Two side chains, three supramolecules: exploration of fluorenone derivatives towards crystal engineering.

Structural diversity obtained through two-dimensional molecular self-assembly induced by the chain length effect has gained immense attention, not only because of its significance in crystal engineering but also for its potential application in nanoscience and nanotechnology. Three kinds of fluorenone derivative, named F-C7C7, F-C14C7, and F-C14C14, were synthesized and used for systematic exploration of their crystalline difference. At first, scanning electron microscopy and X-ray powder diffraction were performed to investigate their differences in morphology and three-dimensional crystal structure. Then scanning tunneling microscopy experiments were conducted to compare the self-assembled monolayers. Moreover, different solvents were used to repeatedly investigate the occurrence of structural diversity. F-C7C7 could not self-assemble into a stable monolayer on the graphite surface under ambient conditions due to its weak molecule-substrate interaction. F-C14C7 was observed to self-assemble into twist, plier-like, octamer-curve, and random structures in 1-octanoic acid, 1-phenyloctane, n-tetradecane, and dichloromethane, respectively. However, when the same solvents were used and at similar concentrations, the F-C14C14 molecules were arranged into interval, mixed, linear, and plier-like configurations. These self-assembled nanopatterns formed under the driving forces of dipole-dipole interactions, hydrogen bonds, and chain-chain, molecule-substrate, and molecule-solvent van der Waals interactions. Furthermore, from the viewpoint of thermal analysis, differential scanning calorimetry, as well as polarized optical microscopy, was performed to further elucidate the difference between these three compounds in the solid and liquid crystal states. The present system is believed to provide understanding of how the chain length effect induces different crystalline properties, and to open up the possibility of fabricating diverse self-assembled networks for crystal engineering.

[1]  Yuan Fang,et al.  Dynamic control over supramolecular handedness by selecting chiral induction pathways at the solution-solid interface. , 2016, Nature chemistry.

[2]  Li Xu,et al.  Hydroxyl versus Carboxyl Substituent: Effects of Competitive and Cooperative Multiple Hydrogen Bonds on Concentration-Controlled Self-Assembly , 2016 .

[3]  Li Xu,et al.  Fabrication of chiral networks for a tri-substituted anthraquinone derivative using molecular self-assembly. , 2016, Physical chemistry chemical physics : PCCP.

[4]  Li Xu,et al.  Structural transition control between dipole–dipole and hydrogen bonds induced chirality and achirality , 2016 .

[5]  Li Xu,et al.  Chiral Transition of the Supramolecular Assembly by Concentration Modulation at the Liquid/Solid Interface , 2015 .

[6]  Li Xu,et al.  Concentration-dependent structure and structural transition from chirality to nonchirality at the liquid-solid interface by coassembly. , 2015, Nanoscale.

[7]  Li Xu,et al.  Self-assembly polymorphism of 2,7-bis-nonyloxy-9-fluorenone: solvent induced the diversity of intermolecular dipole-dipole interactions. , 2015, Physical chemistry chemical physics : PCCP.

[8]  T. Müller,et al.  Cover Picture: Stereo‐ and Regioselective Phyllobilane Oxidation in Leaf Homogenates of the Peace Lily (Spathiphyllum wallisii): Hypothetical Endogenous Path to Yellow Chlorophyll Catabolites (Chem. Eur. J. 1/2015) , 2015 .

[9]  Yibao Li,et al.  Competitive Influence of Hydrogen Bonding and van der Waals Interactions on Self-Assembled Monolayers of Stilbene-Based Carboxylic Acid Derivatives , 2014 .

[10]  Zhuomin Li,et al.  Two-dimensional self-assembly of single-, poly- and co-crystals at the liquid/solid interface , 2014 .

[11]  Li Xu,et al.  Steric matching and the concentration induced self-assembled structural variety of 2,7-bis(n-alkoxy)-9-fluorenone at the aliphatic solvent/graphite interface. , 2014, Physical chemistry chemical physics : PCCP.

[12]  Shuai Wang,et al.  Two-Dimensional Supramolecular Self-Assembly of Stilbene Derivatives with Ester Groups: Molecular Symmetry and Alkoxy Substitution Effect , 2014 .

[13]  S. De Feyter,et al.  A tale of tails: alkyl chain directed formation of 2D porous networks reveals odd-even effects and unexpected bicomponent phase behavior. , 2013, ACS nano.

[14]  L. Wan,et al.  Structural Motif Modulation in 2D Supramolecular Assemblies of Molecular Dipolar Unit Tethered by Alkylene Spacer , 2013 .

[15]  Li Xu,et al.  Dipole-Controlled Self-Assembly of 2,7-Bis(n-alkoxy)-9-fluorenone: Odd–Even and Chain-Length Effects , 2013 .

[16]  Li Xu,et al.  Hydrogen-bonding-induced polymorphous phase transitions in 2D organic nanostructures. , 2013, Chemistry, an Asian journal.

[17]  L. Wan,et al.  Globally homochiral assembly of two-dimensional molecular networks triggered by co-absorbers , 2013, Nature Communications.

[18]  S. De Feyter,et al.  Solvent-induced homochirality in surface-confined low-density nanoporous molecular networks. , 2012, Journal of the American Chemical Society.

[19]  S. De Feyter,et al.  Role of substrate in directing the self-assembly of multicomponent supramolecular networks at the liquid-solid interface. , 2012, ACS nano.

[20]  Li Xu,et al.  Self-Assembly Polymorphism: Solvent-Responsive Two-Dimensional Morphologies of 2,7-Ditridecyloxy-9-fluorenone by Scanning Tunneling Microscopy , 2012 .

[21]  M. Ohta,et al.  Entropy-controlled 2D supramolecular structures of N,N'-bis(n-alkyl)naphthalenediimides on a HOPG surface. , 2012, ACS nano.

[22]  S. De Feyter,et al.  One building block, two different nanoporous self-assembled monolayers: a combined STM and Monte Carlo study. , 2012, ACS nano.

[23]  Li Xu,et al.  Two-Dimensional Self-Assembled Molecular Structures Formed by the Competition of van der Waals Forces and Dipole–Dipole Interactions , 2012 .

[24]  M. K. Khan,et al.  Effects of carbon atom parity and alkyl side chain length on the crystallization and morphology of biscarbamates, a set of model compounds for polyurethanes. , 2011, The journal of physical chemistry. B.

[25]  S. De Feyter,et al.  Role of pseudopolymorphism on concentration dependent competitive adsorption at a liquid/solid interface. , 2010, Chemical communications.

[26]  K. Lava,et al.  Hydrogen bonding versus van der Waals interactions: competitive influence of noncovalent interactions on 2D self-assembly at the liquid-solid interface. , 2010, Chemistry.

[27]  Charles A. Johnson,et al.  Self-assembled monolayers of alkoxy-substituted octadehydrodibenzo[12]annulenes on a graphite surface: attempts at peri-benzopolyacene formation by on-surface polymerization. , 2010, Chemistry.

[28]  J. Pei,et al.  One‐Dimensional Microwires Formed by the Co‐Assembly of Complementary Aromatic Donors and Acceptors , 2009 .

[29]  D. Beljonne,et al.  Expression of chirality in molecular layers at surfaces: insights from modelling. , 2009, Chemical Society reviews.

[30]  R. Raval.  Chiral expression from molecular assemblies at metal surfaces: insights from surface science techniques. , 2009, Chemical Society reviews.

[31]  F. Rosei,et al.  Supramolecular assembly of heterocirculenes in 2D and 3D. , 2009, Chemical communications.

[32]  Qing Chen,et al.  Structural selection of graphene supramolecular assembly oriented by molecular conformation and alkyl chain , 2008, Proceedings of the National Academy of Sciences.

[33]  M. Surin,et al.  Programmable hierarchical three-component 2D assembly at a liquid-solid interface: recognition, selection, and transformation. , 2008, Nano letters.

[34]  E. Lacaze,et al.  Molecular chirality at fluid/solid interfaces: expression of asymmetry in self-organised monolayers , 2008 .

[35]  F. Tao,et al.  Understanding odd-even effects in organic self-assembled monolayers. , 2007, Chemical reviews.

[36]  M. van der Auweraer,et al.  Structural transformation of a two-dimensional molecular network in response to selective guest inclusion. , 2007, Angewandte Chemie.

[37]  L. Wan,et al.  Scanning tunneling microscopy of the formation, transformation, and property of oligothiophene self-organizations on graphite and gold surfaces , 2007, Proceedings of the National Academy of Sciences.

[38]  F. D. De Schryver,et al.  Two-dimensional porous molecular networks of dehydrobenzo[12]annulene derivatives via alkyl chain interdigitation. , 2006, Journal of the American Chemical Society.

[39]  Xinquan Hu,et al.  Chain-length effects on molecular conformation in and chirality of self-assembled monolayers of alkoxylated benzo[c]cinnoline derivatives on highly oriented pyrolytic graphite. , 2006, The journal of physical chemistry. B.

[40]  F. D. De Schryver,et al.  Molecular geometry directed Kagomé and honeycomb networks: toward two-dimensional crystal engineering. , 2006, Journal of the American Chemical Society.

[41]  E. W. Meijer,et al.  2D self-assembly of oligo(p-phenylene vinylene) derivatives: from dimers to chiral rosettes. , 2004, Small.

[42]  S. M. Barlow,et al.  Two-dimensional organisational chirality through supramolecular assembly of molecules at metal surfaces , 2004 .

[43]  M. Ratner,et al.  Electron Transport in Molecular Wire Junctions , 2003, Science.

[44]  F. D. Schryver,et al.  Two-dimensional supramolecular self-assembly probed by scanning tunneling microscopy , 2003 .

[45]  L. Wan,et al.  Adsorption mode of cinchonidine on Cu(111) surface. , 2002, Journal of the American Chemical Society.

[46]  J. Gimzewski,et al.  Electronics using hybrid-molecular and mono-molecular devices , 2000, Nature.

[47]  S. Valiyaveettil,et al.  Scanning tunneling microscopy: a unique tool in the study of chirality, dynamics, and reactivity in physisorbed organic monolayers. , 2000, Accounts of chemical research.

[48]  J. Brédas,et al.  A theoretical approach to the STM imaging of adsorbates on the graphite surface , 1991 .

[49]  E. O. Lawrence.  Neutron-proton exchange. , 1947, Chemistry.