Dual-Channel Probe of Carbon Dots Cooperating with Lanthanide Complex Employed for Simultaneously Distinguishing and Sequentially Detecting Tetracycline and Oxytetracycline

Tetracycline (TC) and oxytetracycline (OTC) are the most widely used broad-spectrum antimicrobial agents in tetracycline drugs, and their structures and properties are very similar, so it is a great challenge to distinguish and detect these two antibiotics with a single probe at the same time. Herein, a dual-channel fluorescence probe (SiCDs@mMIPs-cit-Eu) was developed by integrating two independent reaction sites with SiCDs-doped mesoporous silica molecular imprinting group and europium complex group into a nanomaterial. The synergistic influence of inner filter effect and “antenna effect” can be guaranteed to solve the distinction between TC and OTC. Moreover, this novel strategy can also sequentially detect TC and OTC in buffer solution and real samples with high sensitivity and selectivity. This method revealed good responses to TC and OTC ranging from 0 to 5.5 μM with a detection limit of 5 and 16 nM, respectively. Combined with the smartphone color-scanning application, the portable and cheap paper-based sensor was designed to realize the multi-color visual on-site detection of TC and OTC. In addition, the logic gate device was constructed according to the fluorescence color change of the probe for TC and OTC, which provided the application possibility for the intelligent detection of the probe.

Charging and ultralong phosphorescence of lanthanide facilitated organic complex

Emission from the triplet state of an organo-lanthanide complex is observed only when the energy transfer to the lanthanide ion is absent. The triplet state lifetime under cryogenic conditions for organo-lanthanide compounds usually ranges up to tens of milliseconds. The compound LaL1(TTA)3 reported herein exhibits 77 K phosphorescence observable by the naked eye for up to 30 s. Optical spectroscopy, density functional theory (DFT) and time-dependent DFT techniques have been applied to investigate the photophysical processes of this compound. In particular, on-off continuous irradiation cycles reveal a charging behaviour of the emission which is associated with triplet-triplet absorption because it shows a shorter rise lifetime than the corresponding decay lifetime and it varies with illumination intensity. The discovery of the behaviour of this compound provides insight into important photophysical processes of the triplet state of organo-lanthanide systems and may open new fields of application such as data encryption, anti-counterfeiting and temperature switching.

Thermal, Spectroscopy and Luminescent Characterization of Hybrid PMMA/Lanthanide Complex Materials

Novel hybrid materials based on the poly(methyl methacrylate) (PMMA) matrix and lanthanide(III) carboxylates Eu:2,6-DClB and Tb:2,6-DClB were synthesized and carefully analyzed in the context of their potential application in optically active polymer-based optical fibers. To determine the usefulness of the obtained materials, a careful thermal, mass spectroscopy, and optical characterization was performed, focusing on the features critical for the technology of optical fiber processing. In addition, the luminescent features of both lanthanide complexes and the resulting hybrid composites were carefully investigated to identify the processes responsible for light emission and to analyze the influence of the PMMA host on light emission intensity and spectral characteristics. The obtained results showed that both lanthanide carboxylate complexes exhibited intense luminescence in the red and green spectral range, typical of europium and terbium dopants, and that those features were well preserved after introducing them into the PMMA polymer. Thermal analysis also proved that introducing the luminescent additives did not significantly affect the thermal properties of both hybrid materials, thus enabling further processing into the form of optical fibers.

EXPRESS: A Lanthanide Complex Fluorescent Probe for the Detection of Melamine

Melamine is a kind of small molecule compound, which has been illegally adulterated in dairy food because of the rich nitrogen content and stable chemical properties. Therefore, the detection of melamine is of great significance to food safety and human's health protection. Melamine can emit weak fluorescence, making it difficult to detect melamine directly. However melamine can significantly enhance the emission of the tetracycline-europium (EuTC) complex at a wavelength of 616 nm, hence this work uses EuTC complex as a fluorescent probe to detect melamine. According to the characterizations of absorption spectra, molecular electrostatic potential distribution and the time-resolved spectra, we speculated that tetracycline and melamine may form a complex through hydrogen bonding interaction, causing the melamine closer approach to Eu3+ and reducing the non-radiative energy loss of water molecules to EuTC complex, which significantly enhanced the fluorescence intensity of EuTC. The fluorescence intensity with melamine concentration in the range of 0.5~40 μM shows a good linear relationship, and the correlation coefficient is 0.9951 with the detection limit of 0.0785 μM, which shows a high sensitivity in detection of melamine. As far as we know, EuTC complex is the first time that has been used as a fluorescent probe to detect melamine, which provides a supplement and extension for the detection of melamine in fluorescence spectroscopy.

Cell-Permeable Lanthanide-Platinum(IV) Anti-Cancer Prodrugs

Platinum compounds are a vital part of our anti-cancer arsenal, determining the location and speciation of platinum compounds is crucial. We have synthesised a lanthanide complex bearing a salicylic group...

Samarium(III) catalyzed synthesis of alkenylboron compounds via hydroboration of alkynes

The homoleptic lanthanide complex Sm[N(TMS)2]3 is an efficient rare-earth catalyst for the hydroboration of alkynes to the corresponding alkenylboron compounds. Practical applications were demonstrated in a gram-scale synthesis and further...