核酸碱基桥连配体对金属-生物分子框架配合物(MBioFs)的形貌与吸收性质的影响

合成了一系列金属-生物分子框架配合物,核酸碱基作为连接分子决定了其多样的微观结构及不同的吸收性质。     

Polyrotaxane metal-organic frameworks (PMOFs)

Polyrotaxane metal-organic frameworks (PMOFs), a relatively rare branch of entangled networks, have received significant attention due to their unusual entanglement topologies. The PMOFs we described here are still at an early stage of development. This feature article summarizes the recent developments in structural types of PMOFs from our own group and others. We make some generalizations about the various classes of PMOFs, and develop the definitions and nomenclature of these entanglements, including classification into trivial and nontrivial polyrotaxanes, and limits on what constitutes a (nontrivial) polyrotaxane. Finally, the synthetic strategies toward the design and preparation of new PMOFs are elucidated.     

Metal-peptide frameworks (MPFs): "bioinspired" metal organic frameworks

Chiral metal-organic frameworks (MOFs) have attracted a growing interest for their potential use in energy technologies, asymmetric catalysis, chiral separation, and on a more basic level, the creation of new topologies in inorganic materials. The current paper is the first report on a peptide-based MOF, a metal peptide framework (MPF), constructed from an oligovaline peptide family developed earlier by our group (Mantion, A.; et al. Macromol. Biosci. 2007, 7, 208). We have used a simple oligopeptide, Z-(L-Val)2-L-Glu(OH)-OH, to grow porous copper and calcium MPFs. The MPFs form thanks to the self-assembling properties of the peptide and specific metal-peptide and metal-ammonia interactions. They are stable up to ca. 250 degrees C and have some internal porosity, which makes them a promising prototype for the further development of MPFs.     

Porous interpenetrated zirconium-organic frameworks (PIZOFs): a chemically versatile family of metal-organic frameworks

We present the synthesis and characterization of porous interpenetrated zirconium-organic frameworks (PIZOFs), a new family of metal-organic frameworks obtained from ZrCl(4) and the rodlike dicarboxylic acids HO(2)C[PE-P(R(1),R(2))-EP]CO(2) H that consist of alternating phenylene (P) and ethynylene (E) units. The substituents R(1),R(2) were broadly varied (alkyl, O-alkyl, oligo(ethylene glycol)), including postsynthetically addressable substituents (amino, alkyne, furan). The PIZOF structure is highly tolerant towards the variation of R(1) and R(2). This together with the modular synthesis of the diacids offers a facile tuning of the chemical environment within the pores. The PIZOF structure was solved from single-crystal X-ray diffraction analysis. The PIZOFs are stable under ambient conditions. PIZOF-2, the PIZOF prepared from HO(2)C[PE-P(OMe,OMe)-EP]CO(2)H, served as a prototype to determine thermal stability and porosity. It is stable up to 325 °C in air as determined by using thermogravimetry and powder X-ray diffraction. Argon sorption isotherms on PIZOF-2 revealed a Brunauer-Emmett-Teller (BET) surface area of 1250 m(2) g(-1) and a total pore volume of 0.68 cm(3) g(-1).     

Zr(IV) and Hf(IV) based metal-organic frameworks with reo-topology

Zr and Hf based MOFs with enhanced pore accessibility for large molecules and good hydrothermal stability were obtained using a bent dithienothiophene dicarboxylate and Zr(4+) or Hf(4+) source. A modulator (benzoic acid) facilitates formation of an eight-connecting cluster leading to a new framework which adopts reo topology.     

Preface: Special topic on Metal-organic frameworks (MOFs)

正Metal-organic frameworks,MOFs,are coordination networks with organic ligands and voids.At the fundamental level,MOFs epitomize the beauty of chemical structures and the power of combining organic and inorganic chemistry,two disciplines that are often regarded as disparate.MOFs have recently emerged as an extensive class of crystalline materials with ultrahigh porosity and internal surface     

Three-dimensional open frameworks based on cobalt(II) and nickel(II) m-pyridinecarboxylates

Three-dimensional open frameworks [Co2(nicotinate)4(mu-H2O)]-CH3CH2OH-H2O, 1, and [Ni2(nicotinate)4(mu-H2O)]-CH3CH2OH-H2O, 2, were obtained by hydro(solvo)thermal reactions between 3-cyanopyridine and cobalt(II) nitrate and nickel(II) perchlorate, respectively. Both 1 and 2 exhibit complicated 3-D structures based on [M2(nicotinate)4(mu-H2O)] (M = Co or Ni) building blocks and possess open channels that are occupied by removable solvent molecules. 3-D open frameworks [M2L4(mu-H2O)]-HL-(H2O)x (where M = Co, x = 2, 3, and M = Ni, x = 1, 4, and L = trans-3-(3-pyridyl)acrylate) were similarly prepared with trans-3-(3-pyridyl)acrylic acid in place of 3-cyanopyridine. Compounds 3 and 4 are isostructural and exhibit network topologies similar to that of 1 with open channels occupied by disordered trans-3-(3-pyridyl)acrylic acid and water guest molecules. Crystal data for 1: triclinic space group Ponebar, a = 10.534(1) A, b = 11.907(1) A, c = 14.046(1) A, alpha = 106.645(1) degrees, beta = 101.977(1) degrees, gamma = 112.078(1) degrees, and Z = 4. Crystal data for 2: tetragonal space group P4/ncc, a = 20.089(1) A, c = 14.016(1) A, and Z = 4. Crystal data for 3: monoclinic space group C2/c, a = 14.082(2) A, b = 15.278(2) A, c = 18.537(2) A, beta = 105.360(2) degrees, and Z = 2. Crystal data for 4: monoclinic space group C2/c, a = 14.082(1) A, b = 15.250(1) A, c = 18.606(1) A, beta = 106.747(1) degrees, and Z = 2.     

Metal-organic frameworks incorporating Cu3(mu3-OH) clusters

Interaction of 4,4-bi(1,2,4-triazole) (btr) with copper(II) chloride (bromide) in aqueous or aqueous alcohol media led to a series of coordination polymers featuring the formation of mu 3-hydroxotricopper(II) clusters and their integration into 3D frameworks. These unprecedented structures originate in the propagation of trigonal hydroxotricopper(II) clusters bridged by tri- or tetradentate organic ligands. Complex [{Cu3(mu3-OH)}{Cu3(mu3-O)}(mu4-btr)3(H2O)4(OH)2Cl6]Cl.0.5H2O adopts a structure of SrSi2 topology, with eight-fold interpenetration of the coordination frameworks. The structure of [{Cu3(mu3-OH)}2(mu3-btr)6(mu4-btr)(mu-X)X4]X5.nH2O (X = Br, n = 6; X = Cl, n = 8) involves 2D coordination layers [{Cu3(mu3-OH)}(mu3-btr)3]n with an exceptional (3,6)-net topology, which are cross-linked by tetradentate btr ligands and bridging chloride (bromide) ions.     

Twelve-connected porous metal-organic frameworks with high H(2) adsorption

The twelve-connected metal-organic frameworks {[Ni(3)(OH)(L)(3)].n(solv)}(infinity) and {[Fe(3)(O)(L)(3)].n(solv)}(infinity) [LH(2) = pyridine-3,5-bis(phenyl-4-carboxylic acid)] have been prepared and characterised: these materials can be desolvated to form porous materials that show adsorption of H(2) up to 4.15 wt% at 77 K.     

Heterometallic metal-organic frameworks based on tris(dipyrrinato) coordination complexes

A novel class of heterometallic metal-organic frameworks (MOFs) has been synthesized and characterized. The MOFs rely on the use of tris(dipyrrinato) coordination complexes as the bridging structure and silver(I) ions as the linking unit. The building blocks and resulting MOFs have been structurally characterized by using single-crystal X-ray diffraction. The modular nature of this approach is demonstrated by the use of both iron(III) and cobalt(III) complexes. The MOFs have strong electronic absorption features originating from the metal-dipyrrin chromophore and have continuous channels throughout the lattice that are occupied by ordered and disordered solvent molecules.     

Copper(II) camphorates with tunable pore size in metal-organic frameworks

Three new homochiral metal-organic coordination polymers [Cu₂camph₂dabco] · DMF•2H₂O, [Cu₂camph₂bipy] · 3DMF•2H₂O, and [Cu₂camph₂bpe] · 4DMF•2H₂O (H₂camph is (+)-camphoric acid, bipy is 4,4’-bipyridyl, bpe is trans-bis(4-pyridyl)ethylene) were synthesized by heating copper(II) nitrate, (+)-camphoric acid, and N-donor ligands of different length (dabco, bipy, bpe) in DMF and characterized by powder X-ray diffraction, IR spectroscopy, and TGA. The obtained compounds are isostructural with the previously reported porous zinc(II) camphorates.     

New cobalt(II) and zinc(II) coordination frameworks incorporating a pyridyl-pyrazole ditopic ligand

The metal-directed assembly of new molecular frameworks incorporating 4-(4-pyridyl)pyrazole (L), containing non-linear coordination vectors, is presented. Three metallo-arrays of types [Co(LH)2(NO3)4], [Co(LH)2(H2O)4][NO3]4.H2O and [Zn2(L-H)2Cl2].2EtOH are reported. The cobalt(II) in [Co(LH)2(NO3)4] displays distorted octahedral geometry, with the two protonated pyridyl-pyrazole ligands coordinated through their pyrazole nitrogen atoms in a trans-orientation; the remaining four coordination sites are occupied by nitrate anions. Two internal hydrogen bonds occur between each pyrazole NH and the oxygens of adjacent coordinated nitrato ligands. Short intermolecular hydrogen bonds also occur between the two pyridinium hydrogens and bound nitrate ligands on different molecules to yield a two-dimensional hydrogen-bonded array. Two of these arrays interpenetrate to form an extended two dimensional layer; such layers stack throughout the crystal structure. A second product of type [Co(LH)2(H2O)4][NO3]4.H2O exists as two crystallographically independent, but chemically similar, forms. In each form, the two protonated pyridyl-pyrazole ligands occupy trans positions about the cobalt, with the remaining four coordination sites being filled by water molecules to yield a distorted octahedral coordination geometry. Intramolecular hydrogen-bonding is observed between the two non-coordinated pyrazoyl nitrogen atoms and bound water oxygen atoms. The third complex, [Zn2(L-H)2Cl2].2EtOH, contains dimer units consisting of two zinc(II) ions bridged by two pyrazoylate groups in which the coordination geometry of each zinc approximates a tetrahedron. Each zinc is bound to two deprotonated pyridine-pyrazole ligands (L-H), one pyridyl group (from a different dimeric unit) and one chloro ligand. Each pyridyl nitrogen thus connects each of these zinc dimers to an adjacent dimer unit, forming a three-dimensional network containing small voids. The latter are occupied by ethanol molecules which form hydrogen bonds to the chloro ligands.     

Single-crystal-to-single-crystal transformations and selective adsorption of porous copper(II) frameworks

A unique 4-fold interpenetrated (10,3)-b copper(II) framework exhibits reversible dehydration and rehydration in a single-crystal-to-single-crystal (SC-SC) process, and the dehydrated material can encapsulate CH(3)OH molecules, again in a SC-SC fashion, and shows selective adsorption of H(2) and CO(2) over N(2).     

Efficient proton conduction in porous and crystalline covalent-organic frameworks(COFs)

To attain the objectives of carbon peaking and carbon neutrality, the development of stable and highperformance ion-conducting materials holds enormous relevance in various energy storage and conversion devices. Particularly, crystalline porous materials possessing built-in ordered nanochannels exhibit remarkable superiority in comprehending the ion transfer mechanisms with precision. In this regard,covalent organic frameworks(COFs) are highly regarded as a promising alternative due to their pre...     

Spin-crossover behavior in cyanide-bridged iron(II)-gold(I) bimetallic 2D Hofmann-like metal-organic frameworks

The synthesis and characterization of new two-dimensional (2D) cyanide-bridged iron(II)-gold(I) bimetallic coordination polymers formulated, {Fe(3-Xpy)2[Au(CN)2]2} (py = pyridine; X = F (1), Cl (2), Br (3), and I (4)) and the clathrate derivative {Fe(3-Ipy)2[Au(CN)2]2}.1/2(3-Ipy) (5), are reported. The iron(II) ion lies in pseudoctahedral [FeN6] sites defined by four [Au(CN)2](-) bridging ligands and two 3-Xpy ligands occupying the equatorial and axial positions, respectively. Although only compounds 2 and 4 can be considered strictly isostructurals, all of the components of this family are made up of parallel stacks of corrugated {Fe[Au(CN)2]2}n grids. The grids are formed by edge sharing of {Fe4[Au(CN)2]4} pseudosquare moieties. The stacks are constituted of double layers sustained by short aurophilic contacts ranging from 3.016(2) to 3.1580(8) A. The Au...Au distances between consecutive double layers are in the range of 5.9562(9)-8.790(2) A. Compound 5, considered a clathrate derivative of 4, includes one-half of a 3-Ipy molecule per iron(II) atom between the double layers. Compound 1 undergoes a half-spin transition with critical temperatures Tc downward arrow = 140 K and Tc upward arrow = 145 K. The corresponding thermodynamic parameters derived from differential scanning calorimetry (DSC) are Delta H = 9.8 +/- 0.4 kJ mol(-1) and Delta S = 68.2 +/- 3 J K mol(-1). This spin transition is accompanied by a crystallographic phase transition from the monoclinic P2(1)/c space group to the triclinic P1 space group. At high temperatures, where 1 is 100% high-spin, there is only one crystallographically independent iron(II) site. In contrast, the low temperature structural analysis shows the occurrence of two crystallographically independent iron(II) sites with equal population, one high-spin and the other low-spin. Furthermore, 1 undergoes a complete two-step spin transition at pressures as high as 0.26 GPa. Compounds 2- 4 are high-spin iron(II) complexes according to their magnetic and [FeN6] structural characteristics. Compound 5, characterized for having two different iron(II) sites, displays a two-step spin transition with critical temperatures of Tc(1) = 155 K, Tc(2) downward arrow = 97 K, and Tc(2) upward arrow = 110 K. This change of spin state takes place in both sites simultaneously. All of these results are compared and discussed in the context of other {Fe(L) x [M(I)(CN)2]} coordination polymers, particularly those belonging to the homologous compounds {Fe(3-Xpy)2[Ag(CN)2]2} and their corresponding clathrate derivatives.     

Spin-crossover behavior in cyanide-bridged iron(II)-silver(I) bimetallic 2D Hofmann-like metal-organic frameworks

Two new series of compounds formulated {Fe(3-Xpyridine)2[Ag(CN)2]2} (X = F (1), Cl (2), Br (3), I (4)) and {Fe(3-Xpyridine)2[Ag(CN)2][Ag(3-Xpyridine)(CN)2]}.3-Xpy (X = Br (5), I (6)) have been synthesized and characterized. The six compounds are made up of stacking of slightly corrugated two-dimensional coordination polymers defined by sharing {Fe4[Ag(CN)2]4}n motifs. The stacking is different for the two families. In compounds 1-4 the layers are organized by pairs displaying argentophilic interactions; the Ag...Ag distance was found to be in the interval 3.0-3.3 A, while the Ag...Ag separation between two consecutive layers belonging to different pairs was found to be around 6 A. Compounds 5 and 6 are isostructural with a crystal packing defined by an almost homogeneous distribution of layers separated by around 8.3 A (referred to the Fe...Fe interlayer distance). Between the layers an uncoordinated 3-Xpyridine molecule is included. Another 3-Xpyridine molecule, which remains in the plane defined by the {Fe4[Ag(CN)2]4}n windows, coordinates one silver atom. Both series display quite different properties; at 300 K, 1-4 are pale-yellow and display similar distorted [FeN6] octahedron cores characteristic of the iron(II) ion in the high-spin state. 1 and 2 undergo a two-step (T(1)1/2 = 96 K and T(2)1/2 = 162 K) and a 50% spin transition (T1/2 = 106 K), respectively. Compounds 3 and 4 are high-spin compounds at ambient pressure. 5 and 6 are deep red in color at 300 K and undergo spin-crossover behavior at significantly higher temperatures T1/2 = 306 and 261 K, respectively.