212712-07-7

Upstream product

• 81-88-9 rhodamine B 
• 7585-39-9 β‐cyclodextrin 

Relevant academic research and scientific papers

Characterization of group-inclusion complexations of rhodamine derivatives with native and 2,6-di-O-methylated β-cyclodextrins

The inclusion complexations of rhodamine derivatives with native and 2,6-di-O-methylated β-cyclodextrins (β-CD and DM-β-CD) were studied spectrophotometrically. Rhodamine derivatives were shown to form 1:1 inclusion complexes with β-CDs by the continuous variation method. The structures of the inclusion complexes were characterized by 1H-1H rotating frame nuclear Overhauser effect spectroscopy (ROESY) NMR measurements. It was found that native β-CD encapsulates the xanthenyl ring of rhodamines into the cyclodextrin cavity, while DM-β-CD forms two group-in complexes (phenyl-in and xanthenyl-in (bidirectional (bimodal) inclusion complexes)) with rhodamines bearing moderately bulky functional groups. Furthermore, we demonstrated the unique thermodynamics for the group-inclusion complex formation by DM-β-CD. The quantum yields for the inclusion complexes of rhodamines were determined using a quantum measurement apparatus equipped with a half-moon unit. The results indicated that the cyclodextrin inclusion of rhodamines with the bulky amino substituents on the xanthenyl ring largely decreases the quantum yield values. Based on these results, the substituent effects on the fluorescence process for the cyclodextrin inclusion complexes of rhodamines were discussed. This study provides useful insights for the functional group recognition of native and modified β-CDs.

Rhodamine solid complexes as fluorescence probes to monitor the dispersion of cyclodextrins in polymeric nanocomposites

Rhodamines B and 6G have been used to evaluate the dispersion of β-Cyclodextrin in a thermoplastic matrix, poly(ethylene-co-vinyl acetate), by high energy ball milling. In a first stage, a study of the binding properties of β-Cyclodextrin with both fluorophores has been carried out, to determine which of them forms the most stable complex with the macrocycle, its topology and to check whether their fluorescence is kept after the milling process. Both systems have been fully characterized in the solid state (FTIR and XRD, TGA and fluorescence spectroscopy), and in solution (1H NMR ROESY, steady state and time-resolved fluorescence spectroscopy). Then, nanocomposites based on the thermoplastic matrix and the cyclodextrin complexes have been cryomilled and processed in the form of thin films. Only Rhodamine B forms a complex stable enough to track the nanofiller dispersion within the polymer. This labeled cyclodextrin is uniformly dispersed throughout the matrix after the milling and film forming, yielding a blue-shifted and remarkably enhanced fluorescent response when compared to the same material prepared with the mixture of Rhodamine B and β-Cyclodextrin.

Purely organic light-harvesting phosphorescence energy transfer by β-cyclodextrin pseudorotaxane for mitochondria targeted imaging

A new type of purely organic light-harvesting phosphorescence energy transfer (PET) supramolecular assembly is constructed from 4-(4-bromophenyl)-pyridine modified β-cyclodextrin (CD-PY) as a donor, cucurbit[8]uril (CB[8]) as a mediator, rhodamine B (RhB) as an acceptor, and adamantane modified hyaluronic acid (HA-ADA) as a cancer cell targeting agent. Interestingly, the complexation of free CD-PY, which has no RTP emission in aqueous solution, with CB[8] results in the formation of CD-PY@CB[8] pseudorotaxane with an RTP emission at 510 nm. Then the addition of RhB leads to an efficient light-harvesting PET process with highly efficient energy transfer and an ultrahigh antenna effect (36.42) between CD-PY@CB[8] pseudorotaxane and RhB. Importantly, CD-PY@CB[8]@RhB assembles with HA-ADA into nanoparticles with further enhanced delayed emission at 590 nm. The nanoparticles could be successfully used for mitochondria targeted imaging in A549 cancer cells. This aqueous-state PET based on a supramolecular assembly strategy has potential application in delayed fluorescence cell imaging.