Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C∧N∧C) Pincer Ligand─A Comparative Study

Om Prakash; Linnea Lindh; Arvind Kumar Gupta; Yen Tran Hoang Hai; Nidhi Kaul; Pavel Chábera; Fredrik Lindgren; Tore Ericsson; Lennart Häggström; Daniel Strand; Arkady Yartsev; Reiner Lomoth; Petter Persson; Kenneth Wärnmark

doi:10.1021/acs.inorgchem.3c02890

Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C^∧N^∧C) Pincer Ligand─A Comparative Study

Om Prakash, Linnea Lindh, Arvind Kumar Gupta, Yen Tran Hoang Hai, Nidhi Kaul, Pavel Chábera, Fredrik Lindgren, Tore Ericsson, Lennart Häggström, Daniel Strand, Arkady Yartsev, Reiner Lomoth, Petter Persson, Kenneth Wärnmark

Uppsala universitet

Forskningsoutput: Tidskriftsbidrag › Artikel i vetenskaplig tidskrift › Peer review

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We here report the synthesis of the homoleptic iron(II) N-heterocyclic carbene (NHC) complex [Fe(miHpbmi)₂](PF₆)₄ (miHpbmi = 4-((3-methyl-1H-imidazolium-1-yl)pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) and its electrochemical and photophysical properties. The introduction of the π-electron-withdrawing 3-methyl-1H-imidazol-3-ium-1-yl group into the NHC ligand framework resulted in stabilization of the metal-to-ligand charge transfer (MLCT) state and destabilization of the metal-centered (MC) states. This resulted in an improved excited-state lifetime of 16 ps compared to the 9 ps for the unsubstituted parent compound [Fe(pbmi)₂](PF₆)₂ (pbmi = (pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) as well as a stronger MLCT absorption band extending more toward the red spectral region. However, compared to the carboxylic acid derivative [Fe(cpbmi)₂](PF₆)₂ (cpbmi = 1,1′-(4-carboxypyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)), the excited-state lifetime of [Fe(miHpbmi)₂](PF₆)₄ is the same, but both the extinction and the red shift are more pronounced for the former. Hence, this makes [Fe(miHpbmi)₂](PF₆)₄ a promising pH-insensitive analogue of [Fe(cpbmi)₂](PF₆)₂. Finally, the excited-state dynamics of the title compound [Fe(miHpbmi)₂](PF₆)₄ was investigated in solvents with different viscosities, however, showing very little dependency of the depopulation of the excited states on the properties of the solvent used.

Originalspråk	engelska
Sidor (från-till)	2909-2918
Antal sidor	10
Tidskrift	Inorganic Chemistry
Volym	63
Nummer	6
DOI	https://doi.org/10.1021/acs.inorgchem.3c02890
Status	Published - 2024 feb.

Ämnesklassifikation (UKÄ)

Atom- och molekylfysik och optik (Här ingår: Kemisk fysik, kvantoptik)
Organisk kemi

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10.1021/acs.inorgchem.3c02890

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Prakash, O., Lindh, L., Gupta, A. K., Hoang Hai, Y. T., Kaul, N., Chábera, P., Lindgren, F., Ericsson, T., Häggström, L., Strand, D., Yartsev, A., Lomoth, R., Persson, P., & Wärnmark, K. (2024). Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C^∧N^∧C) Pincer Ligand─A Comparative Study. Inorganic Chemistry, 63(6), 2909-2918. https://doi.org/10.1021/acs.inorgchem.3c02890

@article{8f4113b64e184224801f5e26a06c07f5,

title = "Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C∧N∧C) Pincer Ligand─A Comparative Study",

abstract = "We here report the synthesis of the homoleptic iron(II) N-heterocyclic carbene (NHC) complex [Fe(miHpbmi)2](PF6)4 (miHpbmi = 4-((3-methyl-1H-imidazolium-1-yl)pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) and its electrochemical and photophysical properties. The introduction of the π-electron-withdrawing 3-methyl-1H-imidazol-3-ium-1-yl group into the NHC ligand framework resulted in stabilization of the metal-to-ligand charge transfer (MLCT) state and destabilization of the metal-centered (MC) states. This resulted in an improved excited-state lifetime of 16 ps compared to the 9 ps for the unsubstituted parent compound [Fe(pbmi)2](PF6)2 (pbmi = (pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) as well as a stronger MLCT absorption band extending more toward the red spectral region. However, compared to the carboxylic acid derivative [Fe(cpbmi)2](PF6)2 (cpbmi = 1,1′-(4-carboxypyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)), the excited-state lifetime of [Fe(miHpbmi)2](PF6)4 is the same, but both the extinction and the red shift are more pronounced for the former. Hence, this makes [Fe(miHpbmi)2](PF6)4 a promising pH-insensitive analogue of [Fe(cpbmi)2](PF6)2. Finally, the excited-state dynamics of the title compound [Fe(miHpbmi)2](PF6)4 was investigated in solvents with different viscosities, however, showing very little dependency of the depopulation of the excited states on the properties of the solvent used.",

author = "Om Prakash and Linnea Lindh and Gupta, \{Arvind Kumar\} and \{Hoang Hai\}, \{Yen Tran\} and Nidhi Kaul and Pavel Ch{\'a}bera and Fredrik Lindgren and Tore Ericsson and Lennart H{\"a}ggstr{\"o}m and Daniel Strand and Arkady Yartsev and Reiner Lomoth and Petter Persson and Kenneth W{\"a}rnmark",

year = "2024",

month = feb,

doi = "10.1021/acs.inorgchem.3c02890",

language = "English",

volume = "63",

pages = "2909--2918",

journal = "Inorganic Chemistry",

issn = "0020-1669",

publisher = "The American Chemical Society (ACS)",

number = "6",

}

Prakash, O, Lindh, L, Gupta, AK, Hoang Hai, YT, Kaul, N, Chábera, P, Lindgren, F, Ericsson, T, Häggström, L, Strand, D , Yartsev, A, Lomoth, R, Persson, P & Wärnmark, K 2024, 'Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C^∧N^∧C) Pincer Ligand─A Comparative Study', Inorganic Chemistry, vol. 63, nr. 6, s. 2909-2918. https://doi.org/10.1021/acs.inorgchem.3c02890

Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C^∧N^∧C) Pincer Ligand─A Comparative Study. / Prakash, Om; Lindh, Linnea; Gupta, Arvind Kumar et al.
I: Inorganic Chemistry, Vol. 63, Nr. 6, 02.2024, s. 2909-2918.

Forskningsoutput: Tidskriftsbidrag › Artikel i vetenskaplig tidskrift › Peer review

TY - JOUR

T1 - Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C∧N∧C) Pincer Ligand─A Comparative Study

AU - Prakash, Om

AU - Lindh, Linnea

AU - Gupta, Arvind Kumar

AU - Hoang Hai, Yen Tran

AU - Kaul, Nidhi

AU - Chábera, Pavel

AU - Lindgren, Fredrik

AU - Ericsson, Tore

AU - Häggström, Lennart

AU - Strand, Daniel

AU - Yartsev, Arkady

AU - Lomoth, Reiner

AU - Persson, Petter

AU - Wärnmark, Kenneth

PY - 2024/2

Y1 - 2024/2

N2 - We here report the synthesis of the homoleptic iron(II) N-heterocyclic carbene (NHC) complex [Fe(miHpbmi)2](PF6)4 (miHpbmi = 4-((3-methyl-1H-imidazolium-1-yl)pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) and its electrochemical and photophysical properties. The introduction of the π-electron-withdrawing 3-methyl-1H-imidazol-3-ium-1-yl group into the NHC ligand framework resulted in stabilization of the metal-to-ligand charge transfer (MLCT) state and destabilization of the metal-centered (MC) states. This resulted in an improved excited-state lifetime of 16 ps compared to the 9 ps for the unsubstituted parent compound [Fe(pbmi)2](PF6)2 (pbmi = (pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) as well as a stronger MLCT absorption band extending more toward the red spectral region. However, compared to the carboxylic acid derivative [Fe(cpbmi)2](PF6)2 (cpbmi = 1,1′-(4-carboxypyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)), the excited-state lifetime of [Fe(miHpbmi)2](PF6)4 is the same, but both the extinction and the red shift are more pronounced for the former. Hence, this makes [Fe(miHpbmi)2](PF6)4 a promising pH-insensitive analogue of [Fe(cpbmi)2](PF6)2. Finally, the excited-state dynamics of the title compound [Fe(miHpbmi)2](PF6)4 was investigated in solvents with different viscosities, however, showing very little dependency of the depopulation of the excited states on the properties of the solvent used.

AB - We here report the synthesis of the homoleptic iron(II) N-heterocyclic carbene (NHC) complex [Fe(miHpbmi)2](PF6)4 (miHpbmi = 4-((3-methyl-1H-imidazolium-1-yl)pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) and its electrochemical and photophysical properties. The introduction of the π-electron-withdrawing 3-methyl-1H-imidazol-3-ium-1-yl group into the NHC ligand framework resulted in stabilization of the metal-to-ligand charge transfer (MLCT) state and destabilization of the metal-centered (MC) states. This resulted in an improved excited-state lifetime of 16 ps compared to the 9 ps for the unsubstituted parent compound [Fe(pbmi)2](PF6)2 (pbmi = (pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) as well as a stronger MLCT absorption band extending more toward the red spectral region. However, compared to the carboxylic acid derivative [Fe(cpbmi)2](PF6)2 (cpbmi = 1,1′-(4-carboxypyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)), the excited-state lifetime of [Fe(miHpbmi)2](PF6)4 is the same, but both the extinction and the red shift are more pronounced for the former. Hence, this makes [Fe(miHpbmi)2](PF6)4 a promising pH-insensitive analogue of [Fe(cpbmi)2](PF6)2. Finally, the excited-state dynamics of the title compound [Fe(miHpbmi)2](PF6)4 was investigated in solvents with different viscosities, however, showing very little dependency of the depopulation of the excited states on the properties of the solvent used.

UR - https://www.scopus.com/pages/publications/85184825680

U2 - 10.1021/acs.inorgchem.3c02890

DO - 10.1021/acs.inorgchem.3c02890

M3 - Article

C2 - 38301278

AN - SCOPUS:85184825680

SN - 0020-1669

VL - 63

SP - 2909

EP - 2918

JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 6

ER -