Redox-active pyrrole (Py) monomers were intercalated into 1D nanochannels of [Cd(NDC)0.5(PCA)]·Gx (H2NDC = 2,6-napthalenedicarboxylic acid, HPCA = 4-pyridinecarboxylic acid, G = guest molecules) (1) - a fluorescent 3D MOF (λem = 385 nm). Subsequent activation of 1⊃Py upon immersing into iodine (I2) solution resulted in an increment of the bulk electrical conductivity by ∼9 orders of magnitude. The unusual increase in conductivity was attributed to the formation of highly oriented and conducting polypyrrole (PPy) chains inside 1D nanochannels and specific host-guest interaction in 1⊃PPy thereof. The Hall-effect measurements suggested 1⊃PPy to be an n-type semiconductor material with remarkably high-carrier density (η) of ∼1.5 × 10(17) cm(-3) and mobility (μ) of ∼8.15 cm(2) V(-1) s(-1). The fluorescence property of 1 was almost retained in 1⊃PPy with concomitant exciplex-type emission at higher wavelength (λem = 520 nm). The here-presented results on [MOF⊃Conducting Polymer] systems in general will serve as a prototype experiment toward rational design for the development of highly conductive yet fluorescent MOF-based materials for various optoelectronic applications.

Commercial supercapacitors, mainly made of activated carbon, offers insufficient capacitance at high cost. Recently, graphene-based materials are emerging as smart alternatives. Reduction of graphene oxide (GO) is an elegant and important approach to produce reduced graphene oxide (rGO), because it holds the promise to closely resemble its physicochemical properties with pristine graphene. The conventional reducing agents such as sodium borohydride and hydrazine are strong reducing agents, and cannot be recycled. The fast reaction kinetics bring an imbalance in the desirable properties of rGO. Here, we present onepot chemical reduction of GO in aqueous medium by an unconventional mild reducing agent (FeCl2/HCl) where pure rGO is isolated and the reducing agent is recycled upon simple treatment of the filtrate with HCl. The fabricated all-solid-state supercapacitor of assynthesized rGO exhibited significantly higher specific capacitance (171 F/g at 1.1 A/g), remarkable cycling stability (>80% retention of capacitance beyond 100,000 continued cycles), and flexibility (>500 bending cycles), which is comparatively better than those of rGO derived from conventional reducing agents. Use of commercially available organic electrolyte further boosted the supercapacitor performance (282 F/g at 1.8 A/g) of rGO. 1

(MOFs) in common organic solvents which heavily limits thin-film processing on various support substrates for fabrication of devices. SURMOFs are in principle possible to achieve virtually on any support including flexible plastic and cloth substrates with molecular-level control of the dimensionality as well as functionality. [2] Subsequent loading of guest molecules opens-up an immense opportunity of SURMOFs for applications in storage and separation of gas and liquid, making highly specific sensors, performing unconventional catalysis, and overall, for the development of stimuli responsive electronic and magnetic thin-film devices. [3] As for the electronic applications of metal-organics, the experimental challenges are, in general, i) patterning feasibility as thin-films by employing standard lithographic techniques, ii) controllable thickness and orientation, iii) film homogeneity, iv) reasonable porosity, v) desirable electrical conductivity, vi) tuning electrical conductivity of thin-films by physical and chemical stimuli, and finally, vii) stability of the thin-films at ambient conditions, specifically against moisture and heat. At a glance, SURMOFs appear suitable platforms to overcome all these challenges to a considerable extent except the facts that MOFs are i) intrinsically poor conductors of electricity (due to insulating nature of the organic ligands and an energy mismatch in the overlap between ligand's p orbitals and metal ion's d orbitals); and ii) usually nonhydrophobic and sensitive to moisture. [4] Such important issues bring to the origin of this work: How to fabricate SURMOF thin-film devices hydrophobic as well electrically conductive?In order to achieve reasonably good electrical conductivity, so far, HKUST-1-based (a porous metal-organic coordination polymer comprised of Cu ion and 1,3,5-benzene tricarboxylic acid (BTC) ligand (benzene tricarboxylic acid) SURMOF thinfilm device was infiltrated with organic electrophile guest tetracyanoquinodimethane (TCNQ) and the subsequent redoxreaction between Cu 2+ ions and TCNQ molecules resulted in a significant increase in the conductivity value within the semiconducting span. [5] However, HKUST-1-based SURMOF thin-films are not really hydrophobic. Another disadvantage

Metal−organic coordination polymers (CPs) downsized to thin films with controllable electrical conductivity are promising for electronic device applications. Here we demonstrate, for the first time, thermally driven resistive switching in thin films of semiconducting CPs consisting of silver ion and tetracyanoquinodimethane ligand (AgTCNQ). High-quality and highly hydrophobic thin films of Ag-TCNQ were fabricated through a layer-by-layer approach upon sacrificing a pre-deposited layer of Cu-TCNQ on a thiolated Au substrate. Reversible switching between the high-resistance state (HRS) at 300 K and the low-resistance state (LRS) at 400 K with an enhancement factor of as high as ∼10 6 in the electrical resistance was realized. The phenomenon is attributed to the alternation of the Schottky barrier at the metal−semiconductor interface by thermal energy and not due to the formation of a conductive filament. Our discovery of thermally driven resistive switching as well as sacrificial growth of CP thin films on an organically modified substrate holds promise for the development of solution-processable non-volatile memory devices.

Owing to long spin-relaxation time and chemically customizable physical properties, molecule-based semiconductor materials like metal-phthalocyanines offer promising alternatives to conventional dilute magnetic semiconductors/oxides (DMSs/DMOs) to achieve room-temperature (RT) ferromagnetism. However, air-stable molecule-based materials exhibiting both semiconductivity and magnetic-order at RT have so far remained elusive. We present here the concept of supramolecular arrangement to accomplish possibly RT ferromagnetism. Specifically, we observe a clear hysteresis-loop (H ≈ 120 Oe) at 300 K in the magnetization versus field (M-H) plot of the self-assembled ensembles of diamagnetic Zn-phthalocyanine having peripheral F atoms (ZnFPc; S = 0) and paramagnetic Fe-phthalocyanine having peripehral H atoms (FePc; S = 1). Tauc plot of the self-assembled FePc···ZnFPc ensembles showed an optical band gap of ∼1.05 eV and temperature-dependent current-voltage (I-V) studies suggest semiconducting characteristics in the material. Using DFT+U quantum-chemical calculations, we reveal the origin of such unusual ferromagnetic exchange-interaction in the supramolecular FePc···ZnFPc system.