63549-37-1Relevant articles and documents
Temporary crown ether compounds induced by UV irradiation
Itagaki, Hideyuki,Masuda, Wakako,Hirayanagi, Yukiko,Sugimoto, Kazuya
, p. 3316 - 3322 (2002)
A new reversible photoresponsive system using a photophysical process is presented and proved in detail. 1,n-bis(3-(1-pyrenyl)propylcarboxy)oxaalkanes (DP3n: n = 3 to 6), linear oligooxyethylenes with pyrenyl groups at both ends, were shown to form a relatively stable cyclic structure analogous to a crown ether in fluid solution during their photoexcited states, occurring due to the formation of an intramolecular excimer between two terminal pyrenyl groups. Moreover, DP34 molecules were found to capture and transport cadmium ions more effectively when they were irradiated. Accordingly, these compounds are referred to as photoinduced crown ether compounds (PICs) because they work as a crown ether when irradiated and they can select metal ions to capture according to their diameters. Our study is the first to attempt to use excimers to fix the conformation of a molecule for relatively long periods and to put this photophysical process to practical use.
Folded short azapeptide for conformation switching-based fluorescence sensing
Yuan, Yuan,Yan, Xiao-Sheng,Li, Xiao-Rui,Cao, Jin-Lian,Li, Zhao,Jiang, Yun-Bao
, p. 13137 - 13140 (2017)
Herein, we report a conformation switching-based fluorescence sensing scheme using dipeptide-based amidothioureas (azapeptides) that contain a folded β-turn structure. Amidothiourea is equipped at its two termini with an electron acceptor and an electron donor or two fluorophores, such that it exhibits enhanced exciplex or excimer emission because of the turn structure in which the two termini are brought into close proximity; on the other hand, it exhibits a dramatic ratiometric fluorescence response upon anion binding to the thiourea moiety because of the resultant extended conformation of the anion binding complex.
Cholic acid-based high sensitivity fluorescent sensor for α,ω-dicarboxylate: an intramolecular excimer emission quenched by complexation
Liu, Shun-Ying,He, Yong-Bing,Chan, Wing Hong,Lee, Albert W.M.
, p. 11687 - 11696 (2006)
Fluorescent receptors (1 and 2) bearing two binding units on C3 and C24 and two signal display units on C7 and C12 of cholic acid, respectively, were designed and synthesized. Both 1 and 2 emit a much weaker fluorescence than that of the control compound
Selective transportation of metal ions by photo-induced crown ether compounds
Itagaki, Hideyuki,Masuda, Wakako,Hirayanagi, Yukiko
, p. 402 - 406 (1999)
A novel photoresponsive system that we call a photo-induced crown ether (PIC) is described, in which excimers are used to fix the conformation of a molecule for relatively long periods. 1,n-bis(3-(1-pyrenyl)propylcarboxy)-oxaalkanes (DP3n: n=3-6), linear oligooxyethylenes with pyrenyl groups at both ends, were prepared and investigated to determine whether they might work as PICs. DP35 molecules were found to capture and transport calcium ions more effectively when they were irradiated. This result is consistent with the finding that five-unit crown ether transported the greatest amount of calcium ions.
Chiral Discrimination in Excimer Formation
Tran, Chieu D.,Fendler, Janos H.
, p. 2923 - 2928 (1980)
Steady-state and nanosecond time resolved spectroscopy have been used to determine parameters for excimer formation for N--D-tryptophan methyl ester (pyr-D-Trp), N--L-tryptophan methyl ester (pyr-L-Trp), and their racemate, pyr-DL-Trp, in methanol and for pyr-D-Trp in optically active (R)-(-)-2-octanol, (S)-(+)-2-octanol, and racemic (RS)-(+/-)-2-octanol.Appreciable differences have been noted between the behavior of the pure enantiomer and its racemate in MeOH.Thus, the rate constant of excimer formation for pyr-DL-Trp, (6.9+/-0.5) 109 M-1 s-1, is greater than those for the pure enantiomers, (4.0+/-0.7) 109 M-1 s-1.The quantum efficiency of pyr-DL-Trp excimer formation (qD/qM = 0.7+/-0.1) is smaller than that for pyr-D-Trp or pyr-L-Trp (qD/qM = 1.1+/-0.2).Differences in equilibrium constants for excimer formation indicated a chiral discrimination energy of 700 cal mol-1.Chiral discrimination originates in differential electrostatic, dispersion, and resonance integrations.Appreciable differences have also been observed in the kinetic and thermodynamic parameters for pyr-D-Trp excimer formation in (R)-(-)-2-octanol and (S)-(+)-2-octanol.
Dendrimers functionalized with a single pyrene label: Synthesis, photophysics, and fluorescence quenching
Cardona, Claudia M.,Wilkes, Tom,Ong, Winston,Kaifer, Angel E.,McCarley, Tracy Donovan,Pandey, Siddarth,Baker, Gary A.,Kane, Maureen N.,Baker, Sheila N.,Bright, Frank V.
, p. 8649 - 8656 (2002)
We have used a wide variety of molecular (i.e., nitromethane, acrylamide, N,N'-dimethylaniline, and methyl iodide) and ionic (iodide and cupric ions) quenchers to assess the relative structural permeabilities of a single, pyrenyl residue attached to the tertiary amine within a series of asymmetric poly(amido) dendrimers possessing carboxylate moieties at their periphery. From these quenching experiments, chain segmental densities and pyrene accessibility are probed as a function of dendrimer generation number (Pn, n = 1, 2, or 3), providing insight into the roles of size and electrostatics in this process. With the exception of dendrimer quenching by Cu2+, we observe classic Stern-Volmer behavior for Pn fluorescence quenching by all quenching agents. The recovered Stern-Volmer quenching constants (Ksv) and bimolecular quenching rates (kq) generally decrease as n increases. This result is explained by a blocking of the pyrenyl residue by the growing dendrimer network. The decrease is particularly dramatic for the anionic heavy atom quencher I-. This observation is rationalized in terms of pronounced electrostatic repulsion between the I- quencher and the terminal COO- residues of the dendrimer combined with an increase in the molecular network density surrounding the pyrenyl moiety as n increases. The Cu2+ quenching of the dendrimers is inconsistent with a diffusion-controlled reaction. Binding between the dendrimer and the Cu2+ is demonstrated.
Pyrene-phosphonate conjugate: Aggregation-induced enhanced emission, and selective Fe3+ ions sensing properties
Padghan, Sachin D.,Bhosale, Rajesh S.,Bhosale, Sidhanath V.,Antolasic, Frank,Al Kobaisi, Mohammad,Bhosale, Sheshanath V.
, (2017)
A new pyrene-phosphonate colorimetric receptor 1 has been designed and synthesized in a one-step process via amide bond formation between pyrene butyric acid chloride and phosphonate-appended aniline. The pyrene-phosphonate receptor 1 showed aggregation-induced enhanced emission (AIEE) properties in water/acetonitrile (ACN) solutions. Dynamic light scattering (DLS) characterization revealed that the aggregates of receptor 1 at 80% water fraction have an average size of ≈142 nm. Field emission scanning electron microscopy (FE-SEM) analysis confirmed the formation of spherical aggregates upon solvent evaporation. The sensing properties of receptor 1 were investigated by UV-vis, fluorescence emission spectroscopy, and other optical methods. Among the tested metal ions, receptor 1 is capable of recognizing the Fe3+ ion selectively. The changes in spectral measurements were explained on the basis of complex formation. The composition of receptor 1 and Fe3+ ions was determined by using Job’s plot and found to be 1:1. The receptor 1–Fe3+ complex showed a reversible UV-vis response in the presence of EDTA.
A Poly(cobaloxime)/Carbon Nanotube Electrode: Freestanding Buckypaper with Polymer-Enhanced H2-Evolution Performance
Reuillard, Bertrand,Warnan, Julien,Leung, Jane J.,Wakerley, David W.,Reisner, Erwin
, p. 3952 - 3957 (2016)
A freestanding H2-evolution electrode consisting of a copolymer-embedded cobaloxime integrated into a multiwall carbon nanotube matrix by π-π interactions is reported. This electrode is straightforward to assemble and displays high activity towards hydrogen evolution in near-neutral pH solution under inert and aerobic conditions, with a cobalt-based turnover number (TONCo) of up to 420. An analogous electrode with a monomeric cobaloxime showed less activity with a TONCo of only 80. These results suggest that, in addition to the high surface area of the porous network of the buckypaper, the polymeric scaffold provides a stabilizing environment to the catalyst, leading to further enhancement in catalytic performance. We have therefore established that the use of a multifunctional copolymeric architecture is a viable strategy to enhance the performance of molecular electrocatalysts.
Triggering Gel Formation and Luminescence through Donor-Acceptor Interactions in a C3-Symmetric Tris(pyrene) System
Lai, Thanh-Loan,Pop, Flavia,Melan, Caroline,Canevet, David,Sallé, Marc,Avarvari, Narcis
, p. 5839 - 5843 (2016)
Straightforward modulation of the gelation, absorption and luminescent properties of a tris(pyrene) organogelator containing a C3-symmetric benzene-1,3,5-tricarboxamide central unit functionalized by three 3,3′-diamino-2,2′-bipyridine fragments
Defect Engineering into Metal-Organic Frameworks for the Rapid and Sequential Installation of Functionalities
Park, Hyojin,Kim, Seongwoo,Jung, Byunghyuck,Park, Myung Hwan,Kim, Youngjo,Kim, Min
supporting information, p. 1040 - 1047 (2018/02/14)
Postsynthetic treatments are well-known and important functionalization tools of metal-organic frameworks (MOFs). Herein, we have developed a practical and rapid postsynthetic ligand exchange (PSE) strategy using a defect-controlled MOF. An increase in the number of defects amounts to MOFs with enhanced rates of ligand exchange in a shorter time frame. An almost quantitative exchange was achieved by using the most defective MOFs. This PSE strategy is a straightforward method to introduce a functionality into MOFs including bulky or catalytically relevant moieties. Furthermore, some mechanistic insights into PSE were revealed, allowing for a sequential ligand exchange and the development of multifunctional MOFs with controlled ligand ratios.
Trigger-responsive chain-shattering polymers
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Page/Page column 37; 38, (2017/04/29)
Disclosed are polymers containing a backbone comprising alternating N-protected hydroxymethylaniline units (“spacer”) and linker units.
