Metal–Organic Charge Transfer Complexes of Pb(TCNQ)₂ and Pb(TCNQF₄)₂ as New Catalysts for Electron Transfer Reactions

Abstract

The fundamental properties and applications of organic charge transfer complexes based on Pb(TCNQ)2 (Pb = lead, TCNQ = 7,7,8,8‐tetracyanoquinodimethane) and its fluorinated derivatives are relatively unknown. Here, a facile solid–liquid approach for the synthesis of Pb(TCNQ)2 and Pb(TCNQF4)2 is reported. These materials are thoroughly analyzed to obtain insights into their unique morphological, vibrational and optical properties, the latter extending across the UV–Vis–IR region. Subsequently, the catalytic potential of these materials is evaluated by employing a model redox reaction, which revealed two orders of magnitude higher catalytic activity of the fluorinated derivative over non‐fluorinated Pb(TCNQ)2 crystals. Overall, the work presented here adds a new member to the growing yet limited library of metal–organic charge transfer complexes and validates the outstanding redox catalysis performance of this group of materials.

Increased Crystallization of CuTCNQ in Water/DMSO Bisolvent for Enhanced Redox Catalysis

“…Considering that the CuTCNQ samples fabricated using 5 mM TCNQ 0 showed good hydrophilicity, we assessed these samples as a catalyst for a pseudo first-order redox reaction in which ferricyanide is reduced to ferrocyanide in the presence of excess thiosulfate ions. This reaction can be easily monitored using UV-Vis absorbance spectroscopy by measuring the change in the absorbance intensity of ferricyanide at 420 nm [ 30 , 32 , 33 , 35 , 36 ]. For all the catalytic reactions, the amount of catalyst was kept constant at ca.…”

“…The rich electrical, chemical, magnetic, and optoelectronic properties of charge-transfer complexes based on 7,7,8,8-tetracyanoquinodimethane (TCNQ) has seen substantial interest in using these materials for a range of applications ( Figure S1, Supplementary Materials show the chemical structure of TCNQ) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. The pioneering work led by Dunbar, Miller, Robson, and Bond have seen the development of several strategies including physical [ 9 , 10 ], photochemical [ 11 , 12 , 13 ], vapor deposition [ 9 , 14 , 15 ], electrochemical [ 5 , 13 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], and wet-chemical synthesis methods [ 19 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ] for the fabrication of TCNQ-based charge transfer complexes. The resultant materials have been used as sensors [ 14 , 15 , 37 , 38 ], photocatalysts […”

“…The pioneering work led by Dunbar, Miller, Robson, and Bond have seen the development of several strategies including physical [ 9 , 10 ], photochemical [ 11 , 12 , 13 ], vapor deposition [ 9 , 14 , 15 ], electrochemical [ 5 , 13 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], and wet-chemical synthesis methods [ 19 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ] for the fabrication of TCNQ-based charge transfer complexes. The resultant materials have been used as sensors [ 14 , 15 , 37 , 38 ], photocatalysts [ 19 , 23 , 24 , 25 , 26 , 29 , 30 , 31 , 32 , 33 , 35 , 36 ], data storage systems [ 39 ...…”

“…This is because, after the addition of fresh TCNQ 0 , the reaction would contain more of the TCNQ 0 species than TCNQ − species [ 34 ]. This approach resulted in structures of over 50 µm, which was previously limited to 10–15 µm through conventional wet-chemical synthesis [ 19 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Furthermore, we proposed the use of a bisolvent mixture where a small fraction of water was mixed with TCNQ 0 dissolved in MeCN.…”

Comparative Structural Study of Three Tetrahalophthalic Anhydrides: Recognition of X···O(anhydride) Halogen Bond and πh···O(anhydride) Interaction

“…Charge transfer (CT) complexes are widely applied in different fields including sensors [ 1 ], ferroelectrics [ 2 , 3 , 4 ], ferromagnets [ 5 ], light-emitting devices [ 6 , 7 ], conducting materials [ 8 , 9 ], and catalytic systems [ 10 ]. Tetrahalophthalic anhydrides (TXPA) are known to form CT complexes of π···π type with a number of polycyclic aromatic compounds as electron charge acceptors [ 11 , 12 , 13 ].…”