Three point-like massive particles/atoms are connected with three springs forming an equilateral triangle replicating a prototype triatomic molecule. The triangle is inscribed within a stationary frame via three addit...Three point-like massive particles/atoms are connected with three springs forming an equilateral triangle replicating a prototype triatomic molecule. The triangle is inscribed within a stationary frame via three additional springs confining the vibrations of the molecule to a 2D space. It is the objective of this research flavored investigation to seek the normal vibrational modes for this three-body six-spring structure. The entire analysis including symbolic, numeric, and graphics is carried out by adapting a suitable Computer Algebra System (CAS), Mathematica. For a comprehensive understanding, the frequency of the normal mode is used for a visual animation;an actual mechanical replica of the “molecule” for the scenario on hand is fabricated.展开更多
It is recognized that the interstellar methanol-107GHz masers and OH-4.765 GHz masers towards Class II sources are associated with each other and coexist towards ultracompact HII regions. Therefore we suggest a new pu...It is recognized that the interstellar methanol-107GHz masers and OH-4.765 GHz masers towards Class II sources are associated with each other and coexist towards ultracompact HII regions. Therefore we suggest a new pumping mechanism - methanol masers without population inversion. It can explain the formation of 107GHz methanol masers, with the 4.765 GHz OH masers acting as a driving coherent microwave field. It is argued that this mechanism is compatible with the astronomical conditions.展开更多
Mechanically interlocked polymers(MIPs)are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and tran...Mechanically interlocked polymers(MIPs)are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and translational mechanical movements at the molecular level.However,the investigations on their mechanical properties are lagging far behind their structural fabrication,especially for linear polyrotaxanes in bulk.Herein,we report stretchable poly[2]rotaxane elastomers(PREs)which integrate numerous mechanical bonds in the polymeric backbone to boost macroscopic mechanical properties.Specifically,we have synthesized a hydroxyfunctionalized[2]rotaxane that subsequently participates in the condensation polymerization with diisocyanate to form PREs.Benefitting from the peculiar structural and dynamic characteristics of the poly[2]rotaxane,the representative PRE exhibits favorable mechanical performance in terms of stretchability(∼1200%),Young’s modulus(24.6 MPa),and toughness(49.5 MJ/m^(3)).Moreover,we present our poly[2]rotaxanes as model systems to understand the relationship between mechanical bonds and macroscopic mechanical properties.It is concluded that the mechanical properties of our PREs are mainly determined by the unique topological architectures which possess a consecutive energy dissipation pathway including the dissociation of host−guest interaction and consequential sliding motion of the wheel along the axle in the[2]rotaxane motif.展开更多
Aiming at the construction of novel rotaxanes with desired luminescent properties for practical applications, recently the rapid development of rotaxanes decorated with aggregation-induced emission(AIE) luminogens(i.e...Aiming at the construction of novel rotaxanes with desired luminescent properties for practical applications, recently the rapid development of rotaxanes decorated with aggregation-induced emission(AIE) luminogens(i.e., AIEgens) has been witnessed. The combination of AIEgens and rotaxanes leads to the successful construction of a novel type of luminescent rotaxanes with many attractive features. In particular, the unique controllable dynamic feature of rotaxanes endows the resultant AIEgen-based rotaxanes precisely tunable emissions under external stimuli, leading to the construction of a novel type of smart luminescent materials. In this minireview, the recent progress of AIEgen-based rotaxanes has been summarized, with an emphasis on the design strategy and potential applications.展开更多
The concept of“robust dynamics”describes the incorporation of mechanically interlocked molecules(MIMs)into metal-organic framework(MOF)materials such that large amplitude motions(e.g.,rotation or translation of a ma...The concept of“robust dynamics”describes the incorporation of mechanically interlocked molecules(MIMs)into metal-organic framework(MOF)materials such that large amplitude motions(e.g.,rotation or translation of a macrocycle)can occur inside the free volume pore of the MOF.To aid in the preparation of such materials,reticular synthesis was used herein to design rigid molecular building blocks with predetermined ordered structures starting from the well-known MOF NOTT-101.New linkers were synthesized that have a T-shape,based on a triphenylene tetra-carboxylate strut,and their incorporation into Cu(II)-based MOFs was investigated.The single-crystal structures of three new MOFs,UWCM-12(fof),β-UWCM-13(loz),UWCM-14(lil),with naked T-shaped linkers were determined;β-UWCM-13 is the first reported example of the loz topology.A fourth MOF,UWDM-14(lil)is analogous to UWCM-14(lil)but contains a[2]rotaxane linker.Variable-temperature,^(2)H solid-state NMR was used to probe the dynamics of a 24-membered macrocycle threaded onto the MOF skeleton.展开更多
The properties of coordination complexes are dictated by both the metals and the ligands.The use of molecular receptors as second-sphere ligands enables significant modulation of the chemical and physical properties o...The properties of coordination complexes are dictated by both the metals and the ligands.The use of molecular receptors as second-sphere ligands enables significant modulation of the chemical and physical properties of coordination complexes.In this minireview,we highlight recent advances in functional systems based on molecular receptors as second-sphere coordination ligands,as applied in molecular recognition,synthesis of mechanically interlocked molecules,separation of metals,catalysis,and biomolecular chemistry.These functional systems demonstrate that second-sphere coordination is an emerging and very promising strategy for addressing societal challenges in health,energy,and the environment.展开更多
文摘Three point-like massive particles/atoms are connected with three springs forming an equilateral triangle replicating a prototype triatomic molecule. The triangle is inscribed within a stationary frame via three additional springs confining the vibrations of the molecule to a 2D space. It is the objective of this research flavored investigation to seek the normal vibrational modes for this three-body six-spring structure. The entire analysis including symbolic, numeric, and graphics is carried out by adapting a suitable Computer Algebra System (CAS), Mathematica. For a comprehensive understanding, the frequency of the normal mode is used for a visual animation;an actual mechanical replica of the “molecule” for the scenario on hand is fabricated.
基金NationalNatural Science Foundation of China (Nos. l9873003 and 20073005).
文摘It is recognized that the interstellar methanol-107GHz masers and OH-4.765 GHz masers towards Class II sources are associated with each other and coexist towards ultracompact HII regions. Therefore we suggest a new pumping mechanism - methanol masers without population inversion. It can explain the formation of 107GHz methanol masers, with the 4.765 GHz OH masers acting as a driving coherent microwave field. It is argued that this mechanism is compatible with the astronomical conditions.
基金supported by grants from the National Natural Science Foundation of China(22122105,22071152,and 21901161)Natural Science Foundation of Shanghai(20ZR1429200 and 22YF1400800)supported by the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(SN-ZJU-SIAS-006).
文摘Mechanically interlocked polymers(MIPs)are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and translational mechanical movements at the molecular level.However,the investigations on their mechanical properties are lagging far behind their structural fabrication,especially for linear polyrotaxanes in bulk.Herein,we report stretchable poly[2]rotaxane elastomers(PREs)which integrate numerous mechanical bonds in the polymeric backbone to boost macroscopic mechanical properties.Specifically,we have synthesized a hydroxyfunctionalized[2]rotaxane that subsequently participates in the condensation polymerization with diisocyanate to form PREs.Benefitting from the peculiar structural and dynamic characteristics of the poly[2]rotaxane,the representative PRE exhibits favorable mechanical performance in terms of stretchability(∼1200%),Young’s modulus(24.6 MPa),and toughness(49.5 MJ/m^(3)).Moreover,we present our poly[2]rotaxanes as model systems to understand the relationship between mechanical bonds and macroscopic mechanical properties.It is concluded that the mechanical properties of our PREs are mainly determined by the unique topological architectures which possess a consecutive energy dissipation pathway including the dissociation of host−guest interaction and consequential sliding motion of the wheel along the axle in the[2]rotaxane motif.
基金financial support sponsored by the National Natural Science Foundation of China(No.22001073)the Fundamental Research Funds for the Central Universitiesthe Research Fund Program of Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices(No.2020-GDKLFSHMD-07)。
文摘Aiming at the construction of novel rotaxanes with desired luminescent properties for practical applications, recently the rapid development of rotaxanes decorated with aggregation-induced emission(AIE) luminogens(i.e., AIEgens) has been witnessed. The combination of AIEgens and rotaxanes leads to the successful construction of a novel type of luminescent rotaxanes with many attractive features. In particular, the unique controllable dynamic feature of rotaxanes endows the resultant AIEgen-based rotaxanes precisely tunable emissions under external stimuli, leading to the construction of a novel type of smart luminescent materials. In this minireview, the recent progress of AIEgen-based rotaxanes has been summarized, with an emphasis on the design strategy and potential applications.
基金S.J.L.acknowledges the Natural Sciences and Engineering Research Council of Canada for support of a Discovery Grant(101694)and a Canada Research Chair.R.W.S.is also grateful for support from NSERC,the Canadian Foundation for Innovation,the Ontario Innovation Trust,the University of Windsor for the development and maintenance of the SSNMR centre,and for funding from the Florida State University and the National High Magnetic Field Laboratory(NHMFL),which is funded by the National Science Foundation Cooperative Agreement(DM R-1644779)and by the State of Florida.The authors acknowledge M.Revington for technical assistance with solution NM Rspectroscopy and J.Auld for technical assistance with high resolution mass spectrometry.
文摘The concept of“robust dynamics”describes the incorporation of mechanically interlocked molecules(MIMs)into metal-organic framework(MOF)materials such that large amplitude motions(e.g.,rotation or translation of a macrocycle)can occur inside the free volume pore of the MOF.To aid in the preparation of such materials,reticular synthesis was used herein to design rigid molecular building blocks with predetermined ordered structures starting from the well-known MOF NOTT-101.New linkers were synthesized that have a T-shape,based on a triphenylene tetra-carboxylate strut,and their incorporation into Cu(II)-based MOFs was investigated.The single-crystal structures of three new MOFs,UWCM-12(fof),β-UWCM-13(loz),UWCM-14(lil),with naked T-shaped linkers were determined;β-UWCM-13 is the first reported example of the loz topology.A fourth MOF,UWDM-14(lil)is analogous to UWCM-14(lil)but contains a[2]rotaxane linker.Variable-temperature,^(2)H solid-state NMR was used to probe the dynamics of a 24-membered macrocycle threaded onto the MOF skeleton.
基金The authors thank Northwestern University(NU)for their support of this work,which was also funded by the Center for Sustainable Separation of Metals(CSSM)and part of a National Science Foundation(NSF)Center for Chemical Innovation(CCI):grant number CHE1925708.
文摘The properties of coordination complexes are dictated by both the metals and the ligands.The use of molecular receptors as second-sphere ligands enables significant modulation of the chemical and physical properties of coordination complexes.In this minireview,we highlight recent advances in functional systems based on molecular receptors as second-sphere coordination ligands,as applied in molecular recognition,synthesis of mechanically interlocked molecules,separation of metals,catalysis,and biomolecular chemistry.These functional systems demonstrate that second-sphere coordination is an emerging and very promising strategy for addressing societal challenges in health,energy,and the environment.