First observation of the hyperfine structure of an excited quintet state in liquid solution

Franco, Lorenzo; Mazzoni, Martina; Corvaja, Carlo; Gubskaya, V. P.; Berezhnaya, L. Sh.; Нуретдинов, И. А.

doi:10.1039/b417056c

Cited by 26 publications

(25 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The EPR spectra of the monoradicals Ia and Ib and of the biradicals IIa and IIb in liquid solution have been already described [6,12].…”

Section: Resultsmentioning

confidence: 99%

“…For the case of Ib, the exchange interaction constant JTR has been determined to be rather small ([JTR] = 3.5 mT), being comparable in magnitude with the nitrogen isotropic hyperfine constant [6] and smaller than the dipolar interaction in the triplet fullerene. In this case, the eigenfunctions of the total Hamiltonian are more similar to the product of radical and triplet spin function.…”

Section: Monoradicalsmentioning

confidence: 99%

“…(5) describe the Zeeman term of the three spins, the following two terms describe the hyperfine interaction in the radicals, the next four terms describe the dipolar interactions between all spins pairs, and the last three terrns refer to the exchange interaction between the spins pairs, assuming JTR1 = JTR2 = JTR" In case of strong coupling, the main contribution to the Hamiltonian is due to the last three terms of Eq. (5) and their eigenvalues are best described in terms of the total spin states Qt, Ta, Tb, S. The relative energies of the latter states are [16] EQt = --2JTR --1 / 2JRIR2, ETa = +2JrR -l/2JRm2, E s = +4JrR -1/241R2 , E% = +3/2JRm2, The exchange interaction constant JvR for the monoradical la is negative [6,21]. Moreover, from the simulation of the room temperature EPR spectrum IJR1~[ = 4.0 mT, which is much smaller than JTR in the case of strong coupling.…”

Section: Biradicalsmentioning

confidence: 99%

“…6. A similar argument applies for T a, whose dipolar interaction tensor in the strong coupling limit is given by [16] l)Ta = 1/2(/)T + /)RIT + DR2T) --(1/4)/)RIR2" (6) The ZFS values for the C60 monoadduct triplets, which define the D T tensor, are D T = 8.2 and E T = 0.8 mT, respectively [15], while the dipolar coupling between the two radicals DR~rU can be calculated from the geometry of IIa using the point dipolar approximation, which gives D M = 4.0 toT and E~ = 0. Conside¡ that Eq.…”

Section: Biradicalsmentioning

confidence: 99%

“…These properties facilitate the observation of the excited state and simplify the EPR spectrum, which makes the analysis easier, since only the hyperfine stmcture due to the spin label nuclei occurs. In a recent work we have been able to detect an excited quintet state in liquid solution by using a doubly spin-labeled C60 derivative [6].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

TR-EPR of single and double spin-labeled C60 derivatives in frozen matrices

et al. 2006

View full text Add to dashboard Cite

Abstraet. Time-resolved electron paramagnetic resonance spectra of two single spin-labeled and two double spin-labeled C6o derivatives in frozen solution are recorded with pulsed laser excitation and 100 ns time resolution. Quartet and quintet excited species are detected which arise from the electron spin coupling of the triplet excited fullerene moiety with the unpaired spin(s) of the nitroxide label(s). Despite the similar molecular structure, in both series of single and double labeled derivatives a different behavior was found, which is due to substantial difference of the energy of exchange coupling.

show abstract

“…The EPR spectra of the monoradicals Ia and Ib and of the biradicals IIa and IIb in liquid solution have been already described [6,12].…”

Section: Resultsmentioning

confidence: 99%

Section: Monoradicalsmentioning

confidence: 99%

Section: Biradicalsmentioning

confidence: 99%

Section: Biradicalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

TR-EPR of single and double spin-labeled C60 derivatives in frozen matrices

et al. 2006

View full text Add to dashboard Cite

show abstract

Metalloporphyrins as Building Blocks for Quantum Information Science

Santanni,

Privitera

2024

Advanced Optical Materials

View full text Add to dashboard Cite

The intrinsic quantum nature of molecules opens exciting opportunities for developing the field of quantum information science. In this context, porphyrins stand out as ideal building blocks for quantum technologies thanks to their unique optical and electrical properties as well as their capacity to accommodate metal atoms and ions. This review bridges the chemistry and physics of porphyrins, providing an overview of recent advances in porphyrin‐based molecular qubits. Starting from qubits, the review explores the potential of porphyrin units to combine, leading to the formation of quantum logic gates and hierarchical higher‐dimensional structures. Next, the exploitation of porphyrins' unique photophysical properties for realizing long‐lived high spin states is examined. These states are promising for the photogeneration of multi‐level systems and the optical initialization and control of molecular qubits. With a critical eye on the current state‐of‐the‐art, the review elucidates the future perspectives of porphyrins for advancing quantum technologies.

show abstract

Catalytic Synergism in a C₆₀IL₁₀TEMPO₂Hybrid in the Efficient Oxidation of Alcohols

et al. 2014

View full text Add to dashboard Cite

A novel fullerene [5:1]hexakisadduct bearing two 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) radicals and ten 1-propyl-3-methylimidazolium bromide moieties has been synthesized and characterized. Such an C 60 IL 10 TEMPO 2 hybrid has been successfully employed as a catalyst in the selective oxidation of a wide series of alcohols and is highly active at just 0.1 mol% loading. Moreover, it can be easily recovered by adsorption onto a multilayered covalently-linked SILP phase (mlc-SILP) through a "release and catch" approach and reused for up to 12 cycles without loss in efficiency. Interestingly, a catalytic synergistic effect of TEMPO and imidazolium bromide moieties combined in the same hybrid has been clearly shown.Keywords: alcohols; fullerene; ionic liquids; oxidation; TEMPO; 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)In the last decades TEMPO-like catalysts have emerged as powerful, metal-free and environmentally sustainable alternatives in the oxidation of primary and secondary alcohols to the corresponding carbonyl compounds.[1] Nevertheless, their high price prompted scientists examine the development of supported TEMPO catalysts in order to obtain recyclable materials. Hence, TEMPO has been covalently immobilized onto various supports such as silica, [2] magnetic nanoparticles, [3] soluble [4] and insoluble [5] organic polymers, and carbon nanotubes. [6] However, although several of these materials were catalytically active and easily recyclable, they often suffer from the inherent drawback of heterogeneous catalysis, namely the reduced mass transfer that makes reactions slower than in the case of their homogeneous counterparts. [7] In this regard, very recently a new approach called "release and catch" has been highlighted. [8] In this strategy, the catalytic system is non-covalently immobilized on the support, but the catalytic moiety is released in solution over the course of the reaction and it is recaptured at the end of the reaction. In such a manner, the benefits of homogeneous (high catalytic activity and reaction rates) and heterogeneous catalysis (easy separation and recycling) are combined. Interestingly, the "release and catch" approach has found application in organometallic-based catalysts, [9] organocatalysts [10] and metal-based catalysts. [11] In the past few years, we have been engaged in the use of silica-supported ionic liquid-like phase monolayers (SILLP) and multilayers (mlc-SILP) as reversible catalyst reservoirs. Both kinds of materials were excellently employed for organocatalyst recovery and recycling [10,12] as well as in the immobilization of Pd nanoparticles for C À C coupling processes in batch [13] and in flow. [14] On the other hand, we started exploring new recyclable TEMPO-based systems: 10 mol% of ionic liquidtagged TEMPO derivatives were easily recovered with the help of mlc-SILP and recycled in up to 13 consecutive cycles with no loss in activity, [12d] whilst a series of fullerene-TEMPO derivatives with two, four and twelve TEMPO moieties can be quickly ...

show abstract

First observation of the hyperfine structure of an excited quintet state in liquid solution

Abstract: After pulsed photoexcitation of a new fullerene-linked bisnitroxide, a well resolved transient EPR spectrum is detected which is assigned to an excited quintet spin state generated by spin coupling of the nitroxides and the fullerene excited triplet.

Cited by 26 publications

References 14 publications

TR-EPR of single and double spin-labeled C60 derivatives in frozen matrices

TR-EPR of single and double spin-labeled C60 derivatives in frozen matrices

Metalloporphyrins as Building Blocks for Quantum Information Science

Catalytic Synergism in a C₆₀IL₁₀TEMPO₂Hybrid in the Efficient Oxidation of Alcohols

Contact Info

Product

Resources

About

First observation of the hyperfine structure of an excited quintet state in liquid solution

Abstract: After pulsed photoexcitation of a new fullerene-linked bisnitroxide, a well resolved transient EPR spectrum is detected which is assigned to an excited quintet spin state generated by spin coupling of the nitroxides and the fullerene excited triplet.

Cited by 26 publications

References 14 publications

TR-EPR of single and double spin-labeled C60 derivatives in frozen matrices

TR-EPR of single and double spin-labeled C60 derivatives in frozen matrices

Metalloporphyrins as Building Blocks for Quantum Information Science

Catalytic Synergism in a C60IL10TEMPO2Hybrid in the Efficient Oxidation of Alcohols

Contact Info

Product

Resources

About

Catalytic Synergism in a C₆₀IL₁₀TEMPO₂Hybrid in the Efficient Oxidation of Alcohols