Benthol A, a dinoflagellate-derived polyol/polyether marine natural product endowed with potent antimalaria and appreciable antiviral activity, consists of a 72 C atom linear backbone featuring 35 stereogenic centers and four stereogenic alkenes. The constitution and configuration of this intriguing "super-carbon-chain compound" had been assigned by the isolation team by a combination of spectroscopic, chemical, and computational means. Outlined in this and the accompanying paper is the first total synthesis of this challenging target, which came along with a subtle structure revision. During the synthesis of the building blocks, a spectral irregularity was noticed in that the 13C NMR chemical shifts as well as some of the 3JH,H coupling constants of the synthetic samples deviated notably from the data reported for the entire C31-C41 region of benthol A corresponding to the tetrahydropyran E-ring and its vicinity. A systematic approach made it possible to narrow down the likely site of error to a single, incorrectly assigned stereocenter, i.e., the C40 position; interestingly, the configuration of this site had been determined by the isolation team solely by computational means. In chemical terms, our studies showed how the proper choice of a propargylic protecting group allows the regiochemical course of a gold-catalyzed spiroacetalization reaction to be steered. Moreover, carbonyl homologation by the addition of a highly functionalized but entirely unstabilized diazo derivative generated in situ to an equally highly functionalized aldehyde proved adequate for the coupling of elaborate building blocks (Buchner-Curtius-Schlotterbeck reaction).
ADP-ribosylation (ADPr), long recognized as a canonical protein post-translational modification, has recently expanded to include targeting nucleic acids, uncovering a diverse landscape of noncanonical biological functions. Emerging evidence suggests that ADPr at the 5'-phosphate terminus of DNA is implicated in the DNA damage response, yet understanding its precise molecular function has been hampered by the lack of structurally defined chemical probes. Here, we report the stereoselective synthesis of deoxynucleotide-phospho-ADPr (dN-P-ADPr) probes, representing native fragments of terminal DNA-ADPr. Our strategy leverages a mild, stereocontrolled glycosylation to construct the challenging ribosyl-phosphate linkage, followed by P(III)-P(V) coupling to establish the pyrophosphate bridge. This robust toolkit enabled the systematic biochemical profiling of DNA-ADPr hydrolases across diverse kingdoms of life. Remarkably, using these newly developed probes, we uncover hydrolases across the diversity of life capable of reversing ADPr modifications at phosphorylated DNA ends. We further show that these enzymes exhibit an absolute preference for the native-like α-anomer, independent of the identity of the adjacent DNA nucleobase, suggesting that substrate recognition is governed primarily by the ADPr-phosphate linkages rather than the local nucleobase context. Together, these synthetic probes and biochemical insights provide an essential foundation for deciphering the biological landscape of noncanonical ADPr.
Chemically controlled reactions in polymerization processes are traditionally assumed to have chain-length-independent rate coefficients. However, this work challenges that assumption by using multiscale modeling to demonstrate that chemically controlled polymer-polymer reactions can exhibit significant chain length effects. Taking reversible addition-fragmentation chain transfer (RAFT) polymerization as a case study, we compare the chain length convergence of the reaction entropy for two processes: the addition of a growing polymer radical to a simultaneously growing polymeric RAFT agent, and the analogous reaction involving a low molecular weight RAFT agent. While the latter reaches equilibrium within 10 monomer additions, the former shows delayed convergence, with effects persisting to degrees of polymerization (DP) of 100 or more. A similar trend was observed in the Diels-Alder step-growth polymerization, where rapid convergence occurred when one chain length was fixed and short, but markedly slower convergence was observed when both reacting chain lengths increased simultaneously. These results reveal that entropy contributions, which scale logarithmically with chain length, lead to significant chain length dependence in the equilibrium constants (Keq). Because these effects arise from fundamental entropic considerations rather than specific features of the reacting species, they are expected to manifest broadly in the kinetics and thermodynamics of other chemically controlled polymer-polymer reactions. Our findings provide a mechanistic basis for resolving discrepancies in experimental estimates of fragmentation rate coefficients, shedding light on debate surrounding rate retardation in RAFT systems. More broadly, this work underscores the importance of chain length effects in the kinetics and thermodynamics of chemically controlled polymer-polymer reactions.
Proton-coupled electron transfers (PCETs) to metal oxides are key reactions for sustainable catalytic and energy storage processes. The factors that control PCET reactions on metal oxides are, however, not well understood, with the effect of particle morphology/surface faceting on the thermodynamics and kinetics of PCET being essentially untested. We measured the thermodynamics and kinetics of PCET from CpCr(CO)3H to five V2O5 samples of varying morphologies/surface faceting. Their nanostructures were assessed by Rietveld refinement accounting for preferred crystallite orientation, giving a semiquantitative measurement of surface faceting. PCET to V2O5 occurs via proton insertion-coupled electron transfer (PICET), where H· diffuses into the bulk of the particle. The thermodynamics of PICET are controlled by particle structure, with nonequilibrium morphologies requiring structural rearrangement during PICET. The kinetics of PICET are controlled by the rate of H· diffusion into the bulk, with diffusion along the interconnected V2O5 layers being 10x faster than between the layers. Samples with hindered H· diffusion also show low activity in the oxidation of methanol, demonstrating that diffusion of H· into the bulk occurs during catalysis. This work demonstrates that particle morphology is critical for PCET reactions to anisotropic metal oxides and must be considered when examining their reactivity.
The total synthesis of the dinoflagellate-derived "super-carbon-chain compound" benthol A rigorously confirmed what the analysis of one of the required building blocks had forecasted, namely that the configuration of the secondary -OH group at C40 had been misassigned by the isolation team as the only one of a total of 35 stereogenic centers decorating the backbone of this polyol/polyether derivative. This conclusion bears implications because the original assignment had been solely based on computational data, which had resulted in a remarkably high score of 99.93% that was ultimately misleading. The multiconvergent blueprint underlying the successful approach accounts for the fact that alongest linear sequence of 32 steps sufficed to reach this intricate marine natural product. The inherent flexibility should also empower future studies aiming at a detailed mapping of the pharmacophore of this compound endowed with significant antiplasmodial activity.
Developing a detailed understanding of ternary nanoparticle (TNP) formation is essential for their optimized rational synthesis and development of synthetic routes for new TNPs. Herein, we explore the reaction of Cu3-xP and dibenzyl diselenide (Bn2Se2) to form colloidal Cu3PSe4 TNPs. Temperature-resolved X-ray scattering (XRD and PDF), electron microscopy (TEM and STEM), and spectroscopy (EDS, EELS, XPS, and MAS NMR) reveal that Cu3-xP reacts by surface coordination of Se leading to fragmentation followed by rearrangement to Cu-Se binary phases, during which all obvious crystalline P-containing phases disappear via XRD. However, partially oxidized P in solid phases was observed using STEM-EDS and XPS, in which P is found to preform P-Se bonds prior to Cu3PSe4 formation. Using a combination of 31P MAS NMR and PDF analysis obtained from synchrotron total scattering data, P-Se bonds in [PSe4]3- tetrahedral building blocks were identified within intermediate Cu-Se phases containing P cation substitution (PCu), denoted (Cu,P)-Se, that assemble into Cu3PSe4. We hypothesize that these intermediate compounds with their substoichiometric, vacancy-rich structures and significant Cu disorder are important for accessing Cu3PSe4─offering a new insight into complex TNP syntheses. We summarize our findings by writing plausible pseudoelementary steps (PESteps) in which the Cu3-xP precursor converts to smaller fragments of Cu-Se phases containing P en route to the final Cu3PSe4 product. Additional interesting aspects of this system include the use of Bn2Se2 as a readily monitorable probe for the reaction and the Se-P bond formation that facilitates Cu-P bond cleavage in an overall 8-electron redox reaction involving P3- and 4 Se0. The results obtained lay the groundwork for future mechanistic investigations, notably kinetics studies working from the PESteps aimed ultimately at the rational design and synthesis of complex ternary pnictogen chalcogenide nanoparticles.
Electrochemical nitrate (NO3-) reduction is a promising pathway toward the production of ammonia (NH3). While copper (Cu) electrodes are commonly used for this reaction, the influence of Cu surface structure on reaction selectivity is poorly understood. Here, we performed electrochemical NO3- reduction in alkaline electrolytes with Cu(100), Cu(110), and Cu(111) single-crystal electrodes and quantified the product distributions across a range of applied potentials. Our systematic study of electrocatalytic NO3- reduction demonstrated that the Cu(100) and Cu(110) surfaces exhibited similar selectivity and rates for NH3 production, but the Cu(100) surface provided >95% Faradaic efficiency toward NH3 over the broadest range of applied potentials. In contrast, the Cu(111) surface was significantly less selective for NH3 production. Further comparing the electrochemical behavior of Cu single crystals to their corresponding product distributions revealed that nitrite (NO2-) reduction voltammograms were strong predictors of electrocatalytic performance for all three low-index Cu surfaces in alkaline electrolytes. Quantum mechanical calculations indicate that the Cu(100) surface exhibits the lowest potential-determining step for NO3- reduction to NH3, supporting our experimental findings. Detailed analysis of metal-adsorbate interactions also revealed the role of Cu surface structure in stabilizing key reaction intermediates to promote selective NH3 production. Our combined experimental and computational study establishes electrocatalytic selectivity of low-index Cu facets for NH3 synthesis and offers practical guidelines for the design of Cu-based electrocatalysts capable of selective electrochemical NO3- reduction in alkaline solutions.
The chirality-induced spin selectivity (CISS) effect has been invoked to explain recent reports of differences in the time-resolved EPR signals between chiral and achiral molecules. However, the microscopic origin of these differences and their connection to CISS remain contested, particularly since these systems lack a metal interface. Here, we introduce an intramolecular spinterface-like mechanism that naturally arises within donor-chiral bridge-acceptor (D-χB-A) complexes and quantitatively reproduces experimentally reported observed spin polarization in time-resolved EPR studies. In our two-electron Lindblad model, the photoexcited charge-transfer electron traversing the chiral bridge exchanges with the residual donor electron, which acts as a localized magnetic moment analogous to an induced magnetic moment on an electrode surface. The resulting through-bridge charge current produces an effective solenoidal field at the donor-bridge interface, breaking spin degeneracy and directional symmetry, thus enabling spin-selective transport without invoking intrinsic spin-orbit coupling on the bridge. We show that the interplay among this current-induced field, donor thermalization (which breaks time-reversal symmetry), and bridge spin mixing yields tens-of-percent polarization over realistic experimental conditions and charge-transfer time scales, matching reported CISS signatures in triads and DNA hairpins. By explicitly resolving the dependence on solenoidal coupling strength, temperature, and spin-mixing rates, the model identifies the regime in which internal spinterfaces can generate robust CISS-like spin filtering. These findings demonstrate that CISS-like signals in isolated D-χB-A complexes are fully compatible with a spinterface mechanism, providing a unified conceptual framework for interpreting both device-based and molecule-internal CISS platforms.
The advent of novel free-electron laser sources enabling time-resolved X-ray photoelectron spectroscopy (tr-XPS) provides a unique opportunity to monitor local chemical environments in real time by measuring sub-eV shifts in core-electron binding energies. These shifts reflect the interplay between electronic excitation and nuclear motion, an interplay that remains largely unexplored. In our combined theoretical and experimental study of fluoropyridine (C5H4FN), we investigate this link by monitoring the evolving chemical environment at the N and F atomic sites as the photoexcited S1 state relaxes to the ground state via a conical intersection. We find that the F site responds primarily to vibrational relaxation, showing minimal sensitivity to the electronic excited state. In contrast, excitation to S1 induces a measurable energy shift at the N site and significantly enhances its sensitivity to local vibrations within the ring. This behavior arises from a photoinduced redistribution of charge, which also increases the Coulomb interaction between the 1s electron at the N atom and the atomic partial charge at an adjacent C atom. This insight opens new avenues for exploring ultrafast dynamics and conical intersection pathways in more complex systems, from photostable DNA bases to light-harvesting materials.
Aqueous zinc-air battery (ZAB) is considered as a promising long-term energy storage technology due to its low cost, high safety, and high theoretical energy density. However, the zinc (Zn) anode suffers from issues such as dendrite growth, hydrogen evolution reaction (HER), corrosion, passivation, and volume deformation during cycling. To enhance the interfacial stability and deposition/dissolution behavior of the Zn anode, this work introduces indium tetrafluoroborate (In(BF4)3) into the electrolyte as a functional additive. The results demonstrate that the incorporation of indium (In) effectively regulates Zn nucleation behavior, promotes uniform Zn deposition, and significantly suppresses dendrite formation. Moreover, the dynamic alloy interface formed with In participates in reversible redox reactions that enable local defect self-healing, thus improving interfacial integrity and the compactness of the deposited structure. After modification, the ZAB achieves an ultralong cycle life of over 400 h under a current density of 5 mA cm-2 and 20 min per cycle, and ultrahigh reversibility for 320 h at current density of 2 mA cm-2 and 4 h per cycle under high depth of discharge/charge. The ZABs with In(BF4)3 additive exhibit reduced voltage polarization and excellent rate capability at various current densities, exhibiting enhanced cycling stability and electrochemical performance significantly. This work shows clearly the strategy of in situ constructing a Zn-In alloy layer by electrolyte engineering, which can guide the design and preparation of a stable Zn anode for not only ZABs but also the other Zn-based batteries.
The discovery and development of high-performance catalysts, which is crucial across all catalysis areas, requires advanced technologies and innovative approaches. Recently, machine learning (ML) has shown promise in accelerating this process, but its capability and examples of discovery of truly novel catalysts have remained limited. In this study, we describe an ML approach that goes beyond the traditional element pool, incorporating elements that have not been previously studied, to develop highly efficient catalysts for ethanol synthesis via CO2 hydrogenation. Starting with an initial data set of 58 catalysts (274 data points obtained at reaction temperatures ranging from 240-400 °C), we conducted 24 iterations of a closed-loop discovery system (ML predictions + experimental validation), testing a total of 555 catalysts (2477 data points), and building a large experimental data set. More than 50 catalysts with superior activity were discovered through this data-driven approach. The multielemental Pd(0.8)-Au(0.3)/K(2.5)-Sr(1)-Fe(20)-Zn(4)-Cd(2)-Yb(1)-Re(1)/CeO2(25%)-ZrO2 catalyst, where the numbers in parentheses represent weight percent (wt %), was identified as the most effective catalyst for ethanol synthesis (ethanol space-time yield: 8.2 mmol gcat-1 h-1 with a CO2 conversion of 57.6% and an ethanol selectivity of 23.2% under reaction conditions of 360 °C, 4 MPa, 12 L gcat-1 h-1, H2/CO2 = 3/1). Comprehensive characterizations, including in situ/operando techniques such as X-ray absorption spectroscopy (XAS), ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), enable us to highlight the critical roles of each constituting element in improving ethanol synthesis efficiency.
The most commonly encountered aromatic structure is the benzenoid ring, which is observed in a wide variety of pharmaceuticals and organic materials. However, studies on nonbenzenoid conjugated polyene aromatic molecules remain scarce, largely due to synthetic challenges and inherent angle strain. Herein, we report an unprecedented single-copper relay dual-catalyzed cascade sequence for the efficient construction of a unique aromatic N-bridged [10]annulene (NBA) framework (also called cycl[3,2,2]azine), in which a copper-catalyzed 10π electrocyclization is involved. To gain insight into the reaction mechanism, a series of control experiments and density functional theory calculations were conducted. The developed reaction exhibits broad functional-group tolerance and can be extended to different classes of 14π components. Significantly, the resulting NBA compounds display strong fluorescence with full-color tunability. Therefore, these innovations not only deepen our understanding of the aromaticity of nonbenzenoid systems but also highlight the potential of metal-catalyzed electrocyclization in synthetic chemistry.
Biomolecular condensation is a key process for cells to maintain their normal physiological activities. However, the process of phase transition remains mysterious, especially for the initial moments of condensation. Herein, we investigated the first microsecond of peptide condensation through temperature jump infrared spectroscopy and molecular dynamics simulations. These techniques overcome the limited spatiotemporal resolution of traditional approaches, allowing us to capture the molecular events and kinetic information on the initial moment for phase transition. The results reveal that structural transitions and early assembly of intrinsically disordered proteins occur on ultrafast time scales. Unexpectedly, backbone hydrogen bonding emerges as the overlooked key mediator to stabilize the local structure for the ultrafast condensation of hydrophobic polypeptides compared to hydrophobicity. By locking local structures, hydrogen bonds help to form more stable interaction interfaces. These findings indicate that hydrogen bonding could enable hydrophobic disordered proteins to adopt preorganized conformations in response to environmental stimuli and serve as a key factor in mediating the assembly kinetics in complex cellular environments.
Redox-active covalent organic frameworks (COFs) are promising materials for electronics, sensing, and catalysis. However, their synthesis is hampered by the scarcity of redox-active monomers and the difficulty of functionalizing as-synthesized frameworks without compromising crystallinity. Here, we introduce a reductive N-methylation strategy that enables the universal and mild conversion of imine-linked COFs into crystalline tertiary amine-linked frameworks (NMe-COFs). The method preserves structural order while imparting strong electron-donating and redox-responsive properties. Among the NMe-COFs, COF-300-NMe exhibits an 11-fold increase in iodine uptake with a distinct gate-opening adsorption profile─a behavior that computational studies attribute to enhanced framework flexibility and raised electronic energy levels. Furthermore, incorporation of the electron acceptor 7,7,8,8-tetracyanoquinodimethane into COF-300-NMe yields a charge-transfer complex exhibiting distinct spin signatures. This work establishes a versatile postsynthetic linkage conversion strategy, paving the way toward stimuli-responsive soft COFs and purely organic spin-active materials.
Molecules derived from lignocellulosic biomass are oxygenates with multiple oxygen-containing functional groups, such as hydroxyl and carbonyl groups. Therefore, the ability to selectively reduce a specific oxygenate group is essential for the reductive upgrading of such molecules. Previous studies on electrochemical biomass conversion have shown that alcohol hydrogenolysis, which involves cleavage of the σ(C-Oalcohol) bond, is extremely challenging for furfural and 5-hydroxymethylfurfural (HMF) derivatives, including furfuryl alcohol, 5-methylfurfuryl alcohol (MFA), and 2,5-bis(hydroxymethyl)furan (BHMF). In contrast, HMF itself undergoes alcohol hydrogenolysis relatively easily in acidic aqueous media. Considering that the only structural difference between HMF and BHMF or MFA is the presence of a carbonyl group, this observation raises the question of whether the carbonyl group in HMF facilitates alcohol hydrogenolysis. In this study, we designed systematic experiments to provide a coherent explanation of when and how a carbonyl group enables hydrogenolysis of a copresent alcohol group. Specifically, we show that alcohol hydrogenolysis in HMF proceeds via reduction of the carbonyl group to a ketyl radical, followed by a spin-center shift (SCS) through extended π conjugation. We also elucidate the effect of pH on the selectivity between carbonyl hydrogenation and alcohol hydrogenolysis, both of which share the ketyl radical intermediate. This mechanistic understanding enhances our ability to predict and control alcohol hydrogenolysis in the reductive upgrading of biomass-derived oxygenates.
While the rich diversity of surface sites on high-entropy alloys (HEAs) is essential for tuning electrocatalytic activity, the coverage-dependent lateral interactions that shape reactive interfaces are often neglected in theoretical studies. Here, we develop a machine learning interatomic potential (MLIP)-enabled framework to model the oxygen reduction reaction (ORR) within an Ag-Ir-Ru-Pd-Pt-Cu-Rh-Re alloy composition space. By tracking the binding strengths of O* and OH* intermediates during competitive coadsorption on crowded surfaces, this framework highlights the key role of lateral interactions, including attractive hydrogen-bond networks and electrostatic repulsion, in evaluating electrocatalytic activity. Incorporating these coverage-induced effects improves agreement with reported PtIr and AgPd composition-activity trends relative to an isolated-site baseline. We further show that increasing compositional complexity within the studied alloy space can amplify lateral repulsion under finite-coverage conditions, broadening binding strength distributions and reducing the population of optimal active sites. The competition between local electronic optimization and coverage-dependent lateral interactions gives rise to a volcano-shaped activity-entropy relationship, offering guidance for the rational design of HEA-based ORR electrocatalysts.
Halide-substituted argyrodite materials have attracted increasing attention for energy applications since compositional tuning provides an effective strategy to modulate their structure and transport characteristics. While Li+-based halide argyrodites have been extensively studied, a unified composition-resolved understanding of Cu+-based halide argyrodites that integrates phase evolution, local structure, lattice dynamics, and electronic and ionic transport remain limited. In this work, we investigate Cu6PS5X (X = Cl, Br, I, Cl0.5Br0.5, Cl0.5I0.5, and Br0.5I0.5) within a combined experimental and computational framework. All compositions adopt an average cubic F4̅3m structure at room temperature, while local structural analysis reveals deviations from cubic symmetry consistent with a monoclinic Cc model involving PS43- tetrahedral tilting. 31P MAS NMR spectroscopy corroborates this local symmetry breaking through multiple distinct phosphorus environments arising from relative tetrahedral orientation rather than S2-/X- site disorder. Halide substitution modifies the Cu+ conductivity through changes in the activation energy and the Arrhenius pre-exponential factor, following the Meyer-Neldel behavior, with additional contributions from variations in jump distances and migration pathways. Direction-projected phonon density of states analysis identifies low-frequency Cu+ vibrational components along the crystallographic migration pathways. Analysis of the Meyer-Neldel slope further suggests phonon assisted ion hopping involving multiphonon excitation of low-frequency Cu+ vibrational modes. Together, these findings offer insight into structure-property relationships in Cu6PS5X and suggest that, alongside the migration energy landscape, the vibrational energy scale, thermal population, and directionality of mobile ion modes should be considered when interpreting ion transport, thereby providing a vibrational perspective for the design of solid-state ion conductors.
The structure of the electric double layer at platinum electrodes remains incompletely understood, even for the model Pt(111)/HClO4 interface, which deviates significantly from Gouy-Chapman-Stern theory. While Pt(111) exhibits a true double-layer window (0.40-0.60 VRHE) that enables direct measurement of the double-layer capacitance, stepped Pt surfaces do not because hydrogen and/or hydroxyl species adsorb at low-coordinated step sites across the entire potential range. We previously showed that hydroxyl adsorption on (110)-steps is potential-independent within this nominal double-layer window, leading to decreasing capacitance with increasing (110)-step density due to suppression of the step Helmholtz capacitance. In contrast, (100)-steps exhibit potential-dependent hydroxyl adsorption that introduces a substantial pseudocapacitive contribution and increases capacitance with step density. Here, we selectively passivate Pt step sites by depositing Au* and Ag* adatoms. We find that Au*step-modification suppresses step-specific adsorption, restoring predominantly electrostatic behavior for (100)-type stepped Pt surfaces and reversing the capacitance trends observed for the bare stepped surfaces. In contrast, Ag*step-modification introduced an additional chemical contribution, manifested as substantially increased capacitance and enhanced CO oxidation activity due to adsorption of oxophilic species on Ag*. These results demonstrate that Pt step-site chemistry, and consequently the electrical double-layer structure and electrocatalytic activities, can be tuned and probed to a remarkable degree of controllability through selective adatom modification.
The 1,3-diol unit is an extremely important functional group motif, and significant effort has gone into development of methods to access it with definition of relative and absolute stereochemistry. Conventionally, stereochemical complexity is built up in a stepwise manner alongside functional group interconversion. It is interesting to consider an unconventional approach whereby the diol may be synthesized nonselectively and the stereoisomers "descrambled" by a chiral catalyst in a subsequent step. We report studies toward this goal using a cinchona alkaloid-derived hydrogen atom abstraction catalyst. This catalyst permits selective hydrogen atom abstraction from a given stereoisomer out of, in some cases three or four, depending on diol substitution. The relative rates of abstraction from different stereoisomers determine the ultimate product outcome after hydrogen atom delivery from an achiral thiol. Symmetrical 1,3-diols participate in a kinetic resolution process whereby one enantiomer is converted to the meso diastereomer with extremely high selectivity, a rare example of a kinetic resolution involving conversion of one enantiomer to an achiral diastereomer. Nonsymmetrical 1,3-diols exhibit different outcomes depending on substitution, and their behavior is systematically explored. Notably, sterically differentiated substrates can allow high ee of both syn and anti diastereomers to be achieved from racemic starting material. On the basis of mechanistic studies, a unified rationalization of the behavior of 1,3-diols of various types with our catalyst is presented, and we additionally evaluate the analogous chiral 1,2-diols, uncovering promising outcomes with nonsymmetrical diols.
Explorative chemistry in a reaction system composed of NbI4, Li2(CN2), and Li2O has led to the discovery of a number of niobium oxyiodide cluster compounds. During this reaction, the formation of solid phases was detected alongside gaseous phases, resulting in a range of products with cluster cores of varying shapes. After several niobium oxyiodide cluster compounds have already been identified within this reaction system, two additional compounds, Nb6O3I15 and Nb11O6I24, are discovered and structurally characterized by single-crystal X-ray diffraction. Both structures are based on the butterfly-shaped, oxygen-capped niobium cluster [Nb4O], which is extended to larger cluster fragments. The [Nb4O] cluster core in Nb6O3I15 is extended by two [NbO] units to form a three-dimensional framework, and Nb11O6I24 contains two connected [Nb4O] units, which form chiral units within an antiferrochiral hexagonal packing of strings. The striking string-like character of Nb11O6I24 was investigated in terms of its electronic structure and properties. DFT calculations showed Nb11O6I24 to possess a zero indirect band gap, with a pair of 3-dimensional flat bands surrounding the Fermi level. These unusual features of the electronic band structure suggest the presence of strongly correlated intercluster singlet electron states, arising from the helical shape of the clusters, the hexagonal packing of the strings, and the delocalized nature of cluster electron wave functions.