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2. Correction to “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”

Author

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

Published
2024
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3. 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

Author

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

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 pi-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.

Published
2024
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4. 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

Author

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

Published
2024
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7. Photophysics and Photochemistry of Iron Carbene Complexes

Author

Lindh, Linnea and Lindh, Linnea

Abstract

Nature captures sunlight via light-absorbing molecules.Similarly, photosensitisers are used in applications of solar cells and artificial photosynthesis to absorb sunlight, and transfer the excited electron.Successful photosensitisers have in the past been based on a Ru polipyridyl scaffold, despite Ru being one of the scarcest elements in Earth's crust.This thesis work aims to replace Ru polipyridyl complexes by Fe carbene complexes, that by clever ligand design have approached suitable photosensitiser properties.One crucial property that is not yet competitive for Fe carbene photosensitisers is how long they stay in the excited state, i.e. their lifetime. This is controlled by the deactivation pathways of the molecule, dictated by the excited state landscape. Several Fe carbene photosensitisers were in this thesis investigated by spectroscopic and computational methods, to understand their deactivation pathways. For the Fe(II) carbene complexes investigated, small changes in the ligand structure influenced both what excited state (charge-transfer or metal-centred) that was mainly populated and the lifetime of the state.For the Fe(III) carbene complexes investigated, there was instead one dominating charge-transfer excited state that was rather unaffected by changes to the ligand. Furthermore, for the Fe(II) complexes metal-centred states played a large role in the deactivation pathway but for the Fe(III) complexes this was not the case.Also, one Co(III) carbene complex was investigated which displays remarkable long lifetime and emission from a metal-centred state.As a first step towards application, the electron-transfer properties of some of the photosensitisers were investigated.Fe(II) complexes with a push-pull design were able to transfer electrons to TiO2 in a solar cell configuration.The solar cell performance was however limited by an ultrafast recombination reaction, that brought a majority of the transferred electrons back to the photosensitiser.The Fe(I

Published
2023

9. Competing dynamics of intramolecular deactivation and bimolecular charge transfer processes in luminescent Fe(iii) N-heterocyclic carbene complexes

Author

Rosemann, Nils W., primary, Lindh, Linnea, additional, Bolaño Losada, Iria, additional, Kaufhold, Simon, additional, Prakash, Om, additional, Ilic, Aleksandra, additional, Schwarz, Jesper, additional, Wärnmark, Kenneth, additional, Chábera, Pavel, additional, Yartsev, Arkady, additional, and Persson, Petter, additional

Published
2023
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10. Photophysical Integrity of the Iron(III) Scorpionate Framework in Iron(III)–NHC Complexes with Long-Lived 2LMCT Excited States

Author

Prakash, Om, primary, Lindh, Linnea, additional, Kaul, Nidhi, additional, Rosemann, Nils W., additional, Losada, Iria Bolaño, additional, Johnson, Catherine, additional, Chábera, Pavel, additional, Ilic, Aleksandra, additional, Schwarz, Jesper, additional, Gupta, Arvind Kumar, additional, Uhlig, Jens, additional, Ericsson, Tore, additional, Häggström, Lennart, additional, Huang, Ping, additional, Bendix, Jesper, additional, Strand, Daniel, additional, Yartsev, Arkady, additional, Lomoth, Reiner, additional, Persson, Petter, additional, and Wärnmark, Kenneth, additional

Published
2022
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12. Att å ena sidan vårda, å andra sidan kontrollera - En sociologisk analys av personalens arbetsförhållanden på särskilda ungdomshem

Author

Backman, Victoria, Lindh, Linnea, Backman, Victoria, and Lindh, Linnea

Abstract

The starting point of this examination paper was the aspects of how norms, values, emotions and culture develop and affect the people working in the youth institutional settings like the Swedish National Board of Institutional care (Statens institutionsstyrelse, SiS). Our paper is based on qualitative semi structured interviews with the aim to gather new perspectives with a main focus on descriptive details like; what, how, and why some phenomena in these environments appear. The collected answers have been analyzed through an abductive approach, where we from a theoretical point of view aim to understand our respondent’s answers and why they answer like they do and what perspective that their conception of the world comes from. To guide us through this abductive approach we have used Goffman's perspective on Total institutions and Hochschilds perspective on Emotional labor. Moreover, this study seeks to understand the peculiarities and difficulties of the workplace and how staff working at these secure units experience the environment. We present this through five different themes that we found stood out the most during our interviews. First, we have the complexity between on the one side delivering care and on the other side controlling the placed youths. Thereafter we describe how SiS is an emotional environment. We also address the importance of working with good and competent colleagues that you can share your experiences with, and what consequences lack of competence can entail. And last but not least, how SiS in some parts consists of work-related misconducts that lead to a destructive work environment.

Published
2022

13. Photophysical Integrity of the Iron(III) Scorpionate Framework in Iron(III)-NHC Complexes with Long-Lived 2LMCT Excited States

Author

Prakash, Om, Lindh, Linnea, Kaul, Nidhi, Rosemann, Nils W., Losada, Iria Bolaño, Johnson, Catherine, Chábera, Pavel, Ilic, Aleksandra, Schwarz, Jesper, Gupta, Arvind Kumar, Uhlig, Jens, Ericsson, Tore, Häggström, Lennart, Huang, Ping, Bendix, Jesper, Strand, Daniel, Yartsev, Arkady, Lomoth, Reiner, Persson, Petter, Wärnmark, Kenneth, Prakash, Om, Lindh, Linnea, Kaul, Nidhi, Rosemann, Nils W., Losada, Iria Bolaño, Johnson, Catherine, Chábera, Pavel, Ilic, Aleksandra, Schwarz, Jesper, Gupta, Arvind Kumar, Uhlig, Jens, Ericsson, Tore, Häggström, Lennart, Huang, Ping, Bendix, Jesper, Strand, Daniel, Yartsev, Arkady, Lomoth, Reiner, Persson, Petter, and Wärnmark, Kenneth

Abstract

Fe(III) complexes with N-heterocyclic carbene (NHC) ligands belong to the rare examples of Earth-abundant transition metal complexes with long-lived luminescent charge-transfer excited states that enable applications as photosensitizers for charge separation reactions. We report three new hexa-NHC complexes of this class: [Fe(brphtmeimb)2]PF6 (brphtmeimb = [(4-bromophenyl)tris(3-methylimidazol-2-ylidene)borate]–, [Fe(meophtmeimb)2]PF6 (meophtmeimb = [(4-methoxyphenyl)tris(3-methylimidazol-2-ylidene)borate]–, and [Fe(coohphtmeimb)2]PF6 (coohphtmeimb = [(4-carboxyphenyl)tris(3-methylimidazol-2-ylidene)borate]–. These were derived from the parent complex [Fe(phtmeimb)2]PF6 (phtmeimb = [phenyltris(3-methylimidazol-2-ylidene)borate]– by modification with electron-withdrawing and electron-donating substituents, respectively, at the 4-phenyl position of the ligand framework. All three Fe(III) hexa-NHC complexes were characterized by NMR spectroscopy, high-resolution mass spectroscopy, elemental analysis, single crystal X-ray diffraction analysis, electrochemistry, Mößbauer spectroscopy, electronic spectroscopy, magnetic susceptibility measurements, and quantum chemical calculations. Their ligand-to-metal charge-transfer (2LMCT) excited states feature nanosecond lifetimes (1.6–1.7 ns) and sizable emission quantum yields (1.7–1.9%) through spin-allowed transition to the doublet ground state (2GS), completely in line with the parent complex [Fe(phtmeimb)2]PF6 (2.0 ns and 2.1%). The integrity of the favorable excited state characteristics upon substitution of the ligand framework demonstrates the robustness of the scorpionate motif that tolerates modifications in the 4-phenyl position for applications such as the attachment in molecular or hybrid assemblies.

Published
2022
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14. De unga gör helt rätt när de stämmer staten

Author

Moberg, Christina, Corvellec, Hervé, Lindroth, Anders, Isacson, Manuela, Nilsson, Linn, Nicholas, Kimberly, Björck, Svante, Lee, Jayeon, Gerle, Elisabeth, Caretta, Martina Angela, Galafassi, Diego, Hornborg, Alf, Ullström, Sara, Olsson, Lennart, Jerneck, Anne, Koch, Max, Roldin, Pontus, Sunesson, Sune, Kritzberg, Emma, Hammarlund, Dan, Wamsler, Christine, Krause, Torsten, Tyler, Torbjörn, Malmqvist, Ebba, Osberg, Gustav, Reindl, Katharina, Lefstad, Lina, Björnerås, Caroline, De Rosa, Salvatore Paolo, Koglin, Till, Bjermo, Tim, Isaxon, Christina, Isgren, Ellinor, Richter, Jessika Luth, Johansson, Erik, Jarenmark, Martin, Friberg, Johan, Wårlind, David, Jack, Tullia, Holmberg, Karl, Bergman Rosamond, Annika, Vogl, Valentin, Olofsson, Johanna, Magalhaes Teixeira, Barbara, Palm, Ellen, Algers, Jonas, Gjerløv Fiig, Natasha Amalie, Ramasar, Vasna, Lopez de Lapuente Portilla, Aitzkoa, Khan, Jamil, Palm, Jenny, Haraldsson, Joakim, Barmark, Mimmi, Stroh, Emilie, Filipsson, Helena L., Sernhed, Kerstin, Wengelin, Mattias, Bauer, Fredric, Persson, Tomas, Brandstedt, Eric, Mccormick, Kes, Carton, Wim, Stattin, Simon, Gren, Nina, Nikoleris, Alexandra, Wickenberg, Per, Garson, Katja, Zackari, Karin, Droste, Nils, Gunnemyr, Mattias, Hansson, L-A, Lantz, Emelie, Sternudd, Catharina, Ekström, Hanna, Jonsson, Anna, Dahlner, Anders, Sörgärde, Nadja, Alcer, David, Rennstam, Jens, Gabrielsson, Sara, Ottosson, Mikael, Eklundh, Lars, Andersson, Magnus, Schwarz, Jesper, Tilsted, Joachim Peter, Kiss, Bernadett, Halldenius, Lena, Knaggård, Åsa, Persson, Andreas, Kolte, Olof, Lindh, Linnea, Chertkovskaya, Ekaterina, Hultman, Mats, Thånell, Karina, Manners, Ian, Kristensson, Adam, Nieradzik, Lars, Lundberg, Anna, Cronberg, Nils, Rydhe, Eskil, Klemmensen, Robert, Herlitz, Anders, Perrey, Hanno, Pugh, Rhiannon, Björkdahl, Annika, Lundberg, Tove, Mårsell, Erik, Samper, Juan Antonio, Sandström, Ida, Ståhl, Lars-Henrik, Prentice, Honor C, Carlson, Stefan, Andréasson, Per-Gunnar, Liljas, Anders, Zalar, Alva, Fridlund, Patrik, Sporre, Moa, Löndahl, Jakob, Björling, Fiona, Kalm, Sara, Barinaga, Ester, Mulinari, Shai, Mulinari, Diana, Lindqvist, Anna, Vestberg, Susanna, Claréus, Benjamin, Boije af Gennäs Erre, Ellen, Viborg, Gardar, Nilsson, Kjell, Tagesson, Alexander, Brogaard, Sara, Davidson, Per, Harrie, Lars, Elvén Eriksson, Helena, Hickmann, Thomas, Fauré, Eléonore, Wullenkord, Marlis, Giertz, Anders, Germundsson, Tomas, Nilsson, Frida L, Montesino, Norma, Sjöström, Cheryl, Pettersson, Gert, Alkan Olsson, Johanna, Cardeña, Etzel, Mottaghi, Misagh, Sundkvist, Emma, Tellhed, Una, Mundaca, Luis, Lindström, Lena, Sörensen, Johanna, Mobini, Shifteh, Hederström, Veronica, Becker, Per, Klysing, Amanda, Mattisson, Kristoffer, Svensson, Jakob, Svenbro, Maja, Hanson, Helena, Oudin, Anna, Flanagan, Erin, Takman, Maria, Ritthammer, Sofia, Månefjord, Josefin, Sonander, Anna, Nafstad, Ida, Sjöström, Peter, Dietler, Dominik, Hassel, Henrik, Käll, Jannice, Akselsson, Roland, Bohgard, Mats, Ingvarson, Johan, Steen, Karin, Cedergren, Alexander, Nordbeck, Patric, Davidsson, Simon, Angelöw, Amanda, Ahrné, Siv, Lantto, Reid, Psouni, Elia, Nicoson, Christie, Jeppsson, Bengt, Côte, Muriel, Alvesson, Mats, Leo Sandberg, Elinn, Möllergren, Glenn, Karlsson, Daniel, Bäckman, Johan, Angelopulos Baroutsis, Nicoletta, Alenius Wallin, Linn, Lundell, Elin, Stedt, Johanna, Forsberg, Klara, Gnewski, Martina, Larsson, Marie, Grillitsch, Markus, Takedomi Karlsson, Mariko, Månefjord, Hampus, Giese, Laura, Betsholtz, Alexander, Wrisberg, Anton, Söderlind, Marie, Vilhelmsson, Andreas, Stedt, Kristoffer, al., et, Moberg, Christina, Corvellec, Hervé, Lindroth, Anders, Isacson, Manuela, Nilsson, Linn, Nicholas, Kimberly, Björck, Svante, Lee, Jayeon, Gerle, Elisabeth, Caretta, Martina Angela, Galafassi, Diego, Hornborg, Alf, Ullström, Sara, Olsson, Lennart, Jerneck, Anne, Koch, Max, Roldin, Pontus, Sunesson, Sune, Kritzberg, Emma, Hammarlund, Dan, Wamsler, Christine, Krause, Torsten, Tyler, Torbjörn, Malmqvist, Ebba, Osberg, Gustav, Reindl, Katharina, Lefstad, Lina, Björnerås, Caroline, De Rosa, Salvatore Paolo, Koglin, Till, Bjermo, Tim, Isaxon, Christina, Isgren, Ellinor, Richter, Jessika Luth, Johansson, Erik, Jarenmark, Martin, Friberg, Johan, Wårlind, David, Jack, Tullia, Holmberg, Karl, Bergman Rosamond, Annika, Vogl, Valentin, Olofsson, Johanna, Magalhaes Teixeira, Barbara, Palm, Ellen, Algers, Jonas, Gjerløv Fiig, Natasha Amalie, Ramasar, Vasna, Lopez de Lapuente Portilla, Aitzkoa, Khan, Jamil, Palm, Jenny, Haraldsson, Joakim, Barmark, Mimmi, Stroh, Emilie, Filipsson, Helena L., Sernhed, Kerstin, Wengelin, Mattias, Bauer, Fredric, Persson, Tomas, Brandstedt, Eric, Mccormick, Kes, Carton, Wim, Stattin, Simon, Gren, Nina, Nikoleris, Alexandra, Wickenberg, Per, Garson, Katja, Zackari, Karin, Droste, Nils, Gunnemyr, Mattias, Hansson, L-A, Lantz, Emelie, Sternudd, Catharina, Ekström, Hanna, Jonsson, Anna, Dahlner, Anders, Sörgärde, Nadja, Alcer, David, Rennstam, Jens, Gabrielsson, Sara, Ottosson, Mikael, Eklundh, Lars, Andersson, Magnus, Schwarz, Jesper, Tilsted, Joachim Peter, Kiss, Bernadett, Halldenius, Lena, Knaggård, Åsa, Persson, Andreas, Kolte, Olof, Lindh, Linnea, Chertkovskaya, Ekaterina, Hultman, Mats, Thånell, Karina, Manners, Ian, Kristensson, Adam, Nieradzik, Lars, Lundberg, Anna, Cronberg, Nils, Rydhe, Eskil, Klemmensen, Robert, Herlitz, Anders, Perrey, Hanno, Pugh, Rhiannon, Björkdahl, Annika, Lundberg, Tove, Mårsell, Erik, Samper, Juan Antonio, Sandström, Ida, Ståhl, Lars-Henrik, Prentice, Honor C, Carlson, Stefan, Andréasson, Per-Gunnar, Liljas, Anders, Zalar, Alva, Fridlund, Patrik, Sporre, Moa, Löndahl, Jakob, Björling, Fiona, Kalm, Sara, Barinaga, Ester, Mulinari, Shai, Mulinari, Diana, Lindqvist, Anna, Vestberg, Susanna, Claréus, Benjamin, Boije af Gennäs Erre, Ellen, Viborg, Gardar, Nilsson, Kjell, Tagesson, Alexander, Brogaard, Sara, Davidson, Per, Harrie, Lars, Elvén Eriksson, Helena, Hickmann, Thomas, Fauré, Eléonore, Wullenkord, Marlis, Giertz, Anders, Germundsson, Tomas, Nilsson, Frida L, Montesino, Norma, Sjöström, Cheryl, Pettersson, Gert, Alkan Olsson, Johanna, Cardeña, Etzel, Mottaghi, Misagh, Sundkvist, Emma, Tellhed, Una, Mundaca, Luis, Lindström, Lena, Sörensen, Johanna, Mobini, Shifteh, Hederström, Veronica, Becker, Per, Klysing, Amanda, Mattisson, Kristoffer, Svensson, Jakob, Svenbro, Maja, Hanson, Helena, Oudin, Anna, Flanagan, Erin, Takman, Maria, Ritthammer, Sofia, Månefjord, Josefin, Sonander, Anna, Nafstad, Ida, Sjöström, Peter, Dietler, Dominik, Hassel, Henrik, Käll, Jannice, Akselsson, Roland, Bohgard, Mats, Ingvarson, Johan, Steen, Karin, Cedergren, Alexander, Nordbeck, Patric, Davidsson, Simon, Angelöw, Amanda, Ahrné, Siv, Lantto, Reid, Psouni, Elia, Nicoson, Christie, Jeppsson, Bengt, Côte, Muriel, Alvesson, Mats, Leo Sandberg, Elinn, Möllergren, Glenn, Karlsson, Daniel, Bäckman, Johan, Angelopulos Baroutsis, Nicoletta, Alenius Wallin, Linn, Lundell, Elin, Stedt, Johanna, Forsberg, Klara, Gnewski, Martina, Larsson, Marie, Grillitsch, Markus, Takedomi Karlsson, Mariko, Månefjord, Hampus, Giese, Laura, Betsholtz, Alexander, Wrisberg, Anton, Söderlind, Marie, Vilhelmsson, Andreas, Stedt, Kristoffer, and al., et

Abstract

1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav

Published
2022

15. Photophysical Integrity of the Iron(III) Scorpionate Framework in Iron(III)–NHC Complexes with Long-Lived 2LMCT Excited States.

Author

Prakash, Om, Lindh, Linnea, Kaul, Nidhi, Rosemann, Nils W., Losada, Iria Bolaño, Johnson, Catherine, Chábera, Pavel, Ilic, Aleksandra, Schwarz, Jesper, Gupta, Arvind Kumar, Uhlig, Jens, Ericsson, Tore, Häggström, Lennart, Huang, Ping, Bendix, Jesper, Strand, Daniel, Yartsev, Arkady, Lomoth, Reiner, Persson, Petter, and Wärnmark, Kenneth

Published
2022
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16. Dye-sensitized solar cells based on Fe N-heterocyclic carbene photosensitizers with improved rod-like push-pull functionality.

Author

Lindh, Linnea, Gordivska, Olga, Persson, Samuel, Michaels, Hannes, Hao Fan, Chábera, Pavel, Rosemann, Nils W., Gupta, Arvind Kumar, Benesperi, Iacopo, Uhlig, Jens, Prakash, Om, Sheibani, Esmaeil, Kjaer, Kasper S., Boschloo, Gerrit, Yartsev, Arkady, Freitag, Marina, Lomoth, Reiner, Persson, Petter, and Wärnmark, Kenneth

Published
2021
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18. 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.

Author

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, and Wärnmark K

Abstract

We here report the synthesis of the homoleptic iron(II) N -heterocyclic carbene (NHC) complex [Fe(miHpbmi) 2 ](PF 6 ) 4 (miHpbmi = 4-((3-methyl-1 H -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-1 H -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 ](PF 6 ) 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 ](PF 6 ) 2 (cpbmi = 1,1'-(4-carboxypyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)), the excited-state lifetime of [Fe(miHpbmi) 2 ](PF 6 ) 4 is the same, but both the extinction and the red shift are more pronounced for the former. Hence, this makes [Fe(miHpbmi) 2 ](PF 6 ) 4 a promising pH-insensitive analogue of [Fe(cpbmi) 2 ](PF 6 ) 2 . Finally, the excited-state dynamics of the title compound [Fe(miHpbmi) 2 ](PF 6 ) 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.

Published
2024
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19. Photophysical Integrity of the Iron(III) Scorpionate Framework in Iron(III)-NHC Complexes with Long-Lived 2 LMCT Excited States.

Author

Prakash O, Lindh L, Kaul N, Rosemann NW, Losada IB, Johnson C, Chábera P, Ilic A, Schwarz J, Gupta AK, Uhlig J, Ericsson T, Häggström L, Huang P, Bendix J, Strand D, Yartsev A, Lomoth R, Persson P, and Wärnmark K

Abstract

Fe(III) complexes with N -heterocyclic carbene (NHC) ligands belong to the rare examples of Earth-abundant transition metal complexes with long-lived luminescent charge-transfer excited states that enable applications as photosensitizers for charge separation reactions. We report three new hexa -NHC complexes of this class: [Fe(brphtmeimb) 2 ]PF 6 (brphtmeimb = [(4-bromophenyl)tris(3-methylimidazol-2-ylidene)borate] - , [Fe(meophtmeimb) 2 ]PF 6 (meophtmeimb = [(4-methoxyphenyl)tris(3-methylimidazol-2-ylidene)borate] - , and [Fe(coohphtmeimb) 2 ]PF 6 (coohphtmeimb = [(4-carboxyphenyl)tris(3-methylimidazol-2-ylidene)borate] - . These were derived from the parent complex [Fe(phtmeimb) 2 ]PF 6 (phtmeimb = [phenyltris(3-methylimidazol-2-ylidene)borate] - by modification with electron-withdrawing and electron-donating substituents, respectively, at the 4-phenyl position of the ligand framework. All three Fe(III) hexa -NHC complexes were characterized by NMR spectroscopy, high-resolution mass spectroscopy, elemental analysis, single crystal X-ray diffraction analysis, electrochemistry, Mößbauer spectroscopy, electronic spectroscopy, magnetic susceptibility measurements, and quantum chemical calculations. Their ligand-to-metal charge-transfer ( 2 LMCT) excited states feature nanosecond lifetimes (1.6-1.7 ns) and sizable emission quantum yields (1.7-1.9%) through spin-allowed transition to the doublet ground state ( 2 GS), completely in line with the parent complex [Fe(phtmeimb) 2 ]PF 6 (2.0 ns and 2.1%). The integrity of the favorable excited state characteristics upon substitution of the ligand framework demonstrates the robustness of the scorpionate motif that tolerates modifications in the 4-phenyl position for applications such as the attachment in molecular or hybrid assemblies.

Published
2022
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