Carlos

A double BN bridged bipyridyl (BNBP) is a novel electron-deficient building block for polymer electron acceptors in all-polymer solar cells. The BN bridging units endow BNBP with fixed planar configuration and low-lying LUMO/HOMO energy levels. As a result, the polymer based on BNBP units (P-BNBP-T) exhibits high electron mobility, low-lying LUMO/HOMO energy levels, and strong absorbance in the visible region, which is desirable for polymer electron acceptors. Preliminary all-polymer solar cell (all-PSC) devices with P-BNBP-T as the electron acceptor and PTB7 as the electron donor exhibit a power conversion efficiency (PCE) of 3.38 %, which is among the highest values of all-PSCs with PTB7 as the electron donor.

A bridge too far: An electron-deficient building block comprises a double BN bridged bipyridyl (BNBP) moiety. The polymer constructed from the BNBP units exhibits high electron mobility, low-lying LUMO/HOMO energy levels, and strong absorbance in the visible range, and shows excellent device performance as polymer electron acceptor for all-polymer solar cells.

By incorporating an anthracene moiety into a framework, a multiresponsive luminescent metal–organic framework (1) has been synthesized, which exhibits both direct chemiluminescence (CL) and dual tunable photoluminescence. By utilizing the CL, 1 has been explored as a selective visual sensor for hydrogen peroxide. Moreover, 1 also exhibits tunable fluorescence response toward different analytes. For electron-rich aromatics, “turn-on” and “turn-off” responses can be simply switched by varying the excitation wavelength. For nitroaromatics, 1 exhibits novel linear quantitative quenching response. Density functional theory (DFT) calculations and experiments have been carried out to study the unique fluorescence response. The multiple luminescence properties and dual tunable sensing response indicate that incorporating anthracene moieties into frameworks should be a promising strategy to develop unprecedented luminescent materials with remarkable sensing properties.

A 3D metal-organic framework (MOF) consisting of an anthracene moiety is reported, which is the first example of a MOF exhibiting both direct chemiluminescence and dual tunable photo­luminescence. The material is explored as a selective visual sensor for probing hydrogen peroxide, a dual sensor for aromatics, and a quantitative sensor for nitroaromatics.

The crystalline packing of a π-extended D_3h-symmetric triptycene reveals a particular π stacking motif with an almost-eclipsed arrangement of adjacent π planes despite the steric repulsion of tert-butyl substituents. Four model compounds were analyzed by using single-crystal X-ray diffraction and theoretical calculations to study the influence of dispersion interactions of molecular parts and understand the relationship between the molecular structure and this unique packing motif.

Eclipse all else: The particular π stacking motif in the crystal packing of a π-extended D_3h-symmetric triptycene, which reveals an almost-eclipsed arrangement of the tert-butyl substituents (see figure), was investigated by using single-crystal X-ray diffraction and theoretical calculations for four model compounds

Supramolecular polymers are a class of macromolecules stabilized by weak non-covalent interactions. These self-assembled aggregates typically undergo stimuli-induced reversible assembly and disassembly. They thus hold great promise as so-called functional materials. In this work, we present the design, synthesis, and responsive behavior of a short supramolecular oligomeric system based on two hetero-complementary subunits. These “monomers” consist of a tetrathiafulvalene-functionalized calix[4]pyrrole (TTF-C[4]P) and a glycol diester-linked bis-2,5,7-trinitrodicyanomethylenefluorene-4-carboxylate (TNDCF), respectively. We show that when mixed in organic solvents, such as CHCl₃, CH₂ClCH₂Cl, and methylcyclohexane, supramolecular aggregation takes place to produce short oligomers stabilized by hydrogen bonding and donor–acceptor charge-transfer (CT) interactions. The self-associated materials were characterized by ¹H NMR and UV/Vis/NIR absorption spectroscopy, as well as by concentration- and temperature-dependent absorption spectroscopy and dynamic light scattering (DLS) analyses of both the monomeric and oligomerized species. The self-associated system produced from TTF-C[4]P and TNDCF exhibits a concentration-dependent aggregation behavior typical of supramolecular polymers. Further support for the proposed self-assembly came from theoretical calculations. The fluorescence emitting properties of TNDCF are quenched under conditions that promote the formation of supramolecular aggregates containing TTF-C[4]P and TNDCF. This quenching effect has been utilized as a probe for the detection of substrates in the form of anions (i.e., chloride) and nitroaromatic explosives (i.e., 1,3,5-trinitrobenzene). Specifically, the addition of these substrates to mixtures of TTF-C[4]P and TNDCF produced a fluorescence “turn-on” response.

Explosive fluorescence: The hetero-complementary monomeric subunits, tetrathiafulvalene–calix[4]pyrrole (TTF-C[4]P) and bis-2,5,7-trinitrodicyanomethylenefluorene-4-carboxylate (TNDCF), assemble to form oligomeric structures at higher concentrations. Dual-analyte-responsive behavior is seen, with de-aggregation of the supramolecular oligomers and a corresponding increase in the fluorescence intensity being seen in the presence of 1,3,5-trinitrobenzene (TNB) or Cl⁻ anions.

We present an approach that makes use of DNA base pairing to produce hydrogen-bonded macrocycles whose supramolecular structure can be transferred from solution to a solid substrate. A hierarchical assembly process ultimately leads to two-dimensional nanostructured porous networks that are able to host size-complementary guests.

DNA base pairing is used to produce hydrogen-bonded macrocycles whose supramolecular structure can be transferred from solution to a solid substrate. A hierarchical assembly process ultimately leads to two-dimensional nanostructured porous networks that are able to host size-complementary guests.

Zinc phthalocyanines (ZnPc) have been attached to the peri-position of a perylenemonoimide (PMI) and a perylenemonoanhydride (PMA), affording electron donor–acceptor conjugates 1 and 2, respectively. In addition, a perylene-monoimide-monoanhydride (PMIMA) has been connected to a ZnPc through its imido position to yield the ZnPc-PMIMA conjugate 10. The three conjugates have been studied for photoinduced electron transfer. For ZnPc-PMIMA 10, electron transfer occurs upon both ZnPc and PMIMA excitation, giving rise to a long-lived (340 ps) charge-separated state. For ZnPc-PMI 1 and ZnPc-PMA 2, stabilization of the radical ion pair states by using polar media is necessary. In THF, photoexcitation of either ZnPc or PMI/PMA produces charge-separated states with lifetimes of 375 and 163 ps, respectively.

Long-lived charge separation: Perylenemonoimides (PMI), perylenemonoanhydrides (PMA), and perylene-monoimide-monoanhydrides (PMIMA) are studied as the oxidizing counterpart of phthalocyanines in electron donor–acceptor hybrids. The three systems show different degrees of orbital partitioning and generate long-lived charge-separation states upon photoexcitation.