Combinatorial Selection Among Geometrical Isomers of Discrete Long-Carbon-Chain Naphthalenediimides Induces Local Order at the Liquid/Solid Interface

Abstract

We report two families of naphthalenediimides (NDIs) symmetrically functionalized with discrete carbon chains comprising up to 55 carbon atoms ( C n -NDI-C n , n = 39, 44, 50, and 55) and their self-assembly at the 1-phenyloctane/highly oriented pyrolytic graphite interface (1-PO/HOPG interface). The compounds differ by the presence or absence of two or three internal double bonds in the carbon chains (unsaturated and saturated C n -NDI-C n , respectively). Combinatorial distributions of geometrical isomers displaying either the E - or Z -configuration at each double bond are obtained for the unsaturated compounds. Analysis of the self-assembled monolayers of equally long unsaturated and saturated C n -NDI-C n by scanning tunneling microscopy (STM) reveal that all C n -NDI-C n tend to form lamellar systems featuring alternating areas of aromatic cores and carbon chains. Extended chain lengths are found to significantly increase disorder in the self-assembled monolayers due to misalignments and enhanced strength of interchain interactions. This phenomenon is antagonized by the local order-inducing effect of the internal double bonds: unsaturated C n -NDI-C n give qualitatively more ordered self-assembled monolayers compared to their saturated counterparts. The use of combinatorial distributions of unsaturated C n -NDI-C n geometrical isomers does not represent a limitation to achieve local order in the self-assembled monolayers. The self-assembly process operates a combinatorial search and selects the geometrical isomer(s) affording the most thermodynamically stable pattern, highlighting the adaptive character of the system. Finally, the antagonistic interplay between the extended carbon chain lengths and the presence of internal double bonds brings to the discovery of the lamellar “phase C” morphology for unsaturated C n -NDI-C n with n ≥ 50.

Self‐Assembly of Discrete Oligomers of Naphthalenediimides in Bulk and on Surfaces

“…[36] As observed previously with similar unsaturated alkyldiamines, the double bonds were formed preferably in the cis-configuration. [33,34] The Wittig olefination resulted in a mixture of inseparable cis-and trans-isomers of which the ratio was quantified by 13 C NMR.…”

“…For the oligomers of set 1, the distance corresponding to the first Bragg reflection is in the range of the extended length of the molecules, and the experimental correlation functions can be well reproduced with model electron density profiles corresponding to a stretched conformation with tilted extended alkyl chains. [34] For C 3 -NDI 3 , the three NDI cores are not resolved separately in the electron density profile, owing to their spatial proximity in the crystals. In contrast, when the NDI cores are separated by 12 methylene units, they pack in layers sufficiently spaced apart to be resolved in the electron density profiles, which also explains the relative increase of intensity of the third and fourth order Bragg reflections in the MAXS intensity.…”

“…Moreover, these structures were assembled at the 1-phenyloctane/highly oriented pyrolytic graphite (HOPG) interface and it was found that monolayers of the unsaturated compounds mostly resulted in larger well-ordered domains compared to the saturated counterparts. [33,34] Encouraged by these interesting results on the assembly of NDIs, we herein explore the synthesis and assembly properties of discrete NDI dimers, trimers, tetramers and pentamers spaced by various saturated and unsaturated alkyl chains (Figure 1). We investigate their synthetic accessibility, solubility, processability and long-range assembly by varying the linker length, degree of polymerization and sequence.…”

Nanostructures in Chinese herbal medicines (CHMs) for potential therapy

“…For a better understanding of the CHM effect, high-throughput activity screening, computational methods, network pharmacology, and chinmedomics have been developed, although these techniques have certain disadvantages and application limitations. 14 In recent years, with the development of nanobiology, nanomedicine, and supramolecular chemistry 15,16 as well as the breakthrough of various electron microscopy and imaging technologies, the characteristics of CHMs have been revealed, greatly expanding the understanding of the material basis of CHMs, which cannot be explained from the perspective of chemical components alone. For example, puerarin, berberine (BBR) and baicalin (BA), the active components of the classic Gegen Qinlian decoction, are characterized by poor solubility and low oral bioavailability.…”

Stepwise Adsorption of Alkoxy‐Pyrene Derivatives onto a Lamellar, Non‐Porous Naphthalenediimide‐Template on HOPG

“…In addition, we tested other potentialt emplates from the unsaturated and saturated C n -NDI-C n [49,51] family to elucidate essential structural parameters (the complete list of C n -NDI-C n tested is reported in Figure S5). Surprisingly enough, although these compounds are structurally very similart ouC 33 -NDI-uC 33 ,t heir assistance towards subsequenta dsorption of the PyrOR compounds was extremely modest.…”