Site-Selective Guest Inclusion in Molecular Networks of Butadiyne-Bridged Pyridino and Benzeno Square Macrocycles on a Surface

Abstract

We present here the formation of a modular 2D molecular network composed of two different types of square-shaped butadiyne-bridged macrocycles, having intrinsic molecular voids, aligned alternately at the solid-liquid interface. Site-selective inclusion of a guest cation took place at every other molecular void in the molecular network with two different recognition sites.

Square Tiling by Square Macrocycles at the Liquid/Solid Interface: Co‐crystallisation with One‐ or Two‐Dimensional Order

“…Complex 1a·3 and cyclophane 2a randomly mixed on the surface forming the non-porous A pattern, 18 which is not surprising in view of the same substituents in these macrocycles. Occasionally, randomly mixed domains were observed in the case of a mixture of 1c·3 and cyclophane 2c (on an average 17%, Figure S4b), in addition to segregated domains of each component.…”

“…17 Previously, we reported that butadiyne-bridged pyridino and benzo square macrocycles 1a and 2c (Scheme 1) form a molecular network in which 1a and 2c aligned alternately in one-FULL PAPER dimension (1D alternating pattern) via attractive dipole-dipole interactions between the ester groups of 1a and the ether groups of 2c. 18 Note that this alternating network structure is different from the pattern formed by each single component (1a or 2c). Tropylium ion selectively binds 1a forming a 1 to 1 complex on the graphite surface.…”

“…The syntheses of square-shaped macrocycles 1c and 2b-d were conducted based on the previously reported methods 18,19 starting from bis(trimethylsilylethynyl)benzene or bis(trimethylsilylethynyl)pyridine derivatives as outlined in Scheme 2 (See also Supporting Information). STM Observations of Self-Assembled Monolayers Formed by Macrocycles at the Liquid/Graphite Interface All STM observations were performed at the interface between an organic solvent and graphite at room temperature.…”

“…18 For ideal random and perfect alternating orderings formed by equal number of two macrocycles, the CF values should become 0.5 and 1, respectively. Moreover, a CF value of 0 indicates perfect domain separation.…”

“…While originally we reported that cyclophane 2c formed the nonporous A pattern, 18 careful re-examination revealed that this pattern appears as a minor structure. The majority of the domains of 2c consist of the porous pattern (vide supra).…”