New fluorescent chemosensors for metal ions in solution

Block copolymer vesicles can be prepared in solution from a variety of different amphiphilic systems. Polystyrene-block-poly(acrylic acid), polystyrene-block-poly(ethylene oxide), and many other block copolymer systems can produce vesicles of a wide range of sizes; those in the range of 100–1000 nm have been explored extensively. Different factors, such as the absolute and relative block lengths, the presence of additives (ions, homopolymers, and surfactants), the water content in the solvent mixture, the nature and composition of the solvent, the temperature, and the polydispersity of the hydrophilic block, provide control over the types of vesicles produced. Their high stability, resistance to many external stimuli, and ability to package both hydrophilic and hydrophobic compounds make them excellent candidates for use in the medical, pharmaceutical, and environmental fields. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 923–938, 2004

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/polb.10739

Preparation of block copolymer vesicles in solution

The synthesis, aggregation behavior, and catalytic activity of rhodium complexes of a series of Xantphos derivatives with surface-active pendant groups, −4-C6H4O(CH2)nC6H4(SO3Na)− (n = 0, 3, 6) is described. Electron microscopy experiments show that these ligands and their complexes form vesicles in water if the hydrophobic part of the ligand is large enough (n = 3, 6). The formed aggregates are stable at elevated temperatures (90 °C), and their presence leads to a significant enhancement of the solubility of organic substrates in aqueous solution. This enhanced solubility results directly in a higher reaction rate in the rhodium-catalyzed hydroformylation of 1-octene. Furthermore, recycling experiments show that the TOF and the high selectivity toward the more valuable linear aldehyde remains approximately the same in four consecutive runs. This indicates that the aggregates stay intact during the recycling and the active rhodium complex is retained in the water-phase quantitatively.

Accelerated Biphasic Hydroformylation by Vesicle Formation of Amphiphilic Diphosphines

New highly sensitive and selective catalytic DNA biosensors for metal ions

Polyamine-based anion receptors: extraction and structural studies

The protonation and metal ion (Cu2+, Zn2+, Cd2+, Pb2+) complexation abilities of three heteroditopic cryptands in solution are described and the relevant equilibrium constants are reported. The two distinct binding subunits of the ligands act cooperatively in the coordination of M(H2O)2+ (M = metal ion) species. The cryptand L1 binds five protons in very acidic solution and crystallizes as [(H5L1)(ClO4)5].4 H2O in the monoclinic space group P21ln with a = 14.281(4), b = 14.313(7), c = 24.082(8) A, β = 92.00(2)°, Z = 4, R = 0.079, and wR2 = 0.2010. The molecule shows an endo-endo conformation with a pseudo-threefold symmetry axis passing through the two bridgehead nitrogen atoms. All the cryptands (L1-L3) readily form inclusion complexes with Cu2+, Ni2+, Zn2+, Cd2+, and Pb2+ ions at the tren end of the cavity. The crystal structure of [(NiL2Cl)Cl].5.5 H2O.CH3OH is also reported [C2/c, a = 26.671(6), b = 16.784(4), c = 18.591(8) A, β = 101.006(14)°, Z = 8, R = 0.091, and wR2 = 0.1424]. The NiII ion resides in a trigonal-bipyramidal coordination environment with the equatorial sites occupied by the three secondary nitrogen atoms of the cryptand and the axial sites occupied by a bridgehead nitrogen atom and a Cl- ion.

Complexation Properties of Heteroditopic Cryptands towards Cu2+, Zn2+, Cd2+, and Pb2+ in Aqueous Solution: Crystal Structures of [(H5L1)(ClO4)5]·4 H2O and [(NiL2Cl)Cl]·5.5 H2O·CH3OH

Spontaneous formation of vesicles by a cryptand-based bola-amphiphile

Photophysical properties of tris-acetylpyrene derivative of a cryptand in different environments

Time-resolved emission studies of tris-acetylpyrene derivative of a cryptand exhibiting localised monomer, intramolecular exciplex and intramolecular excimer emissions in different environments

Prasun Bandyopadhyay

Papers

Complexation Properties of Heteroditopic Cryptands towards Cu2+, Zn2+, Cd2+, and Pb2+ in Aqueous Solution: Crystal Structures of [(H5L1)(ClO4)5]·4 H2O and [(NiL2Cl)Cl]·5.5 H2O·CH3OH

Spontaneous formation of vesicles by a cryptand-based bola-amphiphile

Photophysical properties of tris-acetylpyrene derivative of a cryptand in different environments

Time-resolved emission studies of tris-acetylpyrene derivative of a cryptand exhibiting localised monomer, intramolecular exciplex and intramolecular excimer emissions in different environments

Photophysical properties of tris-methoxycoumarin derivative of a cryptand