New inclusion complexes (n-C₄H₉)₄N^＋C₁₈H₁₃O₄^－•B(OH)₃ (1) and (n-C₄H₉)₄N^＋C₁₈H₁₃O₄^－ (2) have been prepared and characterized by X-ray crystallography. Crystal data: compound 1, monoclinic P2(1)/c, a＝1.5699(1) nm, b＝0.9955(6) nm, c＝2.2933(1) nm, β＝109.962(3)°, Z＝4, and R₁＝0.0434, wR＝0.0759; compound 2, monoclinic C2/c, a＝1.4005(3) nm, b＝1.2821(2) nm, c＝1.7657(3) nm, β＝100.388(1)°, Z＝4, and R₁＝0.0584, wR＝0.0966. In the crystal structure of 1, the tetramers formed by two trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (EADA) anions and two boric acid molecules are connected through O—H…O hydrogen bonds to generate a channel type host lattice. The tetra-n-butylammonium cations are stacked in double columns within each channel with cross-sectional size of about 2.30 nm×0.93 nm. In the crystal structure of 2, similar honeycomb host lattices with big size are also formed along the [101] direction by three-dimensional accumulation of EADA anions. The tetra-n-butylammonium cations are accommodated in a zigzag fashion within each channel.

Key words: trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid, boric acid, tetrabutylammonium salt, inclusion compound, crystal structure