Chiral π-conjugated molecules provide new materials with outstanding features for current and perspective applications, especially in the field of optoelectronic devices. In thin films, processes s...

Chiroptical Properties in Thin Films of π-Conjugated Systems.

Supramolecular polymers exhibit fascinating structures, and their properties, and thus applications, depend both on the strength and dynamics of the non-covalent bonds and on the functional properties of the monomeric building blocks. In this Review, we highlight the progress in methods developed to control supramolecular polymerization based on physicochemical insights into the thermodynamics and kinetics of non-covalent interactions. Prerequisites for polymer formation and stability, such as high binding strength (thermodynamics) between complementary receptor units, are briefly discussed, while the main focus is on the kinetic control of pathway selectivity, which in recent years has allowed seed-induced living supramolecular polymerization, chain growth-type supramolecular polymerization and the preparation of specific supramolecular polymer polymorphs and supramolecular block copolymers. Beginning with a historical retrospective, this Review highlights the progress from thermodynamically and kinetically controlled self-assembly processes towards seed-induced living supramolecular polymerization, which allows the formation of highly ordered, functional materials such as supramolecular block copolymers.

Supramolecular polymerization through kinetic pathway control and living chain growth

Pathway complexity, hierarchical organization, out of equilibrium, and metastable or kinetically trapped species are common terms widely used in recent, high-quality publications in the field of supramolecular polymers. Often, the terminologies used to describe the different self-assembly pathways, the species involved, as well as their relationship and relative stability are not trivial. Different terms and classifications are commonly found in the literature, however, in many cases, without clear definitions or guidelines on how to use them and how to determine them experimentally. The aim of this Minireview is to classify, differentiate, and correlate the existing concepts with the help of recent literature reports to provide the reader with a general insight into thermodynamic and kinetic aspects of complex supramolecular polymerization processes. A good comprehension of these terms and concepts should contribute to the development of new complex, functional materials.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ange.201905724

Revising complex supramolecular polymerization under kinetic and thermodynamic control

This review surveys recent progress in the chemistry of polycyclic heteroaromatic molecules with a focus on structural diversity and synthetic methodology. The article covers literature published during the period of 2016-2020, providing an update to our first review of this topic (Chem. Rev.2017, 117 (4), 3479-3716).

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds.

Exploration of molecular functions and material properties based on the control of chirality would be a scientifically elegant approach. Here, the fabrication and function of chiral-featured materials from both chiral and achiral components using a supramolecular nanoarchitectonics concept are discussed. The contents are classified in to three topics: i) chiral nanoarchitectonics of rather general molecular assemblies; ii) chiral nanoarchitectonics of metal-organic frameworks (MOFs); iii) chiral nanoarchitectonics in liquid crystals. MOF structures are based on nanoscopically well-defined coordinations, while mesoscopic orientations of liquid-crystalline phases are often flexibly altered. Discussion on the effects and features in these representative materials systems with totally different natures reveals the universal importance of supramolecular chiral nanoarchitectonics. Amplification of chiral molecular information from molecules to materials-level structures and the creation of chirality from achiral components upon temporal statistic fluctuations are universal, regardless of the nature of the assemblies. These features are thus surely advantageous characteristics for a wide range of applications.

Supramolecular Chiral Nanoarchitectonics.

The phenomenon of polymorphism is ubiquitous in biological systems and has also been observed in various types of self-assembled materials in solution and in the solid state. In the field of supramolecular polymers, different kinetic vs thermodynamic self-assembled species may exist in competition, a phenomenon termed as pathway complexity. In these examples, the transient kinetic species often has a very short lifetime and rapidly converts into the thermodynamic product. In this work, we report a π-conjugated Pt(II) complex 1 that self-assembles in nonpolar medium into two competing supramolecular polymers with distinct molecular packing (slipped (A) vs pseudoparallel (B)) that do not interconvert over time in a period of at least six months at room temperature. Precise control of temperature, concentration, and cooling rate enabled us to ascertain the stability conditions of both species through a phase diagram. Extensive experimental studies and theoretical calculations allowed us to elucidate the pack...

Unraveling Concomitant Packing Polymorphism in Metallosupramolecular Polymers.

The formation of helical structures through the supramolecular polymerization of a variety of self-assembling units is reviewed. These scaffolds are usually obtained by efficient transfer or amplification of chirality phenomena, in which the starting self-assembling molecules possess different elements of asymmetry, such as point or axial chirality. Relevant examples of helical supramolecular structures investigated under thermodynamic control are reviewed, and the helical outcome of remarkable examples of chiral entities obtained through kinetic control are also highlighted. Finally, selected examples of flexible macroscopic chirality and catalysis are described to illustrate the applicability of helical aggregates.

Hierarchy of Asymmetry in Chiral Supramolecular Polymers: Toward Functional, Helical Supramolecular Structures.

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Yeray Dorca

Papers

Revising complex supramolecular polymerization under kinetic and thermodynamic control

Unraveling Concomitant Packing Polymorphism in Metallosupramolecular Polymers.

Hierarchy of Asymmetry in Chiral Supramolecular Polymers: Toward Functional, Helical Supramolecular Structures.

Revision komplexer supramolekularer Polymerisation unter kinetischer und thermodynamischer Kontrolle

C3‐Symmetrical π‐Scaffolds: Useful Building Blocks to Construct Helical Supramolecular Polymers