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Perturbation of Spin Crossover Behavior by Covalent Post‐Synthetic Modification of a Porous Metal–Organic Framework 下载免费PDF全文
John E. Clements Dr. Jason R. Price Dr. Suzanne M. Neville Prof. Cameron J. Kepert 《Angewandte Chemie (International ed. in English)》2014,53(38):10164-10168
Covalent post‐synthetic modification is a versatile method for gaining high‐level synthetic control over functionality within porous metal–organic frameworks and for generating new materials not accessible through one‐step framework syntheses. Here we apply this topotactic synthetic approach to a porous spin crossover framework and show through detailed comparison of the structures and properties of the as‐synthesised and covalently modified phases that the modification reaction proceeds quantitatively by a thermally activated single‐crystal‐to‐single‐crystal transformation to yield a material with lowered spin‐switching temperature, decreased lattice cooperativity, and altered color. Structure–function relationships to emerge from this comparison show that the approach provides a new route for tuning spin crossover through control over both outer‐sphere and steric interactions. 相似文献
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Dr. Carlos Bartual‐Murgui Dr. Amal Akou Dr. Helena J. Shepherd Dr. Gábor Molnár Prof. Dr. J. Antonio Real Dr. Lionel Salmon Dr. Azzedine Bousseksou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(44):15036-15043
A study of the spin‐crossover (SCO) behavior of the tridimensional porous coordination polymer {Fe(bpac)[Pt(CN)4]} (bpac=bis(4‐pyridyl)acetylene) on adsorption of different mono‐ and polyhalobenzene guest molecules is presented. The resolution of the crystal structure of {Fe(bpac)[Pt(CN)4]} ? G (G=1,2,4‐trichlorobenzene) shows preferential guest sites establishing π???π stacking interactions with the host framework. These host–guest interactions may explain the relationship between the modification of the SCO behavior and both the chemical nature of the guest molecule (electronic factors) and the number of adsorbed molecules (steric factors). 相似文献
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Reversible Guest Binding in a Non‐Porous FeII Coordination Polymer Host Toggles Spin Crossover 下载免费PDF全文
Dr. Anders Lennartson Dr. Peter Southon Dr. Natasha F. Sciortino Prof. Cameron J. Kepert Prof. Cathrine Frandsen Prof. Steen Mørup Dr. Stergios Piligkos Prof. Christine J. McKenzie 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):16066-16072
Formation of either a dimetallic compound or a 1 D coordination polymer of adiponitrile adducts of [Fe(bpte)]2+ (bpte=[1,2‐bis(pyridin‐2‐ylmethyl)thio]ethane) can be controlled by the choice of counteranion. The iron(II) atoms of the bis(adiponitrile)‐bridged dimeric complex [Fe2(bpte)2(μ2‐(NC(CH2)4CN)2](SbF6)4 ( 2 ) are low spin at room temperature, as are those in the polymeric adiponitrile‐linked acetone solvate polymer {[Fe(bpte)(μ2‐NC(CH2)4CN)](BPh4)2 ? Me2CO} ( 3? Me2CO). On heating 3? Me2CO to 80 °C, the acetone is abruptly removed with an accompanying purple to dull lavender colour change corresponding to a conversion to a high‐spin compound. Cooling reveals that the desolvate 3 shows hysteretic and abrupt spin crossover (SCO) S=0?S=2 behaviour centred at 205 K. Non‐porous 3 can reversibly absorb one equivalent of acetone per iron centre to regenerate the same crystalline phase of 3? Me2CO concurrently reinstating a low‐spin state. 相似文献
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Nanoporosity,Inclusion Chemistry,and Spin Crossover in Orthogonally Interlocked Two‐Dimensional Metal–Organic Frameworks 下载免费PDF全文
Tania Romero‐Morcillo Dr. Noelia De la Pinta Dr. Lorena M. Callejo Lucía Piñeiro‐López Prof. Dr. M. Carmen Muñoz Prof. Dr. Gotzon Madariaga Prof. Dr. Sacramento Ferrer Prof.Dr. Tomasz Breczewski Prof. Dr. Roberto Cortés Prof. Dr. José A. Real 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(34):12112-12120
[Fe(tvp)2(NCS)2] ( 1 ) (tvp=trans‐(4,4′‐vinylenedipyridine)) consists of two independent perpendicular stacks of mutually interpenetrated two‐dimensional grids. This uncommon supramolecular conformation defines square‐sectional nanochannels (diagonal≈2.2 nm) in which inclusion molecules are located. The guest‐loaded framework 1@guest displays complete thermal spin‐crossover (SCO) behavior with the characteristic temperature T1/2 dependent on the guest molecule, whereas the guest‐free species 1 is paramagnetic whatever the temperature. For the benzene–guest derivatives, the characteristic SCO temperature T1/2 decreases as the Hammet σp parameter increases. In general, the 1@guest series shows large entropy variations associated with the SCO and conformational changes of the interpenetrated grids that leads to a crystallographic‐phase transition when the guest is benzonitrile or acetonitrile/H2O. 相似文献
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Encapsulation of a CrIII Single‐Ion Magnet within an FeII Spin‐Crossover Supramolecular Host 下载免费PDF全文
Dr. Mohanad Darawsheh Dr. Leoní A. Barrios Dr. Olivier Roubeau Dr. Simon J. Teat Dr. Guillem Aromí 《Angewandte Chemie (International ed. in English)》2018,57(41):13509-13513
Single functional molecules are regarded as future components of nanoscale spintronic devices. Supramolecular coordination chemistry provides unlimited resources to implement multiple functions to individual molecules. A novel coordination [Fe2] helicate exhibiting spin‐crossover is demonstrated to be ideally suited to encapsulate a [Cr(ox)3]3? complex anion (ox=oxalate), unveiling for the first‐time single ion slow relaxation of the magnetization for this metal. A possibility of tuning the dynamics of this relaxation as well as the performance of the CrIII center as qubit arises from the observation that metastable high spin FeII centers from the host can be generated by irradiation with green light at low temperature. 相似文献
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Masaaki Ohba Dr. Ko Yoneda Gloria Agustí M. Carmen Muñoz Prof. Dr. Ana B. Gaspar Dr. José A. Real Prof. Dr. Mikio Yamasaki Dr. Hideo Ando Yoshihide Nakao Dr. Shigeyoshi Sakaki Prof. Dr. Susumu Kitagawa Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(26):4767-4771
The ins and outs of spin : Using the microporous coordination polymer {Fe(pz)[Pt(CN)4]} ( 1 , pz=pyrazine), incorporating spin‐crossover subunits, two‐directional magnetic chemo‐switching is achieved at room temperature. In situ magnetic measurements following guest vapor injection show that most guest molecules transform 1 from the low‐spin (LS) state to the high‐spin (HS) state, whereas CS2 uniquely causes the reverse HS‐to‐LS transition.
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Jarrod J. M. Amoore Dr. Suzanne M. Neville Dr. Boujemaa Moubaraki Dr. Simon S. Iremonger Dr. Keith S. Murray Prof. Jean‐François Létard Dr. Cameron J. Kepert Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(6):1973-1982
We previously reported the dinuclear material [FeII2(ddpp)2(NCS)4] ? 4 CH2Cl2 ( 1? 4 CH2Cl2; ddpp=2,5‐di(2′,2′′‐dipyridylamino)pyridine) and its partially desolvated analogue ( 1? CH2Cl2), which undergo two‐ and one‐step spin‐crossover (SCO) transitions, respectively. Here, we manipulate the type and degree of solvation in this system and find that either a one‐ or two‐step spin transition can be specifically targeted. The chloroform clathrate 1? 4 CHCl3 undergoes a relatively abrupt one‐step SCO, in which the two equivalent FeII sites within the dinuclear molecule crossover simultaneously. Partial desolvation of 1? 4 CHCl3 to form 1? 3 CHCl3 and 1? CHCl3 occurs through single‐crystal‐to‐single‐crystal processes (monoclinic C2/c to P21/n to P21/n) in which the two equivalent FeII sites become inequivalent sites within the dinuclear molecule of each phase. Both 1? 3 CHCl3 and 1? CHCl3 undergo one‐step spin transitions, with the former having a significantly higher SCO temperature than 1? 4 CHCl3 and the latter, and each has a broader SCO transition than 1? 4 CHCl3, attributable to the overlap of two SCO steps in each case. Further magnetic manipulation can be carried out on these materials through reversibly resolvating the partially desolvated material with chloroform to produce the original one‐step SCO, or with dichloromethane to produce a two‐step SCO reminiscent of that seen for 1? 4 CH2Cl2. Furthermore, we investigate the light‐induced excited spin state trapping (LIESST) effect on 1? 4 CH2Cl2 and 1? CH2Cl2 and observe partial LIESST activity for the former and no activity for the latter. 相似文献
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Tuning the Spin‐Crossover Behaviour of a Hydrogen‐Accepting Porous Coordination Polymer by Hydrogen‐Donating Guests 下载免费PDF全文
Jin‐Yan Li Yan‐Cong Chen Ze‐Min Zhang Wei Liu Dr. Zhao‐Ping Ni Prof. Ming‐Liang Tong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(4):1645-1651
A Hoffman‐like coordination polymer with appreciable porosity and uncoordinated pyridyl groups, namely, [Fe(2,5‐bpp){Au(CN)2}2] ? x Solv (2,5‐bpp=2,5‐bis(pyrid‐4‐yl)pyridine; Solv=solvent), was synthesised and characterised. A series of fascinating spin‐crossover behaviours with abrupt, stepwise and hysteretic features were obtained by exchange with a range of protic solvents (ethanol, n‐propanol, isopropyl alcohol, sec‐butanol and isobutanol). Guest–host hydrogen‐bonding interactions involving the H‐accepting site of the framework are primarily responsible for the pronounced cooperativity of these spin‐crossover behaviours. Meanwhile, the tunable critical temperatures over a range of about 130 K are presumably attributable to a certain degree of competition between internal pressure and local electronic influences of solvents. 相似文献
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A Perylene‐Based Microporous Coordination Polymer Interacts Selectively with Electron‐Poor Aromatics 下载免费PDF全文
Dr. Ly D. Tran Jialiu Ma Dr. Antek G. Wong‐Foy Prof. Adam J. Matzger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(16):5509-5513
The design, synthesis, and properties of the new microporous coordination polymer UMCM‐310 are described. The unique electronic character of the perylene‐based linker enables selective interaction with electron‐poor aromatics leading to efficient separation of nitroaromatics. UMCM‐310 possesses high surface area and large pore size and thus permits the separation of large organic molecules based on adsorption rather than size exclusion. 相似文献
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Exchange of Coordinated Solvent During Crystallization of a Metal–Organic Framework Observed by In Situ High‐Energy X‐ray Diffraction 下载免费PDF全文
Dr. Yue Wu Matthew I. Breeze Dr. Guy J. Clarkson Dr. Franck Millange Prof. Dermot O'Hare Prof. Richard I. Walton 《Angewandte Chemie (International ed. in English)》2016,55(16):4992-4996
Using time‐resolved monochromatic high energy X‐ray diffraction, we present an in situ study of the solvothermal crystallisation of a new MOF [Yb2(BDC)3(DMF)2]?H2O (BDC=benzene‐1,4‐dicarboxylate and DMF=N,N‐dimethylformamide) under solvothermal conditions, from mixed water/DMF solvent. Analysis of high resolution powder patterns obtained reveals an evolution of lattice parameters and electron density during the crystallisation process and Rietveld analysis shows that this is due to a gradual topochemical replacement of coordinated solvent molecules. The water initially coordinated to Yb3+ is replaced by DMF as the reaction progresses. 相似文献
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Zu‐Jin Lin Dr. Tian‐Fu Liu Dr. Yuan‐Biao Huang Dr. Jian Lü Prof. Rong Cao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(25):7896-7902
Two anionic metal–organic frameworks were successfully prepared based on pre‐designed flexible multicarboxylate ligands and indium cations. Owing to the flexibility of the bridging organic linkers, which could not themselves sustain the frameworks, both of the frameworks showed thermal instability and shrinkage after removal of guest solvent molecules. Inspired by bamboo, we used a guest‐dependent approach to tune the permanent porosity of the MOFs. In this approach, several tetraalkyammonium cations of different sizes were introduced into the channels by cation exchange to act as partitions and to support the main frameworks. This approach significantly enhanced the stability of the framework and its permanent porosity. Moreover, the gas‐adsorption properties (such as gate sorption, hysteresis, and selectivity) of the MOFs were also modulated by the judicious choice of guest cations. 相似文献
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Unraveling Inter‐ and Intrachain Electronics in Polythiophene Assemblies Mediated by Coordination Nanospaces 下载免费PDF全文
Michael W. A. MacLean Takashi Kitao Dr. Takeo Suga Prof. Dr. Motohiro Mizuno Prof. Dr. Shu Seki Dr. Takashi Uemura Prof. Susumu Kitagawa 《Angewandte Chemie (International ed. in English)》2016,55(2):708-713
Strong interchain interactions render unsubstituted polythiophene un‐fusible, non‐melting, and insoluble. Therefore, control of the packing structure, which has a profound effect on the optical and electronic properties of the polymer, has never been achieved. Unsubstituted polythiophene was prepared in the one‐dimensional channels of [La(1,3,5‐benzenetrisbenzoate)]n, where polymer chains form unprecedented assembly structures mediated by the host framework. It is noteworthy that the emission and carrier transport properties were drastically changed by varying the number of chains within a particular assembly. The response of the composite to additional guests is also examined as a method to use the composites as low‐concentration sensors. Our findings show that the encapsulation of polymer chains in host materials is a facile method for understanding the intrinsic properties of conjugated polymers, along with controlling and enhancing their functions. 相似文献
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Masaaki Ohba Ko Yoneda Gloria Agustí M.Carmen Muoz AnaB. Gaspar JosA. Real Mikio Yamasaki Hideo Ando Yoshihide Nakao Shigeyoshi Sakaki Susumu Kitagawa 《Angewandte Chemie (International ed. in English)》2009,48(26):4652-4652
Bidirectional chemo‐switching of magnetism occurs in a microporous coordination polymer containing spin‐crossover subunits, as described by M. Ohba, J. A. Real, S. Kitagawa, and co‐workers in their Communication on page 4767 ff. In situ magnetic measurements reveal that most guest molecules transform the framework spin state from diamagnetic low spin (red) to paramagnetic high spin (yellow), whereas the guest CS2 stabilizes the low‐spin state. These induced spin states are retained as a memory effect after the release of the guest.
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Spatial,Hysteretic, and Adaptive Host–Guest Chemistry in a Metal–Organic Framework with Open Watson–Crick Sites 下载免费PDF全文
Xiao‐Rong Lin Wei Chen Prof. Guang‐Hui Chen Prof. Xiao‐Chun Huang Prof. Dan Li 《Angewandte Chemie (International ed. in English)》2015,54(36):10454-10459
Biological and artificial molecules and assemblies capable of supramolecular recognition, especially those with nucleobase pairing, usually rely on autonomous or collective binding to function. Advanced site‐specific recognition takes advantage of cooperative spatial effects, as in local folding in protein–DNA binding. Herein, we report a new nucleobase‐tagged metal–organic framework (MOF), namely ZnBTCA (BTC=benzene‐1,3,5‐tricarboxyl, A=adenine), in which the exposed Watson–Crick faces of adenine residues are immobilized periodically on the interior crystalline surface. Systematic control experiments demonstrated the cooperation of the open Watson–Crick sites and spatial effects within the nanopores, and thermodynamic and kinetic studies revealed a hysteretic host–guest interaction attributed to mild chemisorption. We further exploited this behavior for adenine–thymine binding within the constrained pores, and a globally adaptive response of the MOF host was observed. 相似文献
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Rui Yang Lei Li Ying Xiong Dr. Jian‐Rong Li Prof. Dr. Hong‐Cai Zhou Prof. Dr. Cheng‐Yong Su 《化学:亚洲杂志》2010,5(11):2358-2368
Assembly of copper(I) halide with a new tripodal ligand, benzene‐1,3,5‐triyl triisonicotinate (BTTP4), afforded two porous metal–organic frameworks, [Cu2I2(BTTP4)]?2 CH3CN ( 1? 2 CH3CN) and [CuBr(BTTP4)]?(CH3CN ? CHCl3 ? H2O) ( 2? solvents), which have been characterized by IR spectroscopy, thermogravimetry (TG), single‐crystal, and powder X‐ray diffraction (PXRD) methods. Compound 1.CH3CN is a polycatenated 3D framework that consists of 2D (6,3) networks through inclined catenation, whereas 2 is a doubly interpenetrated 3D framework possessing the ThSi2‐type ( ths ) (10,3)‐b topology. Both frameworks contain 1D channels of effective sizes 9×12 and 10×10 Å2, which amounts to 43 and 40 % space volume accessible for solvent molecules, respectively. The TG and variable‐temperature PXRD studies indicated that the frameworks can be completely evacuated while retaining the permanent porosity, which was further verified by measurement of the desolvated complex [Cu2I2(BTTP4)] ( 1′ ). The subsequent guest‐exchange study on the solvent‐free framework revealed that various solvent molecules can be adsorbed through a single‐crystal‐to‐single‐crystal manner, thus giving rise to the guest‐captured structures [Cu2I2(BTTP4)]?C6H6 ( 1.benzene ), [Cu2I2(BTTP4)]?2 C7H8 ( 1.2toluene ), and [Cu2I2(BTTP4)]?2 C8H10 ( 1.2ethyl benzene ). The gas‐adsorption investigation disclosed that two kinds of frameworks exhibited comparable CO2 storage capacity (86–111 mL g?1 at 1 atm) but nearly none for N2 and H2, thereby implying its separation ability of CO2 over N2 and H2. The vapor‐adsorption study revealed the preferential inclusion of aromatic guests over nonaromatic solvents by the empty framework, which is indicative of selectivity toward benzene over cyclohexane. 相似文献