Excited-State Dynamics in a Dyad Comprising Terpyridine-Platinum(II) Ethynylene Linked to Pyrrolidino-[60]Fullerene

Ventura, Barbara; Barbieri, Andrea; Zanelli, Alberto; Barigelletti, Francesco; Seneclauze, Julie Batcha; Diring, Stéphane; Ziessel, Raymond

doi:10.1021/ic900069r

Cited by 25 publications

(24 citation statements)

References 57 publications

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“…Here we expand on the former study, by reporting the absorption spectra, luminescence properties and photoinduced intercomponent processes occurring in three new Pt-bodipy systems, 4-6, whose structural formulae are shown in Fig. 1, where the formulae of the parent species 1-3 and those of the formerly studied 4,5 species 7-10, used for reference purposes, are also illustrated. In 6, two pyrene subunits are also present, making these species a novel four-chromophore compound made of one bodipy, one Pt(II)-polypyridine and two pyrene units.…”

Section: Introductionmentioning

confidence: 95%

Hybrid complexes: Pt(ii)-terpyridine linked to various acetylide-bodipy subunits

Nastasi¹,

Puntoriero²,

Campagna³

et al. 2010

Phys. Chem. Chem. Phys.

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By tailoring the chemistry of the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (bodipy) core in order to change its spectroscopic properties, we linked some modified bodipy dyes to Pt(ii)-terpyridine centers thereby preparing three novel hybrid complexes. In one of such species, two pyrene subunits are also present. The absorption spectra and luminescence properties (both at room temperature in acetonitrile solution and at 77 K in butyronitrile rigid matrix) of the new hybrid complexes and of their bodipy parent species have been investigated, and compared with those of previously studied compounds. Absorption spectra showed that the different chromophoric subunits roughly keep their own features in the multicomponent systems, indicating the supramolecular nature of the compounds. Efficient photoinduced intercomponent energy transfer takes place in the various hybrid Pt(ii)-terpyridine-bodipy compounds, by taking advantage of different mechanisms: at room temperature in fluid solution very efficient energy transfer from the (3)MLCT state(s) of the Pt residue to the lowest-lying (3)bodipy is mediated by a charge transfer state via a two-step electron transfer process. Direct energy transfer from (3)MLCT state(s) to the (3)bodipy states takes place at 77 K, most likely via the Dexter mechanism. When two pyrene fragments are grafted to the boron, cascade energy transfer from the pyrene to the (1)bodipy also occurs by the Förster mechanism. For one of the new compounds, (3)bodipy emission with a maximum at 738 nm is also observed at cryogenic temperature.

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Section: Introductionmentioning

confidence: 95%

Hybrid complexes: Pt(ii)-terpyridine linked to various acetylide-bodipy subunits

Nastasi¹,

Puntoriero²,

Campagna³

et al. 2010

Phys. Chem. Chem. Phys.

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“…8,11,12 Fullerenes, in particular C 60 , have high electron affinities, which make them favorable systems regarding their electron-accepting ability. Photoinduced electron transfer and energy transfer in (macro)-molecular assemblies containing donors, such as ferrocene, 13,14 porphyrin, 15 tetrathiafulvalene, 16,17 and others, 18,19 which are covalently linked to fullerene, were extensively studied; their electrochemical and photophysical properties are of particular interest. 20,21 Ruthenium(II) polypyridyl complexes as donors are promising materials due to their intense light absorption in the visible range and extended excited-state lifetimes.…”

Section: ■ Introductionmentioning

confidence: 99%

New Ruthenium Bis(terpyridine) Methanofullerene and Pyrrolidinofullerene Complexes: Synthesis and Electrochemical and Photophysical Properties

et al. 2015

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A series of terpyridine (tpy) methanofullerene and pyrrolidinofullerene dyads linked via p-phenylene or p-phenyleneethynylenephenylene (PEP) units is presented. The coordination to ruthenium(II) yields donor-bridge-acceptor assemblies with different lengths. Cyclic voltammetry and UV-vis and luminescence spectroscopy are applied to study the electronic interactions between the active moieties. It is shown that, upon light excitation of the ruthenium(II)-based (1)MLCT transition, the formed (3)MLCT state is readily quenched in the presence of C60. The photoinduced dynamics have been studied by transient absorption spectroscopy, which reveals fast depopulation of the (3)MLCT (73-406 ps). As a consequence, energy transfer occurs, populating a long-lived triplet state, which could be assigned to the (3)C60* state.

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“…2,[4][5][6][7][8][9][10] There is currently much interest in understanding the behaviour and energy relaxation processes that occur immediately after light absorption. Transition metal donor-bridge-acceptor (DBA) molecular triads and their multi-donor/acceptor relatives have proven to be an effective design motif in which a photoinduced CSS can be attained.…”

Section: Introductionmentioning

confidence: 99%

Electron transfer dynamics and excited state branching in a charge-transfer platinum(ii) donor–bridge-acceptor assembly

et al. 2014

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A linear asymmetric Pt(ii) trans-acetylide donor-bridge-acceptor triad designed for efficient charge separation, NAP[triple bond, length as m-dash]Pt(PBu3)2[triple bond, length as m-dash]Ph-CH2-PTZ (), containing strong electron acceptor and donor groups, 4-ethynyl-N-octyl-1,8-naphthalimide (NAP) and phenothiazine (PTZ) respectively, has been synthesised and its photoinduced charge transfer processes characterised in detail. Excitation with 400 nm, ∼50 fs laser pulse initially populates a charge transfer manifold stemming from electron transfer from the Pt-acetylide centre to the NAP acceptor and triggers a cascade of charge and energy transfer events. A combination of ultrafast time-resolved infrared (TRIR) and transient absorption (TA) spectroscopies, supported by UV-Vis/IR spectroelectrochemistry, emission spectroscopy and DFT calculations reveals a self-consistent photophysical picture of the excited state evolution from femto- to milliseconds. The characteristic features of the NAP-anion and PTZ-cation are clearly observed in both the TRIR and TA spectra, confirming the occurrence of electron transfer and allowing the rate constants of individual ET-steps to be obtained. Intriguingly, has three separate ultrafast electron transfer pathways from a non-thermalised charge transfer manifold directly observed by TRIR on timescales ranging from 0.2 to 14 ps: charge recombination to form either the intraligand triplet (3)NAP with 57% yield, or the ground state, and forward electron transfer to form the full charge-separated state (3)CSS ((3)[PTZ(+)-NAP(-)]) with 10% yield as determined by target analysis. The (3)CSS decays by charge-recombination to the ground state with ∼1 ns lifetime. The lowest excited state is (3)NAP, which possesses a long lifetime of 190 μs and efficiently sensitises singlet oxygen. Overall, molecular donor-bridge-acceptor triad demonstrates excited state branching over 3 different pathways, including formation of a long-distant (18 Å) full charge-separated excited state from a directly observed vibrationally hot precursor state.

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Excited-State Dynamics in a Dyad Comprising Terpyridine-Platinum(II) Ethynylene Linked to Pyrrolidino-[60]Fullerene

Cited by 25 publications

References 57 publications

Hybrid complexes: Pt(ii)-terpyridine linked to various acetylide-bodipy subunits

Hybrid complexes: Pt(ii)-terpyridine linked to various acetylide-bodipy subunits

New Ruthenium Bis(terpyridine) Methanofullerene and Pyrrolidinofullerene Complexes: Synthesis and Electrochemical and Photophysical Properties

Electron transfer dynamics and excited state branching in a charge-transfer platinum(ii) donor–bridge-acceptor assembly

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