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

doi:10.1039/c4cp03995e

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 journal › Article › peer-review

21 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 language	English
Pages (from-to)	25775-25788
Number of pages	14
Journal	Physical Chemistry Chemical Physics
Volume	16
Issue number	47
Early online date	24 Oct 2014
DOIs	https://doi.org/10.1039/c4cp03995e
Publication status	Published - 21 Dec 2014
Externally published	Yes

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Sazanovich, I. V., Best, J., Scattergood, P. A., Towrie, M., Tikhomirov, S. A., Bouganov, O. V., Meijer, A. J. H. M., & Weinstein, J. A. (2014). Ultrafast photoinduced charge transport in Pt(ii) donor-acceptor assembly bearing naphthalimide electron acceptor and phenothiazine electron donor. Physical Chemistry Chemical Physics, 16(47), 25775-25788. https://doi.org/10.1039/c4cp03995e

@article{0ba8778b3e534c4496687bd88baaa1b8,

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

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. ",

keywords = "Electrons, Phenothiazines, Naphthalimides",

author = "Sazanovich, \{Igor V.\} and Jonathan Best and Scattergood, \{Paul A.\} and Michael Towrie and Tikhomirov, \{Sergei A.\} and Bouganov, \{Oleg V.\} and Meijer, \{Anthony J H M\} and Weinstein, \{Julia A.\}",

note = "No record of this in Eprints. HN 21/11/2017",

year = "2014",

month = dec,

day = "21",

doi = "10.1039/c4cp03995e",

language = "English",

volume = "16",

pages = "25775--25788",

journal = "Physical Chemistry Chemical Physics",

issn = "1463-9076",

publisher = "Royal Society of Chemistry",

number = "47",

}

Sazanovich, IV, Best, J, Scattergood, PA, Towrie, M, Tikhomirov, SA, Bouganov, OV, Meijer, AJHM & Weinstein, JA 2014, 'Ultrafast photoinduced charge transport in Pt(ii) donor-acceptor assembly bearing naphthalimide electron acceptor and phenothiazine electron donor', Physical Chemistry Chemical Physics, vol. 16, no. 47, pp. 25775-25788. https://doi.org/10.1039/c4cp03995e

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.

KW - Electrons

KW - Phenothiazines

KW - Naphthalimides

UR - https://www.scopus.com/pages/publications/84912080898

U2 - 10.1039/c4cp03995e

DO - 10.1039/c4cp03995e

M3 - Article

C2 - 25342582

AN - SCOPUS:84912080898

SN - 1463-9076

VL - 16

SP - 25775

EP - 25788

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

IS - 47

ER -

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

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