Abhimanew Dhir

Au microparticles mediated construction of a logic based dual channel molecular keypad lock.

New melamine based ligand with pyrene as a fluorophore is synthesized and characterized. The sequential addition of Au(3+) ions and ascorbic acid to the solution of in EtOH-H2O (9.5 : 0.5 v/v) generates gold microparticles (AuMPs). However, the particle size distribution and fluorescence behaviour on sequential additions are different and contribute to the construction of a new logic based molecular dual channel keypad lock system.

A cytochrome C encapsulated metal organic framework as a bio-material for sulfate ion recognition

An ensemble of a cytochrome c and 2,6-naphthalene dicarboxylate based metal organic framework is synthesized. The bio-material selectively senses sulfate ions in 100% aqueous solution and in the solid phase with practical applications.

Cyanide induced self assembly and copper recognition in human blood serum by a new carbazole AIEE active material

New carbazole based AIEE material is synthesized with fluoro group which shows ESIPT induced AIEE in H2O:THF (80:20, v/v). The material selectively recognizes Cu(2+) and CN(-) ions in contrasting modes with detection limits of 5 × 10(-6)Mol L(-1) and 12×10(-5)Mol L(-1) respectively and acts as a dual action chemosensor. The recognition of copper has also been observed in human serum, thus facilitating the detection of increased level of free Cu(2+) ions and its quantification in human serum.

Nano dispersion of 3D Cd(II) coordination polymer: synthetic blood plasma anticoagulant

A new 2,6-naphthalene dicarboxylate and quinoline based Cd(II) coordination polymer {[Cd(NDC)(QN)]}n (RAM 1) is designed and synthesized. The nano dispersion of RAM 1 behaves as an artificial blood plasma anticoagulant.

New triangular steroid-based A(LS)3 type gelators for selective fluoride sensing application

A new series of cholesteryl based triangular A(LS)3 type molecules, compounds 1–4, has been synthesized and tested for gelation and anion sensing applications. Melamine or benzene-1,3,5-tricarbonyl chloride (BTC) was used as an aromatic platform precursor (A) in these compounds around which three cholesteryl derivatives (S) were arranged using linker units (L). In compounds 1–4, the molecular structures were systematically altered by changing the aromatic platform, the chain lengths of the linker units as well as by introducing additional hydrogen bonding functionalities onto the linker units. It was found that the gelling as well as self-assembly properties of the compounds 1–4 can be controlled by systematically changing their structural components. STEM and TEM analyses on xerogels of 2–4 from triethylamine solvent revealed that the fundamental units of these xerogel networks are fibres which get assembled into more porous fibrous networks as a function of the chain length of the linker units. Moreover, these compounds were capable of sensing the hazardous F− ions selectively out of the 11 anions tested by exhibiting fluorescence enhancement. The F− sensing ability of these compounds could be controlled by changing the length of the linker unit. In some cases, visual changes such as change in color of the gel or gel to sol transformation were also observed on addition of F− ions. A possible mechanism for the observed sensing of F− ions is also proposed in this study.

A sandwich-type zinc complex from a rhodamine dye based ligand: a potential fluorescent chemosensor for acetate in human blood plasma and a molecular logic gate with INHIBIT function

A new fluorescent zinc complex Zn-R1 based on rhodamine-tris(hydroxymethyl)aminomethane spirolactam ligand R has been synthesised and characterised. Single crystal X-ray diffraction analyses revealed that in this complex R exists in its ring opened spirolactam form R1 and the complex Zn-R1 has a distinctive geometry in which the Zn2+ ion is sandwiched between the dye motifs of two R1 ligands. Zn-R1 exhibits very strong orange fluorescence and pink colour in acetonitrile : H2O (9.5 : 0.5%, v/v) solutions and the addition of acetate ions causes quenching of the fluorescence accompanied by a colour change from pink to colourless. The mode of interaction between Zn-R1 and acetate ions has been confirmed by absorption, fluorescence, NMR and HR-MS techniques. Further, Zn-R1 is highly selective towards acetate ions and exhibits potential as a sensor for acetate in solid state and in solutions including human blood plasma-like systems. The reversibility of acetate binding by Zn-R1 is demonstrated by adding an excess of acetate and Zn2+ ions alternately to the solution of Zn-R1 for multiple times. The fluorescence output shown by Zn-R1 on addition/non-addition of Zn2+ and acetate ions as sequential inputs can be used to construct an INHIBIT type molecular logic gate.

Self-assembled material of palladium nanoparticles and a thiacalix[4]arene Cd(II) complex as an efficient catalyst for nitro-phenol reduction

A new material based on the self-assembly of palladium nanoparticles by a thiacalix[4]arene (TCA) based Cd(II) complex is synthesized. Hydrophobic interactions between tert-butyl groups on either ends of the TCA–cadmium complex and palladium nanoparticles generate self-assembled material 5. The material shows its potential application as a heterogeneous recyclable catalyst for the reduction of 4-nitrophenol (4-NP). The rate constants for catalyst 5 observed in 1st and 5th catalytic cycles were 0.117 min−1 and 0.109 min−1, respectively, revealing the efficiency of the catalyst.

Dansyl-carbazole AIEE material for selective recognition of thiourea derivatives

A new dansyl-carbazole based compound DACB is designed and synthesized, which exhibits aggregation induced emission enhancement (AIEE) behaviour in H2O:THF (60:40, v/v). The persistence of AIEE in DACB can be attributed to the presence of intermolecular hydrogen bonding interactions as proved by single crystal X-ray data crystal. The aggregates of DACB in H2O:THF (60:40, v/v) are utilized for recognition of thiourea and urea derivatives. It is observed that aggregates of DACB in H2O:THF (60:40, v/v) selectively recognize thiourea motifs over urea motifs. The affinity pattern observed among thiourea derivatives follows the order, tetramethylthiourea (TMTU) > dimethylthiourea (DMTU) > thiourea (TU).

Selective and Sensitive Fluorescent Detection of Picric Acid by New Pyrene and Anthracene Based Copper Complexes

New pyrene and anthracene based copper complexes 4 and 7 respectively were designed, synthesized and characterized. The fluorescence behaviour of both 4 and 7 were evaluated towards nitro aromatics and anions. Both 4 and 7 possess high selectivity for the detection of well-known explosive picric acid (PA) by showing maximum fluorescence affinity. Furthermore, complex 4 showed similar sensing efficiency towards PA at different pH ranges. It was also used for real world applications, as illustrated by the very fast detection of PA from soil samples observed directly by naked eye.

Multifunctional Zn(II) Complexes: Photophysical Properties and Catalytic Transesterification toward Biodiesel Synthesis

Using 4-substituted derivatives of phenol-based compartmental Schiff-base hydroxyl-rich ligand, four multifunctional binuclear Zn(II) complexes have been synthesized and characterized. The photophysical properties of these complexes were explored in the solid state, in solutions, and in poly(methyl methacrylate) (PMMA) matrix, which revealed their good potential as tunable solid state emitters. Some of these complexes acted as efficient catalysts for the transesterification of esters and canola oil showing their potential in biodiesel generation. Mechanistic investigations using ESI-MS revealed that the transesterification catalyzed by these complexes proceeds through two types of acyl intermediates.