Research output: Contribution to journal › Article › peer-review
Tetraglymes as Prochiral Host Reagents for Ammonia Borane. / Shelyganov, Pavel A.; Virovets, Alexander; Peresypkina, Eugenia et al.
In: Zeitschrift fur Anorganische und Allgemeine Chemie, Vol. 645, No. 3, 15.02.2019, p. 317-322.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Tetraglymes as Prochiral Host Reagents for Ammonia Borane
AU - Shelyganov, Pavel A.
AU - Virovets, Alexander
AU - Peresypkina, Eugenia
AU - Scheer, Manfred
AU - Timoshkin, Alexey Y.
N1 - Publisher Copyright: © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2019/2/15
Y1 - 2019/2/15
N2 - The molecular structure of the complex of ammonia borane (AB) with acyclic ether tetraglyme Me(OCH2CH2)4OMe (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 BH···HN distances of 1.94 Å are shorter than those in the solid ammonia borane (2.02–2.32 Å). 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–H···O 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.
AB - The molecular structure of the complex of ammonia borane (AB) with acyclic ether tetraglyme Me(OCH2CH2)4OMe (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 BH···HN distances of 1.94 Å are shorter than those in the solid ammonia borane (2.02–2.32 Å). 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–H···O 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.
KW - Ammonia borane
KW - Chirality
KW - Crown compounds
KW - Density functional computations
KW - Tetraglyme
KW - CIS ISOMER
KW - THERMOCHEMISTRY
KW - COMPLEXES
KW - CRYSTAL
KW - SUPRAMOLECULAR STRUCTURES
KW - 1-1 ADDUCT
KW - HYDROGEN
KW - KETONES
KW - 2,3,11,12-TETRA-ANISYL-18-CROWN-6
KW - METAL-FREE
UR - http://www.scopus.com/inward/record.url?scp=85054856930&partnerID=8YFLogxK
U2 - 10.1002/zaac.201800333
DO - 10.1002/zaac.201800333
M3 - Article
AN - SCOPUS:85054856930
VL - 645
SP - 317
EP - 322
JO - Zeitschrift fur Anorganische und Allgemeine Chemie
JF - Zeitschrift fur Anorganische und Allgemeine Chemie
SN - 0044-2313
IS - 3
ER -
ID: 17117239