Victor Rubio-Gimenez, Sergio Tatay and Carlos Marti-Gastaldo · Chemical Society Reviews · 2020
Review design strategies for electrical conductivity and magnetic bistability in MOFs and coordination polymers, with emphasis on thin-film processing, nanostructuration and device integration.
The review’s argument is preserved as a navigable set of section summaries.
Introduces conductivity, band/hopping concepts and the taxonomy of guest-induced versus intrinsic conductive frameworks.
Relevance: Core · 5603 · 2. Electrical conductivity in framework materials · Fig. 1
Summarises FET, sensor and switchable-device examples, while noting that conductivity and SCO are mostly exploited separately.
Relevance: Core · 5625 · 5. Integration of conductive MOFs and SCO CPs in functional devices
Frames MOFs/CPs as beyond-CMOS hybrid materials and defines the focus on conductivity, magnetic bistability, thin films and nanodevices.
Relevance: Core · 5602 · 1. Introduction
Detailed comparison of 2D pi-conjugated MOG families, stacking, porosity and conductivity benchmarks in Table 1.
Relevance: Core · 5611 · 2.2.3. Metal-organic graphene analogues · Table 1
Identifies mechanistic, measurement, nanostructuration and interface gaps limiting combined conductivity/SCO devices.
Relevance: Core · 5628 · 6. Conclusions and future outlook
Classifies deposition routes and relates film thickness, morphology, orientation and substrate effects to device performance.
Relevance: Core · 5617 · 4. Nanostructuration strategies for device fabrication · Fig. 15
Explains SCO, FeII-Hofmann frameworks, conductivity/SCO coupling attempts, spin-state conductance controversies and PBA valence tautomerism.
Relevance: Core · 5612 · 3. Magnetic bistability in MOFs and CPs · Fig. 9
Classification systems are attributed to this review and are not treated as a global material registry.
The review separates conductivity generated by pore guests from intrinsic framework conductivity and subdivides intrinsic transport by orbital pathway and redox mechanism.
Categories: guest-induced conductivity · through-space conductivity · through-bond conductivity · mixed-valence/redox modulation · 2D pi-conjugated MOG/MCOF families
5605 · 2.2. Intrinsic conductivity through the framework
FeII-Hofmann frameworks are classified by whether axial ligands connect layers into 3D networks or form interdigitated 2D sheets.
Categories: 3D networks with bis-monodentate ligands · 2D sheets with monodentate ligands · functionalised triazole variants · ultrathin layer-expanded films
5613 · 3.1. FeII Hofmann-type coordination polymers · Fig. 10
Figure 15 divides processing routes by whether the framework is made before transfer, grown directly on the substrate, or assembled sequentially.
Categories: pre-formed material deposition · direct in situ synthesis · layer-by-layer/liquid-phase epitaxy
5617 · 4. Nanostructuration strategies for device fabrication · Fig. 15
MOGs are organised by aromatic core, metal coordination, in-plane lattice and interlayer stacking, all of which influence transport and porosity.
Categories: benzene-based BHT/HIB/HHB systems · triphenylene HHTP/HITP/HTTP/TPHS systems · lanthanide-HHTP 3D systems · phthalocyanine 2D MOFs · MCOFs
5608 · 2.2.3. Metal-organic graphene analogues · Fig. 5
The review interprets contradictory HS/LS conductivity results as partly arising from different transport regimes, morphologies and interfaces.
Categories: large-contact hopping usually LS-more-conductive · single/few-layer tunnelling often HS-more-conductive · exceptions and interface-sensitive cases
5616 · 3.3. Electrical properties of individual spin states
Band transport is associated with high mobility; disorder, defects and grain boundaries promote hopping, while short SCO junctions may tunnel.
Categories: band transport · hopping between localised sites · tunnelling in nanoscale junctions
5603 · 2. Electrical conductivity in framework materials
Review-defined families retain their representative materials and conduction descriptions.
2D conjugated networks built from benzene BHT/HIB/HHB-type linkers.
Conduction: Strong in-plane pi-d coupling can yield high conductivity.
Representative materials: Cu-BHT · Ag-BHT · Ni-BHT · Cu-HIB · Co-HIB
Nodes / linkers: Cu · Ag · Ni · Co · Pd · Pt · BHT · BHS · HIB · HHB · IT · AT
5612 · 2.2.3. Metal-organic graphene analogues · Table 1
Cyanide-bridged FeII frameworks with group-10 tetracyanometallate layers and axial N-donor ligands.
Conduction: Usually poor conductors; SCO and charge transport are sensitive to axial ligands, guests and film thickness.
Representative materials: [Fe(pz)Pt(CN)4] · [Fe(py)2Pt(CN)4] · [Fe(bpac)Pt(CN)4]
Nodes / linkers: FeII · NiII · PdII · PtII · pyrazine · pyridine · pyrimidine · isoquinoline · bpac
5613 · 3.1. FeII Hofmann-type coordination polymers · Fig. 10
Insulating porous MOFs made conductive by conductive or redox-active guests in the pores.
Conduction: Guest channels, nanocluster tunnelling or donor-acceptor coupling generate conductivity.
Representative materials: Ag-NCs@Rb-CD-MOF · TCNQ@HKUST-1 · PEDOT@Cr-MIL-101
Nodes / linkers: Cu paddlewheels · Zr clusters · Rb-CD-MOF nodes · BTC · MIL/UiO linkers · cyclodextrin framework
5604 · 2.1. Guest-induced conductivity · Fig. 2
Frameworks where charge moves through metal-linker bonds or redox hopping between metal nodes.
Conduction: Redox-compatible centres and covalent orbital overlap enable hopping and modulation.
Representative materials: Fe(tri)2(BF4)x · Fe2(BDT)3 · Fe2(BDP)3
Nodes / linkers: FeII/FeIII · RuII/RuIII · Rh dimers · triazolate · tetrazolate · pyrazolate · cyanide
5606 · 2.2.2. Through-bond conductivity
Cyanide-bridged mixed-valence frameworks where charge-transfer-induced spin/valence transitions modulate conductivity.
Conduction: Conductivity changes at the magnetic/valence phase transition and can be electric-field modulated.
Representative materials: FeCo PBAs · MnFe PBAs
Nodes / linkers: Fe · Co · Mn · cyanide
5616 · 3.4. Electrical conductivity and valence tautomerism in PBAs · Fig. 14
FeII triazole-chain CPs with room-temperature hysteretic SCO and spin-state-dependent conductance studies.
Conduction: Conductance can switch across SCO, but HS/LS ordering depends on morphology and transport regime.
Representative materials: [Fe(Htrz)2(trz)](BF4) · Au@[Fe(Htrz)2(trz)](BF4)
Nodes / linkers: FeII · 1,2,4-triazole
5615 · 3.2. Electrical conductivity and SCO · Fig. 13
Layered 2D honeycomb frameworks based on HHTP, HITP, HTTP or TPHS linkers.
Conduction: In-plane delocalisation and redox-active linkers produce semiconducting to metal-like behaviour, but measurements vary strongly.
Representative materials: Ni3(HITP)2 · Cu3(HITP)2 · Cu-CAT-1 · Co-CAT-1 · Ni-CAT-1
Nodes / linkers: Ni · Cu · Co · Fe · Pt · HHTP · HITP · HTTP · TPHS
5610 · 2.2.3. Metal-organic graphene analogues · Fig. 8
Frameworks with tetrathiafulvalene-derived linkers where close pi/S...S contacts mediate transport.
Conduction: Conductivity depends on linker orientation and interlinker contacts.
Representative materials: M2(TTFTB)2 · MIL-135(K)
Nodes / linkers: transition metals · lanthanides · TTF · TTFTB · carboxylate-TTF
5605 · 2.2.1. Through-space conductivity · Fig. 3
Review-level synthesis principles remain separate from primary-study recipes.
Introduce nanoclusters, polymers or redox-active guests into pores to create or modulate charge pathways.
Claimed effects: Can turn insulating porous MOFs conductive.
Controlling variables: guest identity · loading · pore accessibility · exposure time · retained porosity
Representative materials: Ag-NCs@Rb-CD-MOF · TCNQ@HKUST-1
Caveat: Can sacrifice pore volume and complicate mechanism assignment.
5604 · 2.1. Guest-induced conductivity · Fig. 2
Grow films directly on substrates by solvothermal, microwave, CVD, ALD/MLD or vapour-assisted routes.
Claimed effects: Can make adherent films and control nucleation or orientation.
Controlling variables: surface functionalisation · nucleation rate · precursor concentration · temperature · vapour environment
Representative materials: MOF-525 · ZIF-8 · UiO-66
Caveat: Powder precipitation, thick films, amorphous phases or post-crystallisation may occur.
5621 · 4.2. In situ film growth in presence of the substrate · Fig. 22
Use electroactive linkers with close aromatic or S-rich contacts to create through-space conduction.
Claimed effects: Preserves framework identity while providing intrinsic transport.
Controlling variables: interlinker distance · linker orientation · S...S contacts · stacking · metal radius
Representative materials: M2(TTFTB)2
Caveat: Packing can be dominated by inter-linker interactions rather than intended SBUs.
5605 · 2.2.1. Through-space conductivity · Fig. 3
Expose substrates sequentially to metal and linker sources with rinsing to grow films cycle-by-cycle.
Claimed effects: Enables thickness control, patterning, crystallinity and orientation in ultrathin MOF/CP films.
Controlling variables: cycle number · SAM head group · exposure time · rinsing · growth atmosphere
Representative materials: HKUST-1 SURMOFs · Cu-CAT-1 · [Fe(py)2Pt(CN)4]
Caveat: Some FeII-HCPs require low temperature or inert conditions; ALD/MLD analogues may be amorphous.
5622 · 4.3. Sequential growth by layer-by-layer/liquid phase epitaxy · Fig. 23
Combine square-planar metal nodes with redox-active benzene/triphenylene linkers to form conjugated layers.
Claimed effects: Yields high conductivity and mobility values in framework materials.
Controlling variables: linker core · metal identity · stacking mode · defects · interlayer distance · crystallinity
Representative materials: Cu-BHT · Ni3(HITP)2 · Cu-CAT-1
Caveat: Values vary with morphology, crystallinity and measurement geometry.
5611 · 2.2.3. Metal-organic graphene analogues · Table 1
These are the review authors’ synthesis, not newly measured results.
MOF-FETs, MOG chemiresistors and SCO switchable devices exist, but applications combining conductivity and bistability at the atomic level remain limited.
Evidence basis: multi_reference
Caveat: Primary device papers are needed for quantitative performance.
5628 · 6. Conclusions and future outlook
Device integration requires control over film thickness, coverage, homogeneity, roughness, crystallinity and orientation.
Evidence basis: review_reasoning
Caveat: No single route solves all materials.
5617 · 4. Nanostructuration strategies for device fabrication
Guest-induced conductivity can turn porous MOFs conductive but may trade off against porosity and mechanism clarity.
Evidence basis: multi_reference
Caveat: Some examples retain useful porosity.
5604 · 2.1. Guest-induced conductivity · Fig. 2
Intrinsic conductive frameworks are harder to design but can preserve porosity, avoid post-synthetic modification and give higher average conductivities than guest doping.
Evidence basis: review_reasoning
Caveat: Specific materials may deviate.
5605 · 2.2. Intrinsic conductivity through the framework
MOG conductivity values are highly sensitive to crystallinity, morphology, contacts and measurement method, so Table 1 values should not be treated as directly comparable primary measurements.
Evidence basis: multi_reference
Caveat: Especially important for pellets and polycrystalline films.
5611 · 2.2.3. Metal-organic graphene analogues · Table 1
The specific charge-transport mechanism in 2D porous MOGs is unsettled, with band-like and Mott variable-range hopping interpretations both appearing.
Evidence basis: multi_reference
Caveat: Defects and grain boundaries contribute to disagreement.
5610 · 2.2.3. Metal-organic graphene analogues
Highly conductive SCO framework materials remain scarce because most SCO CPs/MOFs are insulating.
Evidence basis: review_reasoning
Caveat: TTF and metallopolymer attempts exist but are limited.
5614 · 3.2. Electrical conductivity and SCO
Nanostructuration can change SCO transition temperature, cooperativity, hysteresis and residual spin fraction, so bulk SCO behaviour cannot be assumed in nanoscale devices.
Evidence basis: multi_reference
Caveat: Particle size, matrix and substrate effects can be hard to separate.
5624 · 4.4. Nanostructuration effects on the spin crossover transition · Fig. 25
There is no general rule for whether HS or LS states are more conductive because results differ by tunnelling, hopping, morphology and interface regime.
Evidence basis: multi_reference
Caveat: Large-contact hopping studies often favour LS, while some tunnelling studies favour HS.
5616 · 3.3. Electrical properties of individual spin states
Charge transport in 2D/3D MOFs and CPs is less mature than in organic semiconductors and carbon nanomaterials because conductivity was historically not targeted.
Evidence basis: multi_reference
Caveat: The review also notes rapid recent progress.
5603 · 2. Electrical conductivity in framework materials
Every row remains visibly secondary and links to a primary dossier only where the mapping is verified.
| Material | Property | Reported value | Context and quality | Primary evidence | Review source |
|---|---|---|---|---|---|
| SecondaryAg-NCs@Rb-CD-MOF | electrical conductivity | 2.15 x 10^-7 S cm^-1 upon light irradiation | light irradiation; tunnelling between Ag nanoclusters Text · Exact Reported | research_0037 | 5604 · 2.1.1. Infiltration of conductive guests · Fig. 2a |
| SecondaryCu-BHT | electrical conductivity | 2500 S cm^-1 | film, 4-probe measurement Table · Exact Reported | No verified corpus mapping | 5611 · Table 1 · Table 1 |
| SecondaryCu-BHT | field-effect mobility | 116 (electrons) / 99 (holes) cm^2 V^-1 s^-1 | MOG-FET; electron and hole mobilities reported Text · Exact Reported | research_0006 | 5626 · 5.1. Field-effect transistors · Fig. 27 |
| SecondaryCu-CAT-1 | reported conductivity range | 1.5 S cm^-1 to 1 x 10^-4 S cm^-1 | single-crystal/rod versus 10 nm thin-film reports Text · Range | research_0005 | 5611 · 2.2.3. Metal-organic graphene analogues · Table 1 |
| SecondaryFe2(BDT)3 | electrical conductivity | exceeding 1 S cm^-1 | air-exposure-modulated Fe oxidation Text · Approximate | No verified corpus mapping | 5606 · 2.2.2. Through-bond conductivity |
| SecondaryFe3(THT)2(NH4)3 | charge carrier mobility | 230 cm^2 V^-1 s^-1 | temperature-dependent four-probe and Hall effect measurements Text · Exact Reported | research_0001 | 5612 · 2.2.3. Metal-organic graphene analogues · Table 1 |
| Secondary[Fe(L)2{Pt(CN)4}] | current-density decay coefficient | beta = 0.03-0.08 A^-1 | out-of-plane transport in <15 nm 2D FeII-HCP ultrathin films Text · Range | No verified corpus mapping | 5614 · 3.2. Electrical conductivity and SCO · Fig. 12 |
| Secondary[Fe(py)2Pt(CN)4] | SCO cooperativity thickness threshold | below 15 growth cycles (<12 nm) | ultrathin 2D FeII-HCP films characterised by XAS/AFM Text · Approximate | No verified corpus mapping | 5625 · 4.4. Nanostructuration effects on the spin crossover transition · Fig. 26 |
| Secondary[Fe(tri)2(BF4)x] | conductivity modulation | eight orders of magnitude increase after O2 exposure | O2 exposure oxidises FeII to FeIII Text · Rounded Reported | No verified corpus mapping | 5606 · 2.2.2. Through-bond conductivity · Fig. 4 |
| SecondaryAu@[Fe(Htrz)2(trz)](BF4) | conductance on/off ratio | 1500 | Au-core/SCO-shell nanoparticles on interdigitated electrodes Text · Exact Reported | No verified corpus mapping | 5616 · 3.2. Electrical conductivity and SCO |
| Secondary[Fe(Htrz)2(trz)](BF4) | DC conductivity in HS state | sigma_HS = 5 x 10^-1 S cm^-1 | pellets of needle-like micrometric crystallites Text · Exact Reported | No verified corpus mapping | 5615 · 3.2. Electrical conductivity and SCO · Fig. 13 |
| SecondaryFe-PTC | electrical conductivity | 10 S cm^-1 | pellet, 4-probe; ferromagnetic ordering at low temperature Text · Exact Reported | research_0045 | 5612 · 2.2.3. Metal-organic graphene analogues |
| SecondaryNi3(HITP)2 | BET surface area | 630 m^2 g^-1 | record BET surface area for a MOG according to review Text · Exact Reported | No verified corpus mapping | 5610 · 2.2.3. Metal-organic graphene analogues · Table 1 |
| SecondaryNi3(HITP)2 | hole mobility in FET | 38-45.4 cm^2 V^-1 s^-1 | MOF-FET devices Text · Range | No verified corpus mapping | 5626 · 5.1. Field-effect transistors · Fig. 27 |
| SecondaryNi3(HITP)2 | electrical conductivity | 40 S cm^-1 | film, van der Pauw measurement Table · Exact Reported | No verified corpus mapping | 5611 · Table 1 · Table 1 |
| SecondaryTCNQ@HKUST-1 | electrical conductivity | as high as 7 x 10^-2 S cm^-1 | TCNQ-infiltrated HKUST-1 thin-film devices Text · Exact Reported | research_0088 | 5605 · 2.1.2. Infiltration of non-conductive guests · Fig. 2e |
Open questions are presented as review-author priorities, not conclusions from the primary database.
Conductive SCO CPs/MOFs are still underdeveloped and limited to few systems.
Proposed direction: Explore conductive polymers, redox-active guests and mixed-valence systems that avoid disrupting SCO ligand fields.
5628 · 6. Conclusions and future outlook
Single-crystal scarcity and polycrystalline heterogeneity make conductivity values hard to compare.
Proposed direction: Report morphology, contacts and method; separate grain-boundary effects from intrinsic transport.
5628 · 6. Conclusions and future outlook
The review says conductivity mechanisms remain insufficiently understood.
Proposed direction: Fundamental studies of anisotropic transport, mobility, carrier density and cleaner single-crystal measurements.
5628 · 6. Conclusions and future outlook
Effects of nanostructuration on device-relevant conductivity and SCO are often overlooked.
Proposed direction: Pair property measurements with AFM, XAS and structural characterisation across controlled film series.
5628 · 6. Conclusions and future outlook
MOG sensor reports often emphasise sensitivity and selectivity without characterising host-guest mechanisms.
Proposed direction: Combine chemiresistive tests with spectroscopic and structural probes of analyte-framework interactions.
5626 · 5.2. Chemical sensors
There is no definitive rule for whether HS or LS is more conductive.
Proposed direction: Control transport regime, electrode spacing, morphology and interface chemistry systematically.
5616 · 3.3. Electrical properties of individual spin states
Mappings show which printed review references have a verified counterpart in the frozen primary corpus.
| Reference | Study | Role and context | Corpus mapping |
|---|---|---|---|
| Ref. 592015 | Title unavailable | guest_induced_conductivity · transport_benchmarkAg nanocluster infiltration benchmark for light-assisted tunnelling conductivity. | research_0037 |
| Ref. 802014 | Title unavailable | guest_induced_conductivity · transport_benchmarkClassic redox-active guest example where TCNQ raises HKUST-1 conductivity. | research_0088 |
| Ref. 972015 | Title unavailable | through_space_conductivity · structure_propertyTTF-based MOF example correlating short S...S contacts with conductivity. | research_0353 |
| Ref. 1132018 | Title unavailable | through_bond_conductivity · redox_modulationO2-modulated Fe triazolate conductivity example. | Unmapped |
| Ref. 1142018 | Title unavailable | through_bond_conductivity · transport_benchmarkHigh-conductivity 3D MOF example in review. | Unmapped |
| Ref. 1292014 | Title unavailable | MOG · transport_benchmarkOriginal Ni3(HITP)2 MOG framing and film conductivity benchmark. | Unmapped |
| Ref. 1302012 | Title unavailable | MOG · CAT_1First M-CAT-1 series of 2D pi-conjugated MOFs. | Unmapped |
| Ref. 1312015 | Title unavailable | MOG · transport_benchmark · FETCu-BHT conductivity and mobility benchmark. | research_0006 |
| Ref. 1452018 | Title unavailable | MOG · transport_benchmarkMaximum Cu-BHT conductivity benchmark in review. | Unmapped |
| Ref. 1462015 | Title unavailable | MOG · sensor · transport_benchmarkCu3(HITP)2 benchmark and first MOG chemiresistive device. | research_0002 |
| Ref. 1532019 | Title unavailable | MOG · measurement_caveatSingle-crystal MOG measurements and morphology caveat. | research_0005 |
| Ref. 1562018 | Title unavailable | MOG · thin_film · FETCu-CAT-1 ultrathin film conductivity and FET context. | Unmapped |
| Ref. 1592020 | Title unavailable | MOG · anisotropic_transport3D LnHHTP anisotropic through-space transport. | research_0047 |
| Ref. 1642017 | Title unavailable | MOG · porosity_benchmarkRecord BET surface area for a MOG according to review. | Unmapped |
| Ref. 1712018 | Title unavailable | MOG · mobility_benchmarkHigh mobility Fe3(THT)2(NH4)3 benchmark. | research_0001 |
| Ref. 1742018 | Title unavailable | MOG · magnetic_conductiveConductive CP related to MOGs with ferromagnetic ordering. | research_0045 |
| Ref. 2462019 | Title unavailable | SCO_conductivity · thin_filmUltrathin 2D FeII-HCP charge transport and linker-dependent hopping. | Unmapped |
| Ref. 2582012 | Title unavailable | SCO_conductivity · measurement_caveatHS/LS conductivity values and sample-dependent contradiction. | Unmapped |
| Ref. 2652011 | Title unavailable | SCO_conductivity · controversyOpposite HS-more-conductive result under tunnelling conditions. | Unmapped |
| Ref. 2662019 | Title unavailable | SCO_conductivity · deviceAu-core/SCO-shell nanoparticles with hysteretic conductance switching. | Unmapped |
| Ref. 2722004 | Title unavailable | valence_tautomerism · PBAFeCo PBA conductivity change coupled to valence tautomerism. | Unmapped |
| Ref. 2932010 | Title unavailable | thin_film_processing · Langmuir_BlodgettLangmuir-Blodgett approach for layered CP/MOF films. | Unmapped |
| Ref. 3262015 | Title unavailable | thin_film_processing · solvothermal_growthSolvothermal MOF-525 thick-film growth example. | Unmapped |
| Ref. 3362016 | Title unavailable | thin_film_processing · CVDMOF-CVD ZIF-8 film example. | Unmapped |
| Ref. 3802017 | Title unavailable | thin_film_processing · sensorCu-CAT-1 spray/LbL and NH3 chemiresistive sensor example. | research_0115 |
| Ref. 3932019 | Title unavailable | SCO_nanostructuration · thin_filmUltrathin 2D FeII-HCP SCO-thickness study. | Unmapped |
| Ref. 4242017 | Title unavailable | FET · deviceSingle example of a MOF dielectric in an FET device. | research_0164 |
| Ref. 4252016 | Title unavailable | FET · MOGNi3(HITP)2 FET mobility benchmark. | Unmapped |
| Ref. 4342015 | Title unavailable | sensor · MOGSolvent-free MOG sensor array example. | research_0145 |
| Ref. 4392015 | Title unavailable | SCO_sensor · deviceActual SCO VOC sensing device highlighted by review. | Unmapped |