# Fileset

[RSC Adv,2026,16,12725.pdf](https://mdr.nims.go.jp/filesets/5fcd669c-f311-4644-bcd1-27d1386898b0/download)

## Creator

[Lara Rae Holstein](https://orcid.org/0009-0008-6412-5108), Megan S. Santamore, Asahi Tsukamoto, [Masayuki Takeuchi](https://orcid.org/0000-0002-0207-0665), Nobuhiko J. Suematsu, [Atsuro Takai](https://orcid.org/0000-0003-3457-3352)

## Rights



## Other metadata

[Hinokitiol-fueled disks form exclusionary zones in the presence of iron](https://mdr.nims.go.jp/datasets/6613faad-b8b5-41cb-83de-e96491205bad)

## Fulltext

Hinokitiol-fueled disks form exclusionary zones in the presence of ironRSC AdvancesPAPEROpen Access Article. Published on 06 March 2026. Downloaded on 3/6/2026 12:58:28 PM.  This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.View Article OnlineView Journal  | View IssueHinokitiol-fueledaMolecular Design and Function Group, N(NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 3nims.go.jpbDepartment of Materials Science and EnSciences, University of Tsukuba, 1-1-1 TenncSchool of Interdisciplinary MathematicalMathematical Sciences, Meiji Institute for A(MIMS), Meiji University, 4-21-1, Nakano, TCite this: RSC Adv., 2026, 16, 12725Received 17th February 2026Accepted 25th February 2026DOI: 10.1039/d6ra01403hrsc.li/rsc-advances© 2026 The Author(s). Published bydisks form exclusionary zones inthe presence of ironLara Rae Holstein, ab Megan S. Santamore,a Asahi Tsukamoto,aMasayuki Takeuchi, ab Nobuhiko J. Suematsu c and Atsuro Takai *abStimuli-responsive, directional motions, such as chemotaxis, are vital for the development of sophisticatedsynthetic systems with autonomous motility. Here, we demonstrate that disks containing hinokitiol exhibitdirectional self-propelled motion on water in response to metal ions, particularly Fe(III) ion. The self-propelled motion arises from surface tension gradients at the air-water interface, generated by theasymmetric release of hinokitiol, which induce Marangoni flows that propel the disks. Upon contact withFe(III), hinokitiol forms a highly surface-active complex that locally lowers the surface tension andestablishes a persistent interfacial gradient. This localized accumulation of the iron complex acts asa chemo-repulsive signal, directing the disks away from iron-rich regions and leading to the formation ofexclusionary zones that influence the trajectories of subsequent disks. These findings demonstrate howself-secreted chemical signals can generate interfacial memory and communication in macroscopicactive systems, providing a molecular design principle for life-like collective behavior.IntroductionDirectional locomotion in response to chemical stimuli repre-sents an essential biological process known as chemotaxis.1Motion away from chemo-repellent species, termed negativechemotaxis, serves as a communication mechanism betweenindividuals that not only enables organisms to migrate fromunfavorable conditions,2 but is also vital for the assembly ofneural networks through the creation of exclusionary zones.3Reproduction of such chemo-repulsive behaviors in syntheticsystems provides opportunities to model physical parameters ofbiological systems which could serve as a framework for nextgeneration responsive materials that exhibit memory andpatterned self-assembly.4 To this end, Marangoni ow hasemerged as a popular avenue by which synthetic, self-propellingobjects can be achieved through interfacial surface tensiongradients, which are typically generated by the release ofsurface-active “fuel” species.5 Some Marangoni motors can bemade to display rudimentary chemotactic behaviors forcommunication and maze-solving when used in conjunctionwith chemical reactions,6 pre-existing gradients,7 or solute-mediated interactions.8 Despite these advances, examples ofational Institute for Materials Science05-0047, Japan. E-mail: TAKAI.Atsuro@gineering, Faculty of Pure and Appliedodai, Tsukuba, Ibaraki 305-8577, JapanSciences, Graduate School of Advanceddvanced Study of Mathematical Sciencesokyo 164-8525, Japanthe Royal Society of Chemistrymacroscopic-level communicative behaviors through self-secreted signals remain rare—particularly in the realm ofchemo-repulsive systems.Herein, we demonstrate that disks containing hinokitiol(HT) autonomously exhibit negative chemotaxis towardaqueous iron, generating exclusionary zones. Inspired not onlyby the biochemical9 and self-propelling10 properties of HT, butalso by its ability to bind and transport a range of metal ions,11we envisioned that HT could be utilized as a potential chemo-tactic fuel enabling synthetic systems to respond to metal ions.Furthermore, building on our previous reports that diskscomposed of fuel and a polymer scaffold can undergo consis-tent and tunable self-propelled motion on aqueous surfaces, weemployed polystyrene-polyisoprene elastomer (SIS) as a scaffoldto construct symmetrical disks, thereby eliminating shape-dependent effects on motion.10,12 While examples of changesin autonomous behaviors induced by metal ion complexationhave been reported,13 this system represents a unique exampleof a macroscopic object displaying negative chemotaxis byproducing a chemo-repellent that is more surface-active than itsown fuel (Fig. 1a).Results and discussionThe complexation of HT with ferric ions (Fe3+) has been re-ported to proceed in a 3 : 1 molar ratio in buffer solution (pH7.0).11b To conrm this coordination behavior under ourconditions, we carried out titration experiments using UV-visabsorption spectroscopy. An aqueous solution of HT (30 mM)at pH 7 was titrated with FeCl3$6H2O at 25 °C. As shown inRSC Adv., 2026, 16, 12725–12729 | 12725http://crossmark.crossref.org/dialog/?doi=10.1039/d6ra01403h&domain=pdf&date_stamp=2026-03-06http://orcid.org/0009-0008-6412-5108http://orcid.org/0000-0002-0207-0665http://orcid.org/0000-0001-5860-4147http://orcid.org/0000-0003-3457-3352http://creativecommons.org/licenses/by-nc/3.0/http://creativecommons.org/licenses/by-nc/3.0/https://doi.org/10.1039/d6ra01403hhttps://pubs.rsc.org/en/journals/journal/RAhttps://pubs.rsc.org/en/journals/journal/RA?issueid=RA016014Fig. 1 (a) Reaction between HT and aqueous FeCl3 to yield thesurface-active complex, FeHT3. (b) UV-vis absorption spectral changesof HT (30 mM, blue) upon addition of FeCl3 to form a 3 : 1 complex(pink) in distilled water at 25 °C. Inset shows the plot of the absorbanceat 425 nm vs. [FeCl3].Fig. 2 (a) Concentration-dependent surface tension of FeCl3 (red),HT(blue), and FeHT3 complex (green) in distilled water at 25 °C. (b)Schematic illustration of the self-confinement and chemo-repulsionmechanisms due to the surface accumulation of FeHT3.RSC Advances PaperOpen Access Article. Published on 06 March 2026. Downloaded on 3/6/2026 12:58:28 PM.  This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.View Article OnlineFig. 1b, the absorption band of HT at 241 nm graduallydecreased and red-shied, accompanied by the emergence ofa new absorption band at 425 nm. The intensity of the 425 nmband reached saturation upon the addition of 10 mMFe3+. Theseresults indicate that HT and Fe3+ form a 3 : 1 complex (FeHT3).The absorbance at 425 nm slightly decreased at concentrationsof FeCl3 above 10 mM, probably due to partial precipitation ofFeHT3 during the UV-vis absorption titration measurements12726 | RSC Adv., 2026, 16, 12725–12729(over 30 min). Such precipitation behavior may also obscurea precise Job plot analysis for conrming the stoichiometryunder the present conditions. Nevertheless, 3 : 1 complexformation was further supported by mass spectrometric anal-ysis (see Fig. S1) as well as previously reported single-crystal X-ray structural analyses obtained under analogous con-ditions.11b Given that complex formation was essentially quan-titative even near the lowest concentrations accessible by UV-visabsorption titration, the stability constant of FeHT3 is estimatedto be greater than 1018 M−3.Also, HT is known to form metal complexes with variousstoichiometries, including 1 : 2 complexes with divalent metalions.11b,14 First, to examine whether the identity of the counter-anion affects the complexation behavior of HT with Fe3+, UV-visabsorption titration was performed using Fe(NO3)3$9H2O underconditions analogous to those used for FeCl3 (Fig. S2a).Although the concentration of Fe(NO3)3 required to reachsaturation was slightly higher than that of FeCl3, the nalabsorption spectrum obtained aer saturation was essentiallyidentical to that observed in the presence of FeCl3, indicatingthe formation of the same FeHT3 complex. Next, we examinedthe complexation behavior of HT with FeCl2$4H2O and CuCl2-$2H2O under conditions analogous to those used for FeCl3. Inboth cases, complex formation was observed (see Fig. S2b andS2c). Although a direct quantitative comparison is notstraightforward due to differences in coordination modesbetween trivalent and divalent metal complexes, the FeHT3complex formation is particularly stable and exhibited a simpleand well-dened change in the UV-vis absorption spectrum.To investigate the effect of FeHT3 formation on the self-propelled motion of HT at the air-water interface, the swim-ming behavior of pristine HT clumps and HT-SIS disks wasmonitored in a circular Petri dish on a homogeneous solution ofaqueous FeCl3 at different concentrations (see SI for theexperimental setup). Overall, pristine HT clumps displayedrapid continuous motions on aqueous FeCl3 solution (Fig. S3; SIMovie 1). HT-SIS disks exhibited similar self-propelled behaviorbefore coming to a halt as they became conned by anincreasingly shrinking barrier in the presence of FeCl3 (SI Movie2). Notably, the distinct switching behavior from continuous tooscillatory motion observed in the absence of FeCl3 becamemuch less apparent.10 Compared to pristine HT clumps, HT-SISdisks, which represent a lower supply of HT, continued to swimlonger than pristine HT clumps. The motion was maintainedthe longest at low iron concentrations (10 mM, Fig. S4a). As theconcentration of FeCl3 was increased to 50 mM, the duration ofthe self-propelled motion decreased (Fig. S4b): a trend thatcontinued at high iron concentrations (100 mM, Fig. S4c). Aercoming to a halt on a 100 mM FeCl3 solution, a HT-SIS disktransferred to fresh iron solution resumed motion whilea second HT-SIS disk placed on the original solution did notmove (Fig. S5). These observations indicate that the accumula-tion of FeHT3 on the surface can hinder self-propelled motionby trapping the disk.To assess the possible inuence of counter-anions onmotion behavior, self-propelled motion of HT-SIS disks wasstudied using Fe(NO3)3 instead of FeCl3. The resulting self-© 2026 The Author(s). Published by the Royal Society of Chemistryhttp://creativecommons.org/licenses/by-nc/3.0/http://creativecommons.org/licenses/by-nc/3.0/https://doi.org/10.1039/d6ra01403hFig. 3 (a) Schematic illustration of the aqueous conditions during the chemotactic motions of the first and second HT-SIS disks. (b) UV-visabsorption spectra recorded at different positions from the Fe3+ source, measured 5 min after placing aqueous FeCl3 at the 0 cm position. Theinset shows the calculated FeCl3 concentrations based on the absorption coefficient at 300 nm (1.07× 104 M−1 cm−1). (c) Trajectories of the firstHT-SIS disk on an Fe3+ gradient. (d) UV-vis absorption spectra showing the band assigned to FeHT3 at different positions after the first disk hadbeen allowed to swim for 600 s. The inset shows the calculated FeHT3 concentrations based on the absorption coefficient at 425 nm (1.20 ×104 M−1 cm−1). (e) Trajectories of a secondHT-SIS disk in the presence of the FeHT3 barrier generated by the first disk. In (c) and (e), the color barrepresents the average speed (mm s−1) of the disk. The approximate starting points of the first and second disks are indicated with an x.Paper RSC AdvancesOpen Access Article. Published on 06 March 2026. Downloaded on 3/6/2026 12:58:28 PM.  This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.View Article Onlinepropelled behaviors were comparable to those observed forFeCl3 (Fig. S6a), indicating that the observed chemotacticresponse is largely insensitive to the nature of the counter-anionunder the present conditions. Similarly, self-propelled motionwas observed using FeCl2 and CuCl2 as alternative metal ionsources. The behavior of disks in the presence of FeCl2 showedno obvious deviation from that observed for FeCl3 (Fig. S6b). Bycontrast, although HT is expected to form a complex with Cu2+that may inuence the interfacial properties, no self-trapping of© 2026 The Author(s). Published by the Royal Society of Chemistrythe disk was observed (Fig. S6c). These results highlight theimportance of the strong and surface-localized formation of aniron-HT complex, especially FeHT3, in generating sustainedchemotactic connement.To understand the mechanism underlying the change inself-propelled behavior upon FeHT3 formation, concentration-dependent surface tension (g) measurements were conductedusing the Wilhelmy plate method (Fig. 2a). As the concentrationincreased, the surface tension of FeHT3 solutions droppedRSC Adv., 2026, 16, 12725–12729 | 12727http://creativecommons.org/licenses/by-nc/3.0/http://creativecommons.org/licenses/by-nc/3.0/https://doi.org/10.1039/d6ra01403hRSC Advances PaperOpen Access Article. Published on 06 March 2026. Downloaded on 3/6/2026 12:58:28 PM.  This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.View Article Onlinemuch more steeply than that of HT solutions, eventuallyreaching 57 mN m−1. This value is lower than the saturatedsurface tension observed for HT aqueous solutions, which pla-teaued at 62 mNm−1 above 2.5 mM.10 A linear approximation inthe low-concentration region (g = g0 − a[C], where g0 is thesurface tension of distilled water, 72 mN m−1, and C is thesolute concentration) yielded an a value of 368 N m−1 M−1 forFeHT3, in contrast to 4.8 N m−1 M−1 for HT, indicatinga markedly higher surface activity of the FeHT3 complex.Meanwhile, the surface tension of FeCl3 aqueous solutionsremained nearly unchanged under the conditions used in thisstudy. These results indicate that both HT and FeHT3 act assurface-active species responsible for the observed self-propelled motion via Marangoni ow. Importantly, althoughFeHT3 exhibits higher surface activity than HT, its primary roleis not to enhance propulsion but to dene the directionality ofmotion. While HT is released continuously from the disk andgenerates transient surface tension gradients that sustainmotion, FeHT3 is produced locally upon contact between HTand Fe3+ and remains strongly adsorbed at the air-water inter-face, generating persistent, localized reductions in surfacetension (Fig. 2b). This leads to the formation of a relativelypersistent, spatially localized low surface tension region.Consequently, the disk is subjected to a sustained Marangoniforce directed toward regions of higher surface tension, leadingto consistent repulsion from iron-rich areas rather than alteredpropulsion dynamics.Because the high surface activity of FeHT3 enables it tofunction as a chemo-repulsive signal, we examined thechemotactic behavior of HT-SIS disks in an environment whereiron is not homogenously available (Fig. 3a). A 20 mL droplet ofaqueous FeCl3 was placed along the le edge (0 cm position) ofa rectangular container (5 × 20 cm) lled with water to a depthof 3 mm. The rst HT-SIS disk was placed in the center of thedish (10 cm from the le edge) 5 min later. UV-vis spectroscopyindicated a sharp Fe3+ concentration gradient localized near the0 cm position (Fig. 3b). The rst disk exhibited stochastic,negative chemotaxis away from the iron source (Fig. 3c). In therst 120 s the disk moved ballistically across the entire dish,briey slowing as it passed through the iron-rich region (SIMovie 3). Within the next 120 s, the disk appeared to becometrapped for several seconds near the 2 cm position beforebursting free and transitioning to oscillatory motion, nowavoiding the furthermost le side of the dish (SI Movie 4).Finally, aer becoming trapped at 4 cm, the disk cycled betweenperiods where it began to shake in place, becoming increasinglymore violent before moving slightly toward the 20 cm position(SI Movie 5).Aer 600 s, the rst disk was removed, and a second disk wasplaced in the center of the dish. UV-vis absorption spectralanalysis of the aqueous phase at different positions followingthe motion of the rst HT-SIS disk for 600 s conrmed theformation of an FeHT3 concentration gradient (Fig. 3d). Thesecond disk appeared to rebound from an invisible barrier(Fig. 3e, SI Movie 6), indicating that an exclusionary zone hadbeen established by the chemo-repulsive FeHT3 generatedthrough the rst disk's contact with iron.12728 | RSC Adv., 2026, 16, 12725–12729The trajectories of both the rst and second HT-SIS diskstended to shi to the right over time, suggesting diffusion ofFeHT3. As a result, the system developed a persistent surfacetension gradient, which also enabled a disk composed solely ofSIS to migrate toward the right when placed on the surface aer600 s (Fig. S7). Similarly, when a third HT-SIS disk was intro-duced within the exclusionary zone, it was directed away fromthe iron source; meanwhile, the second disk remained outside(Fig. S8). These results demonstrate that environmental modi-cation by the rst disk can direct both fueled and fuel-freeobjects through interfacial gradient formation.Notably, the size of the exclusionary zone appeared todepend strongly on the behavior of the rst disk. Brief ironexposure resulted in the formation of FeHT3 on the disk surfacewhich could provide a strong driving force for ballistic motionacross the dish. Repeated returns to the iron-rich region of thegradient ensured the continued production of FeHT3 whichcould eventually trap the HT-secreting disk near the iron sourceas exhibited in Fig. 3c, when the rst disk remained near the5 cm position for ca. 380 s. As a result, complexation could occurcontinuously, causing the surface pressure to increase and theexclusionary zone to expand to the 10 cm position. Conversely,in the case of the second HT-SIS disk in Fig. 3e, the barrier didnot shi signicantly because HT was not released in an iron-rich environment. On the other hand, when the rst disk wastrapped for ca. 190 s at 5.5 cm, the exclusionary zone did notexpand beyond the 6 cm position (Fig. S9). Thus, the environ-ment is characteristically modied by the behavior of the rstdisk, allowing it to direct itself and others away from the ironsource. This behavior demonstrates that HT-SIS disks canexhibit rudimentary memory effects and indirect, environment-mediated interactions with other Marangoni motors ina manner that is conceptually analogous to living systems.ConclusionsIn conclusion, we have demonstrated that self-propelled, HT-fueled disks on the surface of water can respond to aqueousiron through the formation of the surface-active complexFeHT3. The interplay betweenHT release, FeHT3 formation, andtheir distinct surface activities governs the emergence of nega-tive chemotaxis, enabling the disks to direct their self-propelledmotion via Marangoni ows. Importantly, the locally producedFeHT3 functions as a chemo-repulsive signal that not onlydirects and connes the motion of the disk but also inuencessubsequent disks through the generation of exclusionary zones.These ndings reveal how self-secreted chemical species canmediate communication and environmental memory in self-propelled systems. The present study thus provides a molec-ular design framework for the development of advancedresponsive materials capable of adaptive, life-like motion.Author contributionsLara Rae Holstein: conceptualization, investigation, writing –original dra, writing – review & editing. Megan S. Santamore:investigation. Asahi Tsukamoto: investigation. Masayuki© 2026 The Author(s). Published by the Royal Society of Chemistryhttp://creativecommons.org/licenses/by-nc/3.0/http://creativecommons.org/licenses/by-nc/3.0/https://doi.org/10.1039/d6ra01403hPaper RSC AdvancesOpen Access Article. Published on 06 March 2026. Downloaded on 3/6/2026 12:58:28 PM.  This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.View Article OnlineTakeuchi: writing – review & editing. Nobuhiko J. Suematsu:soware, writing – review & editing. Atsuro Takai: conceptuali-zation, supervision, funding acquisition, writing – originaldra, writing – review & editing.Conflicts of interestThere are no conicts to declare.Data availabilityThe data supporting this article have been included as part ofthe supplementary information (SI). Supplementary informa-tion is available. See DOI: https://doi.org/10.1039/d6ra01403h.AcknowledgementsWe are grateful to Ms. Izumi Matsunaga (NIMS) for her assis-tance with the experiments. This work was supported bya Grant-in-Aid for Scientic Research on KAKENHI (GrantNumbers: JP21H01004, JP23K03347, JP24K01475, andJP23K04725), a Grant-in-Aid for Transformative Research Areas(A) “Materials Science of Meso-Hierarchy” (Grant Number:JP24H01734), and the Inamori Foundation. We also thanksupport from ARIM of MEXT (JPMXP1224NM5109 andJPMXP1225NM5064) andMEXT's Promotion of Distinctive JointUsage/Research Center Support Program (JPMXP0724020292).References1 (a) J. Adler, Science, 1966, 153, 708; (b) V. Kundra,J. A. Escobedo, A. Kazlauskas, H. K. Kim, S. G. Rhee,L. T. Williams and B. R. Zetter, Nature, 1994, 367, 474; (c)G. H. Wadhams and J. P. Armitage, Nat. Rev. Mol. CellBiol., 2004, 5, 1024.2 (a) M. Zaki, N. Andrew and R. H. Insall, Proc. Natl. Acad. Sci.U. S. A., 2006, 103, 18751; (b) J. E. Phillips and R. H. Gomer,Proc. Natl. Acad. Sci. U. S. A., 2012, 109, 10990.3 (a) A. Pini, Science, 1993, 261, 95; (b) O. Maŕın, A. Yaron,A. Bagri, M. Tessier-Lavigne and J. L. R. Rubenstein,Science, 2001, 293, 872.4 (a) B. Liebchen, D. Marenduzzo, I. Pagonabarraga andM. E. Cates, Phys. Rev. Lett., 2015, 115, 258301; (b) K. Feng,J. C. Ureña Marcos, A. K. Mukhopadhyay, R. Niu, Q. Zhao,J. Qu and B. Liebchen, Adv. Sci., 2023, 10, 2300866; (c)T. Sugawara, M. Matsuo and T. Toyota, Bull. Chem. Soc.Jpn., 2024, 98, uoae134; (d) J. Kim, P. Mayorga-Burrezo,S.-J. Song, C. C. Mayorga-Martinez, M. Medina-Sánchez,S. Pané and M. Pumera, Chem. Soc. Rev., 2024, 53, 9190; (e)S. Krishna Mani, L. Lazinski, S. G. Birrer, A. Sapre,L. D. Zarzar and A. Sen, J. Am. Chem. Soc., 2025, 147,47942; (f) C. Wu, Y. Huang, B. Zeng, J. Chen, C. H. Chu,M. Yang, H. C. Shum and J. Tang, J. Am. Chem. Soc., 2025,147, 40225.5 (a) C. Tomlinson, Proc. R. Soc. London, 1862, 11, 575; (b)L. E. Scriven and C. V. Sternling, Nature, 1960, 187, 186; (c)© 2026 The Author(s). Published by the Royal Society of ChemistryN. J. Suematsu and S. Nakata, Chem.–Eur. J., 2018, 24,6308; (d) H. Yu, Y. Wang, Z. Hou, X. Xia, H. Chen, B. Zouand Y. Zhang, Adv. Funct. Mater., 2025, 35, 2424235.6 (a) O. Kuksenok, P. Dayal, A. Bhattacharya, V. V. Yashin,D. Deb, I. C. Chen, K. J. Van Vliet and A. C. Balazs, Chem.Soc. Rev., 2013, 42, 7257; (b) Y. Yasugahira, Y. Tatsumi,O. Yamanaka, H. Nishimori, M. Nagayama and S. Nakata,ChemSystemsChem, 2022, 4, e202100031; (c) D. Babu,N. Katsonis, F. Lancia, R. Plamont and A. Ryabchun, Nat.Rev. Chem., 2022, 6, 377; (d) Y. Hamano, K. Ikeda,K. Odagiri and N. J. Suematsu, Sci. Rep., 2023, 13, 8173; (e)M. Matsuo, K. Ejima and S. Nakata, J. Colloid Interface Sci.,2023, 639, 324; (f) M. Dindo, A. Bevilacqua, G. Soligo,V. Calabrese, A. Monti, A. Q. Shen, M. E. Rosti andP. Laurino, J. Am. Chem. Soc., 2024, 146, 15965.7 (a) I. Lagzi, S. Soh, P. J. Wesson, K. P. Browne andB. A. Grzybowski, J. Am. Chem. Soc., 2010, 132, 1198; (b)C. Jin, C. Krüger and C. C. Maass, Proc. Natl. Acad. Sci. U.S. A., 2017, 114, 5089; (c) T. Furuki, H. Sakuta,N. Yanagisawa, S. Tabuchi, A. Kamo, D. S. Shimamoto andM. Yanagisawa, ACS Appl. Mater. Interfaces, 2024, 16, 43016.8 (a) C. H. Meredith, P. G. Moerman, J. Groenewold, Y.-J. Chiu,W. K. Kegel, A. van Blaaderen and L. D. Zarzar, Nat. Chem.,2020, 12, 1136; (b) A. van der Weijden, M. Winkens,S. M. C. Schoenmakers, W. T. S. Huck and P. A. Korevaar,Nat. Commun., 2020, 11, 4800.9 (a) T. Nozoe, Bull. Chem. Soc. Jpn., 1936, 11, 295; (b)H. Erdtman and J. Gripenberg, Nature, 1948, 161, 719; (c)Z. Jian and Z. Jian, Curr. Med. Chem., 2007, 14, 2597; (d)G. Sennari, R. Saito, T. Hirose, M. Iwatsuki, A. Ishiyama,R. Hokari, K. Otoguro, S. Ōmura and T. Sunazuka, Sci.Rep., 2017, 7, 7259; (e) M. S. Bhuia, R. Chowdhury,M. Afroz, M. S. Akbor, M. S. Al Hasan, J. Ferdous,R. Hasan, M. V. O. B. de Alencar, M. S. Mubarak andM. T. Islam, Chem. Biodiversity, 2025, 22, e202401904.10 L. R. Holstein, M. Takeuchi, N. J. Suematsu and A. Takai, J.Am. Chem. Soc., 2025, 147, 40024.11 (a) P. L. Pauson, Chem. Rev., 1955, 55, 9; (b) A. S. Grillo,A. M. SantaMaria, M. D. Kana, A. G. Cioffi, N. C. Huston,M. Han, Y. A. Seo, Y. Y. Yien, C. Nardone, A. V. Menon,J. Fan, D. C. Svoboda, J. B. Anderson, J. D. Hong,B. G. Nicolau, K. Subedi, A. A. Gewirth, M. Wessling-Resnick, J. Kim, B. H. Paw and M. D. Burke, Science, 2017,356, 608.12 L. R. Holstein, N. J. Suematsu, M. Takeuchi, K. Harano,T. Banno and A. Takai, Angew. Chem., Int. Ed., 2024, 63,e202410671.13 (a) S. Nakata, S.-i. Hiromatsu and H. Kitahata, J. Phys. Chem.B, 2003, 107, 10557; (b) K. Iida, N. J. Suematsu, Y. Miyahara,H. Kitahata, M. Nagayama and S. Nakata, Phys. Chem. Chem.Phys., 2010, 12, 1557.14 (a) M. C. Barret, M. F. Mahon, K. C. Molloy, J. W. Steed andP. Wright, Inorg. Chem., 2001, 40, 4384; (b) Q. Gaydon andD. S. Bohle, Inorg. Chem., 2021, 60, 13567.RSC Adv., 2026, 16, 12725–12729 | 12729https://doi.org/10.1039/d6ra01403hhttp://creativecommons.org/licenses/by-nc/3.0/http://creativecommons.org/licenses/by-nc/3.0/https://doi.org/10.1039/d6ra01403h Hinokitiol-fueled disks form exclusionary zones in the presence of iron Hinokitiol-fueled disks form exclusionary zones in the presence of iron Hinokitiol-fueled disks form exclusionary zones in the presence of iron Hinokitiol-fueled disks form exclusionary zones in the presence of iron Hinokitiol-fueled disks form exclusionary zones in the presence of iron Hinokitiol-fueled disks form exclusionary zones in the presence of iron Hinokitiol-fueled disks form exclusionary zones in the presence of iron Hinokitiol-fueled disks form exclusionary zones in the presence of iron