Phenyl-Substituted Cibalackrot Derivatives: Synthesis, Structure, and Solution Photophysics.

Three symmetrically and three unsymmetrically substituted cibalackrot (7,14-diphenyldiindolo[3,2,1-:3',2',1'-][1,5]naphthyridine-6,13-dione, ) dyes carrying two derivatized phenyl rings have been synthesized as candidates for molecular electronics and especially for singlet fission, a process of interest for solar energy conversion. Solution measurements provided singlet and triplet excitation energies and fluorescence yields and lifetimes; conformational properties were analyzed computationally. The molecular properties are close to ideal for singlet fission.

Experimental comparison of properties of natural and synthetic osmotic dilators.

Purpose: The in vitro study compares natural and synthetic osmotic dilators in selected parameters influencing their clinical efficacy.

Methods: Diameters of Laminaria and synthetic dilators (Dilapan-S and Dilasoft) were measured in dry state, during free swelling in isotonic solution and during swelling against a force. Three aspects were evaluated-diameter increase, speed of action and consistency of action.

Unprecedented meta-substitution of calixarenes: direct way to inherently chiral derivatives.

Electrophilic aromatic substitution in the calix[n]arene series is a well-established procedure leading exclusively to para-substituted derivatives. An unprecedented regioselectivity of the mercuration reaction leading to the meta-substituted calix[4]arenes is described. These compounds represent a new type of substitution pattern in classical calixarene chemistry and open the door for the straightforward synthesis of inherently chiral receptors based on calixarenes.

Synthesis of hexadehydrotribenzo[a,e,i][12]annulenes by acetylene insertion into an open-chain precursor.

A simple synthesis of a hexadehydrotribenzo[a,e,i][12]annulene by insertion of acetylene into an open-chain diiodo precursor under Sonogashira coupling conditions has been developed and used to prepare a rigid three-armed star connector for testing as a building block for a two-dimensional hexagonal hydrogen-bonding array.

N-acetyl-D-glucosamine substituted calix[4]arenes as stimulators of NK cell-mediated antitumor immune response.

A series of calixarenes substituted with 2-acetamido-2-deoxy-beta-D-glucopyranose linked by a thiourea spacer was prepared and tested for binding activity to heterogeneously expressed activation receptors of the rat natural killer cells NKR-P1, and the receptor CD69 (human NK cells, macrophages). In the case of NKR-P1, the binding affinity of beta-D-GlcNAc-substituted calixarenes carrying two or four sugar units was in a good agreement with the inhibitory potencies of the linear chitooligomers (chitobiose to chitotetraose) reported previously. The influence of GlcNAc substitution of the calixarene skeleton on binding affinity for CD69 receptor was more profound and the 5,11,17,23-tetrakis[N-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-thioureido]-25,26,27,28-tetrapropoxycalix[4]arene (cone) (1) proved to be the best CD69 ligand identified to date.

DNA condensation and cell transfection properties of guanidinium calixarenes: dependence on macrocycle lipophilicity, size, and conformation.

Calix[n]arenes functionalized with guanidinium groups at the upper rim and alkyl chains at the lower rim bind to DNA, condense it, and in some cases, promote cell transfection depending on their structure and lipophilicity. Atomic force microscopy (AFM) studies indicate that upon DNA binding the hydrophobic association of the lipophilic chains of cone guanidinium calix[4]arenes drives the formation of intramolecular DNA condensates, characterized by DNA loops emerging from a dense core. Furthermore, hexyl and octyl chains confer to these calixarenes cell transfection capabilities.

Scanning force microscopy of upright-standing, isolated calixarene-porphyrin heterodimers.

A water soluble calixarene[4]arene 1 with four guanidinium substituents on the upper rim and propyl groups below was anchored in the propylamino coating of smooth silica particles, and a tricarboxylate-tripod porphyrin 2 of 2 nm height was attached to these cationic islands. The molecular complex with a height of 3 nm was unequivocally detected on the particles' surface by atomic force microscopy in the tapping mode. Although deposits of 1 (height: 1 nm) and 2 (height: 2 nm) were also evident on the smooth silica particles, 3 nm seems to be the minimal height to identify single objects.

A heterodifunctionalised ferrocene derivative that self-assembles in solution through complementary hydrogen-bonding interactions.

A heterodifunctionalised ferrocene, containing a carboxylic acid and an amidopyridine unit, self-assembles in organic solvents through complementary hydrogen bonds.

Calix[4]arene-porphyrin conjugates as versatile molecular receptors for anions.

[structure: see text] Appending tetraphenylporphyrin units to the calix[4]arene skeleton via the ureido function leads to novel anion receptors designed for anion and/or cation detection by UV-vis spectroscopy. Calixarenes in the cone or 1,3-alternate conformations bearing two ureido moieties on the upper rim represent well-preorganized cavities where the anion can be held by synchronous hydrogen bonding interaction with the NH groups.