Piperazine-based N4-type 16-membered macroheterocycles and their nickel(II) complexes
Square-planar diamagnetic nickel(II) complexes 5a and 5b containing 16-membered diamino-diimino ligands were prepared from the corresponding open-chain complexes 2a and 2b via condensation with o-phthalic dialdehyde in methanol. The solid-state structure of the starting complex 2b revealed the cisoi...
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ISUCT Publishing
2017
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| author | Vatsadze, Sergey Z. Krut’ko, Dmitry P. Blake, Alexander J. Mountford, Philip |
| author_facet | Vatsadze, Sergey Z. Krut’ko, Dmitry P. Blake, Alexander J. Mountford, Philip |
| author_sort | Vatsadze, Sergey Z. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Square-planar diamagnetic nickel(II) complexes 5a and 5b containing 16-membered diamino-diimino ligands were prepared from the corresponding open-chain complexes 2a and 2b via condensation with o-phthalic dialdehyde in methanol. The solid-state structure of the starting complex 2b revealed the cisoid conformation of aryl groups compared to the transoid one found in the case of 2a. At the same time, the cisoid conformation is not retained in acetone solution: rather, the tert-Bu-substituted complex 2b was fully transformed into the trans form whereas its analogue 2aexhibits both cis and transforms in acetone solution. The cisoid conformation was also observed for the cyclic structures 5a and 5b by X-ray analysis and VT NMR experiments. The borohydride reduction of 5a with subsequent cyanide-assisted removal of nickel led to a new 16-membered tetraazamacrocycle 6. Its X-ray structure showed a cisoid conformation supported by two intramolecular hydrogen bonds that was also sustained in solution. VT NMR experiments revealed the degenerative interconvertion of a macrocycle with activation energy ca. 41.9±0.8 kJ/mol. |
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| id | nottingham-43476 |
| institution | University of Nottingham Malaysia Campus |
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| last_indexed | 2025-11-14T19:52:06Z |
| publishDate | 2017 |
| publisher | ISUCT Publishing |
| recordtype | eprints |
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| spelling | nottingham-434762020-05-04T18:49:06Z https://eprints.nottingham.ac.uk/43476/ Piperazine-based N4-type 16-membered macroheterocycles and their nickel(II) complexes Vatsadze, Sergey Z. Krut’ko, Dmitry P. Blake, Alexander J. Mountford, Philip Square-planar diamagnetic nickel(II) complexes 5a and 5b containing 16-membered diamino-diimino ligands were prepared from the corresponding open-chain complexes 2a and 2b via condensation with o-phthalic dialdehyde in methanol. The solid-state structure of the starting complex 2b revealed the cisoid conformation of aryl groups compared to the transoid one found in the case of 2a. At the same time, the cisoid conformation is not retained in acetone solution: rather, the tert-Bu-substituted complex 2b was fully transformed into the trans form whereas its analogue 2aexhibits both cis and transforms in acetone solution. The cisoid conformation was also observed for the cyclic structures 5a and 5b by X-ray analysis and VT NMR experiments. The borohydride reduction of 5a with subsequent cyanide-assisted removal of nickel led to a new 16-membered tetraazamacrocycle 6. Its X-ray structure showed a cisoid conformation supported by two intramolecular hydrogen bonds that was also sustained in solution. VT NMR experiments revealed the degenerative interconvertion of a macrocycle with activation energy ca. 41.9±0.8 kJ/mol. ISUCT Publishing 2017-06-07 Article PeerReviewed Vatsadze, Sergey Z., Krut’ko, Dmitry P., Blake, Alexander J. and Mountford, Philip (2017) Piperazine-based N4-type 16-membered macroheterocycles and their nickel(II) complexes. Macroheterocycles, 10 (1). pp. 98-109. ISSN 1998-9539 16-Membered macroheterocycles Diamagnetic nickel(II) complexes Positron emission tomography X-ray diffraction NMR spectroscopy Conformational analysis https://macroheterocycles.isuct.ru/en/mhc161179v doi:10.6060/mhc161179v doi:10.6060/mhc161179v |
| spellingShingle | 16-Membered macroheterocycles Diamagnetic nickel(II) complexes Positron emission tomography X-ray diffraction NMR spectroscopy Conformational analysis Vatsadze, Sergey Z. Krut’ko, Dmitry P. Blake, Alexander J. Mountford, Philip Piperazine-based N4-type 16-membered macroheterocycles and their nickel(II) complexes |
| title | Piperazine-based N4-type 16-membered macroheterocycles
and their nickel(II) complexes |
| title_full | Piperazine-based N4-type 16-membered macroheterocycles
and their nickel(II) complexes |
| title_fullStr | Piperazine-based N4-type 16-membered macroheterocycles
and their nickel(II) complexes |
| title_full_unstemmed | Piperazine-based N4-type 16-membered macroheterocycles
and their nickel(II) complexes |
| title_short | Piperazine-based N4-type 16-membered macroheterocycles
and their nickel(II) complexes |
| title_sort | piperazine-based n4-type 16-membered macroheterocycles
and their nickel(ii) complexes |
| topic | 16-Membered macroheterocycles Diamagnetic nickel(II) complexes Positron emission tomography X-ray diffraction NMR spectroscopy Conformational analysis |
| url | https://eprints.nottingham.ac.uk/43476/ https://eprints.nottingham.ac.uk/43476/ https://eprints.nottingham.ac.uk/43476/ |