Controllable Synthesis and Fabrication of Semiconducting Nanorod/Nanowire Bundles of Fe[TCNQ]₂(H₂O)₂via Electrochemically Induced Solid−Solid Phase Transformation of TCNQ Microcrystals

Abstract

A generic electrochemical approach has been employed to synthesize, fabricate, and characterize 2-D/3-D nanorod/nanowire bundles of semiconducting/magnetic Fe[TCNQ]2(H2O)2 material. The redox-based TCNQ/Fe[TCNQ]2(H2O)2 solid−solid phase transformation utilizes the one-electron reduction of TCNQ-modified electrodes coupled with ingress of Fe2+ (aq) ions, from bulk solution, into the reduced TCNQ crystal lattice via a nucleation−growth process. The reverse oxidation process, involving Fe[TCNQ]2(H2O)2/TCNQ transformation, also proceeds via an analogous nucleation−growth mechanism. The overall chemically reversible solid−solid transformation therefore can be represented by the reaction TCNQ0 (S) + 2e- + Fe2+ (aq) + 2H2O ⇌ {Fe[TCNQ]2(H2O)2}(S). SEM monitoring of the transformation process revealed substantial differences in both the morphology and crystal size of electrochemically produced Fe[TCNQ]2(H2O)2 material and the parent TCNQ crystals. Importantly, this electrochemical approach provides facile access to fabricate and manipulate the morphology of Fe[TCNQ]2(H2O)2 on conducting (Au, Pt, glassy carbon) and semiconducting (indium tin oxide) surfaces. Other aspects of the solid−solid electrochemical conversion have been probed by voltammetric, spectroscopic, and other surface science techniques.

Organic Solid-State Reactions

“…When TCNQ crystals are adhered to graphite electrodes the electroreduction provides the radical anion that is irreversibly trapped by metal ions that diffuse from the aqueous electrolyte. Thus, semiconducting salts CuTCNQ [102] and Fe(TCNQ) 2 (H 2 O) 2 were synthesized by phase changing solid-to-solid interconversions [103]. The copper salt crystals are needle shaped and the hydrated iron salt occurs as nanorod/nanowire bundles by a nucleation-growth process.…”

Systematic study on electrochemical properties of a series of TCNQ lanthanide complexes

“…Dunbar, Miller and their co-workers reported a series of M[TCNQ] 2 -based materials with significant magnetic properties [26][27][28][29]. Bond and co-workers investigated the electrochemical syntheses of these materials [30][31][32].…”

“…In contrast with the magnetic properties of TCNQ-based lanthanide complexes, their electrochemical properties are hardly known. In view of the importance of electrochemical syntheses for a series of TCNQ-based transition metal materials [30][31][32]36,37], we carry out the systematic investigation of electrochemical properties on the series of TCNQ-based lanthanide complexes 1À3 and IÀVI.…”

Mediated Electron Transfer Across Supported Bilayer Lipid Membrane with TCNQ‐Based Organometallic Compounds

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AbstractSupported bilayer lipid membrane (s-BLM) containing one-dimensional compound 1, TCNQ-based (TCNQ ¼ 7,7,8, organometallic compound {(Cu 2 (m-Cl)(m-dppm) 2 )(m 2 -TCNQ)} 1 , was prepared and characterized on the self-assembled monolayer (SAM) of 1-octadecylmercaptan (C 18 H 37 SH) deposited onto Au electrode. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results showed that the compound 1, dotted inside s-BLM, can act as mediator for electron transfer across the membrane.

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“…s-BLM has attracted extensive interest in recent years [5] and TCNQ as modifiers to mediate the electron transport through the s-BLM [6] has been found. Recently, electrochemical method in controlling the synthesis, morphology, and fabrication of TCNQ-based organometallic compounds has been employed [7]. However, the electrochemical property of TCNQ-based organometallic compounds inside s-BLM remains unknown.…”