Supramolecular Arrangement Research Articles

Crystal Structure, Supramolecular Organization, Hirshfeld Analysis, Interaction Energy, and Spectroscopy of Two Tris(4-aminophenyl)amine-Based Derivatives

The use of tris(4-aminophenyl)amine (TAPA) as central to the synthesis of both polyimines and polyimides and covalent organic frameworks and inorganic cages, among others, has grown in the last few years. The resulting materials exhibit high performance in their area of application. In this contribution, the crystal structures of two TAPA derivatives, triethyl (nitrilotris(benzene-4,1-diyl))tricarbamate (1) and triethyl 2,2′,2″-((nitrilotris(benzene-4,1-diyl))tris(azanediyl))tris(2-oxoacetate) (2), are described. The molecular and supramolecular structures of both compounds were compared between them and with analogous compounds. The analyses of their vibrational and 13C-CPMAS NMR spectroscopies, as well as their thermal stability, were included and corelated with the crystal structure. Hirshfeld surface analysis on the crystal structures of both TAPA derivatives revealed the stabilization of the crystal network via the amide N—H∙∙∙O interactions of dispersive nature in the carbamate, whereas dispersive carbonyl–carbonyl interactions also played a competitive role in the supramolecular arrangement of the oxamate. Interaction energy DFT calculations performed at the B3LYP/6-31G(d,p) level allowed us to estimate the energy contributions and nature of several interactions in terms of the stability of both crystal lattices.

Supramolecular Arrangement and Conformational and Dynamic Properties of Chiral Smectic Liquid Crystals Obtained through Nuclear Magnetic Resonance: A Brief Review

Ferroelectric and antiferroelectric smectic liquid crystalline (LC) phases are still at the center of investigations and interests for both their fundamental properties and variety of technological applications. This review aims to report the main contributions based on different nuclear magnetic resonance (NMR) techniques to the study of chiral liquid crystalline calamitic mesogens forming smectic phases, such as the SmA, the SmC* (ferroelectric), and the SmC*A (antiferroelectric) phases. 2H NMR and 13C NMR techniques and their combination were of help in clarifying the local orientational properties (i.e., the molecular and fragments’ main orientational order parameters) at the transition between the SmA and the SmC* phases, and in the particular case of de Vries liquid crystals, NMR studies gave important clues regarding the actual models describing the molecular arrangement in these two phases formed by de Vries LCs. Moreover, this review describes how the combination of 2H NMR relaxation times’ analysis, 1H NMR relaxometry, and 1H NMR diffusometry was successfully applied to the study of chiral smectogens forming the SmC* and SmC*A phases, with the determination of relevant parameters describing both rotational molecular and internal motions, collective dynamics, and translational self-diffusion motions. Several cases will be reported concerning NMR investigations of chiral ferroelectric and antiferroelectric phases, underlining the great potential of combined NMR approaches to the study of supramolecular, conformational, and dynamic properties of liquid crystals.

Supramolecular blends of C-alkylpyrogallol[4]arenes and polytetrahydrofurans

A small series of the amphiphilic macrocycles – C-alkylpyrogallol[4]arenes has been synthesized and examined by single crystal X-ray analysis which showed the formation of two supramolecular arrangements depending on solvent used for crystallization, i.e., multilayered motif and hexameric capsule. Those structural findings provided an insight into blends prepared from aforementioned macrocycles and various polytetrahydrofurans (polyTHFs). Thus, 1:1 wt ratio mixtures were obtained and investigated by combination of Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). As it turned out, the viscosity of these blends was increased compared to starting materials, which imply that pyrogallol[4]arenes can be successfully utilized as supramolecular cross-linkers enhancing H-bonding between adjacent macromolecular chains. As the major difference between compounds synthesized is the length and geometry of their respective alkyl side chains attached directly to macrocyclic core, i.e., n-propyl- and cyclohexyl- vs. n-dodecyl-, it seemed likely that even insignificant increase in their hydrophobicity can induce high order aggregation of nanoparticles in the slurries, thus affecting their viscosity. Overall, material viscoelastic properties are tunable at macroscopic level by choosing particular pyrogallol[4]arene/solvent combination and adjusting the temperature, which may be advantageous for the design of hybrid materials.

Leukocyte-based delivery systems for enhanced nanotheranostics of inflammation and cancer

As a part of the immune system, leukocytes (LEs) have the features of circumvention of immunogenicity as well as recruitment to sites of inflammation during infection and tumorigenesis. Utilizing LEs as vehicles to carry theranostic agents is a promising strategy for highly efficient targeted delivery and treatment for inflammation and cancer. Specifically, the LEs, similar to 'Trojan horses', can bypass the immune system and thus enhance the therapeutic effects on inflammation and cancer. In this context, the latest progress of LEs-based delivery systems for improving theranostics of inflammations and cancers is summarized, includingin vitroincubation andin vivointernalization strategy. Although the therapeutic efficacy of LEs-based delivery systems has been achieved, the system construction is complex and the effect is not fulfilling demand completely. Encouragingly, a most recent work reported that the supramolecular arrangement of proteins on the nanocarriers would drive them to be selectively uptaken by neutrophils, opening a new avenue for diagnosis and treatment of inflammation. Moreover, enucleated cells are considered as the biomimetic drug delivery vehicle to retain the organelles for a range of diseases in a safe, controllable and effective manner. These novel findings provide more opportunities for researchers to rethink and redesign the LEs-based delivery systems to overcome existing limitations and broaden their usage, especially in clinical medicine.

One dimensional water chain as a zipper in a new polymorph of trans [Cu(vanilin)2(H2O)2].2(H2O) crystal–A case of water induced polymorphism

A new polymorph [Cu(II)(vanillin)2(H2O)2].2(H2O) has been synthesized and characterized by single crystal X-ray structural studies. Two other crystals having same formula and coordination unit but differing supramolecular arrangement due to slightly different role played by water molecules have already been reported in the literature [B. Kozlevˇcar et al. Z. Naturforsch., B: Chem. Sci. 2005, 60, 1273][Kozlevčar et al. Acta Chim. Slov. 2005, 52, 40–43]. The current compound is another polymorph in this system which has arisen again due to a different supramolecular arrangement which is water induced. Hirshfeld surface and energy framework analysis have been employed to compare these three polymorphs by assessing the nature of intermolecular interactions. In the current compound strong OH···O hydrogen bonding interactions between coordinated water molecules and –OH group attached to vanillin ligand leads to parallel alignment of successive coordination units leading to a supramolecular ribbon topology that runs along the crystallographic a-axis. A zigzag chain of single file water chain is positioned in between successive ribbons which acts as a zipper giving rise to a 2D supramolecular arrangement of the molecular complexes. In two other reported polymorphs instead of a single file water chain a cyclic water motif has been observed. The electronic structure of the complex explored using DFT methodology. This set of three polymorphs is an interesting example of water induced polymorphism.

Comparative structural analysis of anhydrous and monohydrated polymorphs of diclofenac diethylammonium: Implications for stability, dissolution, and bioavailability

Diclofenac diethylammonium belongs to the class of non-steroidal anti-inflammatory drugs, and it is widely used to relieve pain and reduce systemic inflammation. This drug exists in polymorphic forms, which can directly affect the ability to process the drug, as well as drug product dissolution, stability, and bioavailability. Considering the worldwide regulatory guidance for polymorphs in drug substances, a detailed structural analysis of two polymorphs exhibiting the anhydrous and monohydrated structures of diclofenac diethylammonium is presented here, using the supramolecular arrangement and its relationship with structural-physicochemical properties. The polymorph’s structures show conformational differences in the carboxylic group caused by coordinated water molecules presented in the monohydrated polymorphic structure. Both polymorphs have the supramolecular arrangement stabilized by NH···O and CH···Cl intermolecular interactions, but the monohydrated molecule presents a strong OH···O intermolecular interaction due to the presence of a water molecule. Hirshfeld surface analysis showed CH···π and π···π contacts in the anhydrous and monohydrated polymorphs, respectively. Theoretical results, including solvent effect with explicit and implicit approaches for water, indicated the kinetic stability of the diclofenac diethylammonium drug and showed susceptible electrophilic attacks occurring in the region close to the carbonyl oxygen atom.

Hirshfeld surface and fingerprint plot analysis of non-covalent interaction (NCI) in CuII −based catecholase models

Understanding of molecular packing is one of the favorable modes to study the mechanistic behavior of a supramolecular system. The present study aims in analyzing the molecular packing and supramolecular arrangement of Cu+2-catecholase system [C13H13BrCuN4O2 (System A), C14H17BrCuN4O3 (System B), and C20H36Cl2Cu2N4O11 ((System C)] with variable auxiliary groups. These systems are well studied for their reversible binding with oxygen and catalytic property towards oxidation of ortho-diphenol. The primary novelty of such study is elucidating the architecture of auxiliary part of the system whose influence is studied but not understood in terms of the molecular packing. The respective supramolecular arrangement of the Cu (II) systems having such auxiliary part is reported herein which illustrates the interaction efficacy with macromolecules like proteins. The respective non covalent interactions (NCI) of aforementioned three antiferromagnetic Cu (II) species are reported using Hirsfeld analyses which also helps in the correlation of structure–property interaction.

Local and global expansivity in water.

The supra-molecular structure of a liquid is strongly connected to its dynamics, which in turn control macroscopic properties such as viscosity. Consequently, detailed knowledge about how this structure changes with temperature is essential to understand the thermal evolution of the dynamics ranging from the liquid to the glass. Here, we combine infrared spectroscopy (IR) measurements of the hydrogen (H) bond stretching vibration of water with molecular dynamics simulations and employ a quantitative analysis to extract the inter-molecular H-bond length in a wide temperature range of the liquid. The extracted expansivity of this H-bond differs strongly from that of the average nearest neighbor distance of oxygen atoms obtained through a common conversion of mass density. However, both properties can be connected through a simple model based on a random loose packing of spheres with a variable coordination number, which demonstrates the relevance of supra-molecular arrangement. Furthermore, the exclusion of the expansivity of the inter-molecular H-bonds reveals that the most compact molecular arrangement is formed in the range of ∼316-331K (i.e., above the density maximum) close to the temperature of several pressure-related anomalies, which indicates a characteristic point in the supra-molecular arrangement. These results confirm our earlier approach to deduce inter-molecular H-bond lengths via IR in polyalcohols [Gabriel et al. J. Chem. Phys. 154, 024503 (2021)] quantitatively and open a new alley to investigate the role of inter-molecular expansion as a precursor of molecular fluctuations on a bond-specific level.

Iterative Design Reveals Molecular Domain Relationships in Supramolecular Peptide-Drug Conjugates.

Supramolecular peptide-drug conjugates (sPDCs) are prepared by covalent attachment of a drug moiety to a peptide motif programmed for one-dimensional self-assembly, with subsequent physical entanglement of these fibrillar structures enabling formation of nanofibrous hydrogels. This class of prodrug materials presents an attractive platform for mass-efficient and site-specific delivery of therapeutic agents using a discrete, single-component molecular design. However, a continued challenge in sPDC development is elucidating relationships between supramolecular interactions in their drug and peptide domains and the resultant impacts of these domains on assembly outcomes and material properties. Inclusion of a saturated alkyl segment alongside the prodrug in the hydrophobic domain of sPDCs could relieve some of the necessity for ordered, prodrug-produg interactions. Accordingly, nine sPDCs are prepared here to iterate the design variables of amino acid sequence and hydrophobic prodrug-alkyl block design. All molecules spontaneously formed hydrogels under physiological conditions, indicating a less hindered thermodynamic path to self-assembly relative to previous prodrug-only designs. However, material studies on the supramolecular arrangement, formation, and mechanical properties of the resultant sPDC hydrogels as well as their drug release profiles showed complex relationships between the hydrophobic and peptide domains in the formation and function of the resulting assemblies. Together, these results indicate that sPDC material properties are intrinsically linked to holistic molecular design with coupled contributions from their prodrug and peptide domains in directing properties of the emergent materials.

Insights on molecular modeling and supramolecular arrangement of bilastine polymorphs.

The advancement in the development of second-generation drugs in the field of antihistamines represents a significant milestone in the management of allergic diseases, targeting the effects of histamine. The efficacy of bilastine in treating allergic disorders has sparked interest in investigating its polymorphism, a crucial property that impacts quality, safety, and effectiveness as per regulatory guidelines. This study examines the polymorphism of bilastine, focusing on two crystalline forms labeled as Form I and Form II. Utilizing advanced analytical techniques, the research explores the structural characteristics and molecular interactions within these forms. Geometric parameters, such as bond lengths, bond angles, and torsion angles, are examined to comprehend molecular conformations and crystal packing arrangements. Hydrogen bonding, covalent bonds, and van der Waals forces contribute to the unique supramolecular arrangements in these forms.This study provides a significant contribution to understanding bilastine's polymorphism, offering critical insights to researchers and regulatory bodies to ensure the quality, efficacy, and safety of antihistamine products. The molecular conformation of two bilastine forms was obtained through DFT with the exchange-correlation functional M06-2X and the 6-311 + + G(d,p) basis set, and the results were compared with the experimental X-ray. The atomic coordinates were obtained directly from the crystalline structures, and charge transfer was also investigated using frontier molecular orbitals (HOMO and LUMO), and MEP map in order to evaluate the energies associated with charge transfers and regions of high electron affinity. The geometric and topological parameters and intermolecular interactions in the crystals were analyzed using Hirshfeld Surface.

Solvent Effects on the Spin Crossover Properties of Manganese (III) (sal‐N‐1,5,8,12) Complexes

AbstractThe interplay of host‐guest interactions and controlled modulation of spin‐crossover (SCO) behavior is one of the most exploited topics regarding data storage, molecular sensing, and optical technologies. This study examines the effect of solvents on the spin‐crossover (SCO) behavior of manganese(III) complexes [Mn(sal‐N‐1,5,8,12)]I•S (S=CH3OH, C2H5OH, CH3CN) (1) and [Mn(sal‐N‐1,5,8,12)]I3 (2), where (sal‐N‐1,5,8,12)2− is 2,2′‐((1E,13E)‐2,6,9,13‐tetraazatetradeca‐1,13‐diene‐1,14‐diyl)diphenol synthesized by salicylaldehyde and 1,2‐bis(3‐aminopropylamino)ethane. The complexes, crystallizing in orthorhombic or monoclinic systems, exhibit similar supramolecular arrangements with one‐dimensional cationic chains at low temperatures. Magnetic studies reveal that solvent inclusion sharpens the SCO transition and lowers the transition temperature. Specifically, 1⋅CH3OH shows a 13 K thermal hysteresis due to methanol‘s mobility through the channels in the cationic framework. Although the solvent‐free compound was not obtained, compound 2 with a linear I3− anion was synthesized, displaying extensive cation‐anion contacts and a distinct 13 K thermal hysteresis upon heating due to altered intermolecular cooperativity. This emphasizes the significant role of solvent introduction and variation in crystal packing and their impact on the SCO properties.

Structural Study of N-(1,3-Benzothiazol-2-yl)-4-Halobenzenesulfonylhydrazides: Hirshfeld Surface Analysis and PIXEL Calculations

Hydrazonylsulfones such as Bt-NHNHSO2R and their iminotautomers have been studied as optical materials and for their biological potential. In this work, a structural study has been carried out on N-(1,3-benzothiazol-2-yl)-4-(halogenobenzenesulfonyl)-hydrazides (1: X = F, Cl, Br). For (1: X = F), single-crystal X-ray diffraction, Hirshfeld surface analysis, and PIXEL calculations were conducted, while in (1: X = Cl) and (1: X = Br), only single-crystal X-ray diffraction studies were successfully conducted due to the disordering of the solvent. Each compound crystallises with two independent but similar amino tautomers in the asymmetric units: compound (1: X = F) crystallises in the monoclinic P21/c, and the isostructural pair (X: 1 = Cl and Br) crystallises in the tetragonal P-421c space group. In the most stable motif of the supramolecular arrangement, the molecules of the asymmetric unit are connected by classical N–H(hydrazinyl)···N(thiazoyl) hydrogen bonds and several face-to-face, offset π···π interactions. This motif has a very powerful influence on the crystal structure due to its direct links with the other weaker motifs. Other significant intermolecular interactions found in the structure include N–H(hydrazonyl)···O(sulfonate) bonds. Analogous intermolecular interactions were found in similar compounds, leading to the conclusion that those interactions are the most important instabilizing the solid state of hydrazonylsulfones.

Impact of Temperature on the Chiroptical Properties of Thin Films of Chiral Thiophene-based Oligomers.

According to the theoretical model based on the Mueller matrix approach, the experimental electronic circular dichroism (ECD) for thin films of chiral organic dyes can be expressed as the sum of several contributions, two of which are the most significant: 1) an intrinsic component (CDiso) invariant upon sample orientation, reflecting the molecular and/or supramolecular chirality, due to 3D-chiral nanoscopic structures; 2) a non-reciprocal component (LDLB) which inverts its sign upon sample flipping, which arises from the interaction of linear dichroism and linear birefringence in locally anisotropic domains, expression of 2D-chiral micro/mesoscopic structures. In this work, we followed in parallel through ECD and differential scanning calorimetry (DSC) the temperature evolution of the supramolecular arrangements of thin films of five structurally related chiral thiophene-based oligomers with different LDLB/CDiso ratio. By increasing the temperature, regardless of phase transitions observed by DSC analysis, systems with strong CDiso revealed no changes in the ECD spectrum, while compounds with dominant LDLB contribution underwent a gradual (and reversible) reduction of (apparent) ECD signals. These findings demonstrated that the concomitant occurrence of intrinsic and non-reciprocal components in the ECD spectrum of thin films of chiral organic dyes is strictly correlated with solid-state organizations of different stability.

Hirshfeld Surfaces Analysis of Intermolecular Interaction in the Series of Steroid Hormone Molecular Crystals

In this work Hirshfeld surface analysis is performed on the crystallographic-characterized crystal cells of the progesterone, 17α-hydroxyprogesterone, and testosterone hormones. The Hirshfeld surfaces are mapped for a detailed visualization of the electron density distribution around a molecule to understand the atomic-pair close contacts and interaction types within a crystal structure of the studied hormones. The intermolecular forces, including Van der Waals forces, hydrogen bonding, and C–H···π interactions, play essential roles in determining the supramolecular arrangement of all the three molecules in their crystals. These forces contribute to the cohesion, stability, and structural organization of the crystals, ultimately influencing their properties and behaviour in various applications. Two-dimensional fingerprint plots with detailed information about the contribution of each contact to the total Hirschfeld surface allowed to provide a visual representation of the relative importance (in %) of identified intermolecular О···Н/H···O, C···Н/H···C, H···Н interactions within a crystal structure of the studied hormones in the context of “molecule-substance” relations.

Isolation of a Cd-Based Coordination Polymer Containing Mixed Ligands: Time- and Temperature-Dependent Synthesis, Sulfonamide Antibiotics Detection, and Schottky Diode Fabrication.

In this study, we present a new cadmium(II)-based two-dimensional coordination polymer [Cd (L)(NA)(H2O)] (L = Iminol form of N-nicotinoyl glycinate, NA = nicotinate), 1, containing two linkers generated from N-nicotinoyl glycine. A comprehensive investigation was carried out during the synthesis of the coordination polymers by varying the reaction time interval and temperature, and it revealed the formation of three distinct phases, of which two phases were previously reported and one was a new compound (1). The structure of compound 1 was determined by single-crystal X-ray diffraction, and it shows a corrugated layer structure with hydrogen bond interactions leading to three-dimensional supramolecular arrangements. Compound 1 exhibited strong emission at 420 nm when excited at 260 nm in an aqueous medium. The emission behavior of this compound was used for the detection of various sulfonamide antibiotics, sulfadiazine, sulfamethazine, sulfachloropyridazine, sulfameter, sulfaquinoxaline, and sulfathiazole, in the presence of common water pollutants. The luminescence quenching response of compound 1 to sulfonamide antibiotics was significant, ranging from 81 to 94%, and the detection sensitivity reached parts per billion (ppb) levels (226-726 ppb). Compound 1 also used for the fabrication of Schottky diode devices with a barrier height of 0.86 eV along with an excellent ideality factor of 1.24.

Template Assisted Formation of 32 and 34π Octaphyrins Embedded with Dithienopyrrole Cores: A New Scaffold to Unravel Proton Coupled Redox Switching and (Anti)Aromaticity.

Herein, we report two distinct octaphyrins obtained by the condensation of new dithieno[3,2-b:2',3'-d]pyrrole based tetrapyrrane under two different acidic conditions. Fourfold meso-substituted octaphyrin was the major product when the reaction was performed in the presence of an aryl aldehyde using trifluoroacetic acid. Whereas, the sixfold meso-substituted octaphyrin was obtained when the precursor was condensed with pentafluorobenzaldehyde using para-toluenesulfonic acid. Such a template effect of aryl aldehydes in oxidative coupling reactions is realized for the first time in literature. Experimental and theoretical studies suggested that the oxidized form of fourfold meso-substituted octaphyrin is 32π antiaromatic and undergoes proton-coupled electron transfer (PCET) to the protonated form of 34π aromatic congener upon treatment with protic acids. Furthermore, small organic molecules such as alcohols and amines were also found to promote chemical reduction. Single crystal X-ray structure revealed that the aromatic counterpart is highly planar and stabilized by several intermolecular H-bonding and F-F interactions, leading to a large 3D supramolecular arrangement and exhibited colorimetric sensing for fluoride and hydroxide anions. On the other hand, sixfold meso-substituted octaphyrin did not show (anti)aromatic features, PCET or anion sensing, but its intriguing absorption features associated with protonation could make it an ideal candidate for pH-dependent bioimaging.

Ethylenediamine control of the solid-state supramolecular chemistry of zinc phthalocyanine

The two axially ligated H-shaped and T-shaped zinc phthalocyanine derivatives, ZnPc(EDA)ZnPc and ZnPc(EDA), were obtained directly by thermal reaction of ZnPc in ethylenediamine (EDA) solution. Both complexes, ZnPc(EDA)ZnPc and ZnPc(EDA), co-crystallize with the EDA and water molecules yielding good-quality single crystals [ZnPc(EDA)ZnPc][ZnPc(EDA)]2∙2EDA·6H2O − 1. The interaction of Zn center of ZnPc with the axial substituent containing lone electron pair on NH2 groups with zinc phthalocyanine in both zinc phthalocyanine derivatives, ZnPc(EDA)ZnPc and ZnPc(EDA), leads to a deviation of Zn from the centre of cavity by 0.442(3) and 0.514(3) Å in the T- and H-shaped molecules as well as causes, as expected, the deformation of the planar molecule ZnPc into a saucer-shape conformation. Thus, in both types of molecules the central Zn atom of ZnPc complexes with EDA molecule exhibits 4 + 1 coordination formed by the four isoindole nitrogen atoms of the Pc macrocycle at the equatorial position and the nitrogen atom of the amino group of the EDA molecule at the axial position. Supramolecular arrangement of the T-shaped and H-shaped ZnPc-derivatives in crystal is characterized by a reduction of π···π interactions and an improvement in inter-system crossing in relation to parent ZnPc, and is controlled by the NH∙∙∙O, NH∙∙∙N and OH∙∙∙O hydrogen bonds formed between the T- and H-shaped molecules and lattice EDA and water molecules, which results in increase its solubility and improved photophysical and photochemical properties. The aggregation behaviour of T- and H-shaped ZnPc derivatives building crystals 1 in solutions was investigated by UV–Vis spectroscopy. In order to support and verify the experimental results, the DFT and time-dependent (TD) DFT calculations were performed.

Methoxylated Quinoline-Chalcones with Potential Pesticidal Activity: From Synthesis to Supramolecular Framework

In this work, the molecular properties of the (E)-3-(4-nitrobenzylidene)-2-(4-methoxyphenyl)- 2,3-dihydro-1-(phenylsulfonyl)-quinolin-4(1H)-one were studied, both in a solid and isolated state. The effect of changing the substituent groups –OCH3 and –Cl in the phenyl portion was verified, where the structural and electronic properties were compared. The density functional theory was employed using the hybrid exchange-correlation functional with long-range correction M06-2X, combined with the polarized and diffuse basis set 6-311++G(d,p), in the gas phase. The electronic structure was also analyzed by frontier molecular orbitals and molecular electrostatic potential maps, where information about its chemical reactivity was obtained. Also, the supramolecular arrangement was analyzed by Hirshfeld surface (HS), 2D fingerprint plots, and quantum theory of atoms in molecules (QTAIM). The natural bond orbitals (NBO) calculations were carried out to analyze the stability and hyperconjugation energy. Finally, molecular docking was carried out to investigate the affinities of the quinoline-chalcone with a bacterial protein (Agrobacterium pathogens) and an ecdysone receptor-potential pesticidal activity. The results encourage further in vitro and in vivo analyses of the two kinds of organisms investigated.

Odd-even effect in chiral side-chain cyanobiphenyl block copolymer assemblies prepared by polymerization-induced chiral self-assembly.

The precise control of the chirality of polymer assemblies is a challenge faced by scientists and has received significant attention in recent years. In this study, we employed the polymerization-induced chiral self-assembly (PICSA) method to create chiral side-chain cyanobiphenyl (CB) block copolymer (BCP) assemblies. The flexible spacers in chiral CB monomers were regulated to exhibit two distinct odd-even effects in the supramolecular asymmetrical arrangement of the CB mesogens inside BCP assemblies. The research results indicated that the liquid crystalline properties of CB mesogens significantly influence the magnitude and sign of their chiroptical properties. These findings have significant implications for the design of polymer assemblies with designable chiroptical functions.

Tunable biomimetic materials elaborated by ice templating and self-assembly of collagen for tubular tissue engineering.

Synthetic tubular grafts currently used in clinical context fail frequently, and the expectations that biomimetic materials could tackle these limitations are high. However, developing tubular materials presenting structural, compositional and functional properties close to those of native tissues remains an unmet challenge. Here we describe a combination of ice templating and topotactic fibrillogenesis of type I collagen, the main component of tissues' extracellular matrix, yielding highly concentrated yet porous tubular collagen materials with controlled hierarchical architecture at multiple length scales, the hallmark of native tissues' organization. By modulating the thermal conductivity of the cylindrical molds, we tune the macroscopic porosity defined by ice. Coupling the aforementioned porosity patterns with two different fibrillogenesis routes results in a new family of tubular materials whose textural features and the supramolecular arrangement of type I collagen are achieved. The resulting materials present hierarchical elastic properties and are successfully colonized by human endothelial cells and alveolar epithelial cells on the luminal side, and by human mesenchymal stem cells on the external side. The proposed straightforward protocol is likely to be adapted for larger graft sizes that address ever-growing clinical needs, such as peripheral arterial disease or tracheal and bronchial reconstructions.