139693-30-4Relevant articles and documents
Molecular interactions, proton exchange, and photoinduced processes prompted by an inclusion process and a [2]pseudorotaxane formation
Mandal, Amal Kumar,Suresh, Moorthy,Kesharwani, Manoj K.,Gangopadhyay, Monalisa,Agrawal, Manoj,Boricha, Vinod P.,Ganguly, Bishwajit,Das, Amitava
, p. 9004 - 9012 (2013)
Appropriate design of the host and guest components allows formation of a novel [2]pseudorotaxane complex with an interrupted photoinduced electron transfer (PET)-coupled fluorescence resonance energy transfer (FRET) response. This is the first example of an inclusion complex with NO6-based azacrown ether as the host unit (H). Different guest molecules (G1, G2, G3, and G4) with varying stopper size are used for the studies. Unlike G1, G2, and G3, G4 with a relatively bulkier stopper fails to form a [2]pseudorotaxane complex. Isothermal titration microcalorimetry measurements reveal a systematic increase in the association constant for H·G1, H·G2, and H·G3 with a change in the stopper size. Thermodynamic data suggest that the formation of H·G1/H·G2/H·G3 is exclusively driven by a large positive entropic gain (TΔS = 19.69/26.80/21.81 kJ·mol-1), while the enthalpy change is slightly negative for H·G1/H·G3 (-2.61/-1.97 kJ·mol-1) and slightly positive for H·G2 (ΔH = 5.98 kJ·mol-1). For these three inclusion complexes, an interrupted PET-coupled FRET response is observed with varying efficiency, which is attributed to the subtle differences in acidity of the NH2+ unit of the guest molecules and thus the proton exchange ability between the host and respective guest. This is substantiated by the results of the computational studies.
Self-Assembly of Stimuli-Responsive [2]Rotaxanes by Amidinium Exchange
Borodin, Oleg,Richter, Stefan,Robertson, Craig C.,Shchukin, Yevhenii,Von Delius, Max
supporting information, p. 16448 - 16457 (2021/10/12)
Advances in supramolecular chemistry are often underpinned by the development of fundamental building blocks and methods enabling their interconversion. In this work, we report the use of an underexplored dynamic covalent reaction for the synthesis of stimuli-responsive [2]rotaxanes. The formamidinium moiety lies at the heart of these mechanically interlocked architectures, because it enables both dynamic covalent exchange and the binding of simple crown ethers. We demonstrated that the rotaxane self-assembly follows a unique reaction pathway and that the complex interplay between crown ether and thread can be controlled in a transient fashion by addition of base and fuel acid. Dynamic combinatorial libraries, when exposed to diverse nucleophiles, revealed a profound stabilizing effect of the mechanical bond as well as intriguing reactivity differences between seemingly similar [2]rotaxanes.
Synthesis and optical properties of molecular rods comprising a central core-substituted naphthalenediimide chromophore for carbon nanotube junctions
Grunder, Sergio,Munoz Torres, David,Marquardt, Christoph,Balaszczyk, Alfred,Krupke, Ralph,Mayor, Marcel
supporting information; experimental part, p. 478 - 496 (2011/03/22)
The synthesis of a series of molecular rods 1-5, designed to bridge the gap of a carbon nanotube junction in order to emit light as a characteristic signal of integrated molecules, is reported. The molecular rods consist of a central naphthalenediimide (NDI) core, which itself is substituted with benzylamino and benzylsulfanyl groups, providing distinct absorption and emission properties. The NDI core is embedded in an oligo(phenylene ethynylene) (OPE) system providing the rod-like structure required to bridge gaps between nanoelectrodes. The number of repeating units of the OPE is varied to adjust the length of the target compounds between 2.3 and 6.6 nm. The OPE parts are terminally functionalized with polyaromatic hydrocarbon groups (naphthalene, phenanthrene, anthracene or pyrene), which possess affinity with the surface of the carbon nanotubes due to van der Waals interactions. Synthetic protocols based on Sonogashira-Hagihara couplings were developed to build up the OPE backbone. Bifunctional iodophenyl acetylene derivative 33 served as a key building block in a coupling-deprotecting-coupling sequence. The NDI building block was synthesized by an aromatic nucleophilic substitution reaction of 2,6-dichloro-1,4,5,8-tetracarboxylic acid naphthalenediimide derivative 9 and the corresponding amine and sulfide (i.e., 11, 12), respectively. The convergent synthesis allows modular assembly of the NDI and OPE parts in a final Sonogashira-Hagihara coupling reaction. The target structures were fully characterized by NMR spectroscopy and mass spectrometry. Further, the optical properties of compounds 3-5 in solution, and on a graphene surface were qualitatively investigated. A Dexter-type energy transfer from the OPE unit to the NDI unit was observed. The studies of target structures 3-5 revealed that diamino-functionalized compound 3 is ideally suited for the envisaged single molecule electroluminescence experiments. The synthesis of a series of over 6-nm long modular rods with a central decoupled naphthalenediimide (NDI) chromophore isreported. Their spectroscopic properties are adjusted by varying the substituents of the NDI core
