Nyakuchena J., Ostresh S., Streater D. et al. · Journal of the American Chemical Society · 2020 · 21050-21058
Open a family to keep every result attached to its sample, method and conditions.
Paraphrased for this database from the authors’ stated interpretations — never quoted verbatim — and kept separate from reported measurements.
FTIR, diffuse reflectance and XRD support formation of crystalline M-THQ frameworks from deprotonated/reduced THQ ligands coordinated to metal nodes.
Caveat: No CIF or full refinement table was supplied in the assigned documents; structure assignment is as reported by the authors.
21052 · 3.1. Synthesis and Characterization of M-THQ · Figure 1 · Linked to 4 structured results
Zn incorporation into Cu-THQ approximately halves the photoconductivity / peak OPTP response, indicating reduced carrier mobility and/or density.
Caveat: Cu/Zn-THQ photoconductivity is estimated indirectly because the frequency-dependent signal was prohibitively small.
21054 · 3.4. Photoconductivity Dynamics via OPTP Spectroscopy · Figure 3d · Linked to 4 structured results
Replacing Cu with Zn reduces electron density/covalency in the O-M-O motif and blocks through-bond intralayer charge transport.
Caveat: Mechanistic claim combines XPS, XTA and DFT interpretation rather than a direct bond-covalency measurement.
21054 · 3.3. Unravelling the Atomic-level Nature · Figure 3 · Linked to 3 structured results
Cu-THQ is photoconductive under optical excitation, with a frequency-dependent terahertz photoconductivity of about 0.2 S/m.
Caveat: The reported conductivity is transient photoconductivity from OPTP, not dark DC conductivity.
21055 · 3.4. Photoconductivity Dynamics via OPTP Spectroscopy · Figure S6d · Linked to 4 structured results
Photoexcited carriers in Cu-THQ form long-lived cool carriers with lifetimes greater than 17 ns or beyond the OTA window, and these carriers are associated with long-term photoconductivity.
Caveat: Different time constants come from different methods and fit windows; OPTP tau3 is modelled as a baseline beyond 300 ps.
21056 · 4. Conclusion · Linked to 3 structured results
The dominant photoconductivity pathway in Cu-THQ is intralayer transport through the O-Cu-O motif, with negligible contribution from interlayer pi-pi stacking.
Caveat: Pathway assignment is an integrated interpretation of OPTP, OTA, XTA and DFT rather than a single direct current-path measurement.
21056 · 4. Conclusion · Linked to 6 structured results
Zn-THQ has negligible photoconductivity under the OPTP conditions, supporting the conclusion that through-space interlayer transport contributes little to the observed Cu-THQ photoconductivity.
Caveat: No numerical detection limit is reported for Zn-THQ.
21053 · 3.2. CT Mechanism by Probing Exciton Dynamics using OTA · Figure S5 · Linked to 4 structured results
Names and aliases are kept exactly within the paper’s own identity model.
| Material | Composition | Structure context | Source |
|---|---|---|---|
| Cu-THQ metal-organic frameworkBrowse family: Cu₃(C₆O₆)₂ (Cu–THQ / Cu–HHB) | Cu-THQ; M-THQ with M = CuCu nodes; Cu2+ centres with mixed-valence Cu features by XPS; square-planar Cu coordination in the model. · Deprotonated tetrahydroxy-1,4-benzoquinone / tetrahydroxyquinone (THQ). Ethylenediamine is present for charge balance. | 2D · Pristine2D kagome M-THQ MOF; XRD agrees with standard kagome lattice and Rietveld refinement suggests Cmcm space group with base-centred orthorhombic unit cell. | 21052 · 3.1. Synthesis and Characterization of M-THQ · Figure 1 |
| Cu/Zn-THQ mixed-node metal-organic framework | Cu/Zn-THQ; Cu/Zn = 44:56Mixed Cu and Zn nodes; Zn2+ is introduced as redox-inactive 3d10 guest/mixed node to perturb in-plane charge delocalisation. · Deprotonated THQ framework linker with ethylenediamine charge-balancing species. | 2D · PristineMixed-node M-THQ MOF retaining crystallinity and porosity; XRD patterns agree with M-THQ kagome-type patterns. | 21052 · 3.1. Synthesis and Characterization of M-THQ · Figure 1 |
| THQ ligand reference | tetrahydroxy-1,4-benzoquinone hydrateNone · Molecular THQ ligand reference. | 0D · Model SystemMolecular ligand/control used for FTIR, diffuse reflectance and OTA comparison. | 21051 · Materials |
| Zn-THQ metal-organic framework | Zn-THQ; M-THQ with M = ZnZn2+ nodes with closed-shell 3d10 configuration. · Deprotonated THQ framework linker with ethylenediamine charge-balancing species. | 2D · PristineM-THQ framework control; DFT predicts a distorted Zn variant arising from Zn2+ coordination influenced by adjacent-layer O1- ions. | 21051 · Synthesis of M-THQ MOFs |
Sample form, processing state and composition status define the context for measurements.
| Sample | Form and role | Processing and geometry | Source |
|---|---|---|---|
| Cu-THQ DFT model unit cellresearch_0062__mat__mat_cu_thq | Model · Model System · Model | User-defined hexagonal unit cell with two deprotonated THQ ligands and three metal ion centres, optimised to triclinic cell. | 21052 · Computational Modeling |
| Cu-THQ film on glass for OTAresearch_0062__mat__mat_cu_thq | Thin Film · Target Sample · Pristine Framework | Film translated continuously during OTA to avoid pump degradation.Glass substrate | 21051 · Femtosecond Optical Transient Absorption (OTA) Spectroscopy |
| Cu-THQ powderresearch_0062__mat__mat_cu_thq | Powder · Target Sample · Pristine Framework | Aqueous room-temperature product filtered, washed with water and acetone, collected by centrifugation, and dried overnight at 80 deg C. | 21051 · Synthesis of M-THQ MOFs |
| Cu-THQ tape-cell sample for OPTP and THz-TDSresearch_0062__mat__mat_cu_thq | Powder · Target Sample · Pristine Framework | Prepared into tape cells cleaned with isopropanol before OPTP/THz measurements.Acrylic tape cell on a business-card support with 7 mm punched hole; Intertape Polymer Group 291 tape, 2.5 mil = 63.5 um. · Acrylic tape thickness 2.5 mil = 63.5 um; sample adequately thick to fully absorb pump pulse. | 21051 · Optical Pump Terahertz Probe (OPTP) Spectroscopy |
| Cu-THQ flowing sample stream for XTAresearch_0062__mat__mat_cu_thq | Unknown · Target Sample · Pristine Framework | 400 nm laser pump and X-ray probe overlapped in flowing sample stream.Flowing sample stream · Stream diameter 550 um | 21051 · X-ray Transient Absorption (XTA) Spectroscopy |
| Cu/Zn-THQ film on glass for OTAresearch_0062__mat__mat_cuzn_thq | Thin Film · Target Sample · Mixed Metal | Film translated continuously during OTA to avoid pump degradation.Glass substrate | 21051 · Femtosecond Optical Transient Absorption (OTA) Spectroscopy · Figure 2 |
| Cu/Zn-THQ powderresearch_0062__mat__mat_cuzn_thq | Powder · Target Sample · Mixed Metal | Prepared by replacing half of the Cu2+ source with Zn(NO3)2.6H2O in the M-THQ synthesis. | 21051 · Synthesis of M-THQ MOFs |
| Cu/Zn-THQ tape-cell sample for OPTP and THz-TDSresearch_0062__mat__mat_cuzn_thq | Powder · Target Sample · Mixed Metal | Prepared into tape cells cleaned with isopropanol before OPTP/THz measurements.Acrylic tape cell on a business-card support with 7 mm punched hole; Intertape Polymer Group 291 tape, 2.5 mil = 63.5 um. · Acrylic tape thickness 2.5 mil = 63.5 um; sample adequately thick to fully absorb pump pulse. | 21051 · Optical Pump Terahertz Probe (OPTP) Spectroscopy |
| Cu/Zn-THQ flowing sample stream for XTAresearch_0062__mat__mat_cuzn_thq | Unknown · Target Sample · Mixed Metal | 400 nm laser pump and X-ray probe overlapped in flowing sample stream.Flowing sample stream · Stream diameter 550 um | 21054 · 3.3. Unravelling the Atomic-level Nature · Figure 3 |
| THQ ligand in chloroform solutionresearch_0062__mat__mat_thq_ligand | Unknown · Model System · Model | Ligand solution used as an OTA control.Chloroform solution | S4 · Supplementary figures · Figure S4 |
| Zn-THQ DFT model unit cellresearch_0062__mat__mat_zn_thq | Model · Model System · Model | User-defined M-THQ computational unit cell with Zn metal centres. | 21055 · 3.5. Electronic Structure Predicted by DFT · Figure 4 |
| Zn-THQ film for OTAresearch_0062__mat__mat_zn_thq | Thin Film · Pristine Control · Pristine Framework | Used for OTA following 450 nm excitation.Glass substrate | S4 · Supplementary figures · Figure S4 |
| Zn-THQ powderresearch_0062__mat__mat_zn_thq | Powder · Pristine Control · Pristine Framework | Prepared using Zn(NO3)2.6H2O in place of Cu(NO3)2.2.5H2O in the M-THQ synthesis. | 21051 · Synthesis of M-THQ MOFs |
| Zn-THQ tape-cell sample for OPTP controlresearch_0062__mat__mat_zn_thq | Powder · Pristine Control · Pristine Framework | Used for normalized OPTP comparison.Acrylic tape cell | S4 · Supplementary figures · Figure S5 |