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Heterocyclic substituted methanides as promising alternatives to the ubiquitous nacnac ligandDedicated to Professor Frank T. Edelmann on the occasion of his 60th birthday.Electronic supplementary information (ESI) available: Tables of data collection parameters, bond lengths and angles for compounds 1-9, 2D-NMR spectra of 3, 4 and 8, additional crystal structures of 4, 5 and 7, nine X-ray files in CIF format. CCDC 995110-995118. For ESI and crystallographic data in CIF or other electronic format
A series of group 13 complexes containing deprotonated bisheterocyclomethanes have been prepared and structurally as well as spectroscopically characterised. In the case of the parent neutral homo-disubstituted bisheterocyclomethanes bis-(benzoxazol-2-yl)-methane (abbreviated as (NCOC 6 H 4 ) 2 CH 2...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Online Access: | Get full text |
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| Summary: | A series of group 13 complexes containing deprotonated bisheterocyclomethanes have been prepared and structurally as well as spectroscopically characterised. In the case of the parent neutral homo-disubstituted bisheterocyclomethanes bis-(benzoxazol-2-yl)-methane (abbreviated as (NCOC
6
H
4
)
2
CH
2
) (
1
) and bis-(benzothiazol-2-yl)-methane (abbreviated as (NCSC
6
H
4
)
2
CH
2
) (
2
), two interesting ligand systems were investigated with respect to their coordination abilities toward group 13 metals. Upon deprotonation of the acidic methylene bridge in each case a β-diketiminate-like structure is formed, where the negative charge becomes delocalised about the whole ligand framework. There is a mesomeric stabilisation between the carbanionic and the amidic resonance structure. The ligands mentioned above were treated with AlMe
3
, AlMe
2
Cl and GaMe
3
to achieve deprotonation of the backbone and coincidental metal complexation. The resulting complexes [Me
2
Al{(NCOC
6
H
4
)
2
CH}] (
3
), [Me
2
Al{(NCSC
6
H
4
)
2
CH}] (
4
), [ClMeAl{(NCOC
6
H
4
)
2
CH}] (
5
), [ClMeAl{(NCSC
6
H
4
)
2
CH}] (
6
), [Me
2
Ga{(NCOC
6
H
4
)
2
CH}] (
7
), and [Me
2
Ga{(NCSC
6
H
4
)
2
CH}] (
8
) were structurally characterized in the solid state by X-ray single crystal diffraction and in solution by different (heteronuclear) 1D/2D-NMR spectroscopic techniques. Each of those molecules shows a nearly planar arrangement with the group 13 metal cation coordinated by the two ring nitrogen atoms of the conjugated heterocycles. Furthermore, in this work (NCOC
6
H
4
)
3
C(C
3
H
7
) (
9
) could be isolated, which might turn out to be a promising analogue of the omnipresent trisoxazoline ligands in asymmetric catalysis.
A series of group 13 complexes containing deprotonated bisheterocyclomethanes have been prepared as well as structurally and spectroscopically characterised. |
|---|---|
| ISSN: | 1477-9226 1477-9234 |
| DOI: | 10.1039/c4dt01008f |