Supramolecular Synthesis of Organic Laminates with Affinity for Aromatic Guests:  A New Class of Clay Mimics

Single-crystal X-ray diffraction analysis of 25 supramolecular laminate structures formed from reaction of trimesic acid or trimellitic acid with 2 equiv of N,N-dibenzylamine reveals an ability to incorporate aromatic guest molecules irrespective of their size and electronic nature. The guest molecules included are nitrobenzene, anisole, veratrole, 1,4-dimethoxybenzene, 1,3,5-trimethoxybenzene, m-xylene, mesitylene, tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, N,N-dibenzylamine, naphthalene, 1-methylnaphthalene, pyrene, and ferrocene. The acid moieties and ammonium cations reproducibly form charge-assisted 2D hydrogen-bonded layers with pendant benzyl groups above and below the layers. In the absence of guest molecules, interdigitation of benzyl groups is observed. Guest molecules interact with the laminates via a plethora of aromatic edge-to-face and face-to-face interactions. The unit cell lengths are based upon multiples of ∼12 × 17 × 21 Å. The 12-Å dimension represents the approximate interlayer separation whereas the 17 × 21 Å dimensions represent the hydrogen-bonded layer.