Correction of luminescence emission spectra by digital computer

A simple Algol program for the correction of luminescence emisson spectra for instrumental variations is described. Suggestions are made as to how the program many be modified to suit individual requirements.     

Elektrochemolumineszenz mit unbedenklichen Chemikalien: Das leuchtende Scherblatt

An experiment is described where a bright luminescence of a razor‐blade from an electric razor can be generated even by a 4, 5 Volt battery. The luminescence is not produced by the metal itself but by solution particles in its immediate vicinity. This conversion of electrical energy into light is explained and the influence of different parameters on the quantum yield is discussed. By this simple and appealing experiment instructors are encouraged to introduce topics of modern research and technology into the curriculum.     

Partial least-squares analysis of time decay data for Eu(III)-tetracycline complexes: simultaneous luminescent determination of tetracycline and oxytetracycline in bovine serum

A simple and sensitive methodology to simultaneously quantify tetracycline and oxytetracycline in bovine serum samples is described. The method combines the advantages of the lanthanide-sensitized luminescence (i.e., sensitivity and selectivity) with partial least-squares (PLS) analysis, and requires no previous separation steps. Due to the strong overlapping of emission and excitation spectra of the analytes and their europium complexes, the luminescence decay curve (intensity of luminescence vs. time) of analyte-Eu complex was selected to resolve mixtures of tetracycline and oxytetracycline. Partial least-squares uses the luminescence decay as discriminatory parameter and regresses the luminescence versus time onto the concentrations of standards. Using a 16-sample aqueous calibration set, 10 validation samples, 11 spiked serum bovine samples and a blank of serum were studied. The analyte recoveries from serum samples ranged from 87 to 104% for tetracycline and from 94 to 106% for oxytetracycline. The results obtained by the developed method were statistically comparable to those obtained with high performance liquid chromatography.     

Yellow Circularly Polarized Luminescence from C1‐Symmetrical Copper(I) Complexes

The synthesis of chiral C₁‐symmetrical copper(I) complexes supported by chiral carbene ligands is described. These complexes are yellow emitters with modest quantum yields. Circularly polarized luminescence (CPL) spectra show a polarized emission band with dissymmetry factors |g_lum|=1.2×10^?3. These complexes are the first reported examples of molecular copper(I) complexes exhibiting circularly polarized luminescence. In contrast with most CPL‐emitting molecules, which possess either helical or axial chirality, the results presented show that simple chiral architectures are suitable for CPL emission and unlock new synthetic possibilities.     

Yellow Circularly Polarized Luminescence from C1-Symmetrical Copper(I) Complexes

The synthesis of chiral C₁-symmetrical copper(I) complexes supported by chiral carbene ligands is described. These complexes are yellow emitters with modest quantum yields. Circularly polarized luminescence (CPL) spectra show a polarized emission band with dissymmetry factors |g_lum|=1.2×10⁻³. These complexes are the first reported examples of molecular copper(I) complexes exhibiting circularly polarized luminescence. In contrast with most CPL-emitting molecules, which possess either helical or axial chirality, the results presented show that simple chiral architectures are suitable for CPL emission and unlock new synthetic possibilities.     

Synthesis and size control of monodisperse manganese-doped ZnS nanoparticles by methacrylate polymer

A simple route to the fabrication of methacrylate polymer containing Mn-doped ZnS nanoparticles is described. The particles prepared have sizes as small as 1.8-2 nm, capped or modified by methacrylate polymer, and the thermal, mechanical, chemical stability, life and luminescence intensity are greatly improved. The particle sizes can be easily controlled by changing the number-average degrees of polymerization, which can be realized by adjusting the molar ratio of monomer to chain-transfer agent.     

DELAYED LUMINESCENCE OF ORGANIC MIXED CRYSTALS. VIII. THE LUMINESCENCE OF IMPURE CRYSTALS*,†

Abstract— This paper represents an attempt to understand the delayed luminescence behavior of a real (i.e. impure) mixed crystal. The growth and decay of delayed luminescence is analyzed and shown to be complex. The studies embrace guest and guest concentration dependencies, temperature dependence and excitation intensity and wavelength variation. It is shown that a simple model enables proper interpretation of certain limiting characteristics of the delayed luminescence growth and decay behavior. It is also shown that the temperature dependence of phosphorescence spectra of mixed crystals is readily rationalized and that the complex growth and decay behavior of real crystals are interpretable in terms of guest-guest, guest-trap and trap-trap annihilation phenomena. Differences in the growth and decay lifetimes of a given luminescence are analyzed fully and the reasons for the differences substantiated experimentally. The systems studied consist of aromatics and simple amino acids.     

Molecular luminescence imaging

Imaging techniques relying on different luminescence processes are powerful bioanalytical tools for life sciences. They are used in multiplexed quantitative assays in different analytical formats and to assess the spatial distribution of a given target molecule, chemical or biochemical process in macro- and microsamples, including the in vivo evaluation of biological and pathological processes. Here, recent progresses in luminescence imaging techniques are described, including new labels for fluorescence, time-resolved fluorescence and bio-chemiluminescence, multiplexed imaging microscopy techniques and whole-body luminescence imaging in live animals.     

Techniques for measuring fluorescence and phosphorescence of biological materials

Abstract— Techniques and instruments for measuring the luminescence, fluorescence. and phosphorescence of proteins and nucleic acids are described. Emphasis is placed on the principles of the instruments and the procedures which are necessary to measure quantitatively the luminescence from biological macromolecules at 77°K. Examples are given of the effect of denaturation on luminescence of both proteins and nucleic acids. on ways in which the luminescence can be associated with particular constituents, and finally on the influence that electronic energy transfer has on the excitation spectra of protein luminescences. These examples typify the relationship of luminescence spectra to the conformation and constitution of macromolecules.     

The photoluminescence of crystallophosphors on the base of NaBi/WO4/2 activated by americium,plutonium and neptunium

The luminescence properties of crystallophosphors on the base of NaBi/WO₄/₂ activated by americium, plutonium and neptunium have been studied. The synthesis of crystallophosphors is described. Crystallophosphors luminescence in the near infra-red region. The excitation and luminescence spectra of crystallophosphors are considered. The dependence of luminescence yield is linear in the wide interval of activator concentration.     

Strukturelle lumineszenzspektren einfacher aromatischer verbindungen in organischer und anorganischer matrix und ihre anwendung

The paper describes structural luminescence spectra of simple organic compounds (SOC) that are widely spread in nature and industry. The conditions for producing SOC luminescence spectra in organic and inorganic matrices were investigated. The results are of theoretical and practical interest for environment protection, because they can be used as a basis for the development of a rapid, most sensitive and selective method for the determination of a series of toxic substances (phenol, analine, pyridine, etc.) in various objects, e.g. natural waters and waste waters. A number of methods for the luminescence determination of aromatic compounds is discussed.     

DETERMINATION OF THE KINETICS OF THE BACK REACTION OF PHOTOSYSTEM II IN THE PRESENCE OF 3–(3,4-DICHLORPHENYL)-1,1-DIMETHYLUREA FROM LUMINESCENCE MEASUREMENTS

Abstract— An alternative method to that used by Mar and Roy (1974) for the determination of the kinetics of the back reaction of photosystem II from the luminescence decay curve in the presence of 3–(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) has been suggested. The new theory relies upon two hypotheses: the well-known recombination hypothesis of luminescence and the assumption that the luminescence yield in the seconds region is given by the variable part of the live fluorescence yield. The second hypothesis was introduced since assuming a constant luminescence yield results in kinetic data that are not consistent with measurements of the kinetics of the back reaction by the restoration of the area over the fluorescence rise curve. The dependence of the live fluorescence yield from the concentration of closed PS II traps was assumed to be represented by Delosme's expression originally derived for the rise curve of the fluorescence yield in the presence of DCMU.
The theory is based on the fact that then the partial and total light sums of luminescence are simple functions of the concentration of the primary electron acceptor Q^- of PS II. Thus, after integrating the luminescence decay curve the theory permits a convenient evaluation of the kinetics of the back reaction [Q^-]( t ) in terms of the partial and total light sum.
This method was applied in order to determine the kinetics of the back reaction in Chlorella fusca in the presence of DCMU. It is shown that the kinetics of deactivation of the S, state can be described using the expression for the kinetics of the back reaction derived by Mar and Roy. As an alternative explanation, a biphasic first order decay of S₂ is proposed.     

Excitation-Dependent Multicolour Luminescence of Organic Materials: Internal Mechanism and Potential Applications

Excitation-dependent emission (Ex-de) materials have been of considerable academic interest and have potential applications in real life. Such multicolour luminescence is a characteristic exception to the ubiquitously accepted Kasha's rule. This phenomenon has been increasingly presented in some studies on different luminescence systems; however, a systematic overview of the mechanisms underlying this phenomenon is currently absent. Herein, we resolve this issue by classifying multicolour luminescence from single chromophores and dual/ternary chromophores, as well as multiple emitting species. The underlying processes are described based on electronic and/or geometrical conditions under which the phenomenon occurs. Before we present it in categories, related photophysical and photochemical foundations are introduced. This systematic overview will provide a clear approach to designing multicolour luminescence materials for special applications.     

固定能量同步发光光谱测定法

本文介绍一种分子发光分析新技术——固定能量同步发光光谱测定法(CESLS)。该法系在激发波长和发射波长的同时扫描过程中保,持两者间有一个固定的能量差。它具有比经典发光分析法和固定波长同步发光光谱测定法更为优越的特点,是一种有潜力的多组分分析方法。尤其在PAHs分析中,可望获得广泛应用。本文还讨论了CESLS参数选择的理论优化问题。     

Determination of lasalocid with sensitized terbium(III) luminescence detection

The luminescence of the lasalocid-terbium(III) system in the presence of Triton X-100 and trioctylphosphine oxide has been studied by obtaining kinetic and equilibrium measurements and using the stopped-flow mixing technique. The initial rate and luminescence signal of this system are directly proportional to the lasalocid concentration, which allows one to develop very simple, fast, automatic methods for the determination of this analyte. Kinetic and equilibrium data can be obtained in only 0.1 and 10 s, respectively. The calibration graphs were linear over the range 0.004-5.0 mug ml(-1) (kinetic method) and 0.01-5.0 mug ml(-1) (equilibrium method) and the detection limits achieved were 1 and 3 ng ml(-1), respectively, equivalent to 2 and 6 ng g(-1) lasalocid in a chicken liver sample, which are similar to those afforded by the chromatographic methods described for this determination. The relative standard deviation of both methods was close to 2%. The analytical recoveries obtained by applying the kinetic and equilibrium methods to drinking water, poultry feed and chicken liver samples ranged from 95.6 to 102.1% and from 95.9 to 104.9%, respectively.     

Electroluminescence of Mercury-like Ions on Aluminum Electrode

Experimental and theoretical aspects of electrochemical excitation of luminescence in mercury-like ions are considered. A technique intended for experimentally studying the luminescence kinetics in a flow cell is described. A model is proposed for the charge transfer and the excitation of mercury-like centers on an aluminum electrode. Effect of experimental parameters on the kinetic curves of radiation is considered. An equation that helps explain the observed regularities is suggested.     

A highly selective G-quadruplex-based luminescent switch-on probe for the detection of gene deletion

A G-quadruplex-based switch-on luminescence assay has been developed for the detection of gene deletion using a cyclometallated iridium(iii) complex as a G-quadruplex-selective probe. Upon hybridization with the target DNA, the two split G-quadruplex-forming sequences assemble into a split G-quadruplex, which greatly enhances the luminescence emission of the iridium(iii) probe. The assay is simple and highly selective.     

On the luminescence of titanium-doped lithium zirconate (Li2ZrO3)

The luminescence of Li₂ZrO₃Ti is described. The emission and excitation spectra are reported. The temperature dependence of the decay time is discussed and points to a complicated energy-level scheme. Further, the decay time of the luminescence of ZrO₂Ti has been measured. It appears to be very long (～1 msec).     

Three-component coordination networks based on [Ru(phen)(CN)4(2-) anions, near-infrared luminescent lanthanide(III) cations, and ancillary oligopyridine ligands: structures and photophysical properties

A series of cyanide-bridged coordination networks has been prepared which contain [Ru(phen)(CN)4](2-) anions, Ln(III) cations, and additional oligopyridine ligands (1,10-phenanthroline, 2,2':6',2'-terpyridine or 2,2'-bipyrimidine) which coordinate to the Ln(III) centres. Five structural types have been identified and examples of each type of structure are described: these are hexanuclear Ru4Ln2 clusters; two-dimensional Ru-Ln sheets with a honeycomb pattern of edge-linked Ru6Ln6 hexagons; one-dimensional chains consisting of two parallel cross-linked strands in a ladder-like arrangement; simple single-stranded chains of alternating Ru/Ln components; and a one-dimensional 'chain of squares' in which Ru2Ln2 squares are linked by bipyrimidine bridging ligands which connect to the Ln(III) corners of adjacent squares in the sequence. The 3MLCT luminescence characteristic of the [Ru(phen)(CN)4](2-) units is quenched in those networks containing Ln(III) which have low-lying near-infrared luminescent f-f states [Pr(III), Nd(III), Er(III), Yb(III)], with sensitised Ln(III)-based near-IR luminescence generated by d --> f energy-transfer. The rate of d --> f energy-transfer, and hence the degree of quenching of the 3MLCT luminescence from the [Ru(phen)(CN)4](2-) units, depends on the availability of f-f levels of an appropriate energy on the Ln(III) centre, with Nd(III) (with a high density of low-lying f-f states) being the most effective energy-acceptor and Yb(III) (with a single low-lying f-f state) being the least effective. Rates of d --> f energy-transfer to different Ln(III) centres could be determined from both the residual (partially quenched) lifetimes of the 3MLCT luminescence, and--in the case of the Yb(III) networks--by a rise-time for the sensitised near-IR luminescence. The presence of the 'blocking' polypyridyl ligands, which reduced the number of cyanide and water ligands that would otherwise coordinate to the Ln(III) centres, resulted in increases in the Ln(III)-based emission lifetimes compared to networks where these blocking ligands were not used.     

Induction of Strong and Tunable Circularly Polarized Luminescence of Nonchiral,Nonmetal, Low‐Molecular‐Weight Fluorophores Using Chiral Nanotemplates

A new strategy is described for generating strong circularly polarized luminescence with highly tunable emission bands through chiral induction in nonchiral, totally organic, low‐molecular‐weight fluorescent dyes by chiral nanotemplate systems. Our approach allows the first systematic investigation to clarify the correlation between the circular dichroism and circularly polarized luminescence intensities. As a result, a dilute solution system with the highest circularly polarized luminescence intensity achieved to date and a dissymmetry factor of over 0.1 was identified.