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Habets T, Speller S, Elemans JAAW. Role of redox-active axial ligands of metal porphyrins adsorbed at solid-liquid interfaces in a liquid-STM setup. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1264-1271. [PMID: 32953370 PMCID: PMC7476586 DOI: 10.3762/bjnano.11.110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/30/2020] [Indexed: 06/11/2023]
Abstract
In a liquid-STM setup environment, the redox behavior of manganese porphyrins was studied at various solid-liquid interfaces. In the presence of a solution of Mn(III)Cl porphyrins in 1-phenyloctane, which was placed at a conductive surface, large and constant additional currents relative to a set tunneling current were observed, which varied with the magnitude of the applied bias voltage. These currents occurred regardless of the type of surface (HOPG or Au(111)) or tip material (PtIr, Au or W). The additional currents were ascribed to the occurrence of redox reactions in which chloride is oxidized to chlorine and the Mn(III) center of the porphyrin moiety is reduced to Mn(II). The resulting Mn(II) porphyrin products were identified by UV-vis analysis of the liquid phase. For solutions of Mn(III) porphyrins with non-redox active acetate instead of chloride axial ligands, the currents remained absent.
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Affiliation(s)
- Thomas Habets
- Radboud University, Institute for Molecules and Materials (IMM), 6525 AJ Nijmegen, Netherlands
| | - Sylvia Speller
- University of Rostock, Institute of Physics, Albert-Einstein-Straße 23, 18059 Rostock, Germany
- University of Rostock, Department Life, Light, Matter, Albert-Einstein-Straße 25, 18059 Rostock, Germany
| | - Johannes A A W Elemans
- Radboud University, Institute for Molecules and Materials (IMM), 6525 AJ Nijmegen, Netherlands
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2
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Habets T, Lensen D, Speller S, Elemans JAAW. Self-Assembly of Covalently Linked Porphyrin Dimers at the Solid-Liquid Interface. Molecules 2019; 24:E3018. [PMID: 31434280 PMCID: PMC6720350 DOI: 10.3390/molecules24163018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/12/2019] [Accepted: 08/17/2019] [Indexed: 12/20/2022] Open
Abstract
The synthesis and surface self-assembly behavior of two types of metal-porphyrin dimers is described. The first dimer type consists of two porphyrins linked via a rigid conjugated spacer, and the second type has an alkyne linker, which allows rotation of the porphyrin moieties with respect to each other. The conjugated dimers were equipped with two copper or two manganese centers, while the flexible dimers allowed a modular built-up that also made the incorporation of two different metal centers possible. The self-assembly of the new porphyrin dimers at a solid-liquid interface was investigated at the single-molecule scale using scanning tunneling microscopy (STM). All dimers formed monolayers, of which the stability and the internal degree of ordering of the molecules depended on the metal centers in the porphyrins. While in all monolayers the dimers were oriented coplanar with respect to the underlying surface ('face-on'), the flexible dimer containing a manganese and a copper center could be induced, via the application of a voltage pulse in the STM setup, to self-assemble into monolayers in which the porphyrin dimers adopted a non-common perpendicular ('edge-on') geometry with respect to the surface.
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Affiliation(s)
- Thomas Habets
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Dennis Lensen
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Sylvia Speller
- Institute of Physics, University of Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
- Department Life, Light & Matter-University of Rostock, 18051 Rostock, Germany
| | - Johannes A A W Elemans
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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3
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Piskorz T, de Vries AH, De Feyter S, van Esch JH. Mechanism of Ostwald Ripening in 2D Physisorbed Assemblies at Molecular Time and Length Scale by Molecular Dynamics Simulations. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2018; 122:24380-24385. [PMID: 30774741 PMCID: PMC6369672 DOI: 10.1021/acs.jpcc.8b06432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/18/2018] [Indexed: 06/09/2023]
Abstract
Ostwald ripening can improve the long-range order of self-assembled monolayers by the growth of large domains and disassembly of smaller ones. Here, coarse-grained molecular dynamics simulations are used to study the dynamics of the stable assembly and the coarsening of defects of physisorbed monolayers of long-chain functionalized alkanes. Our results show that the partial desorption from the surface of one or more adsorbent molecules is the essential process that allows other adsorbent molecules to rearrange on the surface and thereby improve alignment. We also show that the ripening process is faster at higher temperature because the rate of partial desorption is higher.
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Affiliation(s)
- Tomasz
K. Piskorz
- Advanced
Soft Matter, Chemical Engineering, Delft
University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Alex H. de Vries
- Groningen
Biomolecular Sciences and Biotechnology Institute and Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Steven De Feyter
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Jan H. van Esch
- Advanced
Soft Matter, Chemical Engineering, Delft
University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands
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4
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Kim Y, Doh WH, Kim J, Park JY. In Situ Observations of UV-Induced Restructuring of Self-Assembled Porphyrin Monolayer on Liquid/Au(111) Interface at Molecular Level. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:6003-6009. [PMID: 29726687 DOI: 10.1021/acs.langmuir.8b00418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Porphyrin-derived molecules have received much attention for use in solar energy conversion devices, such as artificial leaves and dye-sensitized solar cells. Because of their technological importance, a molecular-level understanding of the mechanism for supramolecular structure formation in a liquid, as well as their stability under ultraviolet (UV) irradiation, is important. Here, we observed the self-assembled structure of free-base, copper(II), and nickel(II) octaethylporphyrin formed on Au(111) in a dodecane solution using scanning tunneling microscopy (STM). As evident in the STM images, the self-assembled monolayers (SAMs) of these three porphyrins on the Au(111) surface showed hexagonal close-packed structures when in dodecane solution. Under UV irradiation (λ = 365 nm), the porphyrin molecules in the SAM or the dodecane solution move extensively and form new porphyrin clusters on the Au sites that have a high degree of freedom. Consequently, the Au(111) surface was covered with disordered porphyrin clusters. However, we found that the porphyrin molecules decomposed under UV irradiation at 254 nm. Molecular-scale observation of the morphological evolution of the porphyrin SAM under UV irradiation can provide a fundamental understanding of the degradation processes of porphyrin-based energy conversion devices.
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Affiliation(s)
- Yongman Kim
- Graduate School of Energy, Environment, Water, and Sustainability (EEWS) , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
- Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 34141 , Republic of Korea
| | - Won Hui Doh
- Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 34141 , Republic of Korea
| | - Jeongjin Kim
- Graduate School of Energy, Environment, Water, and Sustainability (EEWS) , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
- Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 34141 , Republic of Korea
| | - Jeong Young Park
- Graduate School of Energy, Environment, Water, and Sustainability (EEWS) , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
- Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 34141 , Republic of Korea
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5
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Hipps KW, Mazur U. Kinetic and Thermodynamic Control in Porphyrin and Phthalocyanine Self-Assembled Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3-17. [PMID: 28929771 DOI: 10.1021/acs.langmuir.7b02672] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Porphyrins and phthalocyanines are ubiquitous in modern science and technology. Their stability, redox properties, and photoresponse make them candidates for numerous applications. Many of these applications rely on thin films, and these are critically dependent on the first monolayer. In this article, we focus on noncovalently bound self-assembled monolayers of porphyrins and phthalocyanines at the solution-solid interface with special emphasis on the kinetic and thermodynamic processes that define the films and their reaction chemistry. We first discuss the difference between film-formation kinetics and desorption kinetics from fully formed films. We then present evidence that many of these monolayers are controlled by adsorption kinetics and are not in thermodynamic equilibrium. Measurement of the solution-solid interface desorption energy by scanning tunneling microscopy is discussed, and data is presented for cobalt, nickel, and free base octaethylporphyrin. The activation energy for the desorption of these compounds into phenyloctane is about half of the computed desorption energy in vacuum, and this is discussed in terms of the role of the solvent. Preexponential factors are very low compared to desorption into vacuum, and this is attributed to a reduction in the entropy of activation due to the participation of solvent in the transition state. An example of the use of relative desorption kinetics to create a new binary surface structure is given. It is suggested that this is a synthesis route that may have been missed because of the large difference in solution concentrations required to drive binary film formation. Attention then turns to the axial reaction chemistry of metalloporphyrins and metallophthalocyanines supported on conducting surfaces. We show several examples of chemistry unique to the supported complexes: cases where the metal binds ligands more readily and cases where the substrate induces ligand loss. Understanding this new axial coordination chemistry is of great importance in catalysis, sensing, and the growth of 3D materials from a self-assembled template.
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Affiliation(s)
- K W Hipps
- Department of Chemistry and Materials Science & Engineering Program, Washington State University , Pullman, Washington 99163-4630, United States
| | - Ursula Mazur
- Department of Chemistry and Materials Science & Engineering Program, Washington State University , Pullman, Washington 99163-4630, United States
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6
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Reimers JR. How Equilibrium Gets Mimicked During Kinetic and Thermodynamic Control in Porphyrin and Phthalocyanine Self-Assembled Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:18-22. [PMID: 29108413 DOI: 10.1021/acs.langmuir.7b03320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The recent review of Hipps and Mazur is extended to consider the origins and significance of their conclusion that "surface structures vary with relative component concentration in a way that may mimic equilibria but is not". How this situation can arise during self-assembly is discussed, as well as a range of qualitative and quantitative observations and high-level free-energy calculations that document the effect for meso-tetraalkylporphyrins self-assembled monolayer (SAM) polymorphs. This leads to a discussion of modern challenges facing quantification of the effects caused by kinetic control, as well as to the usefulness of equilibrium mimicking in the design and synthesis of SAMs.
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Affiliation(s)
- Jeffrey R Reimers
- International Centre for Quantum and Molecular Structures and School of Physics, Shanghai University , Shanghai 200444, China
- School of Mathematical and Physical Sciences, University of Technology Sydney , Sydney, New South Wales 2008, Australia
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7
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Reimers JR, Panduwinata D, Visser J, Chin Y, Tang C, Goerigk L, Ford MJ, Sintic M, Sum TJ, Coenen MJJ, Hendriksen BLM, Elemans JAAW, Hush NS, Crossley MJ. A priori calculations of the free energy of formation from solution of polymorphic self-assembled monolayers. Proc Natl Acad Sci U S A 2015; 112:E6101-10. [PMID: 26512115 PMCID: PMC4653194 DOI: 10.1073/pnas.1516984112] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Modern quantum chemical electronic structure methods typically applied to localized chemical bonding are developed to predict atomic structures and free energies for meso-tetraalkylporphyrin self-assembled monolayer (SAM) polymorph formation from organic solution on highly ordered pyrolytic graphite surfaces. Large polymorph-dependent dispersion-induced substrate-molecule interactions (e.g., -100 kcal mol(-1) to -150 kcal mol(-1) for tetratrisdecylporphyrin) are found to drive SAM formation, opposed nearly completely by large polymorph-dependent dispersion-induced solvent interactions (70-110 kcal mol(-1)) and entropy effects (25-40 kcal mol(-1) at 298 K) favoring dissolution. Dielectric continuum models of the solvent are used, facilitating consideration of many possible SAM polymorphs, along with quantum mechanical/molecular mechanical and dispersion-corrected density functional theory calculations. These predict and interpret newly measured and existing high-resolution scanning tunnelling microscopy images of SAM structure, rationalizing polymorph formation conditions. A wide range of molecular condensed matter properties at room temperature now appear suitable for prediction and analysis using electronic structure calculations.
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Affiliation(s)
- Jeffrey R Reimers
- International Centre for Quantum and Molecular Structure, College of Sciences, Shanghai University, Shanghai 200444, China; School of Mathematical and Physical Sciences, The University of Technology Sydney, Sydney, NSW 2007, Australia;
| | - Dwi Panduwinata
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Johan Visser
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Yiing Chin
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Chunguang Tang
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Lars Goerigk
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia; School of Chemistry, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Michael J Ford
- School of Mathematical and Physical Sciences, The University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Maxine Sintic
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Tze-Jing Sum
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Michiel J J Coenen
- Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Bas L M Hendriksen
- Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Johannes A A W Elemans
- Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Noel S Hush
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia; School of Biomolecular Science, The University of Sydney, Sydney, NSW 2006, Australia
| | - Maxwell J Crossley
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia;
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8
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Mazur U, Hipps KW. Kinetic and thermodynamic processes of organic species at the solution-solid interface: the view through an STM. Chem Commun (Camb) 2015; 51:4737-49. [PMID: 25634141 DOI: 10.1039/c4cc09840d] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A focused review is presented on the evolution of our understanding of the kinetic and thermodynamic factors that play a critical role in the formation of well ordered organic adlayers at the solution-solid interface. While the current state of knowledge is in the very early stages, it is now clear that assumptions of kinetic or thermodynamic control are dangerous and require careful confirmation. Equilibrium processes at the solution-solid interface are being described by evolving thermodynamic models that utilize concepts from the thermodynamics of micelles. A surface adsorption version of the Born-Haber cycle is helping to extract the thermodynamic functions of state associated with equilibrium structures, but only a very few systems have been so analyzed. The kinetics of surface phase transformation, especially for polymorphic phases is in an early qualitative stage. Adsorption and desorption kinetics are just starting to be measured. The study of kinetics and thermodynamics for organic self-assembly at the solution-solid interface is experiencing very exciting and rapid growth.
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Affiliation(s)
- Ursula Mazur
- Chemistry Department and Materials Science and Engineering Program, Washington State University, Pullman, WA 99164-4630, USA.
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9
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Nirmalraj PN, Thompson D, Riel HE. Capturing the embryonic stages of self-assembly - design rules for molecular computation. Sci Rep 2015; 5:10116. [PMID: 25960364 PMCID: PMC4650799 DOI: 10.1038/srep10116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/30/2015] [Indexed: 12/12/2022] Open
Abstract
The drive towards organic computing is gaining momentum. Interestingly, the building blocks for such architectures is based on molecular ensembles extending from nucleic acids to synthetic molecules. Advancement in this direction requires devising precise nanoscopic experiments and model calculations to decipher the mechanisms governing the integration of a large number of molecules over time at room-temperature. Here, we report on ultrahigh-resolution scanning tunnelling microscopic measurements to register the motion of molecules in the absence of external stimulus in liquid medium. We observe the collective behavior of individual molecules within a swarm which constantly iterate their position to attain an energetically favourable site. Our approach provides a consistent pathway to register molecular self-assembly in sequential steps from visualising thermodynamically driven repair of defects up until the formation of a stable two-dimensional configuration. These elemental findings on molecular surface dynamics, self-repair and intermolecular kinetic pathways rationalised by atom-scale simulations can be explored for developing new models in algorithmic self-assembly to realisation of evolvable hardware.
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Affiliation(s)
| | - Damien Thompson
- Materials and Surface Science Institute and Department of Physics and Energy, University of Limerick, Ireland
| | - Heike E. Riel
- IBM Research–Zurich, Säumerstrasse 4, CH- 8803, Rüschlikon, Switzerland
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10
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Li M, den Boer D, Iavicoli P, Adisoejoso J, Uji-i H, Van der Auweraer M, Amabilino DB, Elemans JAAW, De Feyter S. Tip-Induced Chemical Manipulation of Metal Porphyrins at a Liquid/Solid Interface. J Am Chem Soc 2014; 136:17418-21. [DOI: 10.1021/ja510930z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Min Li
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
- CAS
Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety,
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Duncan den Boer
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
- Institute
for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg
135, 6525 AJ Nijmegen, The Netherlands
| | - Patrizia Iavicoli
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC), Universitat Autónoma de Barcelona, Campus Universitari, 08193 Bellaterra, Catalonia, Spain
| | - Jinne Adisoejoso
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
| | - Hiroshi Uji-i
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
| | - Mark Van der Auweraer
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
| | - David B. Amabilino
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC), Universitat Autónoma de Barcelona, Campus Universitari, 08193 Bellaterra, Catalonia, Spain
| | - Johannes A. A. W. Elemans
- Institute
for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg
135, 6525 AJ Nijmegen, The Netherlands
| | - Steven De Feyter
- Division
of Molecular Imaging and Photonics, KU Leuven−University of Leuven, Celestijnenlaan
200-F, 3001 Leuven, Belgium
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11
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Coenen MJJ, Khoury T, Crossley MJ, Hendriksen BLM, Elemans JAAW, Speller S. Nanostructuring of Self-Assembled Porphyrin Networks at a Solid/Liquid Interface: Local Manipulation under Global Control. Chemphyschem 2014; 15:3484-8. [DOI: 10.1002/cphc.201402449] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Indexed: 11/10/2022]
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12
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Miao X, Xu L, Cui L, Deng W. Steric matching and the concentration induced self-assembled structural variety of 2,7-bis(n-alkoxy)-9-fluorenone at the aliphatic solvent/graphite interface. Phys Chem Chem Phys 2014; 16:12544-53. [PMID: 24832360 DOI: 10.1039/c4cp00871e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Controlling and unraveling structural polymorphism has received special attention in 2D self-assembled monolayers. In this work, we investigated the steric matching and solution concentration controlled structural variety in the self-assembly of 2,7-bis(n-alkoxy)-9-fluorenone (F-OCn) at the n-tetradecane and n-tridecane/graphite interface under different concentrations, respectively. Scanning tunneling microscopy (STM) revealed that the coadsorbed adlayers of F-OCn and solvents (n = 12 to 16) were formed and exhibited concentration dependent 2D phases due to the steric matching. The self-assembled monolayer of F-OCn (n = 12 to 16) evolved from a low-density coadsorbed linear lamellar packing, which was formed at low concentrations, to higher-density patterns at relatively high concentrations. F-OC14 exhibited a complex structural variety, in which a systematic trend of decrease in the molecular density per unit cell with decreasing concentration was obtained. Except for F-OCn (n = 13, 15, 17), the zigzag structure showing the linear lamella with dimers was observed. Systematic experiments revealed that the self-assembly of F-OCn was chain-length dependent. The results provide insight into the structural variety exhibited by a series of organic molecules and furnish important guidelines to control the morphology by changing the solution concentration.
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Affiliation(s)
- Xinrui Miao
- College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
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13
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Coenen MJJ, den Boer D, van den Bruele FJ, Habets T, Timmers KAAM, van der Maas M, Khoury T, Panduwinata D, Crossley MJ, Reimers JR, van Enckevort WJP, Hendriksen BLM, Elemans JAAW, Speller S. Polymorphism in porphyrin monolayers: the relation between adsorption configuration and molecular conformation. Phys Chem Chem Phys 2014; 15:12451-8. [PMID: 23620134 DOI: 10.1039/c3cp50829c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-assembled monolayers of meso-5,10,15,20-tetrakis(undecyl)porphyrin copper(II) on a graphite/1-octanoic acid interface have been studied by Scanning Tunnelling Microscopy. Four distinct polymorphs were observed, varying in their unit cell size. Arrays of unit cells of the various polymorphs seamlessly connect to each other via shared unit cell vectors. The monolayers are not commensurate, but coincident with the underlying graphite substrate. The seamless transition between the polymorphs is proposed to be the result of an adaptation of the molecular conformations in the polymorphs and at the boundaries, which is enabled by the conformational freedom of the alkyl tails of these molecules.
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Affiliation(s)
- Michiel J J Coenen
- Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen, The Netherlands
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14
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Lensen D, Habets T, Elemans JAAW. Dynamic rearrangement of bilayers of porphyrin hetero-dimers at a solid/liquid interface. Chem Commun (Camb) 2014; 50:7291-4. [DOI: 10.1039/c4cc02963a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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