to make them stable and to improve their optical properties. Even though there are previous reports addressing the improved optical properties by polymer encapsulation and silica encapsulation but experimentally it has not been reported yet experimentally. In this work we have synthesized and characterized water soluble polymer encapsulated QDs and proved the facts experimentally. Photoluminescence spectroscopy clearly reveals the role of polymer encapsulation in boosting the optical properties of CdSe QDs. FTIR spectra validate the presence of biocompatible functional groups on CdSe4/PEG (Polymer encapsulated QDs).     

The third-order optical nonlinearity and upconversion luminescence of CdTe quantum dots under femtosecond laser excitation

The aqueous CdTe quantum dots (QDs) were synthesized by the electrostatic reaction method. The optical properties of CdTe QDs were investigated by femtosecond Z-scan and time-resolved luminescence technique in nonresonant spectral region. The nonlinear absorption and refraction are ascribed to two-photon absorption, and time-resolved upconversion photoluminescence produces biexponential decay pattern at infrared femtosecond laser excitation. Upconversion luminescence is composed of a band-edge excitonic state and a photoinduced trapping state. The short-lived band-edge excitonic emission is independent of the detection wavelengths, and long-lived species becomes even longer with the increase of detection wavelengths, which indicates the size dependence of surface excitonic emission. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Spectral, thermal and hardness studies on unidirectional grown dichlorido diglycine zinc dihydrate single crystal

Bulk semi-organic single crystal of dichlorido diglycine zinc dihydrate has been grown by unidirectional crystal growth method from aqueous solution. The phase of the grown crystal was identified using single crystal XRD analysis. The functional groups present in the crystal were confirmed using FTIR and ¹H NMR analysis. Transmission study shows 70% of transmission in the entire visible region, which reveals the good optical quality of the grown crystal. A stable broad peak in the range of violet-green emission was observed in the emission spectrum, which is due to the existence of defects in the crystal. The thermal and mechanical properties of the grown crystal were studied using TG/DTA and the Vickers microhardness tester, respectively.     

Physical and Optical Properties of Calcium Zinc Borophosphate Glasses Doped with Manganese Ions

This article reports on the physical and optical properties, absorption, and luminescence spectra in the visible region, of calcium zinc borophosphate glasses doped with manganese ions. The manganese composition was varied up to 10 mol%. The aim of this work was to investigate the effect of the luminescence properties when the glasses were doped with different compositions of manganese ions. X-ray diffraction profiles confirmed their glassy nature. The optical absorption spectrum showed bands characteristic of manganese ions in octahedral symmetry. Both excitation and emission spectra were recorded for these glasses to understand their optical performances. The emission spectrum showed a single broad band (green region) in octahedral symmetry at 582 nm as a result of transition from the upper ⁴T_1g state to the ⁶A_1g ground state of manganese ions. As the concentration of manganese ions increased, the emission band increased from 582 nm (green-light emission) to 650 nm (red-light emission). Apart from the spectral analysis, different physical properties of these glasses were also analyzed. Based on the physical and optical properties, we found the samples to be more promising for their use as novel luminescent optical materials.     

New fluorescent dyes in the red region for biodiagnostics

The increased sensitivity together with the advent of low-cost optical sources and detectors in the visible-near IR region has led us to current efforts to develop new efficient fluorescent labels for biodiagnostics with absorption and emission beyond 600 nm. In view of the general fluorescence decrease with increasing emission wavelength, we investigated the possibility to shift the absorption of rhodamine dyes toward the region 620–670 nm. The hydrophobic nature of all known long-wavelength dyes results in the tendency to form intra- and intermolecular aggregates in hydrophilic solvents, especially in aqueous environment. Due to the aggregation with biological materials, fluorescence quenching of the dyes is often observed. New strategies for prevention of these processes are considered.     

Inductively Coupled Plasma Optical Emission Spectrometry in the Vacuum Ultraviolet Region

Abstract

Inductively coupled plasma optical emission spectrometry has been applied for trace metal determination in a myriad of sample types. However, the detection of nonmetals is a challenge. For example, the high excitation energies associated with most nonmetals is a barrier for populating the excited state of these elements. Even in the presence of sufficient excitation energy, the principal resonance lines for nonmetals usually lie in the vacuum ultraviolet region, where atmospheric species like oxygen and water vapor absorb the radiation. Several nonmetals (nitrogen, oxygen, and carbon) are also present in the atmosphere, so contamination or background emission signals can hinder quantification. A common approach to solving these problems is to increase throughput by purging the optical path with an inert gas. In addition, unnecessary mirrors or lenses are eliminated when possible. This review provides a survey of the applications of inductively coupled plasma optical emission spectrometry in the vacuum ultraviolet region, with particular emphasis on the detection of sulfur, phosphorus, iodine, and carbon. The alternative of employing nonresonance lines for these elements in the near-infrared region is discussed briefly as well.     

Optical properties of ZnO nanorods realised by aqueous chemical growth

Photoluminescence investigations of ZnO nanorods realised by an advanced two-step aqueous chemical growth process have been carried out revealing well-resolved near-band-edge emission accompanied by phonon replicas. The optical properties of nanorods with different lengths and diameters are quite similar indicating a good control of the growth process without influencing the optical properties even on plastic substrate. The near-band-edge emission has a very broad line-width of 10 meV. Annealing in Ar atmosphere reduces the deep-level emission with a corresponding increase of the near-band-edge emission.     

Effect of Temperature on Re-entrant Condensation of Globular Protein in Presence of Tri-valent Ions

Globular proteins play several essential roles in functioning different mechanisms of the living organisms, and the stability of such protein molecules in an aqueous solution is strongly affected by multivalent ions. In this article, we have systematically studied the effect of temperature (between 5 and 25ºC) on the re-entrant condensation behaviour of bovine serum albumin (BSA) in the presence of trivalent ions, Yttrium (Y³⁺), and Lanthanum (La³⁺). The effect of temperature is explained considering the optical properties of the protein, i.e., from the optical absorption and emission behaviours. The absorption in the visible region and the fluorescence emission of BSA becomes maximum at the lowest temperature. The decrement of mobility at lower temperature is responsible for fluorescence enhancement. Moreover, the activation energy of the turbid or viscus phase of the BSA protein under re-entrant condensation is enhanced in comparison with the transparent phase and the corresponding energy value is estimated from the fluorescence study.

     

Highly directional spaser array for the red wavelength region

The spaser offers an opportunity to achieve coherent optical sources at nanometer scales due to the extreme confinement of optical fields. However, achievement of spasers with directional propagation in the visible wavelength region remains a challenge thus far, owing to the unique optical feedback mechanism and large dissipative losses of the metal cavity. Here, we experimentally demonstrate for the first time a spaser showing highly directional emission in the visible by using a periodic subwavelength hole array perforated in a metal film, which function as plasmonic nanocavities, along with an organic laser dye to supply gain. The lasing occurs in the red wavelength region and shows a single mode. It is suggested that the optical feedback for spasing is provided by the SPP–Bloch wave, which is supported by the fact that no spasing was attained in aperiodic holes as well as in periodic holes that do not support the SPP–Bloch wave at the spasing wavelength.     

微波法制备Mn2+掺杂ZnSe纳米材料及谱学性能研究

过渡金属掺杂的Ⅱ-Ⅳ族纳米材料有望替代CdSe类量子点作为新型的荧光标记物而受到广泛关注.利用微波加热法的体加热特点,以不同有机胺为配体溶剂,控制反应条件,制备了Mn2+掺杂的ZnSe纳米材料,并分别利用TEM、EDS、荧光光谱等手段对其形貌、结构和性能的关系进行了探索.Mn2+掺杂的纳米ZnSe粒子为200～500 nm的球形粒子,表面平整,为单晶的纤锌矿结构.掺杂后纳米粒子的发射峰显示Mn2+的跃迁发射,但不同的配体溶剂和掺杂量对产物的发光性能有明显影响.