Manipulation of Self-Assembled Nanostructure Dimensions in Molecular Janus Particles.

The ability to manipulate self-assembly of molecular building blocks is the key to achieving precise "bottom-up" fabrications of desired nanostructures. Herein, we report a rational design, facile synthesis, and self-assembly of a series of molecular Janus particles (MJPs) constructed by chemically linking α-Keggin-type polyoxometalate (POM) nanoclusters with functionalized polyhedral oligomeric silsesquioxane (POSS) cages. Diverse nanostructures were obtained by tuning secondary interactions among the building blocks and solvents via three factors: solvent polarity, surface functionality of POSS derivatives, and molecular topology. Self-assembled morphologies of KPOM-BPOSS (B denotes isobutyl groups) were found dependent on solvent polarity. In acetonitrile/water mixtures with a high dielectric constant, colloidal nanoparticles with nanophase-separated internal lamellar structures quickly formed, which gradually turned into one-dimensional nanobelt crystals upon aging, while stacked crystalline lamellae were dominantly observed in less polar methanol/chloroform solutions. When the crystallizable BPOSS was replaced with noncrystallizable cyclohexyl-functionalized CPOSS, the resulting KPOM-CPOSS also formed colloidal spheres; however, it failed to further evolve into crystalline nanobelt structures. In less polar solvents, KPOM-CPOSS crystallized into isolated two-dimensional nanosheets, which were composed of two inner crystalline layers of Keggin POM covered by two monolayers of amorphous CPOSS. In contrast, self-assembly of KPOM-2BPOSS was dominated by crystallization of the BPOSS cages, which was hardly sensitive to solvent polarity. The BPOSS cages formed the crystalline inner bilayer, sandwiched by two outer layers of Keggin POM clusters. These results illustrate a rational strategy to purposely fabricate self-assembled nanostructures with diverse dimensionality from MJPs with controlled molecular composition and topology.

[1]  James E. Roberts,et al.  Inorganic-organic hybrid vesicles with counterion- and pH-controlled fluorescent properties. , 2011, Journal of the American Chemical Society.

[2]  Stephen Z. D. Cheng,et al.  Hierarchical structure and polymorphism of a sphere-cubic shape amphiphile based on a polyhedral oligomeric silsesquioxane–[60]fullerene conjugate , 2011 .

[3]  M. Malacria,et al.  A general strategy for ligation of organic and biological molecules to Dawson and Keggin polyoxotungstates. , 2007, Organic letters.

[4]  Janos H. Fendler,et al.  Chemical Self-assembly for Electronic Applications , 2001 .

[5]  A. Müller,et al.  Self-assembly of Janus cylinders into hierarchical superstructures. , 2009, Journal of the American Chemical Society.

[6]  George M. Whitesides,et al.  Beyond molecules: Self-assembly of mesoscopic and macroscopic components , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[7]  C. Barner‐Kowollik,et al.  Mixed, multicompartment, or Janus micelles? A systematic study of thermoresponsive bis-hydrophilic block terpolymers. , 2010, Langmuir : the ACS journal of surfaces and colloids.

[8]  Chih-Hao Hsu,et al.  Selective assemblies of giant tetrahedra via precisely controlled positional interactions , 2015, Science.

[9]  Qian Chen,et al.  Directed self-assembly of a colloidal kagome lattice , 2014 .

[10]  B. Matt,et al.  Functionalization and post-functionalization: a step towards polyoxometalate-based materials. , 2012, Chemical Society reviews.

[11]  T. Fukushima,et al.  Self-Assembled Hexa-peri-hexabenzocoronene Graphitic Nanotube , 2004, Science.

[12]  P. Laaksonen,et al.  Self-assembly of cellulose nanofibrils by genetically engineered fusion proteins , 2011 .

[13]  Ralph Weissleder,et al.  Viral-induced self-assembly of magnetic nanoparticles allows the detection of viral particles in biological media. , 2003, Journal of the American Chemical Society.

[14]  M. Zaworotko,et al.  From molecules to crystal engineering: supramolecular isomerism and polymorphism in network solids. , 2001, Chemical reviews.

[15]  Tianbo Liu,et al.  Supramolecular architectures assembled from amphiphilic hybrid polyoxometalates. , 2012, Dalton transactions.

[16]  S. Stupp,et al.  Self-Assembly and Mineralization of Peptide-Amphiphile Nanofibers , 2001, Science.

[17]  D. Nair,et al.  The Thiol‐Michael Addition Click Reaction: A Powerful and Widely Used Tool in Materials Chemistry , 2014 .

[18]  Shiyong Liu,et al.  One-pot synthesis of amphiphilic polymeric janus particles and their self-assembly into supermicelles with a narrow size distribution. , 2007, Angewandte Chemie.

[19]  K. Nomiya,et al.  Polyoxometalate (POM)-based, multi-functional, inorganic-organic, hybrid compounds: syntheses and molecular structures of silanol- and/or siloxane bond-containing species grafted on mono- and tri-lacunary Keggin POMs. , 2011, Dalton transactions.

[20]  Craig J. Hawker,et al.  The Convergence of Synthetic Organic and Polymer Chemistries , 2005, Science.

[21]  Tao He,et al.  Photochromism in composite and hybrid materials based on transition-metal oxides and polyoxometalates , 2006 .

[22]  Zhanyao Hou,et al.  Synthesis and Self-Assembled Structure of A Cluster-Cluster Hybrid Molecule Composed of POM and POSS Clusters , 2014 .

[23]  Dimitris Elias Katsoulis A Survey of Applications of Polyoxometalates. , 1998 .

[24]  Wei Li,et al.  Janus and ternary particles generated by microfluidic synthesis: design, synthesis, and self-assembly. , 2006, Journal of the American Chemical Society.

[25]  Stephen Z. D. Cheng,et al.  Self-assembly of fullerene-based janus particles in solution: effects of molecular architecture and solvent. , 2014, Chemistry.

[26]  Stephen Z. D. Cheng,et al.  Molecular Nanoparticles Are Unique Elements for Macromolecular Science: From “Nanoatoms” to Giant Molecules , 2014 .

[27]  Yuxing Yang,et al.  A higher yielding route for T8 silsesquioxane cages and X-ray crystal structures of some novel spherosilicates , 2003 .

[28]  Jean-Marie Lehn,et al.  Supramolecular Chemistry—Scope and Perspectives Molecules, Supermolecules, and Molecular Devices (Nobel Lecture) , 1988 .

[29]  Charles E. Hoyle,et al.  Thiol—Ene Click Chemistry , 2010 .

[30]  Xiaohu Gao,et al.  Nanocomposites with spatially separated functionalities for combined imaging and magnetolytic therapy. , 2010, Journal of the American Chemical Society.

[31]  Jean-Marie Lehn,et al.  Supramolecular chemistry , 1994, Science.

[32]  Yu Xiao,et al.  POM-organic-POSS cocluster: creating a dumbbell-shaped hybrid molecule for programming hierarchical supramolecular nanostructures. , 2013, Langmuir : the ACS journal of surfaces and colloids.

[33]  Keigo Kamata,et al.  Epoxidation of olefins with hydrogen peroxide catalyzed by polyoxometalates , 2005 .

[34]  Stephen Z. D. Cheng,et al.  Giant surfactants based on molecular nanoparticles: Precise synthesis and solution self‐assembly , 2014 .

[35]  M. Steigerwald,et al.  Nanoscale Atoms in Solid-State Chemistry , 2013, Science.

[36]  Leroy Cronin,et al.  Self-assembly of organic-inorganic hybrid amphiphilic surfactants with large polyoxometalates as polar head groups. , 2008, Journal of the American Chemical Society.

[37]  C. Pittman,et al.  Polyhedral Oligomeric Silsesquioxane (POSS) Polymers and Copolymers: A Review , 2001 .

[38]  Sharon C. Glotzer,et al.  Self-assembly of anisotropic tethered nanoparticle shape amphiphiles , 2005 .

[39]  M. T. Pope,et al.  Heteropolyanions as nucleophiles. 1. Synthesis, characterization, and reactions of Keggin- and Dawson-type tungstostannates(II) , 1987 .

[40]  Wei Huang,et al.  Molecular self-assembly of a homopolymer: an alternative to fabricate drug-delivery platforms for cancer therapy. , 2011, Angewandte Chemie.

[41]  Andreas Walther,et al.  Janus particles. , 2008, Soft matter.

[42]  P. D. Lickiss,et al.  Recent developments in the chemistry of cubic polyhedral oligosilsesquioxanes. , 2010, Chemical reviews.

[43]  D. Bruce,et al.  Shape amphiphiles: mixing rods and disks in liquid crystals. , 2003, Journal of the American Chemical Society.

[44]  Stephen Z. D. Cheng Phase Transitions in Polymers: The Role of Metastable States , 2008 .

[45]  Erik Luijten,et al.  Janus Particle Synthesis and Assembly , 2010, Advanced materials.

[46]  R. Schinazi,et al.  Polyoxometalates in Medicine. , 1998, Chemical reviews.

[47]  Meng Zhang,et al.  Microwave-assisted rapid facile "Green" synthesis of uniform silver nanoparticles: Self-assembly into multilayered films and their optical properties , 2008 .

[48]  Xun Wang,et al.  Surfactant-encapsulated polyoxometalate building blocks: controlled assembly and their catalytic properties. , 2012, Dalton transactions.

[49]  Eugenio Coronado,et al.  Magnetic clusters from polyoxometalate complexes , 1999 .

[50]  G. Graff,et al.  Ternary self-assembly of ordered metal oxide-graphene nanocomposites for electrochemical energy storage. , 2010, ACS nano.

[51]  M. T. Pope,et al.  Organotin and organogermanium linkers for simple, direct functionalization of polyoxotungstates. , 2004, Dalton transactions.

[52]  M. Kostiainen,et al.  Self-assembly and modular functionalization of three-dimensional crystals from oppositely charged proteins , 2014, Nature Communications.

[53]  Limin Wu,et al.  Fabrication, properties and applications of Janus particles. , 2012, Chemical Society reviews.

[54]  Li-Tang Yan,et al.  A Filled-Honeycomb-Structured Crystal Formed by Self-Assembly of a Janus Polyoxometalate-Silsesquioxane (POM-POSS) Co-Cluster. , 2015, Angewandte Chemie.

[55]  Tianbo Liu Supramolecular structures of polyoxomolybdate-based giant molecules in aqueous solution. , 2002, Journal of the American Chemical Society.

[56]  E. Baker,et al.  The Corynebacterium diphtheriae shaft pilin SpaA is built of tandem Ig-like modules with stabilizing isopeptide and disulfide bonds , 2009, Proceedings of the National Academy of Sciences.

[57]  M. Prato,et al.  Materials chemistry of fullerene C60 derivatives , 2011 .

[58]  A. Ajayaghosh,et al.  RGB Emission through Controlled Donor Self‐Assembly and Modulation of Excitation Energy Transfer: A Novel Strategy to White‐Light‐Emitting Organogels , 2009 .

[59]  P. Gennes,et al.  Soft Matter (Nobel Lecture) , 1992 .

[60]  B. Matt,et al.  Elegant Approach to the Synthesis of a Unique Heteroleptic Cyclometalated Iridium(III)-Polyoxometala , 2012 .

[61]  S. Granick,et al.  Supracolloidal Reaction Kinetics of Janus Spheres , 2011, Science.

[62]  Stephen Z. D. Cheng,et al.  Crystal structure and molecular packing of an asymmetric giant amphiphile constructed by one C60 and two POSSs , 2014 .

[63]  Peixuan Guo,et al.  Controllable self-assembly of nanoparticles for specific delivery of multiple therapeutic molecules to cancer cells using RNA nanotechnology. , 2005, Nano letters.

[64]  I. Robinson Coherent diffraction: giant molecules or tiny crystals? , 2008, Nature materials.

[65]  Toru Torii,et al.  Synthesis of Monodisperse Bicolored Janus Particles with Electrical Anisotropy Using a Microfluidic Co‐Flow System , 2006 .

[66]  P. Gouzerh,et al.  Efficient preparation of functionalized hybrid organic/inorganic Wells-Dawson-type polyoxotungstates. , 2005, Journal of the American Chemical Society.

[67]  Wahyu Setyawan,et al.  Nanotube electronics: Large-scale assembly of carbon nanotubes , 2003, Nature.

[68]  Wen-Bin Zhang,et al.  Breaking symmetry toward nonspherical Janus particles based on polyhedral oligomeric silsesquioxanes: molecular design, "click" synthesis, and hierarchical structure. , 2011, Journal of the American Chemical Society.

[69]  Andreas Walther,et al.  Janus particles: synthesis, self-assembly, physical properties, and applications. , 2013, Chemical reviews.

[70]  B. Matt,et al.  Hybrid polyoxometalates: Keggin and Dawson silyl derivatives as versatile platforms. , 2011, The Journal of organic chemistry.

[71]  Ali Nazemi,et al.  Synthetic Covalent and Non-Covalent 2D Materials. , 2015, Angewandte Chemie.

[72]  Stephen Z. D. Cheng,et al.  Two-dimensional nanocrystals of molecular Janus particles. , 2014, Journal of the American Chemical Society.