首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Reaction of a tris-bidentate ligand L(1) (which can cap one triangular face of a metal polyhedron), a bis-bidentate ligand L(2) (which can span one edge of a metal polyhedron), and a range of M(2+) ions (M = Co, Cu, Cd), which all have a preference for six coordination geometry, results in assembly of the mixed-ligand polyhedral cages [M12(mu(3)-L(1))4(mu-L(2))12](24+). When the components are combined in the correct proportions [M(2+):L(1):L(2) = 3:1:3] in MeNO2, this is the sole product. The array of 12 M(2+) cations has a cuboctahedral geometry, containing six square and eight triangular faces around a substantial central cavity; four of the eight M3 triangular faces (every alternate one) are capped by a ligand L(1), with the remaining four M3 faces having a bridging ligand L(2) along each edge in a cyclic helical array. Thus, four homochiral triangular {M3(L(2))3}(6+) helical units are connected by four additional L(1) ligands to give the mixed-ligand cuboctahedral array, a topology which could not be formed in any homoleptic complex of this type but requires the cooperation of two different types of ligand. The complex [Cd3(L(2))3(ClO4)4(MeCN)2(H2O)2](ClO4)2, a trinuclear triple helicate in which two sites at each Cd(II) are occupied by monodentate ligands (solvent or counterions), was also characterized and constitutes an incomplete fragment of the dodecanuclear cage comprising one triangular {M3(L(2))3}(6+) face which has not yet reacted with the ligands L(1). (1)H NMR and electrospray mass spectrometric studies show that the dodecanuclear cages remain intact in solution; the NMR studies show that the Cd 12 cage has four-fold (D2) symmetry, such that there are three independent Cd(II) environments, as confirmed by a (113)Cd NMR spectrum. These mixed-ligand cuboctahedral complexes reveal the potential of using combinations of face-capping and edge-bridging ligands to extend the range of accessible topologies of polyhedral coordination cages.  相似文献   

2.
A procedure for the synthesis of three‐dimensional hexakisimidazolium cage compounds has been developed. The reaction of the trigonal trisimidazolium salts H3L(PF6)3, decorated with three N‐olefinic pendants, and silver oxide yielded trinuclear trisilver(I) hexacarbene molecular cylinders of the type [Ag3L2]3+ with the olefinic pendants from the two different tricarbene ligands arranged in three pairs. Subsequent UV irradiation gave three cyclobutane links between the two tris‐NHC ligands in three [2+2] cycloaddition reactions, thereby generating a three‐dimensional hexakis‐NHC ligand. Removal of the metal ions resulted in the formation of three‐dimensional hexakisimidazolium cages with a large internal cavity.  相似文献   

3.
We report herein a detailed study of the use of porphyrins fused to imidazolium salts as precursors of N‐heterocyclic carbene ligands 1 M . Rhodium(I) complexes 6 M – 9 M were prepared by using 1 M ligands with different metal cations in the inner core of the porphyrin (M=NiII, ZnII, MnIII, AlIII, 2H). The electronic properties of the corresponding N‐heterocyclic carbene ligands were investigated by monitoring the spectroscopic changes occurring in the cod and CO ancillary ligands of [( 1 M )Rh(cod)Cl] and [( 1 M )Rh(CO)2Cl] complexes (cod=1,5‐cyclooctadiene). Porphyrin–NHC ligands 1 M with a trivalent metal cation such as MnIII and AlIII are overall poorer electron donors than porphyrin–NHC ligands with no metal cation or incorporating a divalent metal cation such as NiII and ZnII. Imidazolium salts 3 M (M=Ni, Zn, Mn, 2H) have also been used as NHC precursors to catalyze the ring‐opening polymerization of L ‐lactide. The results clearly show that the inner metal of the porphyrin has an important effect on the reactivity of the outer carbene.  相似文献   

4.
The synthesis and structural characterisation of a series of cobalt and nickel cages are reported. Eight of these structures contain a [M10(mu3-OH)6(eta2, mu3-xhp),(eta2, mu2-O2CR)6]2+ core (where M = Co or Ni; xhp = 6-chloro- or 6-methyl-2-pyridonate: R = Me, Ph, CHMe2, CH2Cl, CHPh2 or CMe3), where the ten metal atoms describe a centred-tricapped-trigonal prism (ttp). The cage contains six hydroxide ligands around the central metal, and the exterior is coated with pyridonate and carboxylate ligands. For four of the cages additional metal centres are found attached to the upper and/or lower triangular faces of the trigonal prism, generating dodeca- and undecanuclear cages. Three further cages are reported that contain a metal core based on an incomplete centred-tetraicosahedron. These cages involve trimethylacetate as a ligand in company with either 6-methyl-2-pyridonate or 6-chloro-2-pyridonate. Comparison of these latter structures with the trigonal prisms reveal that they can be described as a pentacapped-trigonal prism missing one edge. Magnetic studies of three of the nickel cages with trigonal prismatic cores show spin ground states of S = 8, 4 and 2 for Ni12, Ni11 and Ni10 cages, respectively.  相似文献   

5.
The bis-bidentate bridging ligand L {α,α'-bis[3-(2-pyridyl)pyrazol-1-yl]-1,4-dimethylbenzene}, which contains two chelating pyrazolyl-pyridine units connected to a 1,4-phenylene spacer via flexible methylene units, reacts with transition metal dications to form a range of polyhedral coordination cages based on a 2M:3 L ratio in which a metal ion occupies each vertex of a polyhedron, a bridging ligand lies along every edge, and all metal ions are octahedrally coordinated. Whereas the Ni(II) complex [Ni(8)L(12)](BF(4))(12)(SiF(6))(2) is an octanuclear cubic cage of a type we have seen before, the Cu(II), Zn(II), and Cd(II) complexes form new structural types. [Cu(6)L(9)](BF(4))(12) is an unusual example of a trigonal prismatic cage, and both Zn(II) and Cd(II) form unprecedented hexadecanuclear cages [M(16)L(24)]X(32)(X = ClO(4) or BF(4)) whose core is a skewed tetracapped truncated tetrahedron. Both Cu(6)L(9) and M(16)L(24) cages are based on a cyclic helical M(3)L(3) subunit that can be considered as a triangular "panel", with the cages being constructed by interconnection of these (homochiral) panels with additional bridging ligands in different ways. Whereas [Cu(6)L(9)](BF(4))(12) is stable in solution (by electrospray mass spectrometry, ES-MS) and is rapidly formed by combination of Cu(BF(4))(2) and L in the correct proportions in solution, the hexadecanuclear cage [Cd(16)L(24)](BF(4))(32) formed on crystallization slowly rearranges in solution over a period of several weeks to the trigonal prism [Cd(6)L(9)](BF(4))(12), which was unequivocally identified on the basis of its (1)H NMR spectrum. Similarly, combination of Cd(BF(4))(2) and L in a 2:3 ratio generates a mixture whose main component is the trigonal prism [Cd(6)L(9)](BF(4))(12). Thus the hexanuclear trigonal prism is the thermodynamic product arising from combination of Cd(II) and L in a 2:3 ratio in solution, and arises from both assembly of metal and ligand (minutes) and rearrangement of the Cd(16) cage (weeks); the large cage [Cd(16)L(24)](BF(4))(32) is present as a minor component of a mixture of species in solution but crystallizes preferentially.  相似文献   

6.
Two new bis-bidentate bridging ligands have been prepared, L (naph) and L (anth), which contain two chelating pyrazolyl-pyridine units connected to an aromatic spacer (naphthalene-1,5-diyl and anthracene-9,10-diyl respectively) via methylene connectors. Each of these reacts with transition metal dications having a preference for octahedral coordination geometry to afford {M 8L 12} (16+) cages (for L (anth), M = Cu, Zn; for L (naph), M = Co, Ni, Cd) which have an approximately cubic arrangement of metal ions with a bridging ligand spanning each of the twelve edges, and a large central cavity containing a mixture of anions and/or solvent molecules. The cages based on L (anth) have two cyclic helical {M 4L 4} faces, of opposite chirality, connected by four additional L (anth) ligands as "pillars"; all metal centers have a meridional tris-chelate configuration. In contrast the cages based on L (naph) have (noncrystallographic) S 6 symmetry, with a diagonally opposite pair of corners having a facial tris-chelate configuration with the other six being meridional. An additional significant difference between the two types of structure is that the cubes containing L (anth) do not show significant interligand aromatic stacking interactions. However, in the cages based on L (naph), there are six five-membered stacks of aromatic ligand fragments around the periphery, each based on an alternating array of electron-rich (naphthyl) and electron-deficient (pyrazolyl-pyridine, coordinated to M (2+)) aromatic units. A consequence of this is that the cages {M 8(L (naph)) 12} (16+) retain their structural integrity in polar solvents, in contrast to the cages {M 8(L (anth)) 12} (16+) which dissociate in polar solvents. Consequently, the cages {M 8(L (naph)) 12} (16+) give NMR spectra in agreement with the symmetry observed in the solid state, and their fluorescence spectra (for M = Cd) display (in addition to the normal naphthalene-based pi-pi* fluorescence) a lower-energy exciplex-like emission feature associated with a naphthyl --> pyrazolyl-pyridine charge-transfer excited state arising from the pi-stacking between ligands around the cage periphery.  相似文献   

7.
Three five-component architectures, compounds 3, 4, and 5 were obtained by self-assembly of tripodal 1,3,5-tris(imidazol-1-ylmethyl )-2,4,6-trimethylbenzene (6) and 1,3,5-tris(benzimidazol-2-ylmethyl)benzene (7) ligands with silver(I) salts. The structures of these novel complexes have been determined by X-ray crystallography. The results of structural analysis indicate that these frameworks have same M3L2 components, but different structures. Compounds 3 and 4 are both M3L2 type cage-like complexes, while the 5 is an open trinuclear complex. The complex 3 is a cylindrical cage with simultaneous inclusion of a perchlorate anion inside of the cage as a guest molecule. Such guests can be exchanged for other anions through the open edge of the cage as evidenced by crystal structure of 4. The results demonstrate that the molecular M3L2 type cage can act as a host for anions and provide a nice example of supramolecular architectures with interesting properties and possible applications.  相似文献   

8.
While many metal oxalate salts are known, few are known to form zeolite‐type topologies. The construction of zeolite types, especially those with low framework density such as RHO, from linear ligands is generally perceived as less likely, because the 180° metal‐ligand‐metal geometry deviates too much from the established strategy of using ligands with bent coordination geometry (centered around 145°) to mimic the geometry in natural zeolites. We show the general feasibility of using linear ligands for the synthesis of zeolite types by reporting a family of indium oxalate salts with multiple zeolite topologies, including RHO, GIS, and ABW. Of particular interest is the synthesis of a zeolite RHO net with double 8‐rings and large alpha cages, which are highly desirable zeolite features.  相似文献   

9.
Two new types of coordination cage have been prepared and structurally characterized: [M16(mu-L1)24]X32 are based on a tetra-capped truncated tetrahedral core and have a bridging ligand L1 along each of the 24 edges; [M12(mu-L1)12(mu3-L2)4]X24 are based on a cuboctahedral core which is supported by a combination of face-capping ligands L2 and edge-bridging ligands L1. The difference between the two illustrates how combinations of ligands with different coordination modes can generate coordination cages which are not available using one ligand type on its own.  相似文献   

10.
Hexanuclear coordination cages of the formula [(C5Me4R)M(C7H3NO4)]6 (M = Rh, Ir; R = Me, H) were obtained by stepwise reaction of [(C5Me4R)MCl2]2 with, first, AgOAc and, then, pyridine-3,5-dicarboxylic acid. Crystallographic analyses show that the cages adopt a distorted octahedral geometry with the pyridine-3,5-dicarboxylates functioning as dianionic, bridging ligands, each of which connects three different (C5Me4R)M fragments. The cages act as exoreceptors for the large alkali metal ions K(+) and Cs(+) but show low affinity for Na(+). Crystallographic and NMR spectroscopic analyses indicate that two metal ions can be coordinated to the surface of the cages. The respective binding sites comprise three carbonyl O-atoms from the bridging pyridine-3,5-dicarboxylate ligand.  相似文献   

11.
The two new ligands L(fur) and L(th) consist of two chelating pyrazolyl-pyridine termini connected to furan-2,5-diyl or thiophene-2,5-diyl spacers via methylene groups. Reaction of these with a range of transition metal dications that prefer octahedral coordination affords a series of unusual structures which are all based on a 2M : 3L ratio. [M(8)(L(fur))(12)]X(16) (M = Co, Cu, X = BF(4); and M = Zn, X = ClO(4)) are octanuclear cubes with approximate D(4) symmetry in which two cyclic tetranuclear helicate M(4)L(4) units are connected by four additional 'pillar' ligands. In contrast [Ni(4)(L(fur))(6)](BF(4))(8) is a centrosymmetric molecular square consisting of two dinuclear Ni(2)L(2) units of opposite chirality that are connected by a pair of additional L(fur) ligands such that the four edges of the Ni(4) square are spanned by alternately two and one bridging ligands. [M(4)(L(th))(6)](BF(4))(8) (M = Co, Ni, Cu) are likewise molecular squares with similar structures to [Ni(4)(L(fur))(6)](BF(4))(8) with the significant difference that the two crosslinked double helicate M(2)L(2) units are now homochiral. The Cd(II) complexes both behave quite differently to the first-row metal complexes, with [Cd(L(fur))(BF(4))](BF(4)) being a simple mononuclear complex with a single ligand in which the furan oxygen atom is weakly interacting with the Cd(II) centre. In contrast, in {[Cd(2)(L(th))(3)](BF(4))(4)}(∞), where this quasi-pentadentate coordination mode of the ligand is not possible because thiophene is too poor an electron donor, the ligand reverts to bis-bidentate bridging coordination to afford a one-dimensional chain consisting of an infinite sequence of crosslinked, homochiral, Cd(2)(L(th))(2) double helicate units.  相似文献   

12.
The metal-controlled self-assembly of organometallic molecular cylinders from a series of imidazo[1,5-a]pyridine-based tris-NHC ligands is described in this report. The imidazo[1,5-a]pyridinium salts H3- L (PF6)3 ( L = 4 a – 4 c ) were treated with 1.5 equivalents of Ag2O to yield the trinuclear AgI hexacarbene cages [Ag3( L )2](PF6)3 ( L = 4 a – 4 c ), in which three AgI are sandwiched between the two tricarbene ligands. The silver(I) complexes [Ag3( L )2](PF6)3 underwent a facile transmetalation reaction in the presence of 3 equivalents of [AuCl(tht)] (tht=tetrahydrothiophene) to furnish the trinuclear AuI cylinder-like cages [Au3( L )2](PF6)3 ( L = 4 a – 4 c ) without destruction of the metallosupramolecular structure. The new hexacarbene assemblies feature a large cavity that can easily accommodate a molecule of dimethyl sulfoxide as molecular guest. This is the first study of a unique “host–guest” system containing an organometallic cylinder-like cage derived exclusively from poly-NHC ligands.  相似文献   

13.
A tripodal tris(3-pyridylurea) receptor (L) assembles with metal sulfate salts MSO(4) (M=Mn, Zn) to afford supramolecular cages [SO(4) subset L(2)] that encapsulate the SO(4)(2-) ion via multiple hydrogen bonds in a three-dimensional structure held by second-sphere coordination; (1)H NMR and negative-ion mode ESI-MS spectra reveal significantly strong sulfate binding in solution.  相似文献   

14.
This article describes the developments in coordination self‐assembly based on flexible tripodal ligands with different metal species. Various finite metallocages such as M3L2, M6L8, M6L4, M4L4 and different catenanes based on discrete metallocages constructed from flexible tripodal ligands with suitable metal species are presented here. Many M3L2 metallocages based on ligands L1–L12 and different two‐coordinated metal species have been prepared, in which various Ag(I) salts and other metal species that have been protected by suitable groups, such as Zn(OAc)2, ZnBr2, and PdBr2, have been used as effective acceptors. All of the M6L8‐type metallocages are constructed from ligands L2 or L12–L20 and different four‐coordinated metal species, such as various palladium(II) salts or NiCl2, and have similar topological structures. Only a few discrete M6L4‐type metallocages, based on ligands L21–L24, have been reported, using different strategies such as protecting groups and steric hindrance. All of the M4L4‐type cages have similar topological structures and are constructed from ligands L25–L29 with multiple donor sites. More intriguing interlocking ensembles constructed from discrete metallocages are also described here in detail, namely, three [2]catenanes based on ligands L30–L32 and four polycatenanes based on ligands L33–L34.  相似文献   

15.
Complex [Ag(tpba)N(3)] (1) was obtained by reaction of novel tripodal ligand N,N',N"-tris(pyrid-3-ylmethyl)-1,3,5-benzenetricarboxamide (TPBA) with [Ag(NH(3))(2)]N(3). While the reactions between 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (TITMB) and silver(I) salts with different anions and solvent systems give six complexes: [Ag(3)(titmb)(2)](N(3))(3).CH(3)OH.4 H(2)O (2), [Ag(3)(titmb)(2)](CF(3)SO(3))(2)(OH).5 H(2)O (3), [Ag(3)(titmb)(2)][Ag(NO(3))(3)]NO(3).H(2)O (4), [Ag(3)(titmb)(2)(py)](NO(3))(3).H(2)O (py=pyridine) (5), [Ag(3)(titmb)(2)(py)](ClO(4))(3) (6), and [Ag(3)(titmb)(2)](ClO(4))(3).CHCl(3) (7). The structures of these complexes were determined by X-ray crystallography. The results of structural analysis of complexes 1 and 2, with the same azide anion but different ligands, revealed that 1 is a twofold interpenetrated 3D framework with interlocked cage-like moieties, while 2 is a M(3)L(2) type cage-like complex with a methanol molecule inside the cage. Entirely different structure and topology between 1 and 2 indicates that the nature of organic ligands affected the structures of assemblies greatly. While in the cases of complexes 2-7 with flexible tripodal ligand TITMB, they are all discrete M(3)L(2) type cages. The results indicate that the framework of these complexes is predominated by the nature of the organic ligand and geometric need of the metal ions, but not influenced greatly by the anions and solvents. It is interesting that there is a divalent anion [Ag(NO(3))(3)](2-) inside the cage 4 and an anion of ClO(4)(-) or NO(3)(-) spontaneously encapsulated within the cage of complexes 5, 6 and 7.  相似文献   

16.
《中国化学快报》2021,32(12):3988-3992
We report a facile and tailored method to prepare globally twisted chiral molecular cages through tunable coordination of bis-bipyridine-terminated helicene ligands to a series of transition metals including Fe(II), Co(II), Ni(II) and Zn(II). This system shows an efficient remote transfer of stereogenecity from the helicene core to the bipyridine-metal coordination sites and subsequently the entire cages. While the Fe(II), Co(II) and Ni(II)-derived M2L3 (M for metal and L for ligand) cages exhibit quasi-reversible redox features, the Zn(II) analogues reveal prominent yellow circularly polarized luminescence. Interestingly, with the addition of Na2SO4, the Zn2L3 cages reassemble into sextuple-stranded Zn6L6(SO4)4 cages in which three Zn2L2 units are bound together by four sulfates and further coalesced by offset inter-ligand π-π interactions.  相似文献   

17.
The addition of enantiopure TRISPHAT anions to chiral cationic cages of type [Co(4)(L)(6)(BF(4))](7+) leads to the enantiodifferentiation of the ligands of the racemic salts and, even more effectively, of the achiral tetrafluoroborate anion trapped inside.  相似文献   

18.
Electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) methods were used to study open-chain piperazine-containing ligands (L) and their complexes formed with transition-metal salts. ESI and MALDI measurements were performed with a Fourier transform ion cyclotron resonance (FT-ICR) and a time-of-flight (TOF) mass spectrometer, respectively. Only singly charged complexes, between one ligand and one or several metal ions, were formed in the ESI measurements. Because the net charge was always one, one or several counterions were attached to the complex. Under ESI conditions, the complexes formed between the ligands and metal (Co, Ni, Cu, and Cd) salts were [L + M + X](+), [L + H + M + X(2)](+) and [L + M(2) + X(3)](+) (M = metal ion, X = counterion). In collision induced dissociation reactions the [L + H + M + X(2)](+) complexes easily eliminated one proton and one counterion. Fragmentation pathways were more dependent on the metal ion than the ligand, and elimination of the second counterion occurred with one proton from copper and nickel complexes and with one proton and one hydrogen from cobalt complexes. Differences in the fragmentation of the complexes could be due to electronic configuration of the metal ion. In the MALDI measurements the ratio between the [L + H](+) and [L - H](+) ions varied with the matrix. Fragmentation of the ligands through elimination of 2-methylpyridine end groups occurred with the aromatic matrices containing carboxylic acid and hydroxyl substituents. Ionization of the complexes was not successful with MALDI as the matrix molecules were also attached to the complexes.  相似文献   

19.
The serendipitous discovery of a 3D [Cu(CO(3))(2)(2-)](n) network with the topology of the 4(2)6(4) sodalite net in [Cu(6)(CO(3))(12)(CH(6)N(3))(8)].K(4).8H(2)O paved the way for the deliberate engineering of an extensive series of structurally related guanidinium-templated metal carbonates of composition [M(6)(CO(3))(12)(CH(6)N(3))(8)]Na(3-)[N(CH(3))(4)].xH(2)O, where the divalent metal M in the framework may be Mg, Mn, Fe, Co, Ni, Cu, Zn, or Cd. A closely related crystalline material with a [Ca(CO(3))(2)(2-)](n) sodalite-like framework, but containing K(+) rather than Na(+), of composition [Ca(6)(CO(3))(12)(CH(6)N(3))(8)]K(3)[N(CH(3))(4)].3H(2)O was also isolated. All of these compounds were obtained under the simplest possible conditions from aqueous solution at room temperature, and their structures were determined by single-crystal X-ray diffraction. Pairs of guanidinium cations are associated with the hexagonal windows of the sodalite cages, alkali-metal cations are associated with their square windows, and N(CH(3))(4)(+) ions are located at their centers. Structures fall into two classes depending on the metal, M(II), in the framework. One type, the BC type (Im3m), comprising the compounds for which M(2+) = Ca(2+), Mn(2+), Cu(2+), and Cd(2+), has a body-centered cubic unit cell, while the second type, the FC type (Fd3c), for which M(2+) = Mg(2+), Fe(2+), Co(2+), Ni(2+), and Zn(2+), has a face-centered cubic unit cell with edges on the order of twice those of the BC structural type. The metal M in the BC structures has four close carbonate oxygen donors and four other more distant ones, while M in the FC structures has an octahedral environment consisting of two bidentate chelating carbonate ligands and two cis monodentate carbonate ligands.  相似文献   

20.
The modular engineering of heterometallic nanoporous metal-organic frameworks (MOFs) based on novel tris-chelate metalloligands, prepared using the functionalised β-diketone 1,3-bis(4'-cyanophenyl)-1,3-propanedione (HL), is described. The complexes [M(III)L(3)] (M=Fe(3+), Co(3+)) and [M(II)L(3)](NEt(4)) (M=Mn(2+), Co(2+), Zn(2+), Cd(2+)) have been synthesised and characterised, all of which exhibit a distorted octahedral chiral structure. The presence of six exo-oriented cyano donor groups on each complex makes it a suitable building block for networking through interactions with external metal ions. We have prepared two families of MOFs by reacting the metalloligands [M(III)L(3)] and [M(II)L(3)](-) with many silver salts AgX (X=NO(3)(-), BF(4)(-), PF(6)(-), AsF(6)(-), SbF(6)(-), CF(3)SO(3)(-), tosylate), specifically the [M(III)L(3)Ag(3)]X(3)·Solv and [M(II)L(3)Ag(3)]X(2)·Solv network species. Very interestingly, all of these network species exhibit the same type of 3D structure and crystallise in the same trigonal space group with similar cell parameters, in spite of the different metal ions, ionic charges and X(-) counteranions of the silver salts. We have also succeeded in synthesising trimetallic species such as [Zn(x)Fe(y)L(3)Ag(3)](ClO(4))((2x+3y))·Solv and [Zn(x)Cd(y)L(3)Ag(3)](ClO(4))(2)·Solv (with x+y=1). All of the frameworks can be described as sixfold interpenetrated pcu nets, considering the Ag(+) ions as simple digonal spacers. Each individual net is homochiral, containing only Δ or Λ nodes; the whole array contains three nets of type Δ and three nets of type Λ. Otherwise, taking into account the presence of weak Ag-C σ bonds involving the central carbon atoms of the β-diketonate ligands of adjacent nets, the six interpenetrating pcu networks are joined into a unique non-interpenetrated six-connected frame with the rare acs topology. The networks contain large parallel channels of approximate hexagonal-shaped sections that represent 37-48% of the cell volume and include the anions and many guest solvent molecules. The guest solvent molecules can be reversibly removed by thermal activation with retention of the framework structure, which proved to be stable up to about 270°C, as confirmed by TGA and powder XRD monitoring. The anions could be easily exchanged in single-crystal to single-crystal processes, thereby allowing the insertion of selected anions into the framework channels.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号