New types of foldamer scaffolds are formidably challenging to design and synthesize, yet highly desirable as structural mimics of peptides/proteins with a wide repertoire of functions. In particular, the development of peptidomimetic helical foldamers holds promise for new biomaterials, catalysts, and drug molecules. Unnatural l-sulfono-γ-AApeptides were recently developed and shown to have potential applications in both biomedical and material sciences. However, d-sulfono-γ-AApeptides, the enantiomers of l-sulfono-γ-AApeptides, have never been studied due to the lack of high-resolution three-dimensional structures to guide structure-based design. Herein, we report the first synthesis and X-ray crystal structures of a series of 2:1 l-amino acid/d-sulfono-γ-AApeptide hybrid foldamers, and elucidate their folded conformation at the atomic level. Single-crystal X-ray crystallography indicates that this class of oligomers folds into well-defined right-handed helices with unique helical parameters. The helical structures were consistent with data obtained from solution 2D NMR, CD studies, and molecular dynamics simulations. Our findings are expected to inspire the structure-based design of this type of unique folding biopolymers for biomaterials and biomedical applications.

Equilibrium deuterium isotope effects for exchange of hydroxyl deuterons and protons among tert-butanol, phenol, ethanethiol, diethylamine, and ethanol were measured by using NMR and also calculated theoretically. Deuterated ethanol could be used as a probe for measuring equilibrium isotope effects (EIE) for hydroxyl exchange; tert-butanol, phenol, ethanethiol, diethylamine, and pyrrole were used as five representive examples. A procedure called the “one-atom isotope effect” was used to save time in the calculations.

On the basis of the same reaction starting materials, microporous to mesoporous Mn(II)-tris((4-carboxyl)phenylduryl)amine frameworks (FIR-34 to FIR-36, FIR denotes Fujian Institute of Research) with different interpenetration structures have been obtained by applying different solvents and reaction temperatures. FIR-34 is an 8-fold interpenetrating dia framework constructed from small dinuclear [Mn2(COO)4] secondary building units (SBUs), while FIR-35 based on large Mn5 SBUs is a non-interpenetrating framework with (3,8)-connected tfz-d network. Both of them have low porosity. However, the other non-interpenetrating framework (FIR-36) with large mesopores is built by rod-shaped Mn(II)-carboxylate SBUs. Gas sorption measurements for FIR-36 give a Langmuir surface area of 825.3 m2·g–1 and a H2 uptake of 134.5 cm3·g–1 at 77 K and 1 bar.

Seven new metal–organic frameworks based on 3,4-bis(carboxymethoxy)benzoic acid (H3bcba), 3,5-bis(4-pyridyl)-1,2,4-triazolyl (Hbpt) or 4,4′-bipyridyl (4,4′-bipy), named [Sr3(bcba)2(H2O)3]n (1), [Sr(Hbcba)(H2O)3]n (2), [Zn(Hbcba)(H2O)2]n (3), [Zn3(bcba)2(Hbpt)2(H2O)2]n (4), [Zn3(bcba)2(4,4′-bipy)2]n·nH2O (5), [Eu(bcba)(H2O)]n·nH2O (6) and [Nd(bcba)(H2O)]n·nH2O (7), have been successfully synthesized via hydrothermal reaction. Single crystal X-ray diffraction reveals that complexes 1, 3, 4 have one-dimensional (1D) zigzag chains, while the rest are composed of 1D double chains. The 3D network in complex 2 and 3 is formed by hydrogen bonds. Complex 4 constitutes a (3,3,4)-connected network and complex 5 constitutes a (4,5,6)-connected network. Complex 6 and 7 are isomorphous. In addition, the thermogravimetric analyses (TGA) for complexes 1–6 are discussed, and the luminescent properties of complex 3–6 have been also investigated.A series of metal–organic frameworks based on designed 3,4-bis(carboxymethoxy)benzoic acid ligands were synthesized, structurally characterized, and the luminescent properties of some complexes have been also investigated.Download high-res image (57KB)Download full-size image

Triphenylamine and its derivatives have been widely concerned because of their excellent performance in the area of the photoelectric functional material. In this work, we chose a nanosized tris(4′-carboxybiphenyl)amine (H3TPA) as organic ligand. By employing the H3TPA ligand to assemble with M2+ (M = Zn, Cd, and Pb) ions, respectively, three metal-organic frameworks (FIR-43 to FIR-45, FIR denotes Fujian Institute of Research) have been synthesized under different solvent systems. FIR-43 exhibits a 3-connected two-dimensional (2D) network based on mononuclear [Zn(COO)3] second building unit (SBU). Unlike the anionic framework FIR-43, FIR-44 is a neutral 2D layer constructed by trinuclear [Cd3(COO)6] SBU and displays a (3,6)-NbSe2 topology structure. If the weak Pb–O interactions in the range of 2.79–2.88 Å are considered, FIR-45 is a neutral 3D framework built by hexanuclear [Pb6(DMAE)6(COO)6] SBU (DMAE = N,N-dimethylethanolamine) and represents a (3,6)-connected (4·82)2(42·811·102) topology. Thermogravimetric analyses (TGA) and X-ray powder diffraction (PXRD) patterns were used to evaluate their thermal stability and phase purity. Photoluminescence studies showed that they exhibited strong emitting bands in the visible region with high quantum yields and long luminescent lifetimes.Syntheses, Crystal Structures and Fluorescent Properties of Three Metal-Tris((4-carboxyl)phenylduryl)amine Framewroks.The assembly between nanosized tris((4-carboxyl)phenylduryl)amine ligand and M2+ (M = Zn, Cd, and Pb) ions leads to three new metal-organic frameworks, which show excellent fluorescent properties.Download high-res image (380KB)Download full-size image

The resistance developed by life-threatening bacteria toward conventional antibiotics has become a major concern in public health. To combat antibiotic resistance, there has been a significant interest in the development of antimicrobial cationic polymers due to the ease of synthesis and low manufacturing cost compared to host-defense peptides (HDPs). Herein, we report the design and synthesis of amphiphilic polycarbonates containing primary amino groups. These polymers exhibit potent antimicrobial activity and excellent selectivity to Gram-positive bacteria, including multidrug resistant pathogens. Fluorescence and TEM studies suggest that these polymers are likely to kill bacteria by disrupting bacterial membranes. These polymers also show low tendency to elicit resistance in bacteria. Their further development may lead to new antimicrobial agents combating drug-resistance.

We report the synthesis and characterization of two new DPP-based small molecules, BTDPPCN and TTDPPCN. By variation of π-conjugating spacers from bithiophene to thieno[3,2-b]thiophene, a lower LUMO level is obtained for TTDPPCN, but both compounds have a similar band gap of about 1.6 eV. Under ambient conditions, the excellent ambipolarity of BTDPPCN is demonstrated by balanced charge carrier mobilities of 0.065 and 0.031 cm2 V−1 s−1 for n- and p-channels after thermal annealing. The FETs based on TTDPPCN films also showed ambipolar charge transport properties with a very high electron mobility of 0.80 cm2 V−1 s−1 upon thermal annealing at 90 °C and a hole mobility of 0.024 cm2 V−1 s−1 at 150 °C.

•Two TTF-based small molecules were applied for the construction of OFET.•PY3-based devices exhibited hole mobility of 0.01 cm2 V−1 s−1.•The no OFET performance of PY4-based devices is attributed to poor thin-film morphology and low crystallinity.We report two TTF-based small molecules (PY3 and PY4) in which pyridine acts as an electron withdrawing group for the construction of OFET to investigate the relationship between the FET characteristics and structures. While PY3 thin films demonstrated the highest mobilities up to 0.01 cm2 V−1 s−1, there was no OFET performance for PY4. Atomic force microscope (AFM) and X-ray diffraction (XRD) studies were conducted to gain insight into this dissimilarity.The no OFET performance of PY4 is mainly caused by its poor thin-film morphology and low crystallinity.

•In summary, CP is found to self-assemble into distinct morphological structures under different environmental conditions: this macro cyclic conjugated molecule self organized into nanospheres and nanofibers accompanying natural evaporation of its butanol and toluene solutions on mica, silica and HOPG, respectively.•Intermolecular π-π bonding and electronic attraction is believed to be involved in the self-association processes, and affinity or likeness of the solvent molecules and the molecule-surface interactions may be responsible for the molecules to vary their assembly structures in response to the changes in their solvent and substrate.•The constructions of nanosized fibers may found applications in the field of supramolecular electronics.Cyclo [8] pyrrole (CP) is a porphyrin analogue containing eight α-conjugated pyrrole units which are arranged in a nearly coplanar conformation. The π-π interactions between CP molecules lead to regular aggregations through a solution casting process. Using tapping mode atomic force microscope (AFM), we investigated the morphology of self-assembled aggregates formed by deposition of different CP solutions on different substrates. We found that in the n-butanol solution, nanofibrous structures could be formed on the silicon or mica surface. Interestingly, on the highly oriented pyrolytic graphite (HOPG) surface, or silicon and mica surface with a toluene solution, only irregular spherical structures were identified. The difference in the nanomorphology may be attributed to distinct interactions between molecule-molecule, molecule-solvent and molecule-substrate.Cyclo [8] pyrrole (CP) is found to self-assemble into distinct morphological structures under different environmental conditions: this macro cyclic conjugated molecule self-organize into nanospheres and nanofibers accompanying natural evaporation of its n-butanol and toluene solutions on mica, silica and HOPG, respectively. Intermolecular π-π bonding and electronic attraction are believed to play key roles in the self-association processes, and affinity or likeness of the solvent molecules and the molecule-surface interactions may be responsible for the molecules to vary their assembly structures in response to the changes in solvent and substrate. The constructions of nanosized fibers may find applications in the field of supramolecular electronics.

We report the synthesis and characterization of two new DPP-based small molecules, BTDPPCN and TTDPPCN. By variation of π-conjugating spacers from bithiophene to thieno[3,2-b]thiophene, a lower LUMO level is obtained for TTDPPCN, but both compounds have a similar band gap of about 1.6 eV. Under ambient conditions, the excellent ambipolarity of BTDPPCN is demonstrated by balanced charge carrier mobilities of 0.065 and 0.031 cm2 V−1 s−1 for n- and p-channels after thermal annealing. The FETs based on TTDPPCN films also showed ambipolar charge transport properties with a very high electron mobility of 0.80 cm2 V−1 s−1 upon thermal annealing at 90 °C and a hole mobility of 0.024 cm2 V−1 s−1 at 150 °C.