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[Waka Nakanishi](https://orcid.org/0000-0001-6801-1839), [Masayuki Takeuchi](https://orcid.org/0000-0002-0207-0665), [Keisuke Sagisaka](https://orcid.org/0000-0002-5089-4271)

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[Structural flexibility and mobility of coordination polymers on Cu(111)](https://mdr.nims.go.jp/datasets/8d6f8ff6-b2e4-4d63-8af3-673bd000f716)

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Structural flexibility and mobility of coordination polymers on Cu(111)ChemicalScienceEDGE ARTICLEStructural flexibiaMolecular Design and Function Group, N(NIMS), 1-2-1 Sengen, Tsukuba, IbarakiWaka@nims.go.jpbResearch Center for Autonomous Systems MResearch (IIR), Institute of Science Tokyo (Sciku, Yokohama 226-8501, JapancDepartment of Materials Science and EnSciences, University of Tsukuba, 1-1-1 TenndResearch Center for Advanced Measuremenfor Materials Science (NIMS), 1-2-1 Sengen, TSAGISAKA.Keisuke@nims.go.jp† Electronic supplementary information (theoretical calculations, and Shttps://doi.org/10.1039/d5sc01949d‡ These two authors contributed equally tCite this: Chem. Sci., 2025, 16, 9156All publication charges for this articlehave been paid for by the Royal Societyof ChemistryReceived 11th March 2025Accepted 22nd April 2025DOI: 10.1039/d5sc01949drsc.li/chemical-science9156 | Chem. Sci., 2025, 16, 9156–916lity and mobility of coordinationpolymers on Cu(111)†Waka Nakanishi, ‡*ab Masayuki Takeuchi abc and Keisuke Sagisaka ‡*dCoordination polymers on surfaces have been investigated at the atomic level via scanning tunnelingmicroscopy (STM), revealing a variety of structures and electronic states. However, analysis of theirdynamic behaviour at low temperatures has been hampered due to the strong adsorption of organicligands on metal surfaces. In this study, we designed 2,7-dicyano-9,9-dimethyl-9H-fluorene (DCF) asa ligand for coordination polymers in order to reveal its mobility at low temperatures. The dimethylgroup attached to the ligand reduces the interaction with the metal surface and serves as an indicator ofthe ligand orientation. This enables individual tracking of DCF in the DCF–Cu polymer on Cu(111) aftertheir coordination with copper adatoms. Upon heating from 4 K to 78 K, branched structures were lessmobile, while linear structures and short polymers with free ends exhibited higher mobility. Partialcleavage, recombination, and insertion of the polymer chains were observed in some sections of thepolymer chains. Density functional theory (DFT) calculations suggest that the flexibility of thecoordination angle (180° ± 20°) facilitates such transformations. This study provides a direct observationof the motion differences attributed to polymer chain structures as proposed in real materials.IntroductionCoordination polymers, including metal organic frameworks(MOFs), are supramolecular polymers1,2 composed of coordi-nation bonds between metals and organic ligands. Thesesystems have attracted extensive fundamental research interestdue to their structural diversity and broad range of applications,such as gas storage and separation, catalysis, and energystorage. Recently, attention has shied towards exible coor-dination polymers, as their structural exibility allows defor-mation in response to external stimuli, potentially leading tohigher functionality.3–5 The overall exibility of coordinationpolymers originates from the structural exibility of individualorganic ligands and the inherent exibility of coordinationbonds due to the relatively weak bonding interactions betweenational Institute for Materials Science305-0047, Japan. E-mail: NAKANISHI.aterialogy (ASMat), Institute of Integratedence Tokyo), 4259 Nagatsuta-cho, Midori-gineering, Faculty of Pure and Appliedodai, Tsukuba, Ibaraki 305-8577, Japant and Characterization, National Institutesukuba, Ibaraki 305-0047, Japan. E-mail:ESI) available: Conditions for synthesis,TM experiments. See DOI:o this work.2metals and ligands.6–8 While the average properties of coordi-nation polymers have been characterized by X-ray diffraction(XRD), nuclear magnetic resonance (NMR), differential scan-ning calorimetry (DSC), etc.,4,5 a detailed understanding of theirexibility at the molecular level remains elusive. In particular,the role of local distortions and strains in contributing to theoverall exibility has not been explored. Recently, transmissionelectron microscopy (TEM)9–11 and scanning tunneling micros-copy (STM)12,13 have been used for observing and understandingstructures at the molecular level. TEM offers excellent temporalresolution on the order of milliseconds to several seconds,making it suitable for analysing dynamics. On the other hand,STM provides outstanding height and lateral resolution on thepicometer scale, which is ideal for detailed analysis of molec-ular structural changes. Both techniques are complementary toeach other in elucidating the polymer structural properties atthe molecular level.Coordination polymers on metal surfaces serve as idealmodels for investigating dynamic molecular structures usingSTM. These polymers are synthesized through the reaction ofadatoms with ligands on metal surfaces.14,15 Ligands with largep-conjugated planar structures, such as phthalocyanines andporphyrins, are commonly employed due to their stability onsurfaces, facilitating STM analysis.16–19 However, these planarligands exhibit strong adsorption onto the metal surface, typi-cally requiring heating above 100 °C to synthesize the coordi-nation polymer on the surface. Under these elevatedtemperatures, the coordination bonds on the metal are oencleaved. Consequently, research employing such large p-© 2025 The Author(s). Published by the Royal Society of Chemistryhttp://crossmark.crossref.org/dialog/?doi=10.1039/d5sc01949d&domain=pdf&date_stamp=2025-05-24http://orcid.org/0000-0001-6801-1839http://orcid.org/0000-0002-0207-0665http://orcid.org/0000-0002-5089-4271https://doi.org/10.1039/d5sc01949dEdge Article Chemical Scienceconjugated planar ligands has been unable to investigate thedynamic exibility of metal–ligand coordination.This study aims to elucidate the structural and temperature-responsive characteristics of metal-coordinated supramolecularpolymers by using the 2,7-dicyano-9,9-dimethyl-9H-uorene(DCF) ligand. This ligand is specically designed to minimizeinteraction with a surface to facilitate enhanced movement onthe substrate,20–26 and its asymmetric structure allows indi-vidual tracking. In DCF, the cyano groups have minimal sterichindrance and the ability to achieve various coordinationnumbers.14,15,20–22 Copper, which typically prefers di-coordination but can also accommodate tri-coordination, waschosen as the central metal. The STM study revealed theformation of dispersed, wavy linear di-coordinated polymers,accompanied by partially tri-coordinated branch networks, onthe Cu(111) surface following mild annealing of DCF in thepresence of Cu adatoms. Our analyses demonstrate that thelocal curvature of the coordination polymers is mainly governedby the combination of three distinct types of DCF trimers, eachcharacterized by specic molecular orientations. This polymerexhibits three temperature-dependent behaviours: from 4 K to40 K, the polymers remain static; at 48 K, their mobility variesdepending on the polymer structure, with signicantmovementobserved in the two-coordinated linear structure, while minimalmovement occurs in the three-coordinated branched structure.At 71 K, the polymer chains exhibit greater movement, accom-panied by processes such as chain scission, insertion, andrecombination. The structures of polymer chains, such as linearand crosslinked congurations, play a crucial role in deter-mining their dynamic behaviour and, consequently, themechanical properties of polymeric materials. This studyutilized STM to directly observe and analyse the structuralchanges of coordination polymer chains. The results demon-strate that coordination polymers onmetal surfaces can serve asgood models for understanding the exibility and mobility ofpolymer materials at the molecular level.Results and discussionMolecular designThe ligand molecule DCF was designed and synthesized inorder to reduce surface interactions and promote the formationof coordination polymers (Fig. 1): dimethyl group was attachedto the uorene structure to prevent the ligand from strongFig. 1 Optimized structure of DCF with the angle between the twocyano groups (left). Schematic view of DCF–Cu polymer on Cu(111), inwhich each of the two methyl groups assists in reducing adsorptiononto the surface and in assignment of the orientation of the ligands(right).© 2025 The Author(s). Published by the Royal Society of Chemistryadsorption onto the metal surfaces.20–26 Furthermore, as will beexplained in detail later, this dimethyl group serves as anindicator of the molecular orientation relative to the polymerchain direction, which is essential for tracking each ligandthroughout the analysis process. Two cyano groups wereintroduced at both ends of the uorene backbone to form theDCF–Cu polymer via coordination with copper adatom. Struc-ture optimization conducted by DFT calculations conrmedthat the two cyano groups form an angle of 156°.Synthesis of the DCF–Cu polymer on Cu(111)Coordination polymers composed of DCF and Cu adatoms weresynthesized on a Cu(111) surface. The DCF–Cu polymer wasformed through the annealing of pre-deposited DCFs andcopper adatoms supplied by the Cu(111) surface. When DCFmolecules were deposited onto a cold Cu(111) surface at 7 K,they predominantly remained as isolated entities (Fig. 2a).Upon mild heating to 323 K, beaded and meandering polymerswere formed (Fig. 2b and c). The ligands typically appear asnearly triangular in STM images, while the coordinated metalremains dark and undetectable, as is common for coordinationpolymers on metal surfaces (Fig. 2b and c).25,26,29–33,37,41 It isreasonable to infer the formation of coordination bonds basedon the observed inter-DCF distances of 1.5–1.6 nm (Fig. S12†).During the annealing process at 323 K, DCFmolecules migratedacross the surface and reacted with copper adatoms supplied bythe Cu(111) substrate, leading to the formation of DCF–Cupolymers. In these polymers, a single copper atomFig. 2 STM images of the DCF molecules on Cu(111) recorded at 4 K,(a) as deposited at 7 K, Vs = + 0.3 V, I= 10 pA. (b) After annealing at 323K, Vs = +0.5 V, I = 10 pA. (c) A high resolution image of the DCF–Cupolymer. Vs = +1.0 V, I = 10 pA. (d) Differential conductance (dI/dV)spectra of the DCF–Cu polymer. Each spectrum was recorded bypositioning the STM tip over the center of the DCF molecule, asindicated by the number in (c). Set point: Vs=+1.0 V, I= 50 pA. Lock-indetection settings: Vmod = 10 mV, f = 850 Hz.Chem. Sci., 2025, 16, 9156–9162 | 9157Chemical Science Edge Articlepredominantly coordinated with two DCF molecules (Fig. 2b).This process ultimately resulted in the formation of 91.1± 0.8%di-coordinate linear polymers and 8.8 ± 0.9% tri-coordinatebranched structures (Fig. S13 and Table S1†).The electronic state of the DCF–Cu polymer was examined bymeasuring dI/dV spectra at multiple locations, including bothlinear and branched parts. As a result, we observed a prominentpeak at +1.45 V at a linear di-coordinated part (location 1 inFig. 2c) and a branched tri-coordinated part (location 2 inFig. 2c). Our DFT calculations attribute this peak to the lowestunoccupied molecular orbital, which is primarily distributedover the DCF molecule (Fig. S10†). This observation is consis-tent with the previous result indicating that the peak position isindependent of the coordination number.21,22 As a reference, weattempted to measure a spectrum on single isolated moleculesbefore coordination. However, these molecules were toomobile, even on the cold surface at 4 K during sample bias-sweeping, to measure the dI/dV spectrum.The adjacent polymer chains of the DCF–Cu polymer main-tain a distinct separation, similar to other coordination poly-mers observed on metal surfaces.27–31 Bader charge analysis,performed on a trans-DCF–Cu–DCF–Cu polymer adsorbed ona Cu(111) slab, indicates that the central copper atom carriesa charge of +0.5e, while the ligand holds a charge of −0.19e,attributed to the electron-withdrawing effect of the cyanogroups (Fig. S11†). Consequently, the polymer exhibits anoverall positive charge of +0.31e per DCF–Cu unit. This elec-trostatic repulsion likely accounts for the observed separationbetween polymer chains.Fig. 3 Coordination structures of the DCF–Cu polymer on Cu(111).(a) STM image of the linear DCF–Cu polymer recorded at 4 K. Imagingconditions: Vs = +0.02 V, I = 50 pA. (b) High resolution STM image ofthe DCF–Cu polymer. The molecular model of the DCF–Cu polymeris superimposed. Triangles in (a) and (b) denote the molecularorientation of the methyl group side. The angle of the trimer (q) isdefined as the angle made by two arrows starting at the methyl groupof the central molecule toward the methyl groups in the two adjacentmolecules. (c) Three optimized structures of the DCF–Cu trimer. (d)Distribution (dots) and the averaged (line) value of the trimer anglesobtained from (a).Origins of polymer shape and structural exibilityThe DCF–Cu polymer exhibits characteristic meanderingfeatures. The winding of microscopic polymers is correlatedwith the exibility and viscoelasticity of macroscopic polymermaterials.32,33 In contrast, it is intriguing to understand whatparameters dominate the meandering shape at the molecularscale. Before initiating a statistical analysis, we examined theorientations of all DCF molecules forming the polymers withinan area of 30 nm × 30 nm (Fig. 3a). With a small sample bias(<0.1 V), the DCF molecule appears as a triangular shape witha bright spot, corresponding to one of the central dimethylgroups (Fig. 3b). This feature allows us to dene the molecularorientation: the dimethyl group side of the molecule is indi-cated by a white triangle in Fig. 3a and b. Moreover, wemeasured the angle formed by three DCF molecules bonded ina row through Cu atoms. In particular, the three brightestpoints corresponding to the methyl group of each moleculewere used to dene the angle of the trimer (Fig. 3b). FromFig. 3a, we collected the angles for 64 sets of timers. We notethat the uctuations in the trimer angle primarily arise fromchanges in the two CN–Cu–CN bond angles within the trimer,and these changes are equivalent to the variations in the angleformed by the three methyl groups (see Fig. S9†).Depending on the molecular orientation, the DCF–Cu trimercan be grouped into three types, as illustrated in Fig. 3c. Type A isa trimer with all three molecules oriented in the same direction.9158 | Chem. Sci., 2025, 16, 9156–9162Type B has two adjacent molecules oriented in the same direc-tion, with the thirdmolecule oriented oppositely. Type C featuresalternating molecular orientations. The molecular congura-tions for each type were optimized using DFT calculations. Thecomputed energies indicate negligible differences among thethree types, with an average stabilization energy of 12.8 kcalmol−1 per cyano group coordination (Fig. S9†). The resulting CN–Cu–CN bonding angles are 180°, with the angles dened by thethree methyl groups being 158° for Type A, 183° for Type B, and© 2025 The Author(s). Published by the Royal Society of ChemistryEdge Article Chemical Science206° for Type C (Fig. 3c and see also Fig. S7–S9†). Each exampleof these types is indicated in Fig. 3a.Measured angles of the trimer from the STM image in Fig. 3aare plotted by type in Fig. 3d. The observed average angles forType A, B, and C are 153°, 177°, and 200°, respectively, agreeingwell with the theoretical predictions. These plots also reveal thatthe angles of the trimer are distributed approximately ±20°from the average values. DFT calculations resulted in the energyincrease by only 2.3 kcal mol−1 when the CN–Cu–CN bond angleis deviated by ±20° from 180°, suggesting that the experimen-tally observed degree of exibility is energetically plausible(Fig. S7b†). Additional DFT calculations predict that DCFmolecules bonded through a Cu atom become twisted as thedeviation of the CN–Cu–CN bond angle exceeds ±20° from 180°(Fig. S7a†). Although the exact valency of the adatom andcoordinated state on metal surfaces remains a subject ofdebate,34–38 the calculation outcome remains consistentregardless of whether the Cu valency is 0, +1, or +2 (Fig. S8†).This result reasonably agrees with the experimental observa-tions that the trimer angle varies within ±20° from 180°, as theplanarity of the molecules is maintained due to constraintsimposed by the substrate surface. From these observations, weconclude that the fundamental structure of the winding DCF–Cu polymer is governed by the combination of three distinctmolecular congurations, dictated by the orientations of threeconsecutive DCFmolecules. Each conguration is characterizedby a specic alignment angle, but it retains its exibility due tothe variation of the CN–Cu–CN coordination bond angle, whichcan deviate by ±20° from 180°. This inherent exibility playsa role in shaping the local structure of the polymers.Temperature-induced motion and polymer structureTo investigate the structural uctuation of the coordinationpolymers upon heating, STM observations were conductedwhile gradually increasing the sample temperature up to 71 K(Fig. 4). The relative orientation of DCF was utilized to track themovement of each DCF molecule within all the polymers indi-vidually (Fig. S14–S16†). Below 40 K, the DCF–Cu polymerremained static, allowing for stable STM observations duringthe heating of the surface. In this temperature range, nostructural changes were observed. Above 40 K, on the otherhand, the mobility of the polymers increased, disrupting STMimaging. As an alternative approach, the sample was heated toeither 48 K or 71 K for 10 minutes and then cooled down to 4 Kto quench the structural changes for STM imaging. Thus, thedata for 48 K and 71 K represent snapshots at those tempera-tures. The STM image for 48 K shows subtle changes in thepolymer's shape (Fig. 4b). Pronounced structural changes wereobserved for polymers with free ends. The branching points,where the three molecules converge, are mostly pinned to thesurface, while the linear segments of the polymers exhibit slightdisplacement. These observations are attributed to the vibra-tional motion of polymer segments induced by thermal activa-tion at 48 K.Heating to 71 K resulted in further signicant positionalchanges of the polymer, along with rearrangement of the© 2025 The Author(s). Published by the Royal Society of Chemistrypolymer chains (Fig. 4c). In the region i (Fig. 4d and g), moleculeC inserted between A and B to form a three-coordinated struc-ture B–C–D (Fig. 4j), while E joined G and F to create anotherthree-coordinated structure (Fig. 4k). In region ii (Fig. 4e and h),the addition–elimination reaction of the polymer chain isobserved: H combined with J, whereas I dissociated (Fig. 4l). Athorough analysis of the trimer angles revealed that the trimerangle centred onmolecule I deviated signicantly (22°) from theaverage angle (Fig. S7 and Table S2†). This observation suggeststhat dissociation likely occurred during the temperatureincrease, as greater strain accumulated at molecule I than atothers. In region iii (Fig. 4f and i), the K–L chain underwenta complete lateral rotation, reversing its position. It is note-worthy that none of the individual molecules ipped theirorientation within any of the polymers. This temperaturesupplied sufficient energy to enable lateral motion of the poly-mers, such as the lateral rotation of a single chain of polymerwith free ends (Region iii), but it is not effective enough toinduce twisting of the polymer chains on the surface.Based on our observations, the structural changes of thepolymer chains upon heating can be understood in terms of thefollowing characteristic properties of the polymer:1. Affinity between Cu adatoms and the cyano-group of themolecules: this interaction, estimated to be average 12.8 kcalmol−1 in vacuum, facilitates the formation of coordinationcomplexes and contributes to the thermal stability of the poly-mer. Upon heating to 71 K, polymers with free termini exhibitenhanced mobility and reactivity compared to closed struc-tures. In some cases, a free-terminal polymer coordinates witha Cu atom within a linear polymer, resulting in a tri-coordinatedconguration that lowers the overall system energy (Fig. 4d andg). Moreover, addition–elimination reactions (Fig. 4e and h)proceed via the transient formation of a tri-coordinationstructure, which subsequently dissociates into a linear poly-mer and a free-terminal polymer, with no net change in systemenergy. These structural transformations are determined by theenergy landscape of the system and the reaction probabilitiesassociated with the highly reactive free-terminal polymers.2. Flexibility of the coordination angle: this property deter-mines the overall polymer shape and constrains the extent ofpolymer motion upon heating. With sufficient thermal energy,the exibility allows the polymers to adjust its bonding anglewith minimal energy cost.3. Interpolymer interaction (repulsion): the polymers carrya slight positive charge, leading to mutual repulsion thatprevents polymer bundling. This effect ensures that polymersmaintain a characteristic separation distance. While thermalvibrations allow for occasional collisions and separations, themajority of interpolymer distance remains relatively constant.As a result of these synergistic effects, certain regions of thepolymer structure undergo signicant rearrangements uponheating, while others exhibit only minor changes. Polymerchains with free ends located on relatively open surface areasexperience greater displacement, which facilitates the forma-tion of branched structures and promotes addition–eliminationreactions. In contrast, initially stable closed structures areconstrained by interpolymer repulsion, which limits theirChem. Sci., 2025, 16, 9156–9162 | 9159Fig. 4 Change in the winding shapes of the DCF–Cu polymer on Cu(111) by heating. (a) Initial shapes of the polymers (gray), (b) after heating to48 K (brown) and (c) 71 K (green). All STM images were recorded at 4 K. For comparison, initial polymers (gray) are superimposed in (b) and (c).(d)–(i) Zoomed images in areas i, ii, and iii indicated in (a). The uppercase letters refer to the positions where insertion (A–D), addition (E and F),addition–elimination (H–J) reactions of the coordination bonds, and locomotion (K and L) are observed. The reaction schemes for insertion (j),addition (k), and addition–elimination (l) reactions are also shown.Chemical Science Edge Articleaccessible surface area for movement; as a result, these struc-tures predominantly exhibit localized vibrational motionwithout substantial displacement.ConclusionsIn this study, by designing and synthesizing the organic ligandDCF with minimized surface interactions and an asymmetricstructure with respect to the coordination direction, it becamepossible to observe the movement of the DCF–Cu polymer onthe Cu(111) surface while maintaining coordination bonds, and9160 | Chem. Sci., 2025, 16, 9156–9162to track individual ligands. This approach enables a molecular-level understanding of temperature-dependent structuralchanges using STM. The design principle is particularly appli-cable to analysing the dynamic behaviour of organic moleculesthat strongly adsorb onto metal surfaces, especially thoseforming supramolecular polymers through weak non-chemicalbonds that are cleaved at high temperatures. This methodprovides the potential to observe and analyse the structure,cleavage, recombination tendencies, and mobility characteris-tics of supramolecular polymers at the molecular level.© 2025 The Author(s). Published by the Royal Society of ChemistryEdge Article Chemical ScienceThe DCF–Cu polymer predominantly exhibits a linear di-coordinated structure with occasional tri-coordinatedbranches, and the structure resembles cross-linked polymermaterials. Through the detailed analysis of STM, the CN–Cu–CNcoordination bond angle, while typically close to 180°, wasrevealed to have a exibility of ±20°, which contributes to theoverall exibility of the polymers. This polymer exhibits threedistinct temperature-dependent behaviours: up to 40 K thepolymers remain static; at 48 K the polymer chains with freeends exhibit mobility; at 71 K movements of linear segments inthe polymers are detected. In contrast, the branched polymerstructures exhibit minimal motion throughout the entiretemperature range. Moreover, the observed strain accumulationand subsequent chain cleavage are directly linked to criticalmechanical properties, including stiffness and durability.Although the topology of the polymer chains signicantlyaffects the physical properties,39–42 yet comprehensive under-standing at the molecular level is lacking. Our insights into thepolymer structure and molecular-level motion illuminate theconnections between molecular-level phenomena and themacroscopic mechanical properties of polymers.Data availabilityThe data supporting this article have been included as part ofthe ESI.†Author contributionsW. N. and K. S. designed the project, performed the experiments(organic synthesis: W. N.; STM: K. S.), conducted theoreticalcalculations, and analysed the data. All authors contributed towriting and editing the manuscript.Conflicts of interestThere are no conicts to declare.AcknowledgementsA part of calculations in this study were performed ona Numerical Materials Simulator at NIMS. This work waspartially supported by JSPS KAKENHI Grant Numbers,22K05088 and 22K04860. This study is also supported bya MEXT “NIMS Molecule and Material Synthesis Platform”program. 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Webb, npj Comput. Mater.,2024, 10, 139.© 2025 The Author(s). Published by the Royal Society of Chemistry Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d Structural flexibility and mobility of coordination polymers on Cu(111)Electronic supplementary information (ESI) available: Conditions for synthesis, theoretical calculations, and STM experiments. See DOI: https://doi.org/10.1039/d5sc01949d