Self-assembled organic and hybrid materials derived from oligo-(-phenyleneethynylenes).

Oligo-(-Phenyleneethynylenes) (OPEs) have garnered widespread interest over the past three decades due to their excellent opto-electronic properties. However, the chief focus has been on the use of mainly small molecules or polymeric systems for the study of their structural diversity in opto-electronic applications. Recently, researchers have started delving deeper into their utility in material applications.

Photochromic Conjugated Microporous Polymer Manifesting Bio-Inspired pcFRET and Logic Gate Functioning.

Design and synthesis of solid-state photochromic materials remain a challenge because of high structural constrain. However, this can be mitigated in attaining structural flexibility by introducing permanent porosity into the system. Here, we report for the first time the design and synthesis of a photochromic conjugated microporous polymer (pcCMP) by assembling photochromic dithienylethene aldehyde and benzene-1,3,5-tricarbohydrazide.

Photoswitchable J-Aggregated Processable Organogel by Integrating a Photochromic Acceptor.

A novel π-chromophoric 1,4-bis(anthracenylethynyl)benzene (BAB)-based highly emissive J-aggregated organogel has been synthesized and characterized. Single-crystal structure determination of asymmetric π-chromophoric bola-amphiphilic (dodecyl and triethyleneglycolmonomethylether containing side chains of bis(anthracenylethynyl)benzene) supports J-aggregation. Further, a photochromic acceptor chromophore, 4,4'-(perfluorocyclopent-1-ene-1,2-diyl)bis(5-methylthiophene-2-carbaldehyde), is noncovalently encapsulated in the gel and photoswitching studies have been performed based on photochromic Förster resonance energy transfer.

Dynamic Resolution of Piezosensitivity in Single Crystals of π-Conjugated Molecules.

Targeted synthesis of piezoresponsive small molecules and in-depth understanding of their mechanism is of utmost importance for the development of smart devices. This work reports the synthesis, structure and piezosensitivity of a bola-amphiphile 1,4-bis(pentyloxy)-2,5-bis(2-pyridineethynyl)-benzene (C5-PPB). Depending on the rate of compression, two different phases in C5-PPB can be generated.

Solvent Adaptive Dynamic Metal-Organic Soft Hybrid for Imaging and Biological Delivery.

A solvent responsive dynamic nanoscale metal-organic framework (NMOF) [Zn(1 a)(H O) ] has been devised based on the self-assembly of Zn and asymmetric bola-amphiphilic oligo-(p-phenyleneethynylene) (OPE) dicarboxylate linker 1 a having dodecyl and triethyleneglycolmonomethylether (TEG, polar) side chains. In THF solvent, NMOF showed nanovesicular morphology (NMOF-1) with surface decorated dodecyl chains. In water and methanol, NMOF exhibited inverse-nanovesicle (NMOF-2) and nanoscroll (NMOF-3) morphology, respectively, with surface projected TEG chains.

In situ Stabilization of Au and Co Nanoparticles in a Redox-Active Conjugated Microporous Polymer Matrix: Facile Heterogeneous Catalysis and Electrocatalytic Oxygen Reduction Reaction Activity.

We report a novel in situ method for synthesis of metal nanoparticles (NPs)-CMP (conjugated microporous polymer) composites based on a redox-active, donor-acceptor CMP, tris-(4-aminophenyl)amine (TPA)-perylenediimide (PDI). The TPA-PDI CMP, comprising triphenylamine as an electron donor and PDI as an acceptor, showed stable charge-separated state and semiconducting behavior. Further, TPA-PDI CMP has been exploited for in situ stabilization of metal (Au and Co) NPs, and two novel nanocomposites (Au@TPA-PDI and Co@TPA-PDI) were prepared.

Solvent-Modulated Emission Properties in a Superhydrophobic Oligo( p-phenyleneethynylene)-Based 3D Porous Supramolecular Framework.

A chromophoric oligo( p-phenyleneethynylene) (OPE) bola-amphiphile with dioxyoctyl side chains (HOPE-C) has been self-assembled with Cd to form a 1D coordination polymer, {Cd(OPE-C)(DMF)(HO)} (1), which is further interdigitated to form a 2D network. Such 2D networks are further interwoven to form a 3D supramolecular framework with surface-projected alkyl chains. The desolvated framework showed permanent porosity, as realized from the CO adsorption profile.

Nanovesicular MOF with Omniphilic Porosity: Bimodal Functionality for White-Light Emission and Photocatalysis by Dye Encapsulation.

A new π-chromophoric and asymmetric bola-amphiphilic oligo-( p-phenylene ethynylene)-based tetracarboxylate (OPE-TC1) linker was designed, synthesized, and self-assembled with Zn(OAc). The resulting nanoscale metal-organic framework (MOF) {Zn(OPE-TC1)} (NMOF-1) showed a vesicular morphology and permanent porosity with omniphilic pore surface. NMOF-1 showed cyan emission with high quantum efficiency (49%).

Metallophthalocyanine-based redox active metal-organic conjugated microporous polymers for OER catalysis.

We report the design and synthesis of two Co2+ and Zn2+ phthalocyanine (PC)-based redox active metal-organic conjugated microporous polymers (MO-CMP), CoCMP and ZnCMP, respectively, obtained by a Schiff base condensation reaction. CoCMP, where Co2+ is stabilized by N4-coordination of PC, has shown stable and efficient electrocatalytic activity towards the OER with a low overpotential of 340 mV.

Pure white light emission and charge transfer in organogels of symmetrical and unsymmetrical π-chromophoric oligo-p-(phenyleneethynylene) bola-amphiphiles.

Two novel bola-amphiphilic oligo-p-(phenyleneethynylene) (OPE) dicarboxylates have been synthesized having non-polar and mixed-polar side chains. This led to gelation in both with vesicular morphology. Upon in situ loading of a suitable dye and redox-active molecule, pure white light emitting and charge transfer (CT)-gels, respectively, were realized.

Reversible Polymorphism, Liquid Crystallinity, and Stimuli-Responsive Luminescence in a Bola-amphiphilic π-System: Structure-Property Correlations Through Nanoindentation and DFT Calculations.

We report the design, synthesis, detailed characterization, and analysis of a new multifunctional π-conjugated bola-amphiphilic chromophore: oligo-(p-phenyleneethynylene)dicarboxylic acid with dialkoxyoctadecyl side chains (OPE-C-1). OPE-C-1 shows two polymorphs at 123 K (OPE-C-1') and 373 K (OPE-C-1″), whose crystal structures were characterized via single crystal X-ray diffraction. OPE-C-1 also exhibits thermotropic liquid crystalline property revealing a columnar phase.

Self-cleaning MOF: realization of extreme water repellence in coordination driven self-assembled nanostructures.

Bio-inspired self-cleaning surfaces have found industrial applications in oil-water separation, stain resistant textiles, anti-biofouling paints in ships Interestingly, self-cleaning metal-organic framework (MOF) materials having high water contact angles and corrosion resistance have not been realized so far. To address this issue, we have used the fundamentals of self-assembly to expose hydrophobic alkyl chains on a MOF surface. This decreases the surface free energy and hence increases hydrophobicity.

Highly Luminescent Microporous Organic Polymer with Lewis Acidic Boron Sites on the Pore Surface: Ratiometric Sensing and Capture of F(-) Ions.

Reversible and selective capture/detection of F(-) ions in water is of the utmost importance, as excess intake leads to adverse effects on human health. Highly robust Lewis acidic luminescent porous organic materials have potential for efficient sequestration and detection of F(-) ions. Herein, the rational design and synthesis of a boron-based, Lewis acidic microporous organic polymer (BMOP) derived from tris(4-bromo-2,3,5,6-tetramethylphenyl)boron nodes and diethynylbiphenyl linkers with a pore size of 1.

Series of dicyanamide-interlaced assembly of zinc-Schiff-base complexes: crystal structure and photophysical and thermal studies.

Four new dicyanamide (dca) bridged multinuclear Zn(II)-Schiff-base complexes, {[Zn2L(1)(μ1,5-dca)dca]·CH3OH}2 (1), [Zn2L(2)(μ1,5-dca)dca]n (2), [Zn3L(3)2(μ1,5-dca)2]n (3), and [(ZnL(4))2Zn(μ1,5-dca)dca]n (4), have been synthesized using four different Schiff bases L(1)H2 = N,N(/)-bis(3-methoxysalicylidenimino)-1,3-diaminopentane, L(2)H2 = N,N'-bis(5-bromo-3-methoxysalicylidenimino)-1,3-diaminopropane, L(3)H2 = N,N'-bis(5-bromosalicylidenimino)-1,3-diaminopropane, and L(4)H2 = N,N'-bis(5-chlorosalicylidenimino)-1,3-diaminopropane and NaN(CN)2 in order to extend the metal-ligand assembly. The directional properties of linear end-to-end bridging dca ligands have resulted in different metal ion connectivities leading to unique variety of templates in each of the complexes. All the ligands and complexes have been characterized by microanalytical and spectroscopic techniques.