Direct triplet sensitization of oligothiophene by quantum dots.

Effective sensitization of triplet states is essential to many applications, including triplet-triplet annihilation based photon upconversion schemes. This work demonstrates successful triplet sensitization of a CdSe quantum dot (QD)-bound oligothiophene carboxylic acid (T6). Transient absorption spectroscopy provides direct evidence of Dexter-type triplet energy transfer from the QD to the acceptor without populating the singlet excited state or charge transfer intermediates. Analysis of T6 concentration dependent triplet formation kinetics shows that the intrinsic triplet energy transfer rate in 1 : 1 QD-T6 complexes is 0.077 ns-1 and the apparent transfer rate and efficiency can be improved by increasing the acceptor binding strength. This work demonstrates a new class of triplet acceptor molecules for QD-based upconversion systems that are more stable and tunable than the extensively studied polyacenes.

1,3,2-Diazaphospholidine (N-Heterocyclic Phosphine)-Mediated Carbon-Phosphorus Bond-Forming, One-Pot Tandem Reaction: A Route to α-Amino Phosphonates.

A novel 1,3,2-diazaphospholidine (N-heterocyclic phosphine)-thiourea-mediated phospha-Mannich/intramolecular nucleophilic substitution reaction has been developed for the construction of an N-C-P bond unit. This transformation enabled a rapid access to cyclic tertiary α-amino phosphonates in one-pot procedure under additive-free mild reaction conditions. This study revealed the critical role of thiourea moiety of the N-heterocyclic phosphine-thiourea in the sequential intramolecular nucleophilic substitution reaction of the phosphonylation.

Utility of Bifunctional N-Heterocyclic Phosphine (NHP)-Thioureas for Metal-Free Carbon-Phosphorus Bond Construction toward Regio- and Stereoselective Formation of Vinylphosphonates.

An efficient and practical protocol for completely regioselective and highly stereoselective synthesis of vinyldiazaphosphonates from N-heterocyclic phosphine (NHP) and allenes via phospha-Michael/intramolecular nucleophilic substitution reaction has been developed. This transformation enabled the synthesis of valuable densely functionalized vinyldiazaphosphonates with a ß-, γ-unsaturated ester moiety under mild reaction conditions. Synthetic utility of vinyldiazaphosphonates was demonstrated by a series of synthetic manipulations.

Dithiafulvenyl-grafted phenylene ethynylene polymers as selective and reversible dispersants for single-walled carbon nanotubes.

Phenylene ethynylene-based π-conjugated polymers grafted with dithiafulvenyl groups on their side chains were found to be efficient in dispersing single-walled carbon nanotubes in a selective and controllable way.

TTFV-based molecular tweezers and macrocycles as receptors for fullerenes.

Hybrids of tetrathiafulvalene vinylogues (TTFVs) and planar arenes were synthesized via the click reaction to form tweezer-like and macrocyclic structures. These compounds were investigated as receptors for fullerenes (C60 and C70) by UV-vis absorption and fluorescence spectroscopy.

Conformational control of TTFV π-frameworks through naphthyl substituents.

With 1- or 2-naphthyl substituted at the vinyl positions, the conformation of the tetrathiafulvalene vinylogue π-framework can be greatly modified from completely planar to highly twisted, and the structural changes lead to markedly different electronic and electrochemical behaviours.

Click synthesized dianthryl-TTFV: an efficient fluorescent turn-on probe for transition metal ions.

Tetrathiafulvalene vinylogue (TTFV) was functionalized with two anthryl fluorophores via Cu(I)-catalyzed alkyne-azide [3 + 2] cycloaddition, forming a dianthryl-TTFV hybrid to show fluorescent turn-on sensing behaviour for Cu(2+), Fe(2+), and Cd(2+) ions in THF with remarkably low detection limit down to the sub-ppm level.

1,2-Bis{4-[1-(anthracen-9-ylmeth-yl)-1H-1,2,3-triazol-4-yl]phen-yl}-1,2-bis-[4,5-bis-(methyl-sulfan-yl)-1,3-dithiol-2-yl-idene]ethane.

The title mol-ecule, C58H44N6S8, has point symmetry 2 (in the Schönfliess notation C2). The related crystallographic twofold axis bis-ects the central ethane bond while it is parallel to the monoclinic unique axis of the unit cell. The dithiole=C-C=dithiole torsion angle is 103.7 (4)° and the triazole-anthracene moieties adopt a pincer-like conformation. The crystal structure features C-H⋯S and C-H⋯N contacts. The distance between the stacked anthracene fragments [centroid-centroid separations of 3.6871 (19) Å, off-set by 1.516 (3) Šand mean anthracene plane-plane separations of 3.361 (2) Å], which are parallel to (101) and (-101), indicates inter-molecular anthracene-anthracene π-π contacts. One of the terminal methyl-sulfanyl groups was modelled as being disordered with two refined orientations that converged to occupancies of 0.809 (5) and 0.191 (5).

Highly sensitive detection of saccharides under physiological conditions with click synthesized boronic acid-oligomer fluorophores.

Two phenylboronic acid based saccharide sensors bearing conjugated oligomer fluorophores with linear and cruciform π-frameworks were synthesized in a modular approach utilizing a Cu-catalyzed alkyne azide cycloaddition (click) reaction. The cruciform fluorophore showed excellent saccharide sensing function under physiological conditions in the mM range, whereas the linear fluorophore gave very limited sensing functions. The different fluorescent sensing behaviours highlight the important role of oligomer fluorophore in the development of effective saccharide sensors.