Ultrafast photoinduced charge transport in Pt(ii) donor-acceptor assembly bearing naphthalimide electron acceptor and phenothiazine electron donor

Igor V. Sazanovich, Jonathan Best, Paul A. Scattergood, Michael Towrie, Sergei A. Tikhomirov, Oleg V. Bouganov, Anthony J H M Meijer, Julia A. Weinstein

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Visible light-induced charge transfer dynamics were investigated in a novel transition metal triad acceptor-chromophore-donor, (NDI-phen)Pt(ii)(-CC-Ph-CH2-PTZ)2 (1), designed for photoinduced charge separation using a combination of time-resolved infrared (TRIR) and femtosecond electronic transient absorption (TA) spectroscopy. In 1, the electron acceptor is 1,4,5,8-naphthalene diimide (NDI), and the electron donor is phenothiazine (PTZ), and [(phen)Pt(-CC-Ph-)], where phen is 1,10-phenanthroline, represents the chromophoric core. The first excited state observed in 1 is a 3MLCT/LL′CT, with {Pt(ii)-acetylide}-to-phen character. Following that, charge transfer from the phen-anion onto the NDI subunit to form NDI--phen-[Pt-(CC)2]+-PTZ2 occurs with a time constant of 2.3 ps. This transition is characterised by appearance of the prominent NDI-anion features in both TRIR and TA spectra. The final step of the charge separation in 1 proceeds with a time constant of ∼15 ps during which the hole migrates from the [Pt-(CC)2] subunit to one of the PTZ groups. Charge recombination in 1 then occurs with two distinct time constants of 36 ns and 107 ns, corresponding to the back electron transfer to each of the two donor groups; a rather rare occurrence which manifests that the hole in the final charge-separated state is localised on one of the two donor PTZ groups. The assignment of the nature of the excited states and dynamics in 1 was assisted by TRIR investigations of the analogous previously reported ((COOEt)2bpy)Pt(CC-Ph-CH2-PTZ)2 (2), (J. E. McGarrah and R. Eisenberg, Inorg. Chem., 2003, 42, 4355; J. E. McGarrah, J. T. Hupp and S. N. Smirnov, J. Phys. Chem. A, 2009, 113, 6430) as well as (bpy)Pt(CC-Ph-C7H15)2, which represent the acceptor-free dyad, and the chromophoric core, respectively. Thus, the step-wise formation of the full charge-separated state on the picosecond time scale and charge recombination via tunnelling have been established; and the presence of two distinct charge recombination pathways has been observed. 

Original languageEnglish
Pages (from-to)25775-25788
Number of pages14
JournalPhysical Chemistry Chemical Physics
Volume16
Issue number47
Early online date24 Oct 2014
DOIs
Publication statusPublished - 21 Dec 2014
Externally publishedYes

Fingerprint

Naphthalimides
Bearings (structural)
phenothiazines
naphthalene
Charge transfer
assembly
Electrons
time constant
polarization (charge separation)
Infrared radiation
electrons
Genetic Recombination
Excited states
Anions
charge transfer
anions
Chromophores
Absorption spectroscopy
chromophores
excitation

Cite this

Sazanovich, Igor V. ; Best, Jonathan ; Scattergood, Paul A. ; Towrie, Michael ; Tikhomirov, Sergei A. ; Bouganov, Oleg V. ; Meijer, Anthony J H M ; Weinstein, Julia A. / Ultrafast photoinduced charge transport in Pt(ii) donor-acceptor assembly bearing naphthalimide electron acceptor and phenothiazine electron donor. In: Physical Chemistry Chemical Physics. 2014 ; Vol. 16, No. 47. pp. 25775-25788.
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abstract = "Visible light-induced charge transfer dynamics were investigated in a novel transition metal triad acceptor-chromophore-donor, (NDI-phen)Pt(ii)(-CC-Ph-CH2-PTZ)2 (1), designed for photoinduced charge separation using a combination of time-resolved infrared (TRIR) and femtosecond electronic transient absorption (TA) spectroscopy. In 1, the electron acceptor is 1,4,5,8-naphthalene diimide (NDI), and the electron donor is phenothiazine (PTZ), and [(phen)Pt(-CC-Ph-)], where phen is 1,10-phenanthroline, represents the chromophoric core. The first excited state observed in 1 is a 3MLCT/LL′CT, with {Pt(ii)-acetylide}-to-phen character. Following that, charge transfer from the phen-anion onto the NDI subunit to form NDI--phen-[Pt-(CC)2]+-PTZ2 occurs with a time constant of 2.3 ps. This transition is characterised by appearance of the prominent NDI-anion features in both TRIR and TA spectra. The final step of the charge separation in 1 proceeds with a time constant of ∼15 ps during which the hole migrates from the [Pt-(CC)2] subunit to one of the PTZ groups. Charge recombination in 1 then occurs with two distinct time constants of 36 ns and 107 ns, corresponding to the back electron transfer to each of the two donor groups; a rather rare occurrence which manifests that the hole in the final charge-separated state is localised on one of the two donor PTZ groups. The assignment of the nature of the excited states and dynamics in 1 was assisted by TRIR investigations of the analogous previously reported ((COOEt)2bpy)Pt(CC-Ph-CH2-PTZ)2 (2), (J. E. McGarrah and R. Eisenberg, Inorg. Chem., 2003, 42, 4355; J. E. McGarrah, J. T. Hupp and S. N. Smirnov, J. Phys. Chem. A, 2009, 113, 6430) as well as (bpy)Pt(CC-Ph-C7H15)2, which represent the acceptor-free dyad, and the chromophoric core, respectively. Thus, the step-wise formation of the full charge-separated state on the picosecond time scale and charge recombination via tunnelling have been established; and the presence of two distinct charge recombination pathways has been observed. ",
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Ultrafast photoinduced charge transport in Pt(ii) donor-acceptor assembly bearing naphthalimide electron acceptor and phenothiazine electron donor. / Sazanovich, Igor V.; Best, Jonathan; Scattergood, Paul A.; Towrie, Michael; Tikhomirov, Sergei A.; Bouganov, Oleg V.; Meijer, Anthony J H M; Weinstein, Julia A.

In: Physical Chemistry Chemical Physics, Vol. 16, No. 47, 21.12.2014, p. 25775-25788.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Ultrafast photoinduced charge transport in Pt(ii) donor-acceptor assembly bearing naphthalimide electron acceptor and phenothiazine electron donor

AU - Sazanovich, Igor V.

AU - Best, Jonathan

AU - Scattergood, Paul A.

AU - Towrie, Michael

AU - Tikhomirov, Sergei A.

AU - Bouganov, Oleg V.

AU - Meijer, Anthony J H M

AU - Weinstein, Julia A.

N1 - No record of this in Eprints. HN 21/11/2017

PY - 2014/12/21

Y1 - 2014/12/21

N2 - Visible light-induced charge transfer dynamics were investigated in a novel transition metal triad acceptor-chromophore-donor, (NDI-phen)Pt(ii)(-CC-Ph-CH2-PTZ)2 (1), designed for photoinduced charge separation using a combination of time-resolved infrared (TRIR) and femtosecond electronic transient absorption (TA) spectroscopy. In 1, the electron acceptor is 1,4,5,8-naphthalene diimide (NDI), and the electron donor is phenothiazine (PTZ), and [(phen)Pt(-CC-Ph-)], where phen is 1,10-phenanthroline, represents the chromophoric core. The first excited state observed in 1 is a 3MLCT/LL′CT, with {Pt(ii)-acetylide}-to-phen character. Following that, charge transfer from the phen-anion onto the NDI subunit to form NDI--phen-[Pt-(CC)2]+-PTZ2 occurs with a time constant of 2.3 ps. This transition is characterised by appearance of the prominent NDI-anion features in both TRIR and TA spectra. The final step of the charge separation in 1 proceeds with a time constant of ∼15 ps during which the hole migrates from the [Pt-(CC)2] subunit to one of the PTZ groups. Charge recombination in 1 then occurs with two distinct time constants of 36 ns and 107 ns, corresponding to the back electron transfer to each of the two donor groups; a rather rare occurrence which manifests that the hole in the final charge-separated state is localised on one of the two donor PTZ groups. The assignment of the nature of the excited states and dynamics in 1 was assisted by TRIR investigations of the analogous previously reported ((COOEt)2bpy)Pt(CC-Ph-CH2-PTZ)2 (2), (J. E. McGarrah and R. Eisenberg, Inorg. Chem., 2003, 42, 4355; J. E. McGarrah, J. T. Hupp and S. N. Smirnov, J. Phys. Chem. A, 2009, 113, 6430) as well as (bpy)Pt(CC-Ph-C7H15)2, which represent the acceptor-free dyad, and the chromophoric core, respectively. Thus, the step-wise formation of the full charge-separated state on the picosecond time scale and charge recombination via tunnelling have been established; and the presence of two distinct charge recombination pathways has been observed. 

AB - Visible light-induced charge transfer dynamics were investigated in a novel transition metal triad acceptor-chromophore-donor, (NDI-phen)Pt(ii)(-CC-Ph-CH2-PTZ)2 (1), designed for photoinduced charge separation using a combination of time-resolved infrared (TRIR) and femtosecond electronic transient absorption (TA) spectroscopy. In 1, the electron acceptor is 1,4,5,8-naphthalene diimide (NDI), and the electron donor is phenothiazine (PTZ), and [(phen)Pt(-CC-Ph-)], where phen is 1,10-phenanthroline, represents the chromophoric core. The first excited state observed in 1 is a 3MLCT/LL′CT, with {Pt(ii)-acetylide}-to-phen character. Following that, charge transfer from the phen-anion onto the NDI subunit to form NDI--phen-[Pt-(CC)2]+-PTZ2 occurs with a time constant of 2.3 ps. This transition is characterised by appearance of the prominent NDI-anion features in both TRIR and TA spectra. The final step of the charge separation in 1 proceeds with a time constant of ∼15 ps during which the hole migrates from the [Pt-(CC)2] subunit to one of the PTZ groups. Charge recombination in 1 then occurs with two distinct time constants of 36 ns and 107 ns, corresponding to the back electron transfer to each of the two donor groups; a rather rare occurrence which manifests that the hole in the final charge-separated state is localised on one of the two donor PTZ groups. The assignment of the nature of the excited states and dynamics in 1 was assisted by TRIR investigations of the analogous previously reported ((COOEt)2bpy)Pt(CC-Ph-CH2-PTZ)2 (2), (J. E. McGarrah and R. Eisenberg, Inorg. Chem., 2003, 42, 4355; J. E. McGarrah, J. T. Hupp and S. N. Smirnov, J. Phys. Chem. A, 2009, 113, 6430) as well as (bpy)Pt(CC-Ph-C7H15)2, which represent the acceptor-free dyad, and the chromophoric core, respectively. Thus, the step-wise formation of the full charge-separated state on the picosecond time scale and charge recombination via tunnelling have been established; and the presence of two distinct charge recombination pathways has been observed. 

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