Long Stability of Atomically Precise Red Emissive Copper Nanoclusters within the Gel and Their Use As a Potential Catalyst and Fluorescent Ink.

Herein, an amphiphile-based hydrogel (with 5% DMF) containing natural amino acid residue has been used to prepare and stabilize red-emitting CuNCs for several months. Though different methods have been attempted, amphiphile and 4-mercaptobenzoic acid (4-MBA)-containing hydrogels are pinpointed to be the base medium to stabilize this new Cu-cluster. From a MALDI-TOF MS analysis it was found that it is a Cu-atom cluster stabilized by three 4-MBA ligands.

1-Naphthylacetic acid appended amino acids-based hydrogels: probing of the supramolecular catalysis of ester hydrolysis reaction.

A 1-naphthaleneacetic acid-appended phenylalanine-derivative (Nap-F) forms a stable hydrogel with a minimum gelation concentration (MGC) of 0.7% w/v (21 mM) in phosphate buffer of pH 7.4.

Thianthrenation-promoted photoinduced alkene difunctionalization and aryl allylation with Morita-Baylis-Hillman adducts.

An organophotoredox-catalyzed alkoxyallylation of feed-stock olefins, through thianthrenation using a Morita-Baylis-Hillman adduct as an allylating agent, is described. Site-selective addition of MeOH to an alkene-thianthrenium salt and its subsequent conversion into a nucleophilic radical species forms the basis of this unique difunctionalization strategy. The scope is also expanded into radical aryl allylation.

Cationic and amphiphilic peptide-based hydrogels with dual activities as anticancer and antibacterial agents.

The emergence of peptide-based functional biomaterials is on the rise. To fulfil this purpose, a series of amphiphilic peptides, such as HN-X-Met-Phe-CH, where X = L-lysine (CP1), X = L-histidine (CP2), and X = L-leucine (CP3), have been designed, synthesised, purified and fully characterised. Herein, we reported peptide-based supramolecular hydrogels with antibacterial and anticancer activities.

Effect of molar ratio and concentration on the rheological properties of two-component supramolecular hydrogels: tuning of the morphological and drug releasing behaviour.

Self-assembled supramolecular hydrogels offer great potential as biomaterials and drug delivery systems. Specifically, peptide-based multicomponent hydrogels are promising materials due to their advantage that their mechanical and physical properties can be tuned to enhance their functionalities and broaden their applications. Herein, we report two-component assembly and formation of hydrogels containing inexpensive complementary anionic, BUVV-OH (A), and cationic, KFFC12 (B), peptide amphiphiles.

Reaction of a Co(III)-peroxo complex with nitric oxide: putative formation of a peroxynitrite intermediate.

A Co(II) complex, [Co(L)(HO)](ClO), 1, having a bidentate ligand L [L = bis(3,5-dimethylpyrazolyl)methane] has been synthesized. Complex 1 in acetonitrile solution at -40 °C, in the presence of HO and NEt, afforded the corresponding Co(III)-peroxo species, [Co(L)(O)], as the transient intermediate 1a. Thermal instability precluded its isolation and further characterization.

Fe-Catalyzed Hydroallylation of Unactivated Alkenes with Vinyl Cyclopropanes.

Catalytic, reductive C-C bond formation between alkenes and vinyl cyclopropane (VCP) through hydrogen atom transfer (MHAT) is developed. Despite VCP's use as probes in radical-clock experiments, translation of this manifold into synthetic methods for accessing elusive C-C bonds remains largely unexplored. This work represents the first foray into this front where the high chemoselectivity of MHAT for alkene over VCP was pivotal for realizing the strategy.

Reaction of a nitrosyl complex of Mn(II)-porphyrinate with superoxide: NOD activity is favoured over SOD activity.

A five-coordinated {Mn(NO)} complex of Mn(II)-porphyrinate, [Mn(TMPP)(NO)], 1 {TMPPH = 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin}, upon reaction with two equivalents of superoxide (O) in THF at -40 °C results in the corresponding Mn-OH complex [Mn(TMPP)(OH)], 2, the formation of a putative Mn-peroxynitrite intermediate. Spectral studies and chemical analysis suggest that one equivalent of superoxide ion is consumed to oxidize the metal center of complex 1 leading to [Mn(TMPP)(NO)], while the subsequent equivalent reacts with [Mn(TMPP)(NO)] to form the corresponding peroxynitrite intermediate. UV-visible and X-band EPR spectroscopic studies suggest the involvement of a Mn-oxo species in the reaction, which forms through the O-O bond cleavage of the peroxynitrite moiety with concomitant release of NO.

Histidine-Containing Amphiphilic Peptide-Based Non-Cytotoxic Hydrogelator with Antibacterial Activity and Sustainable Drug Release.

A histidine-based amphiphilic peptide () has been found to form an injectable transparent hydrogel in phosphate buffer solution over a pH range from 7.0 to 8.5 with an inherent antibacterial property.

Metal ion-induced assembly of dipeptide-attached perylenediimide for fluorometric "turn on" detection of biologically important small molecule.

A dipeptide-appended perylenediimide (PDI-CFF) fluorescent molecule was designed, synthesized, and characterized. Though the molecule does not dissolve in any individual solvent, it dissolves well in an organic/water mixed solvent system such as tetrahydrofuran/water. This new fluorescent molecule was self-assembled in a tetrahydrofuran/water mixture to form both nanofibrous network structures and a nano ring structure.

Amino acid containing amphiphilic hydrogelators with antibacterial and antiparasitic activities.

Nanoscale self-assembly of peptide constructs represents a promising means to present bioactive motifs to develop new functional materials. Here, we present a series of peptide amphiphiles which form hydrogels based on β-sheet nanofibril networks, several of which have very promising anti-microbial and anti-parasitic activities, in particular against multiple strains of including drug-resistant ones. Aromatic amino acid based amphiphilic supramolecular gelators C-Phe-CONH-(CH)-NH ( = 6 for P1 and = 2 for P3) and C-Trp-CONH-(CH)-NH ( = 6 for P2 and = 2 for P4) have been synthesized and characterized, and their self-assembly and gelation behaviour have been investigated in the presence of ultrapure water (P1, P2, and P4) or 2% DMSO(v/v) in ultrapure water (P3).

Ir-Catalyzed Ligand-Free Directed C-H Borylation of Arenes and Pharmaceuticals: Detailed Mechanistic Understanding.

An efficient method for Ir-catalyzed ligand free ortho borylation of arenes (such as, 2-phenoxypyridines, 2-anilinopyridines, benzylamines, benzylpiperazines, benzylmorpholines, benzylpyrrolidine, benzylpiperidines, benzylazepanes, α-amino acid derivatives, aminophenylethane derivatives, and other important scaffolds) and pharmaceuticals has been developed. The reaction underwent via an interesting mechanistic pathway, as revealed by the detailed mechanistic investigations by using kinetic isotope studies and DFT calculations. The catalytic cycle is found to involve the intermediacy of an Ir-boryl complex where the substrate C-H activation is the turnover determining step, intriguingly without any appreciable primary KIE.

An acid-promoted substitution manifold of γ-aminocyclopentenone enables divergent access to polycyclic indole derivatives.

We demonstrated γ-aminocyclopentenones to be a suitable surrogate for reactive cyclopentadienone a -substitution manifold. This approach enabled its orchestrated annulation with "tailored" bis-nucleophiles and to furnish complex β,γ-annulated cyclopentanoids or indole-based polycyclic architectures. This strategy represents a generalized means for direct, regioselective and stereoselective β,γ-functionalization of monosubstituted or unsubstituted aminocyclopentenones.

Reaction of a {Co(NO)} complex with superoxide: Formation of a six coordinated [Co(NO)(O)] species followed by peroxynitrite intermediate.

A nitrosyl complex of cobalt(II) porphyrinate, [Co(FTPP)(NO)], (FTPPH = 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) having {Co(NO)} configuration was synthesized and characterized by means of spectroscopic and structural analyses. Single crystal X-ray structure of the complex revealed the square pyramidal geometry around the cobalt center with a bent nitrosyl group. It reacts with superoxide (O) ion in CHCl at -40 °C to result in the corresponding nitrite (NO) complex.

Can a Nitrosyl of a Mn(II)-Porphyrin Complex Release Nitroxyl/HNO?

In general, the nitrosyl complexes of Mn(II)-porphyrinate having the {Mn(NO)} configuration are not considered as HNO or nitroxyl (NO) donors because of [Mn-NO] nature. A nitrosyl complex of Mn(II)-porphyrin, [Mn(TMPP)(NO)], [TMPPH = 5,10,15,20-tetrakis-4-methoxyphenylporphyrin], is shown to release HNO in the presence of HBF. It is evidenced from the characteristic reaction of HNO with triphenylphosphine and isolation of the [(TMPP)Mn(HO)](BF), .

Unprecedented Reactivity of γ-Amino Cyclopentenone Enables Diversity-Oriented Access to Functionalized Indoles and Indole-Annulated Ring Structures.

Observation of an unexpected, Lewis acid promoted displacement of latent reactive γ-amino group on cyclopentenone presented unparalleled opportunity for enone functionalization and annulations with indole derivatives, which is developed in the current study. Herein, a vast range of C3/N-indolyl enones and indole alkaloid-like compound were accessed in excellent yields (up to 99 %) and selectivity through a one-pot operation. The mechanism most likely involves an unprecedented trait of Piancatelli-type rearrangement where influence of the gem-diaryl group appeared crucial.

Peptide-Based Gel in Environmental Remediation: Removal of Toxic Organic Dyes and Hazardous Pb and Cd Ions from Wastewater and Oil Spill Recovery.

A dipeptide-based synthetic amphiphile bearing a myristyl chain has been found to form hydrogels in the pH range 6.9-8.5 and organogels in various organic solvents including petroleum ether, diesel, kerosene, and petrol.

Multicomponent, Tandem 1,3- and 1,4-Bisarylation of Donor-Acceptor Cyclopropanes and Cyclobutanes with Electron-Rich Arenes and Hypervalent Arylbismuth Reagents.

A tandem catalytic process for 1,3- and 1,4-bisarylation of donor-acceptor (D-A) cyclopropanes and cyclobutanes is disclosed. This strategy capitalizes on the use of two distinct sources of nucleophilic and electrophilic arylating agents, affording the formation of two new C-C bonds in an orchestrated multicomponent fashion with the aid of a catalytic Lewis acid. Mechanistic investigations have revealed it to be a stereoselective process, and products could be easily elaborated into other useful compounds.

Nitric Oxide Dioxygenase Activity of a Nitrosyl Complex of Mn(II)-Porphyrinate in the Presence of Superoxide: Formation of a Mn(IV)-oxo Species through a Putative Peroxynitrite Intermediate.

A nitrosyl complex of Mn-porphyrinate, [(FTPP)Mn(NO)], (FTPPH = 5,10,15,20 (pentafluorophenyl)porphyrin), was synthesized and characterized. Spectroscopic and structural characterization revealed complex as a penta-coordinated Mn-nitrosyl with a linear Mn-N-O (180.0°) moiety.

[3 + 2]-Annulation of Azaoxyallyl Cations and Thiocarbonyls for the Assembly of Thiazolidin-4-ones.

A base-promoted, efficient [3 + 2] annulation between azaoxyallyl cations and thiocarbonyls is reported for flexible access to highly functionalized thiazolidin-4-one derivatives in good to excellent yields. An intriguing feature of this method is the metal or Lewis acid free late-stage entry of distinct set of functional groups at C2 of thiazolidin-4-ones via substitution of a latent amino functional group. Overall, this approach constitutes a general platform for convenient access to this medicinally important scaffold.

Lewis acid catalyzed annulation of spirocyclic donor-acceptor cyclopropanes with exo-heterocyclic olefins: access to highly functionalized bis-spirocyclopentane oxindole frameworks.

Lewis acid catalyzed highly efficient [3+2] annulation of spirocyclic Donor-Acceptor cyclopropanes (DACs) with exo-heterocyclic olefins is reported to furnish various biologically relevant dispiro-2,3-dioxopyrrolidine[cyclopentane]oxindole and dispiropyrazolone[cyclopentane]oxindole frameworks. This report highlights the use of oxindole-activated spiro-DACs as potential synthons to access complex dispirocarbocyclic oxindoles via ring-enlargement of the former, with high yields and diastereoselectivity.

Efficient removal of Hg, Cd and Pb from aqueous solution and mixed industrial wastewater using a designed chelating ligand, 2-pyridyl-N-(2'-methylthiophenyl) methyleneimine (PMTPM).

The present study is focused on the removal of Hg, Cd and Pb ions from aqueous solution using a tridentate chelating agent, 2-pyridyl-N-(2'-methylthiophenyl) methyleneimine (PMTPM); and applicability of such removal from industrial wastewater using PMTPM is also investigated. The results showed that the metal ions removal efficiency using PMTPM was in the order of Hg(99.46%) > Cd(95.