Integration of a (–Cu–S–)n plane in a metal–organic framework affords high electrical conductivity

Abstract

Designing highly conducting metal–organic frameworks (MOFs) is currently a subject of great interest for their potential applications in diverse areas encompassing energy storage and generation. Herein, a strategic design in which a metal–sulfur plane is integrated within a MOF to achieve high electrical conductivity, is successfully demonstrated. The MOF {[Cu 2 (6-Hmna)(6-mn)]·NH 4 } n ( 1 , 6-Hmna = 6-mercaptonicotinic acid, 6-mn = 6-mercaptonicotinate), consisting of a two dimensional (–Cu–S–) n plane, is synthesized from the reaction of Cu(NO 3 ) 2 , and 6,6′-dithiodinicotinic acid via the in situ cleavage of an S–S bond under hydrothermal conditions. A single crystal of the MOF is found to have a low activation energy (6 meV), small bandgap (1.34 eV) and a highest electrical conductivity (10.96 S cm −1 ) among MOFs for single crystal measurements. This approach provides an ideal roadmap for producing highly conductive MOFs with great potential for applications in batteries, thermoelectric, supercapacitors and related areas.

Conductive metal‐organic frameworks: Recent advances in electrochemical energy‐related applications and perspectives

“…Therefore, it is highly feasible to construct the anticipatory MOFs just by simply selecting suitable metal ions. The {[Cu 2 (6‐Hmna) (6‐mn)]·NH 4 } n (6‐Hmna = 6‐mercaptonicotinic acid, 6‐mn = 6‐mercaptonicotinate) synthesized by the reaction of Cu(NO 3 ) 2 and 6,6′‐dithiodinicotinic acid, is a typical orthogonal crystal 27 . As illustrated in Figure 2D, the elemental copper is connected with three sulfur atoms from two 6‐Hmna ligands and one 6‐mn ligand, respectively, and one nitrogen atom from the other 6‐mn, forming tetrahedral CuS 3 N unit.…”

“…As illustrated in Figure 2D, the elemental copper is connected with three sulfur atoms from two 6‐Hmna ligands and one 6‐mn ligand, respectively, and one nitrogen atom from the other 6‐mn, forming tetrahedral CuS 3 N unit. In particular, the existence of Cu–S bond endows this MOF with unique charge transfer characteristics, resulting in high conductivity 27 . All in all, the conductive MOFs are mostly composed of the 2D layered structure and represent an exciting new class of atomic crystals, in which the existence of functional groups (ie, aromatic ring, hydroxyl group, amino group, thiol group, etc) play an important role in their electronic conductivity and electrochemical properties.…”

Coordination Polymer Frameworks for Next Generation Optoelectronic Devices

“…After installation of C 60 , the NU-901-C 60 shows electrical conductivity higher than that of NU-901 (shown in the Table 2). As per reports, the donor-acceptor interactions between TBAPy 4 -/C 60 contribute to the electrical conductivity of the framework [32,38].…”

“…TTF-TCNQ i.e. tetrathiafulvalenetetracyano quinomethane is one of the MOFs that demonstrate metallic conductivity (shown in the Table 2) through-space (π-π stacking) mechanism [38]. Recently, TTF-based ligand consisting of benzoate spacers is used to develop Zn based MOF reported by Dincă et al These MOFs shows columnar stacks of TTF (3.8 Å) with the charge mobility of a magnitude that resembles some best conductive organic polymers [35,36].…”

Blood Pressure Sensors: Materials, Fabrication Methods, Performance Evaluations and Future Perspectives

“…MOF materials are a class of chemical compounds consisting of metal ions or clusters coordinated to organic ligands to form one-dimensional structure, or two or three-dimensional structures [310] with the capability to form ultrahigh porous materials [311], with up to 90% free volume, and a huge internal surface area extending 6000 m 2 /g [312] Although most of the MOF materials are generally associated with a lack of electrical conductivity [313], a few have been reported as electronic conductors [313,314]. MOF materials have been thoroughly studied for major interests such as heterogeneous catalysis and biomedical applications [315,316].…”