Two-dimensional self-assembly of melem and melemium cations at pH-controlled aqueous solution–Au(111) interfaces under electrochemical control

Abstract

Two-dimensional self-assembly of melem at pH-controlled aqueous solution-Au(111) interfaces has been investigated by electrochemical scanning tunneling microscopy. In the solutions with pH>pK_b1 of melem, two ordered self-assembled structures (honeycomb and close-packed structures) and one disordered fibrillar structure were observed as a function of the surface coverage of melem controlled by the electrode potential. In contrast, in the acidic solution with pH<pK_b1 of melem, only the self-assembled honeycomb network was observed in a relatively wide potential range probably due to the presence of monoprotonated melem cations. Dots attributed to counteranions were frequently observed in the pores of the honeycomb network. The lack of close-packed and fibrillar structures at low pH (<pK_b1) is attributed to ionic repulsion of melemium cations.

Graphical abstract

Keywords

self-assembly / scanning tunneling microscopy / electrochemistry / structural phase transition / melem

References

[1] Mali K S, De Feyter S. Principles of molecular assemblies leading to molecular nanostructures. Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, 2013, 371(2000): 20120304

[2] Elemans J A A W, Lei S, De Feyter S. Molecular and supramolecular networks on surfaces: From two-dimensional crystal engineering to reactivity. Angewandte Chemie International Edition, 2009, 48(40): 7298–7332

[3] Kudernac T, Lei S, Elemans J A A W, De Feyter S. Two-dimensional supramolecular self-assembly: Nanoporous networks on surfaces. Chemical Society Reviews, 2009, 38(2): 402–421

[4] Kunitake M, Higuchi R, Tanoue R, Uemura S. Self-assembled p-conjugated macromolecular architectures—a soft solution process based on Schiff base coupling. Current Opinion in Colloid & Interface Science, 2014, 19(2): 140–154

[5] Zhuang X, Mai Y, Wu D, Zhang F, Feng X. Two-dimensional soft nanomaterials: A fascinating world of materials. Advanced Materials, 2015, 27(3): 403–427

[6] Schwarzer A, Saplinova T, Kroke E. Tri-s-triazines (s-heptazines)—from a “mystery molecule” to industrially relevant carbon nitride materials. Coordination Chemistry Reviews, 2013, 257(13‒14): 2032–2062

[7] Wang X, Maeda K, Thomas A, Takanabe K, Xin G, Carlsson J M, Domen K, Antonietti M. A metal-free polymeric photocatalyst for hydrogen production from water under visible light. Nature Materials, 2009, 8(1): 76–80

[8] Franklin E C. The ammono carbonic acids. Journal of the American Chemical Society, 1922, 44(3): 486–509

[9] Finkel’shtein A I, Spiridonova N V. Chemical properties and molecular structure of derivatives of sym-heptazine [1,3,4,6,7,9,9b-heptaaza-phenalene, tri-1,3,5-triazine]. Russian Chemical Reviews, 1964, 33(7): 400–405

[10] Takimoto M, Yokoyama T, Sawada M, Yamashita M. Isolation of melam and melem from fused products of dicyandiamide and melamine and some of their properties. Kogyo Kagaku Zasshi, 1963, 66(6): 793–797

[11] Komatsu T. The first synthesis and characterization of cyameluric high polymers. Macromolecular Chemistry and Physics, 2001, 202(1): 19–25

[12] Jürgens B, Irran E, Senker J, Kroll P, Müller H, Schnick W. Melem (2,5,8-triamino-tri-s-triazine), an important intermediate during condensation of melamine rings to graphitic carbon nitride: Synthesis, structure determination by X-ray powder diffractometry, solid-state NMR, and theoretical studies. Journal of the American Chemical Society, 2003, 125(34): 10288–10300

[13] Miller D R, Swenson D C, Gillan E G. Synthesis and structure of 2,5,8-triazido-s-heptazine: An energetic and luminescent precursor to nitrogen-rich carbon nitrides. Journal of the American Chemical Society, 2004, 126(17): 5372–5373

[14] Schwarzer A, Böhme U, Kroke E. Use of melem as a nucleophilic reagent to form the triphthalimide C₆N₇(phthal)₃—new targets and prospects. Chemistry (Weinheim an der Bergstrasse, Germany), 2012, 18(38): 12052–12058

[15] Uemura S, Aono M, Komatsu T, Kunitake M. Two-dimensional self-assembled structures of melamine and melem at the aqueous solution-Au(111) interface. Langmuir, 2011, 27(4): 1336–1340

[16] Eichhorn J, Schlögl S, Lotsch B V, Schnick W, Heckl W M, Lackinger M. Self-assembly of melem on Ag(111)—emergence of porous structures based on amino-heptazine hydrogen bonds. CrystEngComm, 13(11): 5559–5565

[17] Uemura S, Aono M, Sakata K, Komatsu T, Kunitake M. Thermodynamic control of 2D bicomponent porous networks of melamine and melem: Diverse hydrogen-bonded networks. Journal of Physical Chemistry C, 2013, 117(47): 24815–24821

[18] Yoshimoto S, Itaya K. Adsorption and assembly of ions and organic molecules at electrochemical interfaces: Nanoscale aspects. Annual Review of Analytical Chemistry (Palo Alto, Calif.), 2013, 6(1): 213–235

[19] Uemura S, Tanoue R, Yilmaz N, Ohira A, Kunitake M. Molecular dynamics in two-dimensional supramolecular systems observed by STM. Materials (Basel), 2010, 3(8): 4252–4276

[20] Phan T H, Breuer S, Hahn U, Pham D T, Torres T, Wandelt K. Unusual demetalation and ordered adsorption of a pyridine-appended zinc phthalocyanine at metal-electrolyte interfaces studied by in situ scanning tunneling microscopy and X-ray photoelectron spectroscopy. Journal of Physical Chemistry C, 2014, 118(1): 457–467

[21] Ye T, He Y, Borguet E. Adsorption and electrochemical activity: An in situ electrochemical scanning tunneling microscopy study of electrode reactions and potential-induced adsorption of porphyrins. Journal of Physical Chemistry B, 2006, 110(12): 6141–6147

[22] Dai P X, Chen T, Wang D, Wan L J. Potential dependent adsorption geometry of 2,5-dihydroxybenzoic acid on a Au(111) Surface: An in situ electrochemical scanning tunneling microscopy study. Journal of Physical Chemistry C, 2012, 116(10): 6208–6214

[23] Yuan Q H, Xing Y, Borguet E. An STM study of the pH dependent redox activity of a two-dimensional hydrogen bonding porphyrin network at an electrochemical interface. Journal of the American Chemical Society, 2010, 132(14): 5054–5060

[24] Sattler A, Schnick W. Preparation and structure of melemium melem perchlorate HC₆N₇(NH₂)₃ClO₄·C₆N₇(NH₂)₃. Zeitschrift fur Anorganische und Allgemeine Chemie, 2008, 634(3): 457–460

[25] Sattler A, Seyfarth L, Senker J, Schnick W. Syntheses, crystal structures and spectroscopic properties of the melem adduct C₆N₇(NH₂)₃·H₃PO₄ and the melemium salts (H₂C₆N₇(NH₂)₃)SO₄·2H₂O and (HC₆N₇(NH₂)₃)ClO₄·H₂O. Zeitschrift fur Anorganische und Allgemeine Chemie, 2005, 631(13‒14): 2545–2554

[26] NunknownN0N00N.In our investigation, melem is dissolved into 0.1 mol∙L^‒1 perchloric acid solution (pH= 1.3) at least around 6 × 10^‒5 mol∙L^‒1NunknownN

[27] Li Z, Han B, Wan L J, Wandlowski T. Supramolecular nanostructures of 1,3,5-benzene-tricarboxylic acid at electrified Au(111)/0.05 mol∙L^‒1 H₂SO₄ interfaces: An in situ scanning tunneling microscopy study. Langmuir, 2005, 21(15): 6915–6928

[28] Zhang H M, Xie Z X, Long L S, Zhong H P, Zhao W, Mao B W, Xu X, Zheng L S. One-step preparation of large-scale self-assembled monolayers of cyanuric acid and melamine supramolecular species on Au(111) surfaces. Journal of Physical Chemistry C, 2008, 112(11): 4209–4218

[29] Ivasenko O, Macleod J M, Chernichenko K Y, Balenkova E S, Shpanchenko R V, Nenajdenko V G, Rosei F, Perepichka D F. Supramolecular assembly of heterocirculenes in 2D and 3D. Chemical Communications, 2009, 10: 1192–1194

[30] Griessl S J H, Lackinger M, Jamitzky F, Markert T, Hietschold M, Heckl W. Room-temperature scanning tunneling microscopy manipulation of single C₆₀ molecules at the liquid-solid interface: Playing nanosoccer. Journal of Physical Chemistry B, 2004, 108(31): 11556–11560

[31] Cardenas M L, Lipton-Duffin J, Rosei F. Transformations of molecular frameworks by host-guest response: Novel routes toward two-dimensional self-assembly at the solid-liquid interface. Japanese Journal of Applied Physics, 2011, 50(8S3): 08LA02

[32] Ma X, Yang Y, Deng K, Zeng Q, Zhao K, Wang C, Bai C. Molecular miscibility characteristics of self-assembled 2D molecular architectures. Journal of Materials Chemistry, 2008, 18(18): 2074–2081

[33] Wang H, Kaiser T E, Uemura S, Würthner F. Perylene bisimide J-aggregates with absorption maxima in the NIR. Chemical Communications, 2008, 10: 1181–1183

[34] SamoríP, Severin N, Simpson C D, Müllen K, Rabe J P. Epitaxial composite layers of electron donors and acceptors from very large polycyclic aromatic hydrocarbons. Journal of the American Chemical Society, 2002, 124(32): 9454–9457

[35] Uemura S, Sakata M, Taniguchi I, Hirayama C, Kunitake M. In situ observation of coronene epitaxial adlayers on Au(111) surfaces prepared by the transfer of Langmuir films. Thin Solid Films, 2002, 409(2): 206–210

[36] Elemans J A A W, Lensen M C, Gerritsen J W, van Kempen H, Speller S, Nolte R J M, Rowan A E. Scanning probe studies of porphyrin assemblies and their supramolecular manipulation at a solid-liquid interface. Advanced Materials, 2003, 15(24): 2070–2073

[37] Sek S, Xu S, Chen M, Szymanski G, Lipkowski J. Molecular resolution imaging of an antibiotic peptide in a lipid matrix. Journal of the American Chemical Society, 2008, 130(17): 5736–5743

[38] Gutzler R, Sirtl T, Dienstmaier J F, Mahata K, Heckl W M, Schmittel M, Lackinger M. Reversible phase transitions in self-assembled monolayers at the liquid-solid interface: Temperature-controlled opening and closing of nanopores. Journal of the American Chemical Society, 2010, 132(14): 5084–5090

Acknowledgements

This work was supported by a Grant-in-Aid for Young Scientists (A) (23681016) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, and partly by the Hayashi Memorial Foundation for Female Natural Scientists and Technology Agency and the Tokuyama Science Foundation.

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2016 Higher Education Press and Springer-Verlag Berlin Heidelberg