A World Beyond Hydrogen Bonds?—Chalcogen–Chalcogen Interactions Yielding Tubular Structures

Abstract

It is shown that tubular structures arise in the solid state through close chalcogen-chalcogen (X...X) contacts. As examples a variety of cyclic systems containing sulfur and selenium centers is presented. Common to all of them are close contacts between the chalcogen centers of neighboring stacks giving rise to a zigzag or ladder-type arrangement. In the case of cyclic systems of ring size 24-33 the resulting tubes are able to include hydrocarbons as guest molecules. For 2,7-ditelluraocta-3,5-diyne (17) the close contacts between the tellurium centers of the acyclic C(2) symmetric building blocks generate a helical arrangement in which n-hexane was included. The favored X...X contacts can be traced back to np(X)-sigma*(X[bond]C) interactions.

A survey of tellurium-centered secondary-bonding supramolecular synthons

“…Complementary pairs, capable of molecular recognition through supramolecular synthons with multiple SBIs, would eventually provide a new platform for programmable self-assembly [85]; it is one of the most promising lines of future research. Paraphrasing Gleiter et al [23], there is a world beyond hydrogen bonds waiting to be explored, but realizing its potential still requires an important amount of fundamental research.…”

“…Notwithstanding, some noteworthy cases illustrate the potential of main-group SBIs in this context: pnictogen-centered SBIs [20] can link ribbon polymers [21]; chalcogen-chalcogen contacts [22] assemble supramolecular tubes [6,[23][24][25]; and applications of halogen SBIs have been demonstrated in the design of noncentrosymmetric lattices capable of second harmonic generation (SHG) [26], the resolution of a racemic perfluoroalkyl bromide [27], the separation of mixtures of diiodoperfluoroalkanes [28], and the organization of 1-dimensional molecular magnets with attenuation of antiferromagnetic coupling [29]. Making an analogy to hydrogen bonding, Starbuck and Orpen [30] noted that the rational design of SBI supramolecular systems would greatly benefit from the application of Desiraju's concept of supramolecular synthon: "a structural unit within a supermolecule which can be formed and/or assembled by known or conceivable synthetic operations involving intermolecular interactions" [30].…”

Structural studies on inclusion compounds and solvent sorption behavior of gradually elongated wheel-and-axle-type diol hosts featuring lateral benzo[b]thiophene units

“…4b) and 2b (Fig. 4c), the alkyne bonds are slightly distorted which is specified by the bond angles of 176. again stabilization via intramolecular S···O-contacts but involve also intramolecular S···S-contacts [24][25][26] leading to corresponding torsion angles around the two heteroaromatic and hydroxyl groups as particularized in Table 3. Probably owing to a packing induced distortion of the spacer elements, the alkyne bonds are not linear showing bond angles that range between 176.2 and 179.1 ° (with 4a deviating the most).…”

Morphology Controlled Nanostructures Self‐Assembled from Phthalocyanine Derivatives Bearing Alkylthio Moieties: Effect of Sulfur–Sulfur and Metal–Ligand Coordination on Intermolecular Stacking

“…Chalocogen-chalocogen interactions between molecules are believed to be as useful as hydrogen bonding in the self-assembly of disk-and ring-shaped molecules. [17] In cooperation with the other noncovalent intermolecular interactions, this would be helpful for improving the semiTo investigate the effect of sulfur-sulfur and metal-ligand coordination on the molecular structure and morphology of selfassembled nanostructures, metal-free 2,3,9,10,16,17,23,24-octakis(isopropylthio)phthalocyanine H 2 Pc(b-SC 3 H 7 ) 8 (1) and its copper and lead congeners CuPc(b-SC 3 H 7 ) 8 (2) and PbPc(b-SC 3 H 7 ) 8 (3) are synthesized and fabricated into organic nanostructures by a phase-transfer method. The self-assembly properties are investigated by electronic absorption and Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS).…”