Abstract:Synthese von 1: Methyldiphenylphosphanoxid (0.54 g. 2.5 mmolj und Lithiumbis-(trimethylsily1)amid (0.42 g, 2.5 mmol) wurden in kaltem Hexan/Toluol ( 5 mL/ 5 mL) aufgenommen. Nach kurrein Erwirmen der weil3en Suspension bildet sich eiiie hellgelbe Losung, aus der nach Abkiihlen ( 5 'C, 2 d) 1 in Form farbloser Blocke kristallisiert. Rohausbeute: 0.68 g, 71 %; Schmp. 148-152'C; korrekte Elementaranalyse fur C,,H,,LiNOPSi,; 'H-NMR (C,D,, 250 MHz, 25°C): 6 =7.58 (m, 4Hj, 7.09 (m, 6H). 1.62 (d, J=13.2Hz, 3H, Ph,P(O… Show more
“…Photoinduced electron transfer (PET) is constantly lurking in the shadows. , Low-lying ligand to metal charge transfer (LMCT) excited states also take their toll . Furthermore, energetic proximity of guest lowest excited states can lead to temperature-dependent emission at best 87,131,132 and complete quenching at worst. , Sensors 10 , 11 , and 12 show the evolution of this approach at Nocera's laboratory. , Although the heterobireceptor system in 10 has been known before along with several other β-cyclodextrins capped with crown ethers, no optical investigations were conducted. The antenna action in 10 is limited by the relatively large distance between the complexed benzene guest and the Eu(III) center.…”
“…The three carboxylate side arms in the cap of 12 cure this difficulty provided that Tb(III) is used as the lanthanide center apparently in order to avoid charge transfer problems from the aminocarboxylates to Eu(III). Nocera has also developed physical sensing schemes with these and other delayed luminescent systems for velocimetry in turbulent fluids. , Gouterman's work is also interesting in this respect. , 2 Luminescent sensors based on MC excited states for light-absorbing aromatics.…”
“…Photoinduced electron transfer (PET) is constantly lurking in the shadows. , Low-lying ligand to metal charge transfer (LMCT) excited states also take their toll . Furthermore, energetic proximity of guest lowest excited states can lead to temperature-dependent emission at best 87,131,132 and complete quenching at worst. , Sensors 10 , 11 , and 12 show the evolution of this approach at Nocera's laboratory. , Although the heterobireceptor system in 10 has been known before along with several other β-cyclodextrins capped with crown ethers, no optical investigations were conducted. The antenna action in 10 is limited by the relatively large distance between the complexed benzene guest and the Eu(III) center.…”
“…The three carboxylate side arms in the cap of 12 cure this difficulty provided that Tb(III) is used as the lanthanide center apparently in order to avoid charge transfer problems from the aminocarboxylates to Eu(III). Nocera has also developed physical sensing schemes with these and other delayed luminescent systems for velocimetry in turbulent fluids. , Gouterman's work is also interesting in this respect. , 2 Luminescent sensors based on MC excited states for light-absorbing aromatics.…”
“…When the subunits are light-absorbing and light-emitting centers, the fundamental photophysical processes governing a variety of energy transduction mechanisms may be revealed. − We have been interested in designing supramolecules featuring a photoactive center, capable of emitting visible light, juxtaposed to a docking site for a target analyte. By manipulating the fundamental parameters governing energy flow within the supramolecule (i.e., the radiative, nonradiative, and quenching rate constants), bright luminescence may be triggered from the photoactive center upon the molecular recognition of the target analyte . This approach to optical sensing is superior to those predicated on luminescence quenching because signal is measured against a dark background.…”
Aromatic hydrocarbons trigger a green luminescence on their association to a β-cyclodextrin (CD) modified
with a Tb3+ diethylenetriaminepentaacetic acid (DTPA) macrocycle strapped across the bottom of the CD
cup, [β-CD∪2(Tb⊂DTPA)]. The mechanism of this enhanced luminescence response is investigated with
biphenyl as the aromatic hydrocarbon. Time-resolved emission spectroscopy reveals that excitation energy
at the Tb3+ ion appears 12 μs after light is absorbed by biphenyl included within the CD cup. Excitation
spectra are consistent with a photophysical mechanism comprising absorption-energy transfer-emission (AETE)
from the aromatic hydrocarbon bound to the cavity of CD to the DTPA-encapsulated Tb3+ ion. A comparison
of the luminescence decay kinetics for biphenyl associated to [β-CD∪2(Tb⊂DTPA)] and [β-CD∪2(Gd⊂DTPA)]
complexes indicates that the pathway for the AETE process is absorption to the singlet excited state followed
by intersystem crossing to the triplet, from which energy is transferred to the lanthanide ion.
“…Physical sensing by 3R is accomplished by our development of the molecular tagging velocimetry (MTV) technique to measure the velocimetry of highly turbulent 3D flows. [64][65][66][67][68][69] Chemical and biological sensing by the 3R method is predicated on a rapid equilibrium between the analyte and the receptor site to afford a real-time luminescent response that varies with analyte concentration. 7 The approach is based on the absorption-energy transfer-emission (AETE) sensitization of a lanthanide ion emission, as pioneered by Balzani et al; 70 other sensitization systems using Ln 3+ reporter sites have since appeared.…”
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
