Formation of isolated guest dimers vs. host-guest coordination. X-Ray crystal structures of four carboxylic acid inclusion compounds formed by roof-shaped and scissor-like host molecules

摘要: The crystal structures of the inclusion compounds oftrans-9,10-dihydro-9,10-ethano-anthracene-11,12-dicarboxylic acid host (1) with formic (1a), acetic (1b), and propionic (1c) as guests, coordinatoclathrate 1,1′-binaphthyl-2,2′-dicarboxylic (2) guest (2b) have been studied by single X-ray diffraction. These studies show that small carboxylic acids hosts like1 and2 results in formation isolated, hydrogen-bonded dimers. Additional H-bond contacts between groups are only formed cases1a and2b. dimeric acidic units sitting cavities or host-guest framework no other interactions than those a weak Van der Waals' type neighbouring molecules. Crystal data:1·formic (1:2): triclinic (PĪ),a = 11.6769(6),b 9.4067(4),c 9.0020(4) A,a 81.522(4), β 100.310(6), γ 104.208(6)°,Z 2,R 0.048 for 2392 reflections;1·acetic (1:1): monoclinic (P21/n),a 9.717(2),b 14.462(2),c 13.038(3)A, 104.27(1)°,Z=4,R=0.046 3042 observations;1·propionic 9.897(4),b 14.671(7),c 13.284(7) A, 105.92(6)°,Z 4,R 0.056 2302 reflections;2·acetic (2:3): 12.746(1),b 17.781(2),c 11.010(1) α 105.606(4), 112.992(8), 81.175(6)°,Z 0.067 4375 observations.