Understanding the role of conjugation length on the self-assembly behaviour of oligophenyleneethynylenes.

Oligophenyleneethynylenes (OPEs) are prominent building blocks with exciting optical and supramolecular properties. However, their generally small spectroscopic changes upon aggregation make the analysis of their self-assembly challenging, especially in the absence of additional hydrogen bonds. Herein, by investigating a series of OPEs of increasing size, we have unravelled the role of the conjugation length on the self-assembly properties of OPEs.

A novel ternary combination of deep eutectic solvent-alcohol (DES-OL) system for synergistic and efficient delignification of biomass.

A novel ternary system consisting of deep eutectic solvent-alcohol (DES-OL) mixture was developed for the effective delignification of lignocellulosic biomass. Optimization studies included selecting suitable co-solvent (among n-BuOH, n-PrOH & EtOAc) for treating biomass (rice husk, rice straw and wheat straw), altering the DES-to-alcohol ratio (2:1, 1:1 and 1:2) as well as the reaction temperature (50, 80 and 120 °C). The highest delignification (∼50%) was observed using n-butanol assisted DES (ChCl: OA) at a ratio of 2:1, with high solid loading of 15% (w/v) at 120 °C (∼1.2 bar) in a 60 min reaction. Post pretreatment, high purity lignin was recovered after distilling off butanol for recycling. Microscopy and CPMAS/NMR studies confirmed the effectiveness of DES-OL pretreatment on biomass delignification.

Cost effective and practically viable oil spillage mitigation: Comprehensive study with biochar.

Biochar is carbonaceous mass that is produced from pyrolysis or gasification of biomass. It is so far majorly explored for soil remediation application, but recently it has attracted a lot of interest because of its unexplored applications in the area of adsorption. In this work, detailed study on biochars produced from two different feeds (rice husk and saw dust), at two different temperatures (450 and 550°C) and two different rates (fast and slow) of pyrolysis are discussed for oil spill mitigation. Biochar is characterized in detail by various techniques such as FTIR, 13C CPMAS, FESEM, RAMAN, TGA to determine the structural composition and observe the extent of pyrolysis. Tests to assess the performance of produced biochars as sorbents for oil spill mitigation have been demonstrated. The as produced biochars selectively absorbed crude oil from oil/water biphasic mixtures in various capacities.

Strategies to create hierarchical self-assembled structures via cooperative non-covalent interactions.

Cooperative phenomena are common processes involved in the hierarchical self-assembly of multiple systems in nature, such as the tobacco mosaic virus and a cell's cytoskeleton. Motivated by the high degree of order exhibited by these systems, a great deal of effort has been devoted in the past two decades to design hierarchical supramolecular polymers by combining different classes of cooperative interactions. In this review, we have classified the field of supramolecular polymers depending on the cooperative non-covalent forces driving their formation, with particular emphasis on recent examples from literature. We believe that this overview would help scientists in the field to design novel self-assembled systems with improved complexity and functionalities.

Correction: Strategies to create hierarchical self-assembled structures via cooperative non-covalent interactions.

Correction for 'Strategies to create hierarchical self-assembled structures via cooperative non-covalent interactions' by Christina Rest et al., Chem. Soc. Rev., 2015, DOI: 10.1039/c4cs00497c.

Concentration-dependent rhombitrihexagonal tiling patterns at the liquid/solid interface.

We report STM investigations on a linear oligophenyleneethylene (OPE)-based self-assembling Pd(ii) complex 1 that forms highly-ordered concentration dependent patterns on HOPG. At high concentration, 2D lamellar structures are observed whereas the dilution of the system below a critical concentration leads to the formation of visually attractive rhombitrihexagonal Archimedean tiling arrangements featuring three different kinds of polygons: triangles, hexagons and rhombi. The key participation of the Cl ligands attached to the Pd(ii) centre in multiple C-H···Cl interactions was demonstrated by comparing the patterns of 1 with those of an analogous non-metallic system 2.

Tb3+ sensitization in a deoxycholate organogel matrix, and selective quenching of luminescence by an aromatic nitro derivative.

In this article, we present the discovery of a metallo-organogel derived from a Tb(3+) salt and sodium deoxycholate (NaDCh) in methanol. The gel was made luminescent through sensitization of Tb(3+) by doping with 2,3-dihydroxynaphthalene (DHN) in micromolar concentrations. Rheological measurements of the mechanical properties of the organogel confirmed the characteristics of a true gel. Significant quenching of Tb(3+) luminescence was observed in the deoxycholate gel matrix by 2,4,7-trinitrofluorenone (TNF), but not by several other polynitro aromatics. Microscopic studies (AFM, TEM and SEM) revealed a highly entangled fibrous network. The xerogels retained luminescent properties suggesting the possibility for application in coatings, etc.

Charge-transfer interaction mediated organogels from bile acid appended anthracenes: rheological and microscopic studies.

In this article we present dual-component charge-transfer interaction (CT) induced organogel formation with bile acid anthracene conjugates as donors and 2,4,7-trinitrofluorenone (TNF) as the acceptor. The use of TNF (1) as a versatile electron acceptor in the formation of gels is demonstrated through the formation of gels with different steroidal groups on the anthracene moiety in a variety of solvents ranging from aromatic hydrocarbons to long chain alcohols. Thermal stability and variable temperature fluorescence experiments were performed on these CT gels. Dynamic rheological experiments conducted on these gels suggest that these are viscoelastic soft materials and with the gel strength can be modulated by varying the donor/acceptor ratios.

Supramolecular chirality in organogels: a detailed spectroscopic, morphological, and rheological investigation of gels (and xerogels) derived from alkyl pyrenyl urethanes.

This Article addresses the formation of chiral supramolecular structures in the organogels derived from chiral organogelator 1R (or 2R), and its mixtures with its enantiomer (1S) and achiral analogue 3 by extensive circular dichroism (CD) spectroscopic measurements. Morphological analysis by atomic force microscopy (AFM) and scanning electron microscopy (SEM) were complemented by the measurements of their bulk properties by thermal stability and rheological studies. Specific molecular recognition events (1/3 vs 2/3) and solvent effects (isooctane vs dodecane) were found to be critical in the formation of chiral aggregates. Theoretical studies were also carried out to understand the interactions responsible for the formation of the superstructures.