Kadota K., Chen T., Gormley E.L. et al. · Chemical Science · 2023 · 11410-11416
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.
SEM-EDX underestimates sulfur relative to Fe because air exposure and high vacuum likely hydrolyse the moisture-sensitive [Fe4S4] cluster and induce sulfur vacancies.
Caveat: This is the authors' interpretation of a compositional deviation, not an independently quantified degradation pathway.
3 · Synthesis and structural characterizations · Fig. 2b · Linked to 1 structured result
The product 1 is better described as polymeric [Fe4S4Cl2(Me-NHC)] rather than a discrete [Fe4S4Cl2(Me-NHC)2] complex.
Caveat: PXRD lacks well-defined reflections, so long-range crystallographic structure is not solved.
2 · Synthesis and structural characterizations · Fig. S5 · Linked to 3 structured results
PDF analysis supports preservation of the cuboidal [Fe4S4] cluster in 1 and excludes amorphous iron sulfide as the main phase.
Caveat: Signal-to-noise was too low for definitive Rietveld refinement.
3 · Synthesis and structural characterizations · Fig. 2c and Fig. S12 · Linked to 3 structured results
Charge-delocalised Fe-C bonds between [Fe4S4] clusters and ditopic NHC linkers give 1 a high room-temperature conductivity compared with discrete [Fe4S4] complexes and thiol-linked [Fe4S4] CP/MOFs.
Caveat: The NHC versus thiol comparison partly relies on model calculations and literature thiol CP/MOF values.
4 · Electronic properties · Fig. 3 · Linked to 4 structured results
Longer NHC alkyl substituents suppress solid polymer product formation, likely through lower coordination ability, steric hindrance and increased solubility.
Caveat: The claim is qualitative; yields for the variant series are not tabulated individually.
2 · Synthesis and structural characterizations · Fig. S6 · Linked to 1 structured result
Variable-temperature conductivity is consistent with thermally activated 3D hopping transport.
Caveat: Material is disordered and pressed-pellet measurements may include particle-boundary effects.
5 · Electronic properties · Fig. 4b and Fig. S19 · Linked to 3 structured results
Names and aliases are kept exactly within the paper’s own identity model.
| Material | Composition | Structure context | Source |
|---|---|---|---|
| Alkyl-NHC [Fe4S4] variant products (2-Et, 3-nPr, 4-nBu) | Products from R-BBI-X with R = Et, nPr, nBu and [Fe4S4] precursor; exact formulas not fully establishedIntended [Fe4S4] cluster units. · Ethyl-, n-propyl- and n-butyl-substituted benzobisimidazolylidene NHC linkers. | unknown · PristineSolid products lacked well-defined Bragg peaks by PXRD; longer alkyl chains gave lower yields and nBu gave almost no solid. | 2 · Synthesis and structural characterizations · Fig. S6 |
| R-BBI-X benzobisimidazolium linker salts | R-BBI-X; R = Me, Et, nPr, nBu; X = I or Brnone · Tetraalkyl-benzobisimidazolium salts used as NHC precursors. | 0D · UnknownMolecular linker precursor salts verified by 1H NMR. | S5 · Synthesis of R-BBI-X · Fig. S1 |
| Control-I self-reaction product from Me-NHC conditions | not reportednone · Self-reacted Me-NHC-derived organic control product. | unknown · UnknownCrystalline red powder control; FT-IR and PXRD do not match polymer 1. | 3 · Synthesis and structural characterizations · Fig. S7 and S8 |
| [Fe4S4Cl2(Me-NHC)] organometallic polymer (1) | [Fe4S4Cl2(Me-NHC)]; Me-NHC = tetramethyl-benzobis-imidazolylideneCuboidal [Fe4S4] clusters linked through Fe-C bonds. · Ditopic tetramethyl-benzobis-imidazolylidene N-heterocyclic carbene linker generated from Me-BBI-I. | unknown · PristineExtended polymeric organometallic material; poorly crystalline by benchtop PXRD, but PDF confirms preserved [Fe4S4] cluster correlations. | 2 · Synthesis and structural characterizations · Fig. 1d |
| (PPh4)2(Fe4S4Cl4) discrete [Fe4S4] precursor | (PPh4)2(Fe4S4Cl4)Discrete cuboidal [Fe4S4Cl4]2- cluster with tetraphenylphosphonium counterions. · Tetraphenylphosphonium counterions; chloride terminal ligands. | 0D · PristinePre-formed soluble [Fe4S4] cluster precursor; PXRD compared with simulated pattern in SI. | 2 · Synthesis and structural characterizations · Fig. S2 |
| NHC-ligated [Fe4S4] computational/model cluster | [Fe4S4] cluster with NHC ligands; overall charge +2 e in DFTModel cuboidal [Fe4S4] cluster. · NHC ligands / model Me-NHC environment. | 0D · Model SystemDFT-relaxed model cluster used to analyse frontier orbitals, Mulliken charges and Fe-C covalency. | S4 · Computational Details · Fig. 3d and Fig. S15 |
| BDT/thiolate-ligated [Fe4S4] computational/model cluster | [Fe4S4] cluster with BDT ligands; overall charge -2 e in DFTModel cuboidal [Fe4S4] cluster. · BDT / benzenedithiolate or thiolate ligands. | 0D · Model SystemDFT-relaxed comparison model for thiol-based [Fe4S4] CP/MOF bonding. | S4 · Computational Details · Fig. 3d |
Sample form, processing state and composition status define the context for measurements.
| Sample | Form and role | Processing and geometry | Source |
|---|---|---|---|
| [Fe4S4Cl2(Me-NHC)] (1) powderresearch_0126__mat__mat_fe4s4_me_nhc_polymer | Powder · Target Sample · Pristine Framework | Black precipitate isolated, washed with DMF and DCM, dried under vacuum; handled under N2 where specified. | S7 · Synthesis of [Fe4S4Cl2(Me-NHC)] (1) · Fig. S3 |
| [Fe4S4Cl2(Me-NHC)] (1) rectangular pellet for four-contact VT conductivityresearch_0126__mat__mat_fe4s4_me_nhc_polymer | Pellet · Target Sample · Pristine Framework | Pressed in glovebox, cut rectangular, grease-covered to prevent air exposure, measured in PPMS under vacuum.Sapphire support on PPMS ETO puck with four copper wires · 0.068 mm | S4 · Variable temperature electrical conductivity · Fig. S18 and S19 |
| [Fe4S4Cl2(Me-NHC)] (1) pressed pellet for two-contact conductivityresearch_0126__mat__mat_fe4s4_me_nhc_polymer | Pellet · Target Sample · Pristine Framework | Powder compressed into pressed pellet; DC I-V measured under N2 at 25 C.Modified KBr pellet die with tinned copper wires and stainless-steel circular electrode contacts | S3 · Linear sweep voltammetry · Fig. 3b; Table S1 |
| 2-Et, 3-nPr and 4-nBu alkyl-NHC variant powdersresearch_0126__mat__mat_alkyl_nhc_variant_products | Powder · Target Sample · Pristine Framework | Synthesised by varying R-BBI-X under the procedure of 1; 4-nBu PXRD collected without DMF washing because of limited sample amount. | S7 · Controlled synthesis to vary the alkyl chains of NHC linkers · Fig. S6 |
| R-BBI-X linker precursor saltsresearch_0126__mat__mat_bbi_salt_precursors | Powder · Paper Level Unspecified · Unknown | Off-white/solid molecular products isolated, washed with toluene and dried under vacuum. | S5 · Synthesis of R-BBI-X · Fig. S1 |
| Control-I red powderresearch_0126__mat__mat_control_i | Powder · Pristine Control · Unknown | Control reaction without (PPh4)2(Fe4S4Cl4). | 3 · Synthesis and structural characterizations · Fig. S7 and S8 |
| (PPh4)2(Fe4S4Cl4) pressed-pellet controlresearch_0126__mat__mat_fe4s4cl4_precursor | Pellet · Pristine Control · Pristine Framework | Discrete cluster precursor measured as pressed pellet and as DMF solution for UV-vis.Pressed-pellet two-contact probe setup | S8 · Table S1 · Table S1 |
| DFT NHC-ligated [Fe4S4] model clusterresearch_0126__mat__mat_nhc_model_cluster | Model · Model System · Model | PBE/FHI-aims relaxed computational model. | S4 · Computational Details · Fig. 3d and Fig. S15 |
| DFT BDT/thiolate-ligated [Fe4S4] model clusterresearch_0126__mat__mat_thiol_model_cluster | Model · Model System · Model | PBE/FHI-aims relaxed computational model. | S4 · Computational Details · Fig. 3d |