Intramolecular Electron Transfer between Noncovalently Linked Donor and Acceptor in a [2]Catenane

Hu, Yuelin; Loyen, Dietmar van; Schwarz, Oliver; Bossmann, Stefan H.; Huch, and Volker; Veith, Michael

doi:10.1021/ja980332s

Cited by 25 publications

(25 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At lower temperatures the catenane 1 may exist preferentially in the trans conformation, which has been demonstrated by X-ray analysis to be much more stable than the cis conformation. [20] When the temperature was decreased further to 213 K, the resonances of the a and b protons of the BXV 4 unit in 1 split, at 228 and 225 K, respectively, into two peaks of equal intensity. Those of the phenylene and methylene groups of BXV 4 became much broader.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

A Novel 2,2′-Bipyridine[2]catenane and Its Ruthenium Complex: Synthesis, Structure, and Intramolecular Electron Transfer— A Model for the Photosynthetic Reaction Center

Bossmann

Loyen

et al. 1999

Chem. Eur. J.

Self Cite

View full text Add to dashboard Cite

A novel [2]catenane 1 incorporating 2,2'-bipyridine and cyclobis-(paraquat-p-phenylene) (BXV 4 ) was synthesized by self-assembly. X-ray analysis and molecular modeling revealed the structure of the ligand 1. The complexation of 1 within a ruthenium complex afforded a catenane-type artificial photosynthesis assembly 2, in which the sensitizer (Ru 2 center) and the acceptor (BXV 4 ) are linked noncovalently. Molecular modeling indicated that the catenane complex 2 has two main conformers with different sensitizer ± acceptor distances; its macrocyclic polyether unit is more extended than that in 1.

show abstract

Section: Resultsmentioning

confidence: 99%

“…[20] The hydroquinone ring is positioned in the cavity of the acceptor BXV 4 , on the outside of which is the 2,2'-bipyridine component. The molecular complex has C 2 (2) crystal point symmetry.…”

Section: Resultsmentioning

confidence: 99%

A Novel 2,2′-Bipyridine[2]catenane and Its Ruthenium Complex: Synthesis, Structure, and Intramolecular Electron Transfer— A Model for the Photosynthetic Reaction Center

Bossmann

Loyen

et al. 1999

Chem. Eur. J.

Self Cite

View full text Add to dashboard Cite

show abstract

“…5). 12 This absorption decays at a rate after a time delay of 3.2 ns exhibit feature characteristics of both the singlet and triplet excited states of MgP. For C 60 -malonate 16, the differential absorption spectra in THF - Fig.…”

mentioning

confidence: 93%

“…7 One approach that provides a suitable arrangement of the chromophores is the use of mechanically interlocked rotaxanes and catenanes with attached electron donors and electron acceptors. [8][9][10][11][12] Sauvage's Cu(I) template synthesis [13][14][15][16][17] assures a rigid structure of the catenates, due to a Cu-1,10-phenanthroline ( phen) ([Cu( phen) 2 ] + ) core, in which two rings become linked as a result of tetrahedral complexation of two phens to Cu(I). Thus, a fixed distance between electron donor and electron acceptor is achieved, yielding relatively long lived charge separated states (CSS) upon irradiation.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and photophysical properties of new catenated electron donor–acceptor materials with magnesium and free base porphyrins as donors and C₆₀as the acceptor

et al. 2015

View full text Add to dashboard Cite

A new series of nanoscale electron donor-acceptor systems with [2]catenane architectures has been synthesized, incorporating magnesium porphyrin (MgP) or free base porphyrin (H 2 P) as electron donor and C 60 as electron acceptor, surrounding a central tetrahedral Cu(I)-1,10-phenanthroline ( phen) complex.Model catenated compounds incorporating only one or none of these photoactive moieties were also prepared. The synthesis involved the use of Sauvage's metal template protocol in combination with the 1,3-dipolar cycloaddition of azides and alkynes ("click chemistry"), as in other recent reports from our laboratories. Ground state electron interactions between the individual constituents was probed using electrochemistry and UV-vis absorption spectroscopy, while events occurring following photoexcitation in tetrahydrofuran (under both aerobic and anaerobic conditions) at various wavelengths were followed by means of time-resolved transient absorption and emission spectroscopies on the femtosecond and nanosecond time scales, respectively, complemented by measurements of quantum yields for generation of singlet oxygen. From similar studies with model catenates containing one or neither of the chromophores, the events following photoexcitation could be elucidated. The results were compared with those previously reported for analogous catenates based on zinc porphyrin (ZnP). It was determined that a series of energy transfer (EnT) and electron transfer (ET) processes take place in the present catenates, ultimately generating long-distance charge separated (CS) states involving oxidized porphyrin and reduced C 60 moieties, with lifetimes ranging from 400 to 1060 nanoseconds. Shorter lived short-distance CS states possessing oxidized copper complexes and reduced C 60 , with lifetimes ranging from 15 to 60 ns, were formed en route to the long-distance CS states. The dynamics of the ET processes were analyzed in terms of their thermodynamic driving forces. It was clear that intramolecular back ET was occurring in the inverted region of the Marcus parabola correlating rates and driving forces for electron transfer processes. In addition, evidence for triplet excited states as a product of either incomplete ET or back ET was found. The differences in behavior of the three catenates upon photoexcitation are analyzed in terms of the energy levels of the various intermediate states and the driving forces for EnT and ET processes.

show abstract

“…The Ru 2 (bpy) 3 -BXV 4 subunit of 1 was recently described by the group of Dürr as an artificial model of the photosynthetic reaction center. [6] The Ru 2 (bpy) 3 -heme subunit of 1 was demonstrated to be hybridized with apo-hemoproteins by cofactor reconstitution. [5a, b] The heme moiety of 1 is readily incorporated into the active sites of two distinct hemoproteins, cytochrome b 562 (Cyt-b 562 ) and myoglobin (Mb), to afford two protein-based triads (Cytb 562 (1) and Mb (1)).…”

Section: Introductionmentioning

confidence: 99%

Direct Comparison of Electron Transfer Properties of Two Distinct Semisynthetic Triads with Non-Protein Based Triad: Unambiguous Experimental Evidences on Protein Matrix Effects

Takashima

Tsukiji

et al. 2000

Chem. Eur. J.

Self Cite

View full text Add to dashboard Cite

In order to understand the roles of protein matrix in electron transfer processes (ET) within biological systems, a heme-based donor (Zn-heme: ZnPP)-sensitizer (Ru2+(bpy)3)-acceptor (cyclic viologen: BXV4+) triad 1 was used as a probe molecule. Two semi-synthetic systems, Cyt-b562(1) and Mb(1), in which the triad is incorporated into cytochrome b562 (Cyt-b562) or into myoglobin (Mb), were constructed by cofactor reconstitution. These two semi-synthetic proteins were compared with the triad itself (i.e., without the protein matrix) using absorption spectroscopy, steady state emission and excitation studies, laser flash photolysis experiments, and molecular modeling. Photoexcitation of the ZnPP moiety of Cyt-b562(1) or Mb(1) leads to a direct ET from the triplet state of ZnPP state (3ZnPP) to BXV4+ to generate a final charge-separated (CS) state, Cyt-b562(Zn+)-Ru2+-BXV3+* or Mb(Zn+)-Ru2+-BXV3+*. On the other hand, direct ET from the excited ZnPP moiety to the BXV4+ moiety is also involved in 1 in the absence of the protein matrix, but the excited state of ZnPP involved is not 3ZnPP, but the singlet excited state (1ZnPP) in this pathway. When the Ru2+(bpy)3 moiety of Cyt-b562(1) or Mb(1) is excited, a stepwise ET relay occurs with the ion-pair, Cyt-b562(Zn)-Ru3+-BXV3+* or Mb(Zn)-Ru3*-BXV3+*, as an intermediate, leading to the same final CS state as that generated in the direct ET pathway. The lifetimes of the corresponding final CS states were determined to be 300 ns for 1 in the absence of the protein matrix, 600-900 ns for Cyt-b562(1) and 1.1-18 micros for Mb(1), the values of which are greatly affected by the protein matrix. Molecular modeling study of the three systems consistently explained the differences of their photophysical behavior.

show abstract

Intramolecular Electron Transfer between Noncovalently Linked Donor and Acceptor in a [2]Catenane

Cited by 25 publications

References 27 publications

A Novel 2,2′-Bipyridine[2]catenane and Its Ruthenium Complex: Synthesis, Structure, and Intramolecular Electron Transfer— A Model for the Photosynthetic Reaction Center

A Novel 2,2′-Bipyridine[2]catenane and Its Ruthenium Complex: Synthesis, Structure, and Intramolecular Electron Transfer— A Model for the Photosynthetic Reaction Center

Synthesis and photophysical properties of new catenated electron donor–acceptor materials with magnesium and free base porphyrins as donors and C₆₀as the acceptor

Direct Comparison of Electron Transfer Properties of Two Distinct Semisynthetic Triads with Non-Protein Based Triad: Unambiguous Experimental Evidences on Protein Matrix Effects

Contact Info

Product

Resources

About

Intramolecular Electron Transfer between Noncovalently Linked Donor and Acceptor in a [2]Catenane

Cited by 25 publications

References 27 publications

A Novel 2,2′-Bipyridine[2]catenane and Its Ruthenium Complex: Synthesis, Structure, and Intramolecular Electron Transfer— A Model for the Photosynthetic Reaction Center

A Novel 2,2′-Bipyridine[2]catenane and Its Ruthenium Complex: Synthesis, Structure, and Intramolecular Electron Transfer— A Model for the Photosynthetic Reaction Center

Synthesis and photophysical properties of new catenated electron donor–acceptor materials with magnesium and free base porphyrins as donors and C60as the acceptor

Direct Comparison of Electron Transfer Properties of Two Distinct Semisynthetic Triads with Non-Protein Based Triad: Unambiguous Experimental Evidences on Protein Matrix Effects

Contact Info

Product

Resources

About

Synthesis and photophysical properties of new catenated electron donor–acceptor materials with magnesium and free base porphyrins as donors and C₆₀as the acceptor