Heteroleptic iron(II) complexes of chiral 2,6-bis(oxazolin-2-yl)-pyridine (PyBox) and 2,6-bis(thiazolin-2-yl)pyridine ligands – the interplay of two different ligands on the metal ion spin sate.
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| Title: | Heteroleptic iron(II) complexes of chiral 2,6-bis(oxazolin-2-yl)-pyridine (PyBox) and 2,6-bis(thiazolin-2-yl)pyridine ligands – the interplay of two different ligands on the metal ion spin sate. |
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| Authors: | Shahid, Namrah1 (AUTHOR), Burrows, Kay E.1 (AUTHOR), Pask, Christopher M.1 (AUTHOR), Cespedes, Oscar2 (AUTHOR), Howard, Mark J.1 (AUTHOR), McGowan, Patrick C.1 (AUTHOR), Halcrow, Malcolm A.1 (AUTHOR) m.a.halcrow@leeds.ac.uk |
| Source: | Dalton Transactions: An International Journal of Inorganic Chemistry. 3/21/2022, Vol. 51 Issue 11, p4262-4274. 13p. |
| Subjects: | Metal-spinning, Spin crossover, Ligands (Chemistry), Iron, Pyridine, Metal ions, Solid solutions |
| Abstract: | Complexation of Fe[ClO4]2·6H2O by 1 equiv. 2,6-bis((4S)-4-phenyl-4,5-dihydrooxazol-2-yl)pyridine ((S)-L1Ph) and 2,6-bis((4R)-4-phenyl-4,5-dihydrothiazol-2-yl)pyridine ((R)-L2Ph) cleanly affords [Fe((S)-L1Ph)((R)-L2Ph)][ClO4]2; [Fe((R)-L1iPr)((S)-L2iPr)][ClO4]2 (L1iPr = 2,6-bis(4-isopropyl-4,5-dihydrooxazol-2-yl)pyridine; L2iPr = 2,6-bis(4-isopropyl-4,5-dihydrothiazol-2-yl)pyridine) was prepared by a similar route. The compounds exhibit thermal spin-crossover in solution, at temperatures midway between the corresponding [Fe((R)-L1R)((S)-L1R)][ClO4]2 and [Fe((R)-L2R)((S)-L2R)][ClO4]2 (R = Ph or iPr) species. The spin states of [Fe(LR)(bimpy)][ClO4]2 and [Fe(LR)(bpp)][ClO4]2 (LR = L1R or L2R; bimpy = 2,6-bis(1H-benzimidazol-2-yl)pyridine; bpp = 2,6-di(pyrazol-1-yl)pyridine) are also reported, with most examples exhibiting gradual spin-crossover in solution and the solid state. Although some products undergo partial ligand exchange in solution by 1H NMR, their solution T½ values appear unaffected by this and correlate well with their spin state energies from gas phase DFT calculations. The high-spin state of [Fe(L2R)(bpp)]2+ is more stabilised than expected, compared to the other [Fe(LR)L]2+ complexes studied (L = bimpy, bpp or terpy). That is explained by an interplay between the relative σ-basicities and π-acidities of the two ligands in each molecule. The steric influence of their phenyl or isopropyl 'R' substituents stabilises the heteroleptic complexes by up to 5 kcal mol−1, compared to analogues lacking these groups. [ABSTRACT FROM AUTHOR] |
| Copyright of Dalton Transactions: An International Journal of Inorganic Chemistry is the property of Royal Society of Chemistry and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Items | – Name: Title Label: Title Group: Ti Data: Heteroleptic iron(II) complexes of chiral 2,6-bis(oxazolin-2-yl)-pyridine (PyBox) and 2,6-bis(thiazolin-2-yl)pyridine ligands – the interplay of two different ligands on the metal ion spin sate. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Shahid%2C+Namrah%22">Shahid, Namrah</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Burrows%2C+Kay+E%2E%22">Burrows, Kay E.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Pask%2C+Christopher+M%2E%22">Pask, Christopher M.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Cespedes%2C+Oscar%22">Cespedes, Oscar</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Howard%2C+Mark+J%2E%22">Howard, Mark J.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22McGowan%2C+Patrick+C%2E%22">McGowan, Patrick C.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Halcrow%2C+Malcolm+A%2E%22">Halcrow, Malcolm A.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> m.a.halcrow@leeds.ac.uk</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Dalton+Transactions%3A+An+International+Journal+of+Inorganic+Chemistry%22">Dalton Transactions: An International Journal of Inorganic Chemistry</searchLink>. 3/21/2022, Vol. 51 Issue 11, p4262-4274. 13p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Metal-spinning%22">Metal-spinning</searchLink><br /><searchLink fieldCode="DE" term="%22Spin+crossover%22">Spin crossover</searchLink><br /><searchLink fieldCode="DE" term="%22Ligands+%28Chemistry%29%22">Ligands (Chemistry)</searchLink><br /><searchLink fieldCode="DE" term="%22Iron%22">Iron</searchLink><br /><searchLink fieldCode="DE" term="%22Pyridine%22">Pyridine</searchLink><br /><searchLink fieldCode="DE" term="%22Metal+ions%22">Metal ions</searchLink><br /><searchLink fieldCode="DE" term="%22Solid+solutions%22">Solid solutions</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Complexation of Fe[ClO4]2·6H2O by 1 equiv. 2,6-bis((4S)-4-phenyl-4,5-dihydrooxazol-2-yl)pyridine ((S)-L1Ph) and 2,6-bis((4R)-4-phenyl-4,5-dihydrothiazol-2-yl)pyridine ((R)-L2Ph) cleanly affords [Fe((S)-L1Ph)((R)-L2Ph)][ClO4]2; [Fe((R)-L1iPr)((S)-L2iPr)][ClO4]2 (L1iPr = 2,6-bis(4-isopropyl-4,5-dihydrooxazol-2-yl)pyridine; L2iPr = 2,6-bis(4-isopropyl-4,5-dihydrothiazol-2-yl)pyridine) was prepared by a similar route. The compounds exhibit thermal spin-crossover in solution, at temperatures midway between the corresponding [Fe((R)-L1R)((S)-L1R)][ClO4]2 and [Fe((R)-L2R)((S)-L2R)][ClO4]2 (R = Ph or iPr) species. The spin states of [Fe(LR)(bimpy)][ClO4]2 and [Fe(LR)(bpp)][ClO4]2 (LR = L1R or L2R; bimpy = 2,6-bis(1H-benzimidazol-2-yl)pyridine; bpp = 2,6-di(pyrazol-1-yl)pyridine) are also reported, with most examples exhibiting gradual spin-crossover in solution and the solid state. Although some products undergo partial ligand exchange in solution by 1H NMR, their solution T½ values appear unaffected by this and correlate well with their spin state energies from gas phase DFT calculations. The high-spin state of [Fe(L2R)(bpp)]2+ is more stabilised than expected, compared to the other [Fe(LR)L]2+ complexes studied (L = bimpy, bpp or terpy). That is explained by an interplay between the relative σ-basicities and π-acidities of the two ligands in each molecule. The steric influence of their phenyl or isopropyl 'R' substituents stabilises the heteroleptic complexes by up to 5 kcal mol−1, compared to analogues lacking these groups. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Dalton Transactions: An International Journal of Inorganic Chemistry is the property of Royal Society of Chemistry and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1039/d2dt00393g Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 4262 Subjects: – SubjectFull: Metal-spinning Type: general – SubjectFull: Spin crossover Type: general – SubjectFull: Ligands (Chemistry) Type: general – SubjectFull: Iron Type: general – SubjectFull: Pyridine Type: general – SubjectFull: Metal ions Type: general – SubjectFull: Solid solutions Type: general Titles: – TitleFull: Heteroleptic iron(II) complexes of chiral 2,6-bis(oxazolin-2-yl)-pyridine (PyBox) and 2,6-bis(thiazolin-2-yl)pyridine ligands – the interplay of two different ligands on the metal ion spin sate. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Shahid, Namrah – PersonEntity: Name: NameFull: Burrows, Kay E. – PersonEntity: Name: NameFull: Pask, Christopher M. – PersonEntity: Name: NameFull: Cespedes, Oscar – PersonEntity: Name: NameFull: Howard, Mark J. – PersonEntity: Name: NameFull: McGowan, Patrick C. – PersonEntity: Name: NameFull: Halcrow, Malcolm A. IsPartOfRelationships: – BibEntity: Dates: – D: 21 M: 03 Text: 3/21/2022 Type: published Y: 2022 Identifiers: – Type: issn-print Value: 14779226 Numbering: – Type: volume Value: 51 – Type: issue Value: 11 Titles: – TitleFull: Dalton Transactions: An International Journal of Inorganic Chemistry Type: main |
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