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3. Advancing Dynamic Polymer Mechanochemistry through Synergetic Conformational Gearing

Author

Ofodum, Nnamdi M., Qi, Qingkai, Chandradat, Richard, Warfle, Theodore, and Lu, Xiaocun

Abstract

Harnessing mechanical force to modulate material properties and enhance biomechanical functions is essential for advancing smart materials and bioengineering. Polymer mechanochemistry provides an emerging toolkit for exploring unconventional chemical transformations and modulating molecular structures through mechanical force. One of the key challenges is developing innovative force-sensing mechanisms for precise and in situforce detection. This study introduces mDPAC, a dynamic and sensitive mechanophore, demonstrating its mechanochromic properties through synergetic conformational gearing. Its unique mechanoresponsive mechanism is based on the simultaneous conformational synergy between its phenazine and phenyl moieties, facilitated by a worm-gear-like structure. We confirm mDPAC’s complex mechanochemical response and elucidate its mechanotransduction mechanism through our experimental data and comprehensive simulations. The compatibility of mDPAC with hydrogels is particularly notable, highlighting its potential for applications in aqueous biological environments as a dynamic force sensor. Moreover, mDPAC’s multicolored mechanochromic responses facilitate direct force sensing and visual detection, paving the way for precise and real-time mechanical force sensing in bulk materials.

Published
2024
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4. Force-Induced Near-Infrared Chromism of Mechanophore-Linked Polymers

Author

Qi, Qingkai, primary, Sekhon, Gaganjot, additional, Chandradat, Richard, additional, Ofodum, Nnamdi M., additional, Shen, Tianruo, additional, Scrimgeour, Jan, additional, Joy, Monu, additional, Wriedt, Mario, additional, Jayathirtha, Madhuri, additional, Darie, Costel C., additional, Shipp, Devon A., additional, Liu, Xiaogang, additional, and Lu, Xiaocun, additional

Published
2021
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10. Supercharged, Precise, Megametallodendrimers via a Single-Step, Quantitative, Assembly Process

Author

Xie, Ting-Zheng, primary, Wu, Xiaolei, additional, Endres, Kevin J., additional, Guo, Zaihong, additional, Lu, Xiaocun, additional, Li, Jingyi, additional, Manandhar, Erendra, additional, Ludlow, James M., additional, Moorefield, Charles N., additional, Saunders, Mary Jane, additional, Wesdemiotis, Chrys, additional, and Newkome, George R., additional

Published
2017
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13. Titelbild: Precise Molecular Fission and Fusion: Quantitative Self‐Assembly and Chemistry of a Metallo‐Cuboctahedron (Angew. Chem. 32/2015)

Author

Xie, Ting‐Zheng, primary, Guo, Kai, additional, Guo, Zaihong, additional, Gao, Wen‐Yang, additional, Wojtas, Lukasz, additional, Ning, Guo‐Hong, additional, Huang, Mingjun, additional, Lu, Xiaocun, additional, Li, Jing‐Yi, additional, Liao, Sheng‐Yun, additional, Chen, Yu‐Sheng, additional, Moorefield, Charles N., additional, Saunders, Mary Jane, additional, Cheng, Stephen Z. D., additional, Wesdemiotis, Chrys, additional, and Newkome, George R., additional

Published
2015
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14. Cover Picture: Precise Molecular Fission and Fusion: Quantitative Self-Assembly and Chemistry of a Metallo-Cuboctahedron (Angew. Chem. Int. Ed. 32/2015)

Author

Xie, Ting-Zheng, primary, Guo, Kai, additional, Guo, Zaihong, additional, Gao, Wen-Yang, additional, Wojtas, Lukasz, additional, Ning, Guo-Hong, additional, Huang, Mingjun, additional, Lu, Xiaocun, additional, Li, Jing-Yi, additional, Liao, Sheng-Yun, additional, Chen, Yu-Sheng, additional, Moorefield, Charles N., additional, Saunders, Mary Jane, additional, Cheng, Stephen Z. D., additional, Wesdemiotis, Chrys, additional, and Newkome, George R., additional

Published
2015
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15. Precise Molecular Fission and Fusion: Quantitative Self-Assembly and Chemistry of a Metallo-Cuboctahedron

Author

Xie, Ting-Zheng, primary, Guo, Kai, additional, Guo, Zaihong, additional, Gao, Wen-Yang, additional, Wojtas, Lukasz, additional, Ning, Guo-Hong, additional, Huang, Mingjun, additional, Lu, Xiaocun, additional, Li, Jing-Yi, additional, Liao, Sheng-Yun, additional, Chen, Yu-Sheng, additional, Moorefield, Charles N., additional, Saunders, Mary Jane, additional, Cheng, Stephen Z. D., additional, Wesdemiotis, Chrys, additional, and Newkome, George R., additional

Published
2015
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23. Effects of molecular geometry on the self-assembly of giant polymer–dendron conjugates in condensed state

Author

Dong, Xue-Hui, primary, Lu, Xiaocun, additional, Ni, Bo, additional, Chen, Ziran, additional, Yue, Kan, additional, Li, Yiwen, additional, Rong, Lixia, additional, Koga, Tadanori, additional, Hsiao, Benjamin S., additional, Newkome, George R., additional, Shi, An-Chang, additional, Zhang, Wen-Bin, additional, and Cheng, Stephen Z. D., additional

Published
2014
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25. Shape-persistent, ruthenium(ii)- and iron(ii)-bisterpyridine metallodendrimers: synthesis, traveling-wave ion-mobility mass spectrometry, and photophysical properties

Author

Wang, Jin-Liang, primary, Li, Xiaopeng, additional, Shreiner, Carol D., additional, Lu, Xiaocun, additional, Moorefield, Charles N., additional, Tummalapalli, Sreedhar R., additional, Medvetz, Douglas A., additional, Panzner, Matthew J., additional, Fronczek, Frank R., additional, Wesdemiotis, Chrys, additional, and Newkome, George R., additional

Published
2012
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30. Precise Molecular Fission and Fusion: Quantitative Self-Assembly and Chemistry of a Metallo-Cuboctahedron.

Author

Li, Jing-Yi, Guo, Kai, Lu, Xiaocun, Guo, Zaihong, Moorefield, Charles N., Gao, Wen-Yang, Saunders, Mary Jane, Newkome, George R., Liao, Sheng-Yun, Chen, Yu-Sheng, Xie, Ting-Zheng, Wesdemiotis, Chrys, Wojtas, Lukasz, Huang, Mingjun, Cheng, Stephen Z. D., and Ning, Guo-Hong

Subjects
SUPRAMOLECULAR chemistry, MOLECULAR self-assembly, LIGANDS (Chemistry), NUCLEAR magnetic resonance spectroscopy, MASS spectrometry
Abstract

Inspiration for molecular design and construction can be derived from mathematically based structures. In the quest for new materials, the adaptation of new building blocks can lead to unexpected results. Towards these ends, the quantitative single-step self-assembly of a shape-persistent, Archimedean-based building block, which generates the largest molecular sphere (a cuboctahedron) that has been unequivocally characterized by synchrotron X-ray analysis, is described. The unique properties of this new construct give rise to a dilution-based transformation into two identical spheres (octahedra) each possessing one half of the molecular weight of the parent structure; concentration of this octahedron reconstitutes the original cuboctahedron. These chemical phenomena are reminiscent of biological fission and fusion processes. The large 6 nm cage structure was further analyzed by 1D and 2D NMR spectroscopy, mass spectrometry, and collision cross-section analysis. New routes to molecular encapsulation can be envisioned. [ABSTRACT FROM AUTHOR]

Published
2015
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31. Towards Molecular Construction Platforms: Synthesis of a Metallotricyclic Spirane Based on Bis(2,2′:6′,2'-Terpyridine)RuII Connectivity.

Author

Xie, Ting‐Zheng, Guo, Kai, Huang, Mingjun, Lu, Xiaocun, Liao, Sheng‐Yun, Sarkar, Rajarshi, Moorefield, Charles N., Cheng, Stephen Z. D., Wesdemiotis, Chrys, and Newkome, George R.

Subjects
MOLECULAR structure, TRIPTYCENES, CHEMICAL synthesis, NUCLEAR magnetic resonance spectroscopy, REACTION mechanisms (Chemistry)
Abstract

The design and construction of the first multicomponent stepwise assembly of a II-tpy>-based (tpy=terpyridine), three-dimensional, propeller-shaped trismacrocycle, 8, are reported. Key steps in the synthesis involve the preparation of a hexaterpyridinyl triptycene and its reaction with dimeric, 60°-directional, bisterpyridine-RuII building blocks. Characterization includes ESI- and ESI-TWIM-MS and TEM, along with 1D and 2D 1H NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Published
2014
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32. The development of online information retrieval services in the People's Republic of China

Author

Lu Xiaocun

Subjects
ComputingMilieux_GENERAL, World Wide Web, Information retrieval, Political science, General Engineering, Information system, Developing country, People's Republic, Information networks, Document retrieval, China
Abstract

During the 1980s online information retrieval became popular in many countries but its use in China was rare. In recent years, however, China has taken a leap forward in the development of online retrieval services.

Published
1986

34. Cover Picture: Precise Molecular Fission and Fusion: Quantitative Self-Assembly and Chemistry of a Metallo-Cuboctahedron (Angew. Chem. Int. Ed. 32/2015).

Author

Huang, Mingjun, Cheng, Stephen Z. D., Wesdemiotis, Chrys, Guo, Kai, Newkome, George R., Chen, Yu-Sheng, Guo, Zaihong, Li, Jing-Yi, Moorefield, Charles N., Gao, Wen-Yang, Wojtas, Lukasz, Lu, Xiaocun, Xie, Ting-Zheng, Ning, Guo-Hong, Liao, Sheng-Yun, and Saunders, Mary Jane

Subjects
MOLECULAR self-assembly, NUCLEAR fission, NUCLEAR fusion
Published
2015
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35. Design and Construction of Terpyridine-based Two-Dimensional and Three-Dimensional Supramolecular Architectures

Author

Lu, Xiaocun

Subjects
Polymer Chemistry
Abstract

Supramolecular self-assembly focuses on the studies of weak interactions beyond molecules and construction of complicated, well-defined supramolecular architectures which widely exist in natural process and have been used in catalysis, chemical sensing and molecular electronics. Utilization of II-tpy> (M = metal) connectivity to construct specific shaped supramolecular architectures has been well-developed.Bisterpyridines possessing 60° and 120° directionality can readily form triangular and hexagonal metallomacrocycles with group 12 metals, such as: Zn(II) and Cd(II), respectively. The supramolecular rhomboidal architecture could also be formed through a multicomponent self-assembly utilizing a precise stoichiometric ratio (1:1:2) of bisterpyridines with 60° or 120° directionality and metal ions (Zn2+ or Cd2+). However, the triangular construct, which is formed solely by bisterpyridine with 60° branching angle, could also be detected in the same solution. To further probe the self-sorted formation of a rhomboidal architecture, a tristerpyridine possessing three adjacent terpyridine units is used. Such tristerpyridine ligand can readily react with 60°-directed bisterpyridine ligands and metal ions (Zn2+ or Cd2+) in the stoichiometric ratio (2:2:5) to quantitatively form a center-bridged, fused-triangular shaped, rhomboidal structure.A facile heteroleptic self-assembly of hexakisterpyridine and tristerpyridine possessing 60° angles between the adjacent terpyridine moieties with stoichiometric amount of Zn2+ ions (1:6:12) leads to the formation of supramolecular spoked wheel architecture in a 90% isolated yield, which is fully characterized by ESI-MS, NMR, and TEM imaging. When the central hexakisterpyridine of the spoked wheel is replaced with two staggered tristerpyridine ligands possessing 120° angle between the adjacent terpyridine units, a three-dimensional, supramolecular, bicycle-like wheel structure is readily formed, in which two 120°-directed tristerpyridines serve as the hub and spokes and six 60°-based tristerpyridines locate outside as rims.Another analogous supramolecular spoked wheel can also be formed by further redesign of the core ligand. Two tristerpyridine ligands possessing 60° between the adjacent terpyridine units adopt a parallel-staggered conformation with the opposite orientations to replace the core hexaligand. Eight equivalent amount of such tristerpyridine ligands (two serving as core ligands; six as outer rim ligands) can readily react with twelve equivalence of metal ions (Zn2+ or Cd2+) to form a supramolecular mandoline-shaped wheel structure, which contains two vertex-connected, centrally-bridged rhomboidal moieties at the concentration of > 15 mg·mL-1. When the concentration of the Cd2+-based mandoline-shaped structure is reduced, a quasi-tetrahedron structure possessing four tristerpyridine ligands and six Cd2+ ions can be detected and it becomes the only self-assembly product when the concentration is below 0.5 mg·mL-1. The Zn2+ analogue of the mandoline-shaped structure remains intact during the dilution and there is no quasi-tetrahedron structure detected in such supramolecular system.

Published
2013

36. Precise Molecular Fission and Fusion: Quantitative Self-Assembly and Chemistry of a Metallo-Cuboctahedron.

Author

Xie TZ, Guo K, Guo Z, Gao WY, Wojtas L, Ning GH, Huang M, Lu X, Li JY, Liao SY, Chen YS, Moorefield CN, Saunders MJ, Cheng SZ, Wesdemiotis C, and Newkome GR

Subjects
Ligands, Magnetic Resonance Spectroscopy, Nanostructures chemistry, Spectrometry, Mass, Electrospray Ionization, Macromolecular Substances chemistry, Metals chemistry
Abstract

Inspiration for molecular design and construction can be derived from mathematically based structures. In the quest for new materials, the adaptation of new building blocks can lead to unexpected results. Towards these ends, the quantitative single-step self-assembly of a shape-persistent, Archimedean-based building block, which generates the largest molecular sphere (a cuboctahedron) that has been unequivocally characterized by synchrotron X-ray analysis, is described. The unique properties of this new construct give rise to a dilution-based transformation into two identical spheres (octahedra) each possessing one half of the molecular weight of the parent structure; concentration of this octahedron reconstitutes the original cuboctahedron. These chemical phenomena are reminiscent of biological fission and fusion processes. The large 6 nm cage structure was further analyzed by 1D and 2D NMR spectroscopy, mass spectrometry, and collision cross-section analysis. New routes to molecular encapsulation can be envisioned., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2015
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37. One ligand in dual roles: self-assembly of a bis-rhomboidal-shaped, three-dimensional molecular wheel.

Author

Lu X, Li X, Guo K, Wang J, Huang M, Wang JL, Xie TZ, Moorefield CN, Cheng SZ, Wesdemiotis C, and Newkome GR

Subjects
Isomerism, Magnetic Resonance Spectroscopy, Molecular Dynamics Simulation, Spectrometry, Mass, Electrospray Ionization, Zinc chemistry, Ligands, Pyridines chemistry
Abstract

A facile high yield, self-assembly process that leads to a terpyridine-based, three-dimensional, bis-rhomboidal-shaped, molecular wheel is reported. The desired coordination-driven supramolecular wheel involves eight structurally distorted tristerpyridine (tpy) ligands possessing a 60° angle between the adjacent tpy units and twelve Zn(2+) ions. The tpy ligand plays dual roles in the self-assembly process: two are staggered at 180° to create the internal hub, while six produce the external rim. The wheel can be readily generated by mixing the tpy ligand and Zn(2+) in a stoichiometric ratio of 2:3; full characterization is provided by ESI-MS, NMR spectroscopy, and TEM imaging., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2014
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38. Towards molecular construction platforms: synthesis of a metallotricyclic spirane based on bis(2,2':6',2"-terpyridine)RuII connectivity.

Author

Xie TZ, Guo K, Huang M, Lu X, Liao SY, Sarkar R, Moorefield CN, Cheng SZ, Wesdemiotis C, and Newkome GR

Subjects
Macrocyclic Compounds chemistry, Models, Molecular, Organometallic Compounds chemistry, Pyridines chemistry, Macrocyclic Compounds chemical synthesis, Organometallic Compounds chemical synthesis, Pyridines chemical synthesis, Ruthenium chemistry
Abstract

The design and construction of the first multicomponent stepwise assembly of a -based (tpy=terpyridine), three-dimensional, propeller-shaped trismacrocycle, 8, are reported. Key steps in the synthesis involve the preparation of a hexaterpyridinyl triptycene and its reaction with dimeric, 60°-directional, bisterpyridine-Ru(II) building blocks. Characterization includes ESI- and ESI-TWIM-MS and TEM, along with 1D and 2D (1) H NMR spectroscopy., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2014
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39. Dendron-functionalized bis(terpyridine)-iron(II) or -cadmium(II) metallomacrocycles: synthesis, traveling-wave ion-mobility mass spectrometry, and photophysical properties.

Author

Wang JL, Li X, Lu X, Chan YT, Moorefield CN, Wesdemiotis C, and Newkome GR

Abstract

The synthesis, purification, structural analysis, and photophysical properties of a series of five-, six-, and seven-sided Fe(II) macrocycles and the corresponding hexameric Cd(II) macrocycle, all prepared by self-assembly of a 120° bis(terpyridine) ligand modified with first- and second-generation 1→3 C-branched dendrons, are reported. All metallomacrocycles were fully characterized by (1)H and (13)C NMR spectroscopy, traveling-wave ion-mobility mass spectrometry (TWIM MS), molecular modeling, UV/Vis absorption spectroscopy, photoluminescence, and cyclic voltammetry. A gradual increase of the collision cross sections of the Fe(II) metallomacrocycles was observed with a successive increase of the number and molecular size of the ligands. The combination of ion-mobility mass spectrometry and NMR techniques unveils structural features that agree well with calculations. Extinction coefficients and emission are significantly modulated by increasing the ring size and changing the metal ion center from Fe(II) to Cd(II) ., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2011
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