Shelyganov, Pavel A. and Virovets, Alexander and Peresypkina, Eugenia and Scheer, Manfred and Timoshkin, Alexey Y. (2019) Tetraglymes as Prochiral Host Reagents for Ammonia Borane. ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE, 645 (3). pp. 317-322. ISSN 0044-2313, 1521-3749
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The molecular structure of the complex of ammonia borane (AB) with acyclic ether tetraglyme Me(OCH2CH2)(4)OMe (1), 1(AB)(2) was determined by single-crystal X-ray structure analysis for the first time. The crystal structure features two AB molecules, bonded by dihydrogen bonds, per one tetraglyme unit. The intermolecular BHHN distances of 1.94 angstrom are shorter than those in the solid ammonia borane (2.02-2.32 angstrom). A comparison of the hydrogen and dihydrogen bonds in 1(AB)(2) and in the complexes of AB with crown-ethers (CE) was carried out. The complex formation with both the CE and the acyclic polyether 1 activates the B-H bond in AB via N-HO hydrogen bonds and therefore increases the reducing activity of AB. Supposedly, the structure of 1(AB)(2) is related to the initial steps of the AB activation in a polyether solution. The effect of the substituents on the complexation of the substituted derivatives of 1 comes down to a structural adjustment minimizing steric repulsion. Computations reveal that the complexation of diastereomeric disubstituted glymes with AB leads to the formation of diastereomeric complexes that differ noticeably in stability. This is a prerequisite for inducing stereoselectivity, which makes such complexes attractive for potential synthetic applications.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SUPRAMOLECULAR STRUCTURES; CIS ISOMER; 1-1 ADDUCT; METAL-FREE; HYDROGEN; COMPLEXES; 2,3,11,12-TETRA-ANISYL-18-CROWN-6; THERMOCHEMISTRY; CRYSTAL; KETONES; Ammonia borane; Tetraglyme; Crown compounds; Chirality; Density functional computations |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie Chemistry and Pharmacy > Institut für Anorganische Chemie > Chair Prof. Dr. Manfred Scheer |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 17 Apr 2020 07:12 |
| Last Modified: | 17 Apr 2020 07:12 |
| URI: | https://pred.uni-regensburg.de/id/eprint/27538 |
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