Zheng Meng

Dartmouth College · Department of Chemistry

This paper describes a novel synthetic approach for the conversion of zero-valent copper metal into a conductive two-dimensional layered metal–organic framework (MOF) based on 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) to form Cu3(HHTP)2. This process enables patterning of Cu3(HHTP)2 onto a variety of flexible and porous woven (cotton, silk, nylo...

Sensitive and selective detection of chemical and biological analytes is critical in various scientific and technological fields. As an emerging class of multifunctional materials, covalent organic frameworks (COFs) with their unique properties of chemical modularity, large surface area, high stability, low density, and tunable pore sizes and funct...

This paper describes structural elucidation of a layered conductive metal−organic framework (MOF) material Cu 3 (C 6 O 6 ) 2 by microcrystal electron diffraction with sub-angstrom precision. This insight enables the first identification of an unusual π-stacking interaction in a layered MOF material characterized by an extremely short (2.70 Å) close...

This paper describes structural elucidation of a layered conductive metal−organic framework (MOF) material Cu 3 (C 6 O 6 ) 2 by microcrystal electron diffraction with sub‐angstrom precision. This insight enables the first identification of an unusual π‐stacking interaction in a layered MOF material characterized by an extremely short (2.70 Å) close...

This paper describes the demonstration of a series of heterobimetallic, isoreticular 2D conductive metal–organic frameworks (MOFs) with metallophthalocyanine (MPc, M=Co and Ni) units interconnected by Cu nodes towards low‐power chemiresistive sensing of ppm‐levels of carbon monoxide (CO). Devices achieve sub‐part‐per‐million (ppm) limits of detecti...

This paper describes the demonstration of a series of heterobimetallic, isoreticular 2D conductive metal–organic frameworks (MOFs) with metallophthalocyanine (MPc, M=Co and Ni) units interconnected by Cu nodes towards low‐power chemiresistive sensing of ppm‐levels of carbon monoxide (CO). Devices achieve sub‐part‐per‐million (ppm) limits of detecti...

The use of reticular materials in the electrochemical reduction of carbon dioxide to value-added products has the potential to enable tunable control of the catalytic performance through the modulation of chemical and structural features of framework materials with atomic precision. However, the tunable functional performance of such systems is sti...

The development of new two-dimensional (2D) d-π conjugated metal-organic frameworks (MOFs) holds great promise for the construction of a new generation of porous and semiconductive materials. This paper describes the synthesis, structural characterization, and electronic properties of a new d-π conjugated 2D MOF based on the use of a new ligand 2,3...

The recent development of metallophthalocyanine (MPc)-based frameworks has opened the door to a new class of promising multifunctional materials with emergent electrical, magnetic, optical, and electrochemical properties. This perspective article outlines the process of molecular engineering—which uses the strategic selection and combination of mol...

This paper describes the first implementation of an array of two-dimensional (2D) layered conductive metal–organic frameworks (MOFs) as drop-casted film electrodes that facilitate voltammetric detection of redox active neurochemicals in a multi-analyte solution. The device configuration comprises a glassy carbon electrode modified with a film of co...

This paper describes the synthesis of a novel intrinsically conductive two-dimensional (2D) covalent organic framework (COF) through the aro-matic annulation of 2,3,9,10,16,17,23,24-octa-aminophthalocyanine nickel(II) and pyrene-4,5,9,10-tetraone. The intrinsic bulk conductivity of the COF material (termed COF-DC-8) reached 2.51×10⁻³ S/m, and incre...

This paper describes the first demonstration of using a series of isoreticular nickel phthalocyanine- and nickel naphthalocyanine-based bimetallic conductive two-dimensional (2D) metal–organic frameworks (MOFs) as active materials in chemiresistive sensing of gases. Devices achieve exceptional sensitivity at sub-part-per-million (ppm) to part-per-b...

This paper describes the first demonstration of a general concept for achieving facile proton conduction within a class of layered two-dimensional aza-fused π-conjugated covalent organic frameworks (COFs). The built-in phenanthroline moieties promote efficient ad-sorption of water and acidification by H3PO4 to produce excellent proton conductivitie...

The movements of three pairs of different non-photoresponsive rotaxanes could be efficiently controlled by visible light through photo-induced proton-transfer (PIPT) strategy in the presence of photoacid 1-MEH. Moreover, the PIPT...

This Communication describes the use of porous coordination polymers (PCP) with integrated metal bis(dithiolene) units to achieve electrochemically controlled capture and release of ethylene in the solid state. Applying positive potential (+2.0 V) to these PCPs promotes ethylene capture, and subsequent dose of negative potential (−2.0 V) induces th...

The threading of biomolecules through pores or channels in membranes is important to validate the physiological activities of cells. To aid understanding of the controlling factors required for the translocation in space with confined size and distorted conformation, it is desirable to identify experimental systems with minimized complexity. We dem...

A new triptycene-derived oxacalixarene H1 was efficiently synthesized via a template cyclization step, and an anilino substituted macrocycle H2 was subsequently afforded through a straightforward nucleophilic displacement reaction on the active chlorine atom in H1. H1 adopted a fixed boat-like 1,3-alternate conformation and showed moderate complexa...

Ratchet mechanism has proved to be a key principle in designing molecular motors and machines that exploit random thermal fluctuations for directional motion with energy input. To integrate ratchet mechanism into artificial systems, precise molecular design is prerequisite to control the pathway of relative motion between their subcomponents, which...

A new class of chiral macrocyclic arene composed of three chiral 2,6-dihydroxyltriptycene subunits bridged by methylene groups was designed and synthesized. Structural studies showed that the macrocyclic molecule adopts a hex-nut-like structure with a helical chiral cavity and highly fixed conformation. Efficient resolution was achieved through the...

The manipulation of supramolecular devices to carry out sophisticated and programmed tasks is bound up with the spatial allocation of their components, especially the threading direction of the guest, which controls the host–guest orientation in the device. However, insights are needed to probe more possibilities for steering the threading directio...

Development of novel macrocyclic hosts with the capability of binding selected substrates in specific complexation modes is always a very important and attractive topic in host-guest chemistry. Recently, we reported a novel macrotricyclic polyether containing two triptycene skeletons with rigid structure and two dibenzo-30-crown-10 moieties, which...

A new acid/base controllable host-guest system based on a triptycene-derived macrotricyclic host and protonated 4,4'-bipyridinium/pyridinium salts was developed. Moreover, the competition complexation process between the host and two different kinds of 4,4'-bipyridinium salts could also be chemically controlled by acid and base.

The motions of biomolecular machines are usually multistep processes, and involved in a series of conformational changes. In this paper, a novel triply interlocked [2](3)catenane composed of a tris(crown ether) host eTC and a circular ditopic guest with three dibenzyl ammonium (DBA) sites and three N-methyltriazolium (MTA) sites was reported. Due t...

A novel triply interlocked [2]rotaxane based on triptycene-derived tris(crown ether) host and a guest embed with three dibenzylammonium and three N-methyltriazolium recognition sites was designed and synthesized, which showed pulley-like shuttling motion controlled by acid and base.

Iptycenes are a class of aromatic compounds that contain several arene units fused to a bicyclo[2.2.2]octatriene bridgehead system. This unique, rigid, three-dimensional molecular structure provides several open electron-rich cavities with an abundance of reactive positions, and makes them useful for a wide range of applications. There is no doubt...

According to the threading-followed-by-stoppering approach, a tristable molecular shuttle could be efficiently synthesized in 76% yield using a K(+) ion template and a bulky isocyanate stopper. This high yield was reasoned from the combination of the powerful template effect and highly effective stoppering reaction. Through detailed studies of the...

A "pseudosuitane"-type complex between a triptycene-derived bis(crown ether) host and 1,1'-(anthracene-9,10-diyl)bis(N-benzylmethanaminium) can be formed in the solution and the solid state, which provides us a new method for the synthesis of linear polyrotaxanes.

Synthetic macrocyclic hosts have played key roles in the development of host–guest chemistry. Crown ethers are a class of macrocyclic molecules with unique flexible structures. They have served as the first generation of synthetic hosts, and researchers have extensively studied them in molecular recognition. However, the flexible structures of simp...

New tristable [n]rotaxanes (n = 2, 3, 4) were developed based on host-guest interactions, featuring pyromellitic diimide (PmI), anthraquinone (AQ) and N-methyltriazolium (MtA) units as the three kinds of recognition sites and triptycene-derived macrocycle(s) as the moveable part. In the [2]rotaxane molecular shuttle, the states of the macrocycle on...

Triptycene-derived macrotricyclic polyether containing an anthracene unit is a powerful host for 1,2-bis(pyridium)ethane, diquat and 2,7-diazapyrenium salt with association constants of the 1 : 1 complexes at >10(5) M(-1). Crystal structures showed that π-π stacking interactions between the host and the guests play an important role in the formatio...

A novel [2](2)rotaxane based on pentiptycene-derived bis(crown ether) can be efficiently synthesized via a "click chemistry" method and the subsequent N-methylation. Due to the different affinities of DB24C8 with the ammonium and triazolium stations, the wing-flapping movement of the DB24C8 "wings" in the [2](2)rotaxane can be easily achieved by ac...