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Fish H, Hart S, Lamb KJ, North M, Quek SCZ, Whitwood AC, Woods B, Wu X. Structural analysis of five-coordinate aluminium(salen) complexes and its relationship to their catalytic activity. Dalton Trans 2021; 50:587-598. [PMID: 33367409 DOI: 10.1039/d0dt03598j] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crystal structure of [Al(tBu-salen)]2O·HCl shows major changes compared to that of [Al(tBu-salen)]2O. The additional proton is localized on the bridging oxygen atom, making the aluminium atoms more electron deficient. As a result, a water molecule coordinates to one of the aluminium atoms, which becomes six-coordinate. This pushes the salen ligand associated with the six-coordinate aluminium ion closer to the other salen ligand and results in the geometry around the five-coordinate aluminium atom becoming more trigonal bipyramidal. These results experimentally mirror the predications of DFT calculations on the interaction of [Al(tBu-salen)]2O and related complexes with carbon dioxide. Variable temperature NMR studies of protonated [Al(tBu-salen)]2O complexes revealed that the structures were dynamic and could be explained on the basis of an intramolecular rearrangement in which the non-salen substituent of a five-coordinate aluminium(tBu-salen) unit migrates from one face of a square based pyramidal structure to the other via the formation of structures with trigonal bipyramidal geometries. Protonated [Al(tBu-salen)]2O complexes were shown to have enhanced Lewis acidity relative to [Al(tBu-salen)]2O, coordinating to water, dioxane and 1,2-epoxyhexane. Coordinated epoxyhexane was activated towards ring-opening, to give various species which remained coordinated to the aluminium centers. The protonated [Al(tBu-salen)]2O complexes catalysed the synthesis of cyclic carbonates from epoxides and carbon dioxide both in the presence and absence of tetrabutylammonium bromide as a nucleophilic cocatalyst. The catalytic activity was principally determined by the nature of the nucleophilic species within the catalyst structure rather than by changes to the Lewis acidity of the metal centers.
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Affiliation(s)
- Heather Fish
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Sam Hart
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Katie J Lamb
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Michael North
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Sophie C Z Quek
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Adrian C Whitwood
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Barnaby Woods
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Xiao Wu
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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Akbari A, Ghateazadeh H, Takjoo R, Sadeghi-Nejad B, Mehrvar M, Mague JT. Synthesis & crystal structures of four new biochemical active Ni(II) complexes of thiosemicarbazone and isothiosemicarbazone-based ligands: In vitro antimicrobial study. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.12.109] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Cherkasov SA, Vikulova ES, Nikolaeva NS, Smolentsev AI, Morozova NB. Crystal structure and thermal properties of N,N′-(2,2-dimethylpropylene)-bis(acetylacetoneiminato)palladium(II). J STRUCT CHEM+ 2017. [DOI: 10.1134/s0022476617070277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Keesara S, Narendra Babu G, Pal S. An acetatopalladium(II) complex with 1‐benzyl‐
N
‐(3,5‐di‐
tert
‐butylsalicylidene)piperidin‐4‐amine: Synthesis, structure and catalytic applications in Suzuki–Miyaura coupling of arylboronic acids with hydroxyaryl halides. Appl Organomet Chem 2017. [DOI: 10.1002/aoc.3778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Srinivas Keesara
- School of ChemistryUniversity of Hyderabad Hyderabad 500046 India
| | - G. Narendra Babu
- School of ChemistryUniversity of Hyderabad Hyderabad 500046 India
| | - Samudranil Pal
- School of ChemistryUniversity of Hyderabad Hyderabad 500046 India
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Ahmadi M, Fasihizad A, Machura B, Kruszynski R, Barak T. New complexes of an unsymmetrical tetradentate isothiosemicarbazone: Structural, spectral and thermogravimetric investigations, and their nanoparticles synthesis. Polyhedron 2014. [DOI: 10.1016/j.poly.2014.05.075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Takjoo R, Centore R, Akbari A, Ahmadi M. Square planar nickel(II) complexes derived from 5-bromo-2-hydroxybenzaldehyde S-ethylisothiosemicarbazone: Preparation, characterization and structural studies. Polyhedron 2014. [DOI: 10.1016/j.poly.2014.04.055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bhattacharjee T, Kalita M, Chakravarty D, Barman P, Puranik VG. Synthesis, characterization, and crystal structure determination of palladacycles of para-substituted 2-thiobenzylazobenzenes. J COORD CHEM 2014. [DOI: 10.1080/00958972.2014.922683] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
| | - Mukul Kalita
- Department of Chemistry, National Institute of Technology, Silchar, India
| | | | - Pranjit Barman
- Department of Chemistry, National Institute of Technology, Silchar, India
| | - Vedavati G. Puranik
- Center for Materials Characterizations, National Chemical Laboratory, Pune, India
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Takjoo R, Mague JT, Akbari A, Ahmadi M. Co(III) and Fe(III) complexes of Schiff bases derived from 2,4-dihydroxybenzaldehyde S-allyl-isothiosemicarbazonehydrobromide. J COORD CHEM 2013. [DOI: 10.1080/00958972.2013.856420] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Reza Takjoo
- Department of Chemistry, School of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Joel T. Mague
- Department of Chemistry, Tulane University, New Orleans, LA, USA
| | - Alireza Akbari
- Department of Chemistry, Payame Noor University (PNU), Tehran, Iran
| | - Mehdi Ahmadi
- Department of Chemistry, Payame Noor University (PNU), Tehran, Iran
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