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1.
The two molecular triads 1a and 1b consisting of a porphyrin (P) covalently linked to a fullerene (C60) electron acceptor and tetrathiafulvalene (TTF) electron‐donor moiety were synthesized, and their photochemical properties were determined by transient absorption and emission techniques. Excitation of the free‐base‐porphyrin moiety of the TTF−P2 H−C60 triad 1a in tetrahydro‐2‐methylfuran solution yields the porphyrin first excited singlet state TTF−1P2 H−C60, which undergoes photoinduced electron transfer with a time constant of 25 ps to give TTF−P2 H.+−C60.−. This intermediate charge‐separated state has a lifetime of 230 ps, decaying mainly by a charge‐shift reaction to yield a final state, TTF.+−P2 H−C60.−. The final state has a lifetime of 660 ns, is formed with an overall yield of 92%, and preserves ca. 1.0 eV of the 1.9 eV inherent in the porphyrin excited state. Similar behavior is observed for the zinc analog 1b . The TTF‐PZn.+−C60.− state is formed by ultrafast electron transfer from the porphyrinatozinc excited singlet state with a time constant of 1.5 ps. The final TTF.+−PZn−C60.− state is generated with a yield of 16%, and also has a lifetime of 660 ns. Although charge recombination to yield a triplet has been observed in related donor‐acceptor systems, the TTF.+−P−C60.− states recombine to the ground state, because the molecule lacks low‐energy triplet states. This structural feature leads to a longer lifetime for the final charge‐separated state, during which the stored energy could be harvested for solar‐energy conversion or molecular optoelectronic applications.  相似文献   

2.
A study on electron transfer in three electron donor-acceptor complexes is reported. These architectures consist of a zinc phthalocyanine (ZnPc) as the excited-state electron donor and a fullerene (C60) as the ground-state electron acceptor. These complexes are brought together by axial coordination at ZnPc. The key variable in our design is the length of the molecular spacer, namely, oligo-p-phenylenevinylenes. The lack of appreciable ground-state interactions is in accordance with strong excited-state interactions, as inferred from the quenching of ZnPc centered fluorescence and the presence of a short-lived fluorescence component. Full-fledged femtosecond and nanosecond transient absorption spectroscopy assays corroborated that the ZnPc ⋅ +-C60 charge-separated state formation comes at the expense of excited-state interactions following ZnPc photoexcitation. At a first glance, the ZnPc ⋅ +-C60 charge-separated state lifetime increased from 0.4 to 86.6 ns as the electron donor-acceptor separation increased from 8.8 to 29.1 Å. A closer look at the kinetics revealed that the changes in charge-separated state lifetime are tied to a decrease in the electronic coupling element from 132 to 1.2 cm−1, an increase in the reorganization energy of charge transfer from 0.43 to 0.63 eV, and a large attenuation factor of 0.27 Å−1.  相似文献   

3.
An efficient functional mimic of the photosynthetic antenna‐reaction center has been designed and synthesized. The model contains a near‐infrared‐absorbing aza‐boron‐dipyrromethene (ADP) that is connected to a monostyryl boron‐dipyrromethene (BDP) by a click reaction and to a fullerene (C60) using the Prato reaction. The intramolecular photoinduced energy and electron‐transfer processes of this triad as well as the corresponding dyads BDP‐ADP and ADP‐C60 have been studied with steady‐state and time‐resolved absorption and fluorescence spectroscopic methods in benzonitrile. Upon excitation, the BDP moiety of the triad is significantly quenched due to energy transfer to the ADP core, which subsequently transfers an electron to the fullerene unit. Cyclic and differential pulse voltammetric studies have revealed the redox states of the components, which allow estimation of the energies of the charge‐separated states. Such calculations show that electron transfer from the singlet excited ADP (1ADP*) to C60 yielding ADP.+‐C60.? is energetically favorable. By using femtosecond laser flash photolysis, concrete evidence has been obtained for the occurrence of energy transfer from 1BDP* to ADP in the dyad BDP‐ADP and electron transfer from 1ADP* to C60 in the dyad ADP‐C60. Sequential energy and electron transfer have also been clearly observed in the triad BDP‐ADP‐C60. By monitoring the rise of ADP emission, it has been found that the rate of energy transfer is fast (≈1011 s?1). The dynamics of electron transfer through 1ADP* has also been studied by monitoring the formation of C60 radical anion at 1000 nm. A fast charge‐separation process from 1ADP* to C60 has been detected, which gives the relatively long‐lived BDP‐ADP.+C60.? with a lifetime of 1.47 ns. As shown by nanosecond transient absorption measurements, the charge‐separated state decays slowly to populate mainly the triplet state of ADP before returning to the ground state. These findings show that the dyads BDP‐ADP and ADP‐C60, and the triad BDP‐ADP‐C60 are interesting artificial analogues that can mimic the antenna and reaction center of the natural photosynthetic systems.  相似文献   

4.
A supramolecular triad composed of a fused zinc phthalocyanine-free-base porphyrin dyad (ZnPc-H2P) coordinated to phenylimidazole functionalized C60 via metal-ligand axial coordination was assembled, as a photosynthetic antenna-reaction centre mimic. The process of self-assembly resulting into the formation of C60Im:ZnPc-H2P supramolecular triad was probed by proton NMR, UV-Visible and fluorescence experiments at ambient temperature. The geometry and electronic structures were deduced from DFT calculations performed at the B3LYP/6-31G(dp) level. Electrochemical studies revealed ZnPc to be a better electron donor compared to H2P, and C60 to be the terminal electron acceptor. Fluorescence studies of the ZnPc-H2P dyad revealed excitation energy transfer from 1H2P* to ZnPc within the fused dyad and was confirmed by femtosecond transient absorption studies. Similar to that reported earlier for the fused ZnPc-ZnP dyad, the energy transfer rate constant, kENT was in the order of 1012 s−1 in the ZnPc-H2P dyad indicating an efficient process as a consequence of direct fusion of the two π-systems. In the presence of C60Im bound to ZnPc, photoinduced electron transfer leading to H2P-ZnPc.+:ImC60.− charge separated state was observed either by selective excitation of ZnPc or H2P. The latter excitation involved an energy transfer followed by electron transfer mechanism. Nanosecond transient absorption studies revealed that the lifetime of charge separated state persists for about 120 ns indicating charge stabilization in the triad.  相似文献   

5.
Directly linked to promote strong intramolecular interactions, donor–acceptor dyads and a donor–acceptor–donor triad featuring zinc phthalocyanine (ZnPc) as electron donor and perylenediimide (PDI) as electron acceptor have been synthesized and characterized. Owing to complementary absorption features of the entities, improved light absorption was witnessed in these conjugates. The optimized geometry and electronic structures showed the majority of the highest occupied molecular orbital (HOMO) on the ZnPc entity, whereas the lowest unoccupied molecular orbital (LUMO) was on the PDI entity, suggesting that the charge-separated states would be ZnPc + –PDI . . The electrochemical and free-energy calculations suggested exothermic energy and/or electron transfer processes via the singlet states of PDI or ZnPc entities depending on the excitation wavelength of the laser used. The measured rates using femtosecond pump-probe spectroscopy coupled with global analysis of transient data revealed ultrafast energy transfer from 1PDI* to ZnPc followed by charge separation. However, when ZnPc was selectively excited, only electron transfer was witnessed wherein the time constants for forward and reverse electron transfer processes followed Marcus predictions. The absorption in a wide section of the solar spectrum and the ultrafast charge separation suggest the usefulness of these systems as good photosynthetic models.  相似文献   

6.
High oxidation potential perfluorinated zinc phthalocyanines (ZnFnPcs) are synthesised and their spectroscopic, redox, and light‐induced electron‐transfer properties investigated systematically by forming donor–acceptor dyads through metal–ligand axial coordination of fullerene (C60) derivatives. Absorption and fluorescence spectral studies reveal efficient binding of the pyridine‐ (Py) and phenylimidazole‐functionalised fullerene (C60Im) derivatives to the zinc centre of the FnPcs. The determined binding constants, K, in o‐dichlorobenzene for the 1:1 complexes are in the order of 104 to 105 M ?1; nearly an order of magnitude higher than that observed for the dyad formed from zinc phthalocyanine (ZnPc) lacking fluorine substituents. The geometry and electronic structure of the dyads are determined by using the B3LYP/6‐31G* method. The HOMO and LUMO levels are located on the Pc and C60 entities, respectively; this suggests the formation of ZnFnPc.+–C60Im.? and ZnFnPc.+–C60Py.? (n=0, 8 or 16) intra‐supramolecular charge‐separated states during electron transfer. Electrochemical studies on the ZnPc–C60 dyads enable accurate determination of their oxidation and reduction potentials and the energy of the charge‐separated states. The energy of the charge‐separated state for dyads composed of ZnFnPc is higher than that of normal ZnPc–C60 dyads and reveals their significance in harvesting higher amounts of light energy. Evidence for charge separation in the dyads is secured from femtosecond transient absorption studies in nonpolar toluene. Kinetic evaluation of the cation and anion radical ion peaks reveals ultrafast charge separation and charge recombination in dyads composed of perfluorinated phthalocyanine and fullerene; this implies their significance in solar‐energy harvesting and optoelectronic device building applications.  相似文献   

7.
As an excellent artificial photosynthetic reaction center, the carotene (C)‐porphyrin (P)‐fullerene (F) triad was extensively investigated experimentally. To reveal the mechanism of the intramolecular charge transfer (ICT) on the mimic of photosynthetic solar energy conversion (such as singlet energy transfer between pigments, and photoinduced electron transfer from excited singlet states to give long‐lived charge‐separated states), the ICT mechanisms of C‐P‐F triad on the exciton were theoretically studied with quantum chemical methods as well as the 2D and 3D real space analysis approaches. The results of quantum chemical methods reveal that the excited states are the ICT states, since the densities of HOMO are localized in the carotene or porphyrin unit, and the densities of LUMO are localized in the fullerene unit. Furthermore, the excited states should be the intramolecular superexchange charge transfer (ISCT) states for the orbital transition from the HOMO whose densities are localized in the carotene to the LUMO whose densities are localized in the fullerene unit. The 3D charge difference densities can clearly show that some excited states are ISCT excited states, since the electron and hole are resident in the fullerene and carotene units, respectively. From the results of the electron‐hole coherence of the 2D transition density matrix, not only 3D results are supported, but also the delocalization size on the exciton can be observed. These phenomena were further interpreted with non‐linear optical effect. The large changes of the linear and non‐linear polarizabilities on the exciton result in the charge separate states, and if their changes are large enough, the ICT mechanism can become the ISCT on the exciton.  相似文献   

8.
Efficient photoinduced electron transfer was observed across a [10]cycloparaphenylene ([10]CPP) moiety that serves as a rigid non‐covalent bridge between a zinc porphyrin and a range of fullerenes. The preparation of iodo‐[10]CPP is the key to the synthesis of a porphyrin–[10]CPP conjugate, which binds C60, C70, (C60)2, and other fullerenes (KA>105 m ?1). Fluorescence and pump–probe spectroscopy revealed intramolecular energy transfer between CPP and porphyrin and also efficient charge separation between porphyrin and fullerenes, affording up to 0.5 μs lifetime charge‐separated states. The advantage of this approach towards electron donor–acceptor dyads is evident in the case of dumbbell‐shaped (C60)2, which gave intricate charge‐transfer behavior in 1:1 and 2:1 complexes. These results suggest that [10]CPP and its cross‐coupled derivatives could act as supramolecular mediators of charge transport in organic electronic devices.  相似文献   

9.
Photoinduced electron transfer (ET) between C60 and porphyrin (P) in a new polymer containing porphyrin, poly(p-phenylenevinylene), and pendant fullerene units has been investigated by nanosecond transient absorption and phosphorescence spectroscopy. Compared to the physically doping material systems, binding porphyrin/C60 through chemical bonds in a polymer detains the formation of the triplet states of porphyrins and C60. The formation of intermediate charge transfer state (CSS) of P+-C60 ? was observed, which led to the delayed formation of triplet states of porphyrins and C60. The reduced opto-electronic properties, such as optical limiting performance, were also observed, which resulted from the delayed formation of triplet states. The results presented in this article are significant in understanding the complicated spectral characteristics of the triplet state and charge transfer of the porphyrin and C60 complexes, and are therefore related to the controllable performance of the new materials in applications.  相似文献   

10.
The effect of donor-acceptor distance in controlling the rate of electron transfer in axially linked silicon phthalocyanine-C60 dyads has been investigated. For this, two C60-SiPc-C60 dyads, 1 and 2 , varying in their donor-acceptor distance, have been newly synthesized and characterized. In the case of C60-SiPc-C60 1 where the SiPc and C60 are separated by a phenyl spacer, faster electron transfer was observed with kcs equal to 2.7×109 s−1 in benzonitrile. However, in the case of C60-SiPc-C60 2 , where SiPc and C60 are separated by a biphenyl spacer, a slower electron transfer rate constant, kcs=9.1×108 s−1, was recorded. The addition of an extra phenyl spacer in 2 increased the donor-acceptor distance by ∼4.3 Å, and consequently, slowed down the electron transfer rate constant by a factor of ∼3.7. The charge separated state lasted over 3 ns, monitoring time window of our femtosecond transient spectrometer. Complimentary nanosecond transient absorption studies revealed formation of 3SiPc* as the end product and suggested the final lifetime of the charge separated state to be in the 3–20 ns range. Energy level diagrams established to comprehend these mechanistic details indicated that the comparatively high-energy SiPc.+-C60.− charge separated states (1.57 eV) populated the low-lying 3SiPc* (1.26 eV) prior returning to the ground state.  相似文献   

11.
A new photosynthetic antenna‐reaction‐center model compound composed of covalently linked BF2‐chelated dipyrromethene (BODIPY), BF2‐chelated azadipyrromethene (azaBODIPY), and fullerene (C60), in a “V‐configuration”, has been newly synthesized and characterized by using a multistep synthetic procedure. Optical absorbance and steady‐state fluorescence, computational, and electrochemical studies were systematically performed in nonpolar, toluene, and polar, benzonitrile, solvents to establish the molecular integrity of the triad and to construct an energy‐level diagram revealing different photochemical events. The geometry obtained by B3LYP/6‐31G* calculations revealed the anticipated V‐configuration of the BODIPY‐azaBODIPY‐C60 triad. The location of the frontier orbitals in the triad tracked the site of electron transfer determined from electrochemical studies. The different photochemical events originated from 1BODIPY* were realized from the energy‐level diagram. Accordingly, 1BODIPY* resulted in competitive ultrafast energy transfer to produce BODIPY–1azaBODIPY*–C60 and electron transfer to produce BODIPY . +–azaBODIPY–C60 . ? as major photochemical events. The charge‐separated state persisted for few nanoseconds prior populating 3C60*, which in turn revealed an unusual triplet–triplet energy transfer to produce 3azaBODIPY* prior returning to the ground state. These findings delineate the importance of multimodular systems in energy harvesting, and more importantly, their utility in building multifunction performing optoelectronic devices.  相似文献   

12.
The electron positive boron atom usually does not contribute to the frontier orbitals for several lower‐lying electronic transitions, and thus is ideal to serve as a hub for the spiro linker of light‐emitting molecules, such that the electron donor (HOMO) and acceptor (LUMO) moieties can be spatially separated with orthogonal orientation. On this basis, we prepared a series of novel boron complexes bearing electron deficient pyridyl pyrrolide and electron donating phenylcarbazolyl fragments or triphenylamine. The new boron complexes show strong solvent‐polarity dependent charge‐transfer emission accompanied by a small, non‐negligible normal emission. The slim orbital overlap between HOMO and LUMO and hence the lack of electron correlation lead to a significant reduction of the energy gap between the lowest lying singlet and triplet excited states (ΔET‐S) and thereby the generation of thermally activated delay fluorescence (TADF).  相似文献   

13.
Novel photosynthetic reaction center model compounds of the type donor2–donor1–acceptor, composed of phenothiazine, BF2‐chelated dipyrromethene (BODIPY), and fullerene, respectively, have been newly synthesized using multistep synthetic methods. X‐ray structures of three of the phenothiazine‐BODIPY intermediate compounds have been solved to visualize the substitution effect caused by the phenothiazine on the BODIPY macrocycle. Optical absorption and emission, computational, and differential pulse voltammetry studies were systematically performed to establish the molecular integrity of the triads. The N‐substituted phenothiazine was found to be easier to oxidize by 60 mV compared to the C‐substituted analogue. The geometry and electronic structures were obtained by B3LYP/6‐31G(dp) calculations (for H, B, N, and O) and B3LYP/6‐31G(df) calculations (for S) in vacuum, followed by a single‐point calculation in benzonitrile utilizing the polarizable continuum model (PCM). The HOMO?1, HOMO, and LUMO were, respectively, on the BODIPY, phenothiazine and fullerene entities, which agreed well with the site of electron transfer determined from electrochemical studies. The energy‐level diagram deduced from these data helped in elucidating the mechanistic details of the photochemical events. Excitation of BODIPY resulted in ultrafast electron transfer to produce PTZ–BODIPY.+–C60.?; subsequent hole shift resulted in PTZ.+–BODIPY–C60.? charge‐separated species. The return of the charge‐separated species was found to be solvent dependent. In nonpolar solvents the PTZ.+–BODIPY–C60.? species populated the 3C60* prior to returning to the ground state, while in polar solvent no such process was observed due to relative positioning of the energy levels. The 1BODIPY* generated radical ion‐pair in these triads persisted for few nanoseconds due to electron transfer/hole‐shift mechanism.  相似文献   

14.
A novel photosynthetic‐antenna–reaction‐center model compound, comprised of BF2‐chelated dipyrromethene (BODIPY) as an energy‐harvesting antenna, zinc porphyrin (ZnP) as the primary electron donor, ferrocene (Fc) as a hole‐shifting agent, and phenylimidazole‐functionalized fulleropyrrolidine (C60Im) as an electron acceptor, has been synthesized and characterized. Optical absorption and emission, computational structure optimization, and cyclic voltammetry studies were systematically performed to establish the role of each entity in the multistep photochemical reactions. The energy‐level diagram established from optical and redox data helped identifying different photochemical events. Selective excitation of BODIPY resulted in efficient singlet energy transfer to the ZnP entity. Ultrafast electron transfer from the 1ZnP* (formed either as a result of singlet–singlet energy transfer or direct excitation) or 1C60* of the coordinated fullerene resulting into the formation of the Fc–(C60 . ?Im:ZnP . +)–BODIPY radical ion pair was witnessed by femtosecond transient absorption studies. Subsequent hole migration to the ferrocene entity resulted in the Fc+–(C60 . +Im:ZnP)–BODIPY radical ion pair that persisted for 7–15 μs, depending upon the solvent conditions and contributions from the triplet excited states of ZnP and ImC60, as revealed by the nanosecond transient spectral studies. Better utilization of light energy in generating the long‐lived charge‐separated state with the help of the present “antenna–reaction‐center” model system has been successfully demonstrated.  相似文献   

15.
The charge exchange mass spectra of a selection of C5-C7 ketones have been measured using [CS2]+˙, [COS]+˙ and [N2O]+. as reagent ions. The low energy charge exchange with [CS2]+˙ or [COS]+˙ provides simple primary ion mass spectra, which readily permit structure elucidation in contrast to metastable ion spectra. In several cases, isomer distinction is easier from the charge exchange mass spectra than from the electron impact mass spectra. The energy transfer from [N2O]+˙ is sufficiently high for complex spectra resembling electron impact mass spectra to be obtained.  相似文献   

16.
Efficiencies and rates of electron transfer from various electron donors to excited fullerenes (C60 and C70) have been determined by observing the transient absorption bands in the near-IR region, where the anion radicals of fullerenes appear. From the rise of the absorption bands of C60 −+ and C70 −+ in the near-IR region, electron transfer takes place via the triplet states (TC60 * and TC70 *) under appropriately low concentrations of electron donors. By analysis of the rise curves C60 −+ and C70 −+, contribution of the excited singlet states (SC60 * and SC70 *) in addition to the route of the triplet states (TC60 * and TC70 *) is confirmed. The quantum yield for electron transfer via the triplet states Φct T was evaluated by the ratio of [C60 −+]/[TC60 *] (or [C70 −+/[TC70 *]). The Φct T depends upon the donor-ability, donor concentration, and solvent polarity. The back electron-transfer process, which was evaluated by observing C60 −+, also depends upon the solvent polarity.  相似文献   

17.
Chemical functionalization of C60 fullerene with one to six carbene (CH2) molecule(s) has been investigated using density functional theory. We have found that the reaction is regioselective so that a CH2 molecule prefers to be adsorbed atop a C–C bond which is shared between two hexagonal rings of the C60, releasing energy of ?3.95 eV. Singly occupied molecular orbital (SOMO) of the CH2 interacts with LUMO of the C60 via a [2 + 1] cycloaddition reaction. Energy of the reaction and work function of the system are decreased by increasing the number of adsorbed CH2 molecules. The HOMO/LUMO energy gap of C60 is slightly changed and the electron emission from its surface is facilitated upon the functionalization.  相似文献   

18.
In this paper, we described the design, synthesis, and characterization of two novel naphthalene diimide (NDI) core-based targets modified with terminal fullerene (C60) yield – so called S4 and S5 , in which NDI bearing 1 and 2 molecules of C60, respectively. The absorption, electrochemical and thin-film transistor characteristics of the newly developed targets were investigated in detail. Both S4 and S5 displayed broad absorption in the 450–500 nm region, owing to the effect of conjugation due to fullerene functionalities. The electrochemical measurement suggested that the HOMO and the LUMO energy levels can be altered with the number of C60 units. Both S4 and S5 were employed as organic semiconductor materials in n-channel transistors. The thin film transistor based on S4 exhibited superior electron mobility (μe) values ranging from 1.20×10−4 to 3.58×10−4 cm2 V−1 s−1 with a current on-off ratio varying from 102 to 103 in comparison with the performance of S5 based transistor, which exhibited μe ranging from 8.33×10−5 to 2.03×10−4 cm2 V−1 s−1 depending on channel lengths.  相似文献   

19.
An electronically push–pull type dimethylaminoazobenzene–fullerene C60 hybrid was designed and synthesized by tailoring N,N‐dimethylaniline as an electron donating auxochrome that intensified charge density on the β‐azonitrogen, and on N‐methylfulleropyrrolidine (NMFP) as an electron acceptor at the 4 and 4′ positions of the azobenzene moiety, respectively. The absorption and charge transfer behavior of the hybrid donor‐bridge‐acceptor dyad were studied experimentally and by performing TD‐DFT calculations. The TD‐DFT predicted charge transfer interactions of the dyad ranging from 747 to 601 nm were experimentally observed in the UV‐vis spectra at 721 nm in toluene and dichloromethane. A 149 mV anodic shift in the first reduction potential of the N?N group of the dyad in comparison with the model aminoazobenzene derivative further supported the phenomenon. Analysis of the charge transfer band through the orbital picture revealed charge displacement from the n(N?N) (nonbonding) and π (N?N) type orbitals centered on the donor part to the purely fullerene centered LUMOs and LUMO+n orbitals, delocalized over the entire molecule. The imposed electronic perturbations on the aminoazobenzene moiety upon coupling it with C60 were analyzed by comparing the TD‐DFT predicted and experimentally observed electronic transition energies of the dyad with the model compounds, NMFP and (E)‐N,N‐dimethyl‐4‐(p‐tolyldiazenyl)aniline (AZNME). The n(N?N) → π*(N?N) and π(N?N) → π*(N?N) transitions of the dyad were bathochromically shifted with a significant charge transfer character. The shifting of π(N?N) → π*(N?N) excitation energy closer to the n → π*(N?N) in comparison with the model aminoazobenzene emphasized the predominant existence of charge separated quinonoid‐like ground state electronic structure. Increasing solvent polarity introduced hyperchromic effect in the π(N?N) → π*(N?N) electronic transition at the expense of transitions involved with benzenic states, and the extent of intensity borrowing was quantified adopting the Gaussian deconvolution method. On a comparative scale, the predicted excitation energies were in reasonable agreement with the observed values, demonstrating the efficiency of TD‐DFT in predicting the localized and the charge transfer nature of transitions involved with large electronically asymmetric molecules with HOMO and LUMO centered on different parts of the molecular framework. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010  相似文献   

20.
The chlorination of singly and multiply charged C60 cations has been investigated with the selected-ion flow tube technique. Observations are reported for the reactions of C60·+, C602+ and C60·3+ with Cl2, CCl4, CDCl3, CH2Cl2 and CH3Cl at room temperature (295 ± 2 K) in helium at a total pressure of 0.35 ± 0.02 Torr. C60·+ and C602+ were observed not to chlorinate, or react in any other way, with these five molecules. Chlorine also did not react with C60·3+, but bimolecular chloride transfer and electron transfer reactions, reactions that result in charge reduction/charge separation, were observed to occur with CCl4, CDCl3, CH2Cl2 and CH3Cl. Chloride transfer was the predominant channel seen with CCl4, CDCl3 and CH2Cl2 while electron transfer dominates the reaction with CH3Cl. These results are consistent with trends in chloride affinity and ionization energy. The reluctant chlorination of the first two charge states of C60 is attributed to the energy required to distort the carbon cage upon bond formation, while the observed chloride transfer to C60·3+ is attributed to the greater electrostatic interactions with this ion.  相似文献   

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