Templated versus non-templated synthesis of benzo-21-crown-7 and the influence of substituents on its complexing properties

• Wei Jiang and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2010, 6, No. 14, doi:10.3762/bjoc.6.14

• of guest from secondary dibenzylammonium hexafluorophosphate (360 M−1, 1.0 mM, in acetone-d6) [31] to the anthracenyl methyl-substituted analogue 5-H•PF6 (496 M−1, 1.0 mM, in acetone-d6) [26] increases the binding affinity with DB24C8, which is mainly attributed to stronger π-π stacking interactions

• reasons for this remarkable difference between C7 and the larger analogue dibenzo-24-crown-8. (i) According to related crystal structures [23][24][25], no π-π stacking interactions operate between hosts C7 or 4 and guests 6-H•PF6 or 7-H•PF6. (ii) Even more important, however, are the polarized methylene

Crystal engineering of analogous and homologous organic compounds: hydrogen bonding patterns in trimethoprim hydrogen phthalate and trimethoprim hydrogen adipate

• Packianathan Thomas Muthiah,
• Savarimuthu Francis,
• Urszula Rychlewska and
• Beata Warżajtis

Beilstein J. Org. Chem. 2006, 2, No. 8, doi:10.1186/1860-5397-2-8

• leading to base-pairing, quadruple hydrogen bonded arrays, DDAA and DADA (D- donor, A = acceptor), etc. C-H...π, π-π stacking, etc are further stabilizing the crystal structures. The quadruple hydrogen bonded arrays have been observed in the crystal structures of TMP m-chlorobenzoate, [11] TMP-sorbate