Rhenium triscarbonyl complexes fac‐[Re(CO)3(N^N)] with appropriate ancillary N^N ligands are relevant for fluorescent bio‐imaging. Recently, we have shown that [Re(CO)3] cores can also be efficiently mapped inside cells using their IR signature and that they can thus be used in a bimodal approach. To describe them we have coined the term SCoMPIs for single‐core multimodal probes for imaging. In the context of the use of these SCoMPIs in bio‐imaging, the questions of their cellular uptake and cytotoxicity are critical. We report here a series of compounds derived from the [Re(CO)3Cl(pyta)] core (pyta=4‐(2‐pyridyl)‐1,2,3‐triazole). The pyta ligand is of interest because it can be easily functionalized. Aliphatic side chains (C4, C8, and C12) were appended to this core. A correlative study involving IR and luminescence was performed to monitor and quantify their cellular internalization. We studied the relationship between lipophilicity (log P(o/w)), cytotoxicity (IC50), and cellular uptake, and we showed that both uptake and cytotoxicity increase with the length of the side chain, with a higher uptake for the C12 derivative. This study stresses the distinction that has to be made between apparent toxicity, determined as an incubation concentration IC50, and intrinsic toxicity. Indeed, the intrinsic toxicity of a compound can remain hidden if it is not cell permeable. Therefore it must be kept in mind that IC50 values are composite values, reflecting both cellular uptake and intrinsic toxicity. 相似文献
Light on target : Silica‐coated upconverting nanophosphor (UCNP) nanocomposites have been synthesized with organic dye (fluorescein isothiocyanate, FITC) incorporated in the silica shell. The nanocomposites are well dispersed and have good photostability and biocompatibility. These nanocomposites readily conjugated with folic acid for targeted multimodal bioimaging (see schematic representation).
The luminescent properties of a family of lanthanide metal–organic frameworks LnL ( Ln =Y, La–Yb, except Pm; L =4,4′‐({2‐[(4‐carboxyphenoxy)methyl]‐2‐methylpropane‐1,3‐diyl}bis{oxy})dibenzoic acid) have been explored, and the energy‐transfer process in the compounds has been carefully analyzed. The visible‐emitting Tb0.08Gd0.92L and the near‐infrared (NIR)‐luminescent Yb0.10Gd0.90L show excellent optical performances and can be considered as fluorescent probes for acetone sensing based on luminescence quenching effects arising from host–guest interactions. Moreover, GdL exhibits a strong second harmonic generation (SHG) signal 6.1 times that of potassium dihydrogen phosphate (KDP) and an outstanding phase‐matchable effect. These lanthanide compounds combining fluorescent and nonlinear optical (NLO) properties could meet further requirements as multifunctional materials. 相似文献
Three transition‐metal–carbonyl complexes [V( L )(CO)3(Cp)] ( 1 ), [Co( L )(CO)(Cp)] ( 2 ), and [Co( L2 )(CO)3]+[CoCO)4]? ( 3 ), each containing stable N‐heterocyclic‐chlorosilylene ligands ( L ; L =PhC(NtBu)2SiCl) were synthesized from [V(CO)4(Cp)], [Co(CO)2(Cp)], and Co2(CO)8, respectively. Complexes 1 , 2 , 3 were characterized by NMR and IR spectroscopy, EI‐MS spectrometry, and elemental analysis. The molecular structures of compounds 1 , 2 , 3 were determined by single‐crystal X‐ray diffraction. 相似文献
Self‐assembly of hydrophobic molecules into aqueous colloids contradicts common chemical intuition, but has been achieved through hydration of [Fe(CO){CO(CH2)5CH3}(Cp)(PPh3)] (FpC6). FpC6 has no surface activity, no NMR signals in D2O and no critical aggregation concentration (CAC) in H2O. The molecule, however, contains both acyl and terminal CO groups that are prone to being hydrated. By adding water to a solution in THF, self‐assembly of FpC6 can be initiated through water–carbonyl interactions (WCIs) with the highly polarized acyl CO groups. This aggregation subsequently enhances the hydration of the acyl CO groups and also induces the WCI of otherwise unhydrated terminal CO groups. The resultant metal–carbonyl aggregates have been proved to be bilayer vesicles with iron complexes exposed towards water and alkyl chains forming inner walls (MCsomes). These MCsomes show high structure integration upon dilution due to the hydrophobic nature of the building blocks. The highly polarized CO groups on the surface of the MCsomes result in a negative zeta potential (?65 mV) and create a local electric field, which significantly enhances the IR absorption of CO groups by more than 100‐fold. This is the first discovery of aggregation‐induced self‐enhanced IR absorption (AI‐SRIRA) without the assistant of external dielectric substrates. Highly integrated MCsomes are, therefore, promising as a novel group of materials, for example, for IR‐based sensing and imaging. 相似文献
Two carbonyl complexes of rhenium, [HRe(CO)5] and [CH3Re(CO)5], were used to probe surface sites of TiO2 (anatase). These complexes were adsorbed from the gas phase onto anatase powder that had been treated in flowing O2 or under vacuum to vary the density of surface OH sites. Infrared (IR) spectra demonstrate the variation in the number of sites, including Ti+3? OH and Ti+4? OH. IR and extended X‐ray absorption fine structure (EXAFS) spectra show that chemisorption of the rhenium complexes led to their decarbonylation, with formation of surface‐bound rhenium tricarbonyls, when [HRe(CO)5] was adsorbed, or rhenium tetracarbonyls, when [CH3Re(CO)5] was adsorbed. These reactions were accompanied by the formation of water and surface carbonates and removal of terminal hydroxyl groups associated with Ti+3 and Ti+4 ions on the anatase. Data characterizing the samples after adsorption of [HRe(CO)5] or [CH3Re(CO)5] determined a ranking of the reactivity of the surface OH sites, with the Ti+3? OH groups being the more reactive towards the rhenium complexes but the less likely to be dehydroxylated. The two rhenium pentacarbonyl probes provided complementary information, suggesting that the carbonate species originate from carbonyl ligands initially bonded to the rhenium and from hydroxyl groups of the titania surface, with the reaction leading to the formation of water and bridging hydroxyl groups on the titania. The results illustrate the value of using a family of organometallic complexes as probes of oxide surface sites. 相似文献
Ultra‐small ZnGa2O4:Cr3+ nanoparticles (6 nm) that exhibit near‐infrared (NIR) persistent luminescence properties are synthesized by using a non‐aqueous sol–gel method assisted by microwave irradiation. The nanoparticles are pegylated, leading to highly stable dispersions under physiological conditions. Preliminary in vivo studies show the high potential for these ultra‐small ZnGa2O4:Cr3+ nanoparticles to be used as in vivo optical nanotools as they emit without the need for in situ excitation and, thus, avoid the autofluorescence of tissues. 相似文献
The development of rhenium(I) chemistry has been restricted by the limited structural and electronic variability of the common pseudo‐octahedral products fac‐[ReX(CO)3L2] (L2=α‐diimine). We address this constraint by first preparing the bidentate bis(imino)pyridine complexes [(2,6‐{2,6‐Me2C6H3N?CPh}2C5H3N)Re(CO)3X] (X=Cl 2 , Br 3 ), which were characterized by spectroscopic and X‐ray crystallographic means, and then converting these species into tridentate pincer ligand compounds, [(2,6‐{2,6‐Me2C6H3N?CPh}2C5H3N)Re(CO)2X] (X=Cl 4 , Br 5 ). This transformation was performed in the solid‐state by controlled heating of 2 or 3 above 200 °C in a tube furnace under a flow of nitrogen gas, giving excellent yields (≥95 %). Compounds 4 and 5 define a new coordination environment for rhenium(I) carbonyl chemistry where the metal center is supported by a planar, tridentate pincer‐coordinated bis(imino)pyridine ligand. The basic photophysical features of these compounds show significant elaboration in both number and intensity of the d–π* transitions observed in the UV/Vis spec tra relative to the bidentate starting materials, and these spectra were analyzed using time‐dependent DFT computations. The redox nature of the bis(imino)pyridine ligand in compounds 2 and 4 was examined by electrochemical analysis, which showed two ligand reduction events and demonstrated that the ligand reduction shifts to a more positive potential when going from bidentate 2 to tridentate 4 (+160 mV for the first reduction step and +90 mV for the second). These observations indicate an increase in electrostatic stabilization of the reduced ligand in the tridentate conformation. Elaboration on this synthetic methodology documented its generality through the preparation of the pseudo‐octahedral rhenium(I) triflate complex [(2,6‐{2,6‐Me2C6H3N?CPh}2C5H3N)Re(CO)2OTf] ( 7 , 93 % yield). 相似文献
Two‐dimensional exchange spectroscopy (2D EXSY) is a powerful method to study the interconversion (chemical exchange) of molecular species in equilibrium. This method has recently been realized in femtosecond 2D‐IR spectroscopy, dramatically increasing the time resolution. However, current implementations allow the EXSY signal (and therefore the chemical process of interest) only to be tracked during the lifetime (T1) of the observed spectroscopic transition. This is a severe limitation, as typical vibrational T1 are only a few ps. An IR/Vis pulse sequence is presented that overcomes this limit and makes the EXSY signal independent of T1. The same pulse sequence allows to collect time‐resolved IR spectra after electronic excitation of a particular chemical species in a mixture of species with strongly overlapping UV/Vis spectra. Different photoreaction pathways and dynamics of coexisting isomers or of species involved in different intermolecular interactions can thus be revealed, even if the species cannot be isolated because they are in rapid equilibrium. 相似文献
With the exception of a single accidental synthesis, rhenium corroles are unknown, but of great interest as catalysts and potential radiopharmaceuticals. Oxidative metalation of meso‐triarylcorroles with [Re2(CO)10] in refluxing decalin has provided a facile and relatively high‐yielding route to rhenium(V)–oxo corroles. The complexes synthesized could all be fully characterized by single‐crystal X‐ray structure analyses. 相似文献
Water‐soluble phosphorescent polymeric nanoparticles with an average diameter of approximately 100 nm were synthesized by a coordination cross‐linking reaction. The pyridine blocks in poly(4‐vinyl pyridine‐b‐ethylene oxide) (P4VP‐b‐PEO) were cross‐linked by the iridium chloride‐bridged dimer in DMF solution. Owing to the presence of an iridium complex with different ligands in the core of the polymeric nanoparticles, NP‐1, NP‐2, and NP‐3 showed bright green, yellow, and red phosphorescence, respectively. PEG chains in the shell gave the polymeric nanoparticles solubility and biocompatibility, which was confirmed by an MTT assay using HeLa cells as a model cancer cell line. The flow cytometry and laser confocal fluorescence microscopy results revealed NP‐2, as an example, could be effectively uptaken by HeLa cells. Therefore, these polymeric nanoparticles can be used as luminescent probes for living cells. In addition, 1O2 could be effectively generated in the presence of NP‐2 upon irradiation with visible light (λ>400 nm, 300 mW cm?2), which was confirmed by a clear decrease in the fluorescence intensity of 9,10‐dimethylanthracene (DMA). After incubation with NP‐2 at a concentration of 200 μg mL?1 for 6 h, approximately 90 % of HeLa cells were effectively ablated upon irradiation with visible light for only 10 min, indicating the potential for photodynamic therapy with polymeric nanoparticles. 相似文献
The recent advances in the study of light emission from matter induced by synchrotron radiation: X‐ray excited optical luminescence (XEOL) in the energy domain and time‐resolved X‐ray excited optical luminescence (TRXEOL) are described. The development of these element (absorption edge) selective, synchrotron X‐ray photons in, optical photons out techniques with time gating coincide with advances in third‐generation, insertion device based, synchrotron light sources. Electron bunches circulating in a storage ring emit very bright, widely energy tunable, short light pulses (<100 ps), which are used as the excitation source for investigation of light‐emitting materials. Luminescence from silicon nanostructures (porous silicon, silicon nanowires, and Si–CdSe heterostructures) is used to illustrate the applicability of these techniques and their great potential in future applications. 相似文献
Micro-Raman and luminescence spectroscopy were combined with morphological analysis to study the conservation state of differently degraded paper samples, dated from 1873 to 2021. The aim of the work reported in this paper was to obtain ageing markers based on variations of Raman and fluorescence spectral features. Raman and luminescence spectra were acquired by scanning non-printed areas of books, and Raman and fluorescence maps were built by contrasting spectral parameters point by point, obtaining a micron-scale space resolved imaging of the degradation pattern. Complementary information on paper morphology and surface compactness were obtained by high-resolution scanning electron and atomic force microscopy. The proposed non-destructive procedure is particularly interesting for precious and ancient samples to analyze their degradation processes and to evaluate the performance and effectiveness of restoration treatments. 相似文献
Direct evidence for the blue luminescence of gold nanoclusters encapsulated inside hydroxyl‐terminated polyamidoamine (PAMAM) dendrimers was provided by spectroscopic studies as well as by theoretical calculations. Steady‐state and time‐resolved spectroscopic studies showed that the luminescence of the gold nanoclusters consisted largely of two electronic transitions. Theoretical calculations indicate that the two transitions are attributed to the different sizes of the gold nanoclusters (Au8 and Au13). The luminescence of the gold nanoclusters was clearly distinguished from that of the dendrimers. 相似文献