ISSN:
1573-1111
Keywords:
Inclusion compounds, X-ray crystal structure analysis, 2′-hydroxy-2,4,4,7,4′-pentamethylfavan
;
selective clathration
;
trans-1,4-bis(hydroxymethyl)cyclohexane guest
;
2′-hydroxy-2,4,4,6,5′-pentamethylflavan host
;
N,N-dimethylpiperazine guest
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Consideration of the shape and hydrogen bonding pattern of anentire guest unit, in the known 2:1:2 complex of 2′-hydroxy-2,4,4,7,4′-pentamethylflavan (1) with 1,4-dioxan and water, has indicated a structurally compatible guest,trans-1,4-bis(hydroxymethyl)cyclohexane (3b) which is selectively clathrated from a mixture with itscis isomer (3a). The new complex is triclinic, space group,P $$\bar 1$$ , witha=8.137(1),b=9.106(1),c=14.552(2) Å, α=93.56(1), β=94.08(1), γ=98.62(1)°, and two host and one guest molecule in the unit cell. A novel hydrogen bonded host-guest arrangement has also been found for host (1), involving ethanol and piperazine [triclinic, space groupP $$\bar 1$$ , witha=8.438(1),b=10.252(1),c=14.052(1) Å, α=71.28(1), β=89.72(1), γ=83.88(1)δ]; while for the 1:1 ether adduct of (1) the triclinic unit cell, space groupP $$\bar 1$$ , is approximately doubled in volume [a=8.309(2),b=10.546(3),c=26.664(6) Å, α=102.10(2), β=100.48(2), γ=81.04(2)°], there now being two crystallographically independent host-guest units involving ϕOH·OEt2 hydrogen bonds of length 2.71(1) Å and 2.77(1)Å. In the 2:1 complex of the isomeric host 2′-hydroxy-2,4,4,6,5′-pentamethylfavan (2) withN, N′-dimethylpiperazine (5) [triclinic space groupP $$\bar 1$$ , witha=7.411(1),b=10.143(3),c=15.109(3)Å, α=98.73(2), β=88.30(1), γ=109.72(2)°] the centrosymmetric chair-shaped guest molecule is clamped by two axially oriented ϕOH...N hydrogen bonds of length 2.759(3)Å.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00657494
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