Chromatin inspired bio-condensation between biomass DNA and guanosine monophosphate produces all-nucleic hydrogel as a hydrotropic drug carrier.

The integration of biomolecules into supramolecular nanostructures forms the basis of the natural world. Naturally occurring liquid-liquid phase separation resulting in biomolecular condensates has inspired the formation of biomolecule-based smart materials with multi-dimensional applications. A non-covalent bio-condensation between biomass DNA and guanosine monophosphate (GMP) has been described, mimicking chromatin folding and creating a unique "all-nucleic" DNA-GMP condensates.

Polyoxometalate-Guanosine Monophosphate Hydrogels with Haloperoxidase-like Activity for Antibacterial Performance.

Haloperoxidases represent an important class of enzymes that nature adopts as a defense mechanism to combat the colonial buildup of microorganisms on surfaces, commonly known as biofouling. Subsequently, there has been tremendous focus on the development of artificial haloperoxidase mimics that can catalyze the oxidation of X (halide ion) in the presence of HO to form HOX. The natural intermediate HOX disrupts the bacterial quorum sensing, thus preventing biofilm formation.

Cobalt-Adenosine Monophosphate Supramolecular Hydrogel with pH-Responsive Multi-Nanozymatic Activity.

Self-assembled metal-ion cross-linked multifunctional hydrogels are gaining a lot of attention in the fields of biomedical and biocatalysis. Herein, we report a heat-triggered metallogel that was spontaneously formed by the self-assembly of adenosine 5'-monophosphate (AMP) and cobalt chloride, accompanied by a color transition depicting an octahedral to tetrahedral transition at high temperature. The hydrogel shows excellent stability in a wide pH window from 1 to 12.

Tuning the Photophysical Properties and Photostability of Bis(naphthobipyrrolylmethene) Derived BODIPY via Functionalization.

A series of NIR absorbing and emitting, naphthobipyrrole derived BODIPY dyes are reported. These dyes possess different functional groups viz. -CHO, -CN, -NO , -Br and Ph at its α,α'-positions.

Effect of a Stannous Fluoride Dentifrice on Biofilm Composition, Gene Expression and Biomechanical Properties.

An in situ study was conducted to examine the mode of action of a 0.454% stannous fluoride (SnF)-containing dentifrice in controlling the composition and properties of oral biofilm. Thirteen generally healthy individuals participated in the study.

Controlled assembly of a bicyclic porphyrinoid and its 3-dimensional boron difluoride arrays.

A fully conjugated cryptand-like bicyclic porphyrinoid ligand 4, incorporating three carbazole linkages and four dipyrrin moieties, was prepared the acid-catalysed condensation of an extended 2,2'-bipyrrole analogue containing a central carbazole moiety and 3,4-diethyl-2,5-diformylpyrrole in 79% isolated yield. This new cryptand-like system acts as an effective ligand and allows for complexation of BF (boron difluoride) subunits. Three BODIPY arrays, containing two, three, and four BF subunits, namely 4·2BF, 4·3BF and 4·4BF, could thus be isolated from the reaction of 4 with BF·EtO in the presence of triethylamine at 110 °C, albeit in relatively low yield.

Kinetic trapping of a cobalt(ii) metallocage using a carbazole-containing expanded carbaporphyrinoid ligand.

The -unsubstituted expanded porphyrinoid 3, incorporating two carbazole moieties, acts as an effective ligand for Co(ii) and permits the isolation and X-ray diffraction-based characterization of a 6 : 3 metal-to-ligand metallocage complex that converts spontaneously to the constituent 2 : 1 metal-to-ligand metalloring species in chloroform solution. The discrete metalloring is formed directly when the Co(ii) complex is crystallized from supersaturated solutions, whereas crystallization from more dilute solutions favors the metallocage. Studies with two other test cations, Pd(ii) and Zn(ii), revealed exclusive formation of the monomeric metalloring complexes with no evidence of higher order species being formed.

Carbazole-Containing Carbadecaphyrins: Non-aromatic Expanded Porphyrins that Undergo Proton-Triggered Conformational Changes.

A pair of meso-unsubstituted expanded carbaporphyrins containing two carbazole moieties were prepared in high isolated yields (82 and 76 %, respectively). The two macrocycles, namely 3 and 4, differ with respect to their substitution at the carbazole N-atoms i. e.

Expanded porphyrins: functional photoacoustic imaging agents that operate in the NIR-II region.

Photoacoustic imaging (PAI) relies on the use of contrast agents with high molar absorptivity in the NIR-I/NIR-II region. Expanded porphyrins, synthetic analogues of natural tetrapyrrolic pigments ( heme and chlorophyll), constitute as potentially attractive platforms due to their NIR-II absorptivity and their ability to respond to stimuli. Here, we evaluate two expanded porphyrins, naphthorosarin () and octaphyrin (), as stimuli responsive PA contrast agents for functional PAI.

Photoinduced Enhanced Decomposition of TBHP: A Convenient and Greener Pathway for Aqueous Domino Synthesis of Quinazolinones and Quinoxalines.

Catalyst-free photoinduced processes in aqueous medium represent significant advancement toward development of green and sustainable pathways in organic synthesis. -Butyl hydroperoxide (TBHP) is a widely used oxidant in organic reactions, where the decomposition of TBHP into its radicals by metal catalysts or other reagents is a key factor for efficient catalytic outcome. Herein, we report a simple and environmentally friendly visible light-promoted synthetic pathway for the synthesis of N-heterocyclic moieties, such as quinazolinones and quinoxalines, in the presence of TBHP as an oxidizing agent in aqueous medium that requires no catalysts/photocatalysts.

Excitonically Coupled Cyclic BF Arrays of Calix[8]- and Calix[16]phyrin as Near-IR-Chromophores.

Two giant calix[n]phyrin derivatives namely calix[8]- (4) and calix[16]phyrin (5), involving two and four BF units, respectively, were prepared through the condensation of the bis-naphthobipyrrolylmethene-BF complex (3) with pentafluorobenzaldehyde. Calix[n]phyrins 4 and 5 display extremely high extinction coefficients (3.67 and 4.

Cationic Organic Nanoaggregates as AIE Luminogens for Wash-Free Imaging of Bacteria and Broad-Spectrum Antimicrobial Application.

The increase in the use of bactericides is a matter of grave concern and a serious threat to human health. The present situation demands rapid and efficient detection and elimination of antibiotic-resistant microbes. Herein, we report the synthesis of a simple -symmetric molecular system (TGP) with an intrinsic positive charge through a single-step Schiff base condensation.

Counter Anion-Directed Growth of Iron Oxide Nanorods in a Polyol Medium with Efficient Peroxidase-Mimicking Activity for Degradation of Dyes in Contaminated Water.

Development of nanozymes, which are nanomaterials with intrinsic enzymatic properties, has emerged as an appealing alternative to the natural enzymes with tremendous application potential from the chemical industry to biomedicine. The self-assembled growth of micrometer-sized oxide materials with controlled nonspherical shapes can be an important tool for enhancing activity as artificial enzymes, as the formation of these superstructures often results in high surface area with favorable impact on catalytic activity. Herein, the growth of rod-shaped FeO microstructures via a one-pot microwave-based method and using a water-poly(ethylene glycol) mixture as a solvent is reported, without the involvement of external shape-directing agents.

One-Pot Magnetic Iron Oxide-Carbon Nanodot Composite-Catalyzed Cyclooxidative Aqueous Tandem Synthesis of Quinazolinones in the Presence of -Butyl Hydroperoxide.

The development of synthetic protocols for biologically important molecules using biocompatible catalysts in aqueous medium holds the key in green and sustainable chemistry. Herein, a magnetically recoverable iron oxide-carbon dot nanocomposite has been demonstrated as an effective catalyst for cyclooxidative tandem synthesis of quinazolinones in aqueous medium using alcohols as starting materials. Fluorescent carbon dots, the newest entrant in the nanocarbon family, were used as the stabilizing agent for the iron oxide nanoparticles, and a continuous layer of carbon dots decorates the iron oxide nanoparticle surface as observed by transmission electron microscopy.

Biocompatible Fe and Ca Dual Cross-Linked G-Quadruplex Hydrogels as Effective Drug Delivery System for pH-Responsive Sustained Zero-Order Release of Doxorubicin.

The ultimate aim in developing controlled drug delivery systems is to derive formulations to achieve drug release at a constant rate over a long duration. The drug release profile that follows zero-order kinetics is crucial for reduction in the drug administration frequency, reduced cytotoxicity, and improved convenience and compliance of patients. Designed drug delivery systems for achieving zero-order release are often complex, expensive, and difficult to manufacture.

Shape-persistent pyrrole-based covalent organic cages: synthesis, structure and selective gas adsorption properties.

Two cryptand-like, shape persistent [2+3] imine cages (1 and 2) derived from oligopyrrolic precursors (diformyl dipyrrylpyridine 3 and diformyl bipyrrole 4) were prepared. These cages contain open cavities as inferred from solid state structural analyses and act as selective CO2 gas adsorbing materials in the solid state.

Air-Stable N, N'-Dihydroporphycene: A Quinoxaline-Fused Tetrapyrrolic Macrocycle That Detects Fluoride Anion via Deprotonation.

An air-stable N, N'-dihydroporphycene, the two-electron reduced form of porphycene, possessing two quinoxaline moieties fused at meso positions, was prepared and characterized. Nuclear magnetic resonance (NMR) and ultraviolet-visible light (UV-vis) spectroscopic studies and single-crystal X-ray diffraction analyses support its formulation as a nonaromatic species. Upon treatment with tetrabutylammonium fluoride (TBAF) in chloroform, a color change is produced that is consistent with deprotonation.

Proton-Coupled Redox Switching in an Annulated π-Extended Core-Modified Octaphyrin.

Proton-coupled electron transfer (PCET) is an important chemical and biological phenomenon. It is attractive as an on-off switching mechanism for redox-active synthetic systems but has not been extensively exploited for this purpose. Here we report a core-modified planar weakly antiaromatic/nonaromatic octaphyrin, namely, a [32]octaphyrin(1.

Cd(ii)-nucleobase supramolecular metallo-hydrogels for in situ growth of color tunable CdS quantum dots.

The integration of nanoscale materials into unconventional environments such as gels is a magnificent strategy towards development of engineered hybrid functional systems. Herein, the in situ formation of CdS quantum dots integrated into a metallogel formed through the coordination of Cd2+ with two pyrimidine nucleobases is reported. Thymine and uracil formed spontaneous hydrogels with nanofibrous morphology through coordinative interaction with Cd2+ ions at alkaline pH.

Carbon Dots as Nanodispersants for Multiwalled Carbon Nanotubes: Reduced Cytotoxicity and Metal Nanoparticle Functionalization.

The colloidal stabilization of multiwalled carbon nanotubes (MWCNTs) in an aqueous medium through noncovalent interactions has potential benefits toward the practical use of this one-dimensional carbonaceous material for biomedical applications. Here, we report that fluorescent carbon nanodots can efficiently function as dispersing agents in the preparation of stable aqueous suspensions of CNTs at significant concentrations (0.5 mg/mL).

Probing Carbocatalytic Activity of Carbon Nanodots for the Synthesis of Biologically Active Dihydro/Spiro/Glyco Quinazolinones and Aza-Michael Adducts.

Herein, we report the fluorescent carbon dots as an effective and recyclable carbocatalyst for the generation of carbon-heteroatom bond leading to quinazolinone derivatives and aza-Michael adducts under mild reaction conditions. The results establish this nanoscale form of carbon as an alternative carbocatalyst for important acid catalyzed organic transformations. The mild surface acidity of carbon dots imparted by -COOH functionality could effectively catalyze the formation of synthetically challenging spiro/glycoquinazolinones under the present reaction conditions.

Annulated Isomeric, Expanded, and Contracted Porphyrins.

Compared to porphyrin, its isomeric, expanded, and contracted analogues are less well explored. This contrast is found to be even more drastic in the case of their peripherally annulated counterparts. Nevertheless, the chemistry of annulated isomeric, expanded, and contracted porphyrins started flourishing recently with considerable efforts over the past few years, as evidenced by an increasing number of publications.

β,β'-Bipyrrole Fusion-Driven cis-Bimetallic Complexation in Isomeric Porphyrin.

An unprecedented cis-bimetallic complex of dinaphthoporphycene (DNP), namely [Pd2(μ-DNP)(μ-OAc)2], is reported. The most striking feature of this complex is that two palladiums coordinate to the macrocycle on the same side and are closely held together (Pd-Pd: 2.67 Å) by two bridging acetate ligands exhibiting significant metal-metal bonding interaction (bond order 0.