The energy gap law for NIR-phosphorescent Cr(<scp>iii</scp>) complexes

Yang, Cheng; yang, qingqing; He, Jiang; Zou, Wenjie; Liao, Keyu; Chang, Xiaoyong; Zou, Chao; Lu, Wei

doi:10.1039/d2dt02872g

Cited by 19 publications

(27 citation statements)

References 33 publications

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“…The energies of many MC states are however not merely a function of the ligand field parameter 10 Dq, but rather depend on the ratio of 10 Dq and B, where B is the Racah parameter characterizing the metal−ligand bond covalence. This aspect is now receiving increased attention in the design of photoactive first-row transition metal complexes, 117 even though the nature of bonding in this compound class is usually considered more ionic in comparison to the second or third row. 11,96 Amido πdonor ligands (Figure 6b/Table 5, entry 2) help reduce the repulsion between d-electrons owing to the nephelauxetic effect, 63,108 and the Racah B parameter can be lowered markedly (Figure 8b).…”

Section: ■ Lessons Learned and Future Challengesmentioning

confidence: 99%

“…The energies of many MC states are however not merely a function of the ligand field parameter 10 Dq, but rather depend on the ratio of 10 Dq and B, where B is the Racah parameter characterizing the metal–ligand bond covalence. This aspect is now receiving increased attention in the design of photoactive first-row transition metal complexes, even though the nature of bonding in this compound class is usually considered more ionic in comparison to the second or third row. , Amido π-donor ligands (Figure b/Table , entry 2) help reduce the repulsion between d-electrons owing to the nephelauxetic effect, , and the Racah B parameter can be lowered markedly (Figure b) . With Fe II complexes, this has been useful to approach the HOMO inversion scenario predicted computationally, leading to so-called PALCT excited states, , which can be viewed as a form of charge transfer with a particularly strong contribution of electron density from the covalent Fe–N amido interaction.…”

Section: Lessons Learned and Future Challengesmentioning

confidence: 99%

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Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d⁶ Complexes with Cr⁰, Mn^I, Fe^II, and Co^III

2023

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Many coordination complexes and organometallic compounds with the 4d6 and 5d6 valence electron configurations have outstanding photophysical and photochemical properties, which stem from metal-to-ligand charge transfer (MLCT) excited states. This substance class makes extensive use of the most precious and least abundant metal elements, and consequently there has been a long-standing interest in first-row transition metal compounds with photoactive MLCT states. Semiprecious copper(I) with its completely filled 3d subshell is a relatively straightforward and well explored case, but in 3d6 complexes the partially filled d-orbitals lead to energetically low-lying metal-centered (MC) states that can cause undesirably fast MLCT excited state deactivation. Herein, we discuss recent advances made with isoelectronic Cr0, MnI, FeII, and CoIII compounds, for which long-lived MLCT states have become accessible over the past five years. Furthermore, we discuss possible future developments in the search for new first-row transition metal complexes with partially filled 3d subshells and photoactive MLCT states for next-generation applications in photophysics and photochemistry.

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Section: ■ Lessons Learned and Future Challengesmentioning

confidence: 99%

“…The energies of many MC states are however not merely a function of the ligand field parameter 10 Dq, but rather depend on the ratio of 10 Dq and B, where B is the Racah parameter characterizing the metal–ligand bond covalence. This aspect is now receiving increased attention in the design of photoactive first-row transition metal complexes, even though the nature of bonding in this compound class is usually considered more ionic in comparison to the second or third row. , Amido π-donor ligands (Figure b/Table , entry 2) help reduce the repulsion between d-electrons owing to the nephelauxetic effect, , and the Racah B parameter can be lowered markedly (Figure b) . With Fe II complexes, this has been useful to approach the HOMO inversion scenario predicted computationally, leading to so-called PALCT excited states, , which can be viewed as a form of charge transfer with a particularly strong contribution of electron density from the covalent Fe–N amido interaction.…”

Section: Lessons Learned and Future Challengesmentioning

confidence: 99%

Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d⁶ Complexes with Cr⁰, Mn^I, Fe^II, and Co^III

2023

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“…[a] For Cr III complexes, estimated based on the 2 G→ 4 F energy of the free Cr III ion [6d] . [b] Based on ref.…”

Section: Shifting the Ruby‐like Emission Of Criii Complexes From The ...mentioning

confidence: 99%

The Nephelauxetic Effect Becomes an Important Design Factor for Photoactive First‐Row Transition Metal Complexes

2023

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The expansion of d-orbitals as a result of metal-ligand bond covalence, the so-called nephelauxetic effect, is a well-established concept of coordination chemistry, yet its importance for the design of new photoactive complexes based on first-row transition metals is only beginning to be recognized. Until recently, much focus has been on optimizing the ligand field strength, coordination geometries, and molecular rigidity, but now it becomes evident that the nephelauxetic effect can be a game changer regarding the photophysical properties of 3d metal complexes in solution at room temperature. In Cr III and Mn IV complexes with the d 3 valence electron configuration, the nephelauxetic effect was exploited to shift the well-known ruby-like red luminescence to the near-infrared spectral region. In Fe II and Co III complexes with the low-spin d 6 electron configuration, charge-transfer excited states were stabilized with respect to detrimental metal-centered excited states, to improve their properties and to enhance their application potential. In isoelectronic (3d 6 ) isocyanide complexes of Cr 0 and Mn I , the nephelauxetic effect is likely at play as well, enabling luminescence and other favorable photoreactivity. This minireview illustrates the broad applicability of the nephelauxetic effect in tailoring the photophysical and photochemical properties of new coordination compounds made from abundant first-row transition metals.

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“…(b) [Cr(ppy) 3 ] (Hppy=2‐phenylpyridine) [6b] . (c) [Cr(bpi R1,R2 ) 2 ] + (R 1 =H, Et; R 2 =H, [6c] and R 1 =H, Me, OMe, NMe 2 ; R 2 =H, OMe [6d] ) (bpi=1,3‐bis(2′‐pyridylimino)‐isoindoline). (d) [Cr(bpo) 2 ] + (bpo=1,8‐(bisoxazolyl)carbazolide; R 1 =CH 3 , R 2 =H and R 1 =H, R 2 =CH 3 ) [16] .…”

Section: Shifting the Ruby‐like Emission Of Criii Complexes From The ...mentioning

confidence: 99%

The Nephelauxetic Effect Becomes an Important Design Factor for Photoactive First‐Row Transition Metal Complexes

2023

View full text Add to dashboard Cite

The expansion of d‐orbitals as a result of metal‐ligand bond covalence, the so‐called nephelauxetic effect, is a well‐established concept of coordination chemistry, yet its importance for the design of new photoactive complexes based on first‐row transition metals is only beginning to be recognized. Until recently, much focus has been on optimizing the ligand field strength, coordination geometries, and molecular rigidity, but now it becomes evident that the nephelauxetic effect can be a game changer regarding the photophysical properties of 3d metal complexes in solution at room temperature. In CrIII and MnIV complexes with the d3 valence electron configuration, the nephelauxetic effect was exploited to shift the well‐known ruby‐like red luminescence to the near‐infrared spectral region. In FeII and CoIII complexes with the low‐spin d6 electron configuration, charge‐transfer excited states were stabilized with respect to detrimental metal‐centered excited states, to improve their properties and to enhance their application potential. In isoelectronic (3d6) isocyanide complexes of Cr0 and MnI, the nephelauxetic effect is likely at play as well, enabling luminescence and other favorable photoreactivity. This minireview illustrates the broad applicability of the nephelauxetic effect in tailoring the photophysical and photochemical properties of new coordination compounds made from abundant first‐row transition metals.

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The energy gap law for NIR-phosphorescent Cr(iii) complexes

Abstract: A series of homoleptic Cr(III) complexes containing substituted anionic 1,3-bis(pyridin-2-ylimino)isoindolin-2-ide ligands are phosphorescent with max in the 777970 nm range in degassed fluid solutions. The energy gap law has been...

Cited by 19 publications

References 33 publications

Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d⁶ Complexes with Cr⁰, Mn^I, Fe^II, and Co^III

Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d⁶ Complexes with Cr⁰, Mn^I, Fe^II, and Co^III

The Nephelauxetic Effect Becomes an Important Design Factor for Photoactive First‐Row Transition Metal Complexes

The Nephelauxetic Effect Becomes an Important Design Factor for Photoactive First‐Row Transition Metal Complexes

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The energy gap law for NIR-phosphorescent Cr(iii) complexes

Abstract: A series of homoleptic Cr(III) complexes containing substituted anionic 1,3-bis(pyridin-2-ylimino)isoindolin-2-ide ligands are phosphorescent with max in the 777970 nm range in degassed fluid solutions. The energy gap law has been...

Cited by 19 publications

References 33 publications

Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d6 Complexes with Cr0, MnI, FeII, and CoIII

Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d6 Complexes with Cr0, MnI, FeII, and CoIII

The Nephelauxetic Effect Becomes an Important Design Factor for Photoactive First‐Row Transition Metal Complexes

The Nephelauxetic Effect Becomes an Important Design Factor for Photoactive First‐Row Transition Metal Complexes

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Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d⁶ Complexes with Cr⁰, Mn^I, Fe^II, and Co^III

Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d⁶ Complexes with Cr⁰, Mn^I, Fe^II, and Co^III