Zeyu Zhang, David Dell'Angelo, Mohammad R. Momeni, Yuliang Shi, and Farnaz A. Shakib · ACS Applied Materials & Interfaces · 2021
Use Ni3(HITP)2 as an archetypal pi-stacked 2D MOF to interpret how layer flexibility, structural deformation, and charge-transfer anisotropy can change conductive behaviour.
The review’s argument is preserved as a navigable set of section summaries.
Summarises the chapter-relevant lesson that flexible layered microstructure and dynamics can switch apparent transport behaviour, and that modelling must handle structure, dispersion, and dynamics.
Relevance: Core · 25277 · 5. Concluding Remarks
Frames conductive 2D MOFs as porous materials whose transport is complicated by weakly held, flexible layered structures; introduces the Ni3(HITP)2 and Ni3(HIB)2 metallic/semiconducting disagreement.
Relevance: Core · 25270-25271 · 1. Introduction · Figure 1
Describes why initial crystal structure, dispersion treatment, finite-temperature dynamics, and band-structure settings matter for interpreting electronic properties of layered MOFs.
Relevance: Supporting · 25271-25273 · 2. Computational Details · Table 1
Translates the transport interpretation into design variables: SBU-linker redox matching, orbital contributions at the Fermi level, structural deformation, anisotropy, and quantitative hopping/band analyses.
Relevance: Core · 25276-25277 · 4. Outlook · Figure 6
Organises charge transport around geometry-sensitive intralayer and interlayer pathways, metallic/semiconducting boundaries, and thermally induced structural motions.
Relevance: Core · 25273 · 3. Results and Discussion · Figure 2
Classification systems are attributed to this review and are not treated as a global material registry.
The article separates transport through conjugated metal-linker sheets from transport through stacked aromatic layers, then treats their competition as a main structure-property axis.
Categories: intralayer extended d-pi conjugation · interlayer through-space pi-pi interaction
25273 · 3. Results and Discussion · Figure 2
The article presents a design vocabulary in which node-linker tessellation and external stimuli tune in-plane/out-of-plane orbital contributions.
Categories: SBU-linker redox matching · Fermi-level orbital contributions · framework deformation · temperature · pressure · electric or magnetic fields
25276-25277 · 4. Outlook · Figure 6
Finite-temperature layered MOFs are described through coupled motions that alter orbital overlap and can change the apparent transport regime.
Categories: in-plane slipping · stacking-direction expansion/contraction · out-of-plane SBU deformation · stepped layer geometry
25275-25276 · 3.3. Characterizing Different Dynamical Motions in 2D MOFs · Figures 3-5
The article treats metallic/semiconducting assignment as geometry-sensitive rather than fixed, with direct/indirect gap character relevant to semiconducting interpretations.
Categories: metallic · semiconducting · semimetallic · direct band gap · indirect band gap
25274 · 3.1. Metallic/Semiconducting Boundary · Figure 2
The outlook places conductive MOF design in the broader carrier-transport distinction between delocalised bands and polaronic hopping states.
Categories: delocalized band transport · trapped polaronic hopping
25276 · 4. Outlook · Figure 6
Review-defined families retain their representative materials and conduction descriptions.
Co/Ni/Cu hexaiminotriphenylene alloys cited as evidence that composition can vary conductivity, even though this article stresses flexible structure.
Conduction: The review cites continuous electrical conductivity variation but argues that structure and flexibility can dominate observed behaviour.
Representative materials: M3(Hexaiminotriphenylene)2 (M = Co, Ni, Cu)
Nodes / linkers: Co · Ni · Cu · hexaiminotriphenylene
25271 · 1. Introduction
Benzene-analogue conductive MOFs used as a second example of metallic/semiconducting disagreement.
Conduction: Discussed as first reported metallic, then later reported with intrinsic semiconducting nature and a finite band gap.
Representative materials: Ni3(HIB)2 · M3(hexaiminobenzene)2 (M = Co, Ni, Cu)
Nodes / linkers: Ni · Co · Cu · hexaiminobenzene · hexaaminobenzene
25271 · 1. Introduction
Nickel hexaiminotriphenylene layered conductive MOF used as the archetype for the article's transport/dynamics discussion.
Conduction: Reported as semiconducting in the first synthesis and FET context, metallic in several theoretical studies and single-rod reports; the article interprets this as structure/dynamics sensitive.
Representative materials: Ni3(HITP)2
Nodes / linkers: Ni · 2,3,6,7,10,11-hexaiminotriphenylene
25271 · 1. Introduction · Figure 1
Layered 2D MOFs held by weak van der Waals interactions where extended conjugation and stacking create possible charge-transport channels.
Conduction: Conduction may involve intralayer conjugation and interlayer through-space transport, with anisotropy sensitive to stacking and dynamics.
Representative materials: Ni3(HITP)2 · Co3(HHTP)2 · M3(HITP)2 alloys · M3(HIB)2
Nodes / linkers: Ni · Co · Cu · Zn · hexaiminotriphenylene · hexahydroxytriphenylene · hexaiminobenzene
25270 · Abstract and Introduction · Figure 1
A zinc analogue used as an electronic-structure contrast to Ni3(HITP)2 because Zn2+ has a filled d10 configuration.
Conduction: The filled d10 node disrupts intralayer d-pi conjugation and is used to highlight competition between intralayer and interlayer pathways.
Representative materials: Zn3(HITP)2
Nodes / linkers: Zn · 2,3,6,7,10,11-hexaiminotriphenylene
25275 · 3.2. Through-Space vs Extended-Conjugation CT Pathways · Figure 2c
Review-level synthesis principles remain separate from primary-study recipes.
The outlook proposes balancing intralayer and interlayer carrier transport by controlling SBU-linker matching, deformation, temperature, pressure, and fields.
Claimed effects: Could localise charge states, tune direct/indirect gaps, and design semiconductive transport properties.
Controlling variables: SBU-linker redox matching · framework deformation · temperature · pressure · electric field · magnetic field
Representative materials: pi-stacked 2D MOFs · Ni3(HITP)2
Caveat: The article states that accurate tuning still requires quantitative charge-transfer and reorganisation-energy analysis.
25276-25277 · 4. Outlook · Figure 6
The article stresses that weak interlayer van der Waals interactions must be treated appropriately when interpreting layered conductive MOFs.
Claimed effects: Improves structural realism for the spacing and slip variables that control interlayer and intralayer transport pathways.
Controlling variables: van der Waals interactions · exchange-correlation functional · dispersion correction · interlayer spacing
Representative materials: Ni3(HITP)2
Caveat: The article's own functional comparison is original evidence; only the conceptual lesson is extracted here.
25272 · 2.2. Choice of Exchange-Correlation Functional · Table 1
For theory-to-experiment interpretation, the article argues that input structures should be tied to available single-crystal or PXRD-derived structural evidence rather than arbitrary monolayer stacking.
Claimed effects: Reduces ambiguity in band-structure assignments and helps separate real material behaviour from modelling artefacts.
Controlling variables: input crystal structure · layer stacking · cell-vector optimisation · single-crystal versus pellet structural information
Representative materials: Ni3(HITP)2 · Co3(HHTP)2
Caveat: This is a modelling and interpretation strategy rather than a synthesis recipe.
25271 · 2.1. Input Crystal Structure · Figure 1
These are the review authors’ synthesis, not newly measured results.
Layered conductive MOFs are framed as relevant to supercapacitors, FETs, and chemical sensing, but the article treats these applications as motivation rather than performance extraction.
Evidence basis: multi_reference
Caveat: Application metrics are not extracted because this article does not review them systematically.
25270 · 1. Introduction
Conductive 2D MOFs emerged as a distinct application-relevant class around 2012, after the broader MOF field had been driven by porosity and surface-area applications.
Evidence basis: multi_reference
Caveat: The statement is a historical frame, not a comprehensive historiography.
25270 · 1. Introduction
Electronic-structure interpretation is limited by scarce single-crystal information because most experimental measurements have been performed on polycrystalline pellets.
Evidence basis: multi_reference
Caveat: This is a modelling caveat rather than a claim that pellet measurements are invalid.
25271 · 2.1. Input Crystal Structure
Prior work attributed part of the Ni3(HITP)2 experiment-theory discrepancy to defects and layer displacements in experimental samples versus pristine theoretical models.
Evidence basis: single_reference
Caveat: The article accepts this as important but argues it is not sufficient without finite-temperature dynamics.
25271 · 1. Introduction
Qualitative orbital/deformation rules are useful, but accurate electrical-property tuning requires charge-transfer integrals, reorganisation energy, and hopping-rate analysis.
Evidence basis: multi_reference
Caveat: The article frames this as future research rather than a completed design workflow.
25276-25277 · 4. Outlook · Figure 6
Layered conductive-MOF calculations require careful treatment of dispersion because weak van der Waals forces control spacing and stacking.
Evidence basis: review_reasoning
Caveat: The detailed benchmark values are generated by the article and should not be treated as secondary evidence.
25272 · 2.2. Choice of Exchange-Correlation Functional · Table 1
Conductive behaviour in flexible 2D MOFs cannot be assigned confidently without considering dynamical motions and deformation sites.
Evidence basis: review_reasoning
Caveat: The article supports this through its own computations, so this row should be used as interpretation rather than independent consensus.
25270 · 1. Introduction
Ni3(HIB)2 provides a parallel historical example, with an initial metallic framing followed by later reports of intrinsic semiconducting behaviour.
Evidence basis: multi_reference
Caveat: The article uses this comparison mainly to support a broader structure-property framing.
25271 · 1. Introduction
Ni3(HITP)2 is a central example where experiment, devices, and theory have alternately emphasised semiconducting and metallic behaviour.
Evidence basis: multi_reference
Caveat: The review interprets the disagreement as structurally informative rather than simply erroneous.
25271 · 1. Introduction
Intralayer d-pi conjugation and interlayer pi-pi transport are interconnected: weakening one pathway can strengthen or change the other.
Evidence basis: review_reasoning
Caveat: The article demonstrates this through selected computational exemplars rather than a broad statistical survey.
25275 · 3.2. Through-Space vs Extended-Conjugation CT Pathways · Figure 2
Changing vertical interlayer distance is interpreted as a route to tune metal-semiconductor transitions, but may also destabilise layered structures.
Evidence basis: review_reasoning
Caveat: This relies substantially on the article's original calculations and should be used as a mechanistic hypothesis.
25274 · 3.2. Through-Space vs Extended-Conjugation CT Pathways · Figure 2b
For this class, conductive behaviour can be strongly influenced by flexible and varying structure, not only by chemical composition.
Evidence basis: review_reasoning
Caveat: Composition still matters; the claim is about avoiding composition-only explanations.
25271 · 1. Introduction
Temperature and pressure should be included when modelling flexible layered MOFs because dynamic motions alter the realistic picture of charge-transfer pathways.
Evidence basis: review_reasoning
Caveat: This is a modelling recommendation derived from the article's finite-temperature calculations.
25275-25276 · 3.3. Characterizing Different Dynamical Motions in 2D MOFs · Figure 4
Pi-stacked 2D layered MOFs support two conceptually distinct transport pathways: intralayer extended conjugation and interlayer through-space transport.
Evidence basis: multi_reference
Caveat: The article argues that the two pathways are interdependent rather than independently tuneable in all cases.
25273 · 3. Results and Discussion · Figure 2
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 |
|---|---|---|---|---|---|
| SecondaryNi3(HITP)2 single rods | interlayer distance d | 3.3 | Day et al. reference row in Table 1. Table · Exact Reported | research_0005 | 25272 · 2.2. Choice of Exchange-Correlation Functional · Table 1 |
| SecondaryNi3(HITP)2 | energy gap from manually displaced layers | 15-100 | Theoretical study discussed as a defect/layer-displacement explanation for experiment-theory discrepancy. Text · Range | No verified corpus mapping | 25271 · 1. Introduction |
| SecondaryNi3(HIB)2 | reported band gap | 0.49 | Recent experimental reports emphasising intrinsic semiconducting nature. Text · Exact Reported | research_0495 | 25271 · 1. Introduction |
| SecondaryNi3(HITP)2 | defect-induced band opening range | 20-120 | Previously reported defects in Ni3(HITP)2, cited for comparison with the article's finite-temperature band openings. Text · Range | No verified corpus mapping | 25276 · 3.4. Localized Charge States and Isotropic Behavior at Finite Temperature · Figure 5 |
| SecondaryNi3(HITP)2 | hexagonal-layer a vector inferred from experiment | 21.75 | Experimental comparison value in Table 1; Sheberla et al. reference row. Table · Exact Reported | No verified corpus mapping | 25272 · 2.2. Choice of Exchange-Correlation Functional · Table 1 |
| SecondaryNi3(HITP)2 | hexagonal-layer c vector inferred from experiment | 6.66 | Experimental comparison value in Table 1; Sheberla et al. reference row. Table · Exact Reported | No verified corpus mapping | 25272 · 2.2. Choice of Exchange-Correlation Functional · Table 1 |
| SecondaryNi3(HITP)2 | interlayer distance d inferred from experiment | 3.33 | Experimental comparison value in Table 1; Sheberla et al. reference row. Table · Exact Reported | No verified corpus mapping | 25272 · 2.2. Choice of Exchange-Correlation Functional · Table 1 |
| SecondaryNi3(HITP)2 | slipping distance ds inferred from experiment | ~1.8 | Experimental/theoretical comparison value in Table 1; Sheberla et al. reference row. Table · Approximate | No verified corpus mapping | 25272 · 2.2. Choice of Exchange-Correlation Functional · Table 1 |
Open questions are presented as review-author priorities, not conclusions from the primary database.
The class needs a road map because conductive behaviour is strongly shaped by flexible, varying structure.
Proposed direction: Develop structure-aware maps that relate layer deformation, stacking, and orbital contributions to transport.
25271 · 1. Introduction
Implementation in devices is hampered by incomplete understanding of layered structure and dynamics.
Proposed direction: Link device-relevant transport measurements to microstructure, defects, and dynamic structural states.
25277 · 5. Concluding Remarks
More fundamental studies are needed to separate extended d-pi conjugation from through-space pi-pi interactions.
Proposed direction: Use controlled structural comparisons and dynamical models to isolate intralayer and interlayer contributions.
25273 · 3. Results and Discussion
Transport interpretations can miss intrinsic dynamic deformation if they rely only on static structures.
Proposed direction: Include temperature, pressure, and representative layer motions when assigning conductive behaviour.
25277 · 5. Concluding Remarks
Qualitative orbital rules are insufficient for accurate fine tuning; quantitative charge-transfer and reorganisation-energy analysis is needed.
Proposed direction: Calculate charge-transfer integrals, reorganisation energies, hopping rates, and compare with phonon band structures.
25276-25277 · 4. Outlook
Electronic band calculations remain variable because single-crystal information is scarce for many conductive 2D MOFs.
Proposed direction: Prioritise single-crystal growth, careful PXRD interpretation, and transparent structure-model provenance.
25271 · 2.1. Input Crystal Structure
Mappings show which printed review references have a verified counterpart in the frozen primary corpus.
| Reference | Study | Role and context | Corpus mapping |
|---|---|---|---|
| Ref. 142012 | New Porous Crystals of Extended Metal-Catecholates | historical_framing · structure_sourceCited for the 2012 advent of conductive 2D MOFs and as the experimentally available single-crystal starting point used for Ni3(HITP)2 modelling. | Unmapped |
| Ref. 162020 | Electrically Conductive Metal-Organic Frameworks | review_context · transport_pathwaysUsed as a broad conductive-MOF review and for the statement that extended pi-conjugation creates intra- and interlayer transport paths. | Unmapped |
| Ref. 172017 | Conductive MOF Electrodes for Stable Supercapacitors With High Areal Capacitance | application_contextCited as part of the application motivation for conductive 2D MOFs in supercapacitors. | Unmapped |
| Ref. 192017 | Porous Field-Effect Transistors Based on A Semiconductive Metal-Organic Framework | device_context · controversyUsed to note that Ni3(HITP)2 was made into a 2D MOF FET while being treated as semiconducting. | research_0015 |
| Ref. 202017 | Layer-by-Layer Assembled Conductive Metal-Organic Framework Nanofilms for Room-Temperature Chemiresistive Sensing | application_context · sensor_contextCited as an example of electronically induced chemical sensing applications. | research_0115 |
| Ref. 222019 | Welding Metallophthalocyanines Into Bimetallic Molecular Meshes for Ultra-Sensitive, Low-Power Chemiresistive Detection of Gases | application_context · sensor_contextCited as part of the chemical-sensing application context for conductive framework materials. | Unmapped |
| Ref. 272012 | Electrical Conductive Coordination Polymers | measurement_contextCited in relation to electrical conductance measurements including van der Pauw methods. | Unmapped |
| Ref. 302014 | High Electrical Conductivity in Ni3(2,3,6,7,10,11- hexaiminotriphenylene)2, a Semiconducting Metal-Organic Graphene Analogue | transport_benchmark · controversy · structure_benchmarkKey original synthesis report cited for semiconducting Ni3(HITP)2, PXRD-inferred structural values, layer slip, and the starting point of the metallic/semiconducting disagreement. | Unmapped |
| Ref. 312014 | Quantum Spin Hall and Z2 Metallic States in An Organic Material | theory_context · controversyOne of the theoretical studies grouped as categorising Ni3(HITP)2 as metallic. | Unmapped |
| Ref. 322015 | Metal-Organic Kagome Lattices M3(2,3,6,7,10,11- hexaiminotriphenylene)2 (M = Ni and Cu): from Semiconducting to Metallic by Metal Substitution | theory_context · metal_substitutionCited for theoretical classification and for orbital contributions in monolayer Ni3(HITP)2. | Unmapped |
| Ref. 332016 | Proposed Modification of the Graphene Analogue Ni3(HITP)2 to Yield A Semiconducting Material | theory_context · transport_pathwaysCited for prior theoretical structures and as a comparison point for interlayer-distance convergence and band-shape interpretation. | Unmapped |
| Ref. 342018 | Unraveling The Semiconducting/Metallic Discrepancy In Ni3(HITP)2 | controversy · transport_benchmark · defect_contextKey cited study for the defects/pristine-model explanation and displacement-induced gap ranges in Ni3(HITP)2. | Unmapped |
| Ref. 352019 | Single Crystals of Electrically Conductive Two-Dimensional Metal-Organic Frameworks: Structural and Electrical Transport Properties | single_crystal_context · transport_benchmark · controversyCited for metallic Ni3(HITP)2 single rods and for the Table 1 interlayer-distance comparison. | research_0005 |
| Ref. 362017 | Signature of Metallic Behavior in the Metal-Organic Frameworks M3(Hexaiminobenzene)2 (M = Ni, Cu) | material_comparison · controversyCited as the report of metallic behaviour in HIB frameworks, used as a parallel example to Ni3(HITP)2. | Unmapped |
| Ref. 372020 | Air-Stability and Carrier Type in Conductive M3(Hexaaminobenzene)2, (M = Co, Ni, Cu) | material_comparison · transport_benchmarkCited for intrinsic semiconducting behaviour and the 0.49 eV band gap in Ni3(HIB)2-related discussion. | research_0495 |
| Ref. 382020 | Continuous Electrical Conductivity Variation in M3(Hexaiminotriphenylene)2 (M = Co, Ni, Cu) MOF Alloys | composition_context · material_comparisonCited around the need for road maps in a material class whose conductivity is influenced by flexible structure as well as composition. | research_0041 |
| Ref. 632018 | High-Mobility Band-like Charge Transport in a Semiconducting Two-Dimensional Metal-Organic Framework | transport_mechanism · band_like_transportCited in the discussion that the main route of charge delocalisation in 2D MOFs has been attributed to intralayer d-pi conjugation. | research_0001 |
| Ref. 642020 | Efficient and Tunable One-Dimensional Charge Transport in Layered Lanthanide Metal-Organic Frameworks | transport_mechanism · through_space_transportCited as recent evidence pointing to through-space conductivity in 2D/layered MOFs. | research_0047 |
| Ref. 711996 | Band Structure, Deformation Potentials, and Carrier Mobility in Strained Si, Ge, and SiGe Alloys | design_analogy · mobility_contextCited in support of using structural deformation and orbital contributions to predict mobility trends. | Unmapped |
| Ref. 722021 | Quantum Energy and Charge Transfer at Two-Dimensional Interfaces | charge_transfer_context · outlookCited for the need to analyse charge-transfer integrals and reorganisation energy in fine-tuning electrical properties. | Unmapped |
| Ref. 732004 | Charge-Transfer and Energy-Transfer Processes in Pi-Conjugated Oligomers and Polymers: A Molecular Picture | transport_mechanism · hopping_contextCited for the distinction between delocalised band transport and trapped polaronic hopping depending on electron-phonon coupling. | Unmapped |
| Ref. 751990 | Design and Construction of A New Class of Scaffolding-Like Materials Comprising Infinite Polymeric Frameworks of 3D-Llinked Molecular rods. A Reappraisal of The Zinc Cyanide and Cadmium Cyanide Structures and the Synthesis and Structure of the Diamond-Related Frameworks [N(CH3)4][CuIZnII-(CN) 4 ] and CuI[4,4',4'',4'''-tetracyanotetraphenylmethane]-BF4.xC6H5NO2 | node_linker_design · framework_designCited for the node-and-linker design principle used in the outlook's MOF topology discussion. | Unmapped |
| Ref. 762006 | Structural Diversity and Chemical Trends in Hybrid Inorganic-Organic Framework Materials | node_linker_design · framework_designCited in relation to the (SBU)m(L)n composition/tessellation design notation in the outlook. | Unmapped |