Poly[bis­(N,N-dimethyl­formamide)(μ-formato)(μ5-4-oxidoisophthalato)dizinc(II)]

The title compound, [Zn2(CHO2)(C8H3O5)(C3H7NO)2]n, is a three-dimensional metal–organic framework, of which two independent ZnII atoms (denoted Zn1 and Zn2) are linked by both 4-oxidoisophthalate and formate bridging ligands. The 4-oxidoisophthalate ligands link two Zn1-type and three Zn2-type atoms, forming a corrugated sheet roughly parallel to the ac plane. The formate ions join two neighboring sheets along the b axis, forming a three-dimensional network. Two independent dimethylformamide ligands are coordinated to separate ZnII atoms and fill the voids provided by the framework. Both types of ZnII atoms have a distorted trigonal-bipyramidal coordination geometry

Asymmetric catalytic reactions by NbO-type chiral metal-organic frameworks † ‡

Chiral metal-organic frameworks (MOFs) constitute a unique class of multifunctional hybrid materials and are envisioned as a versatile tool for various enantioselective applications, including the separation of optical isomers and the promotion of catalytic enantioselective reactions. Despite some pioneering works on catalytic enantioselective reactions promoted by chiral MOFs, there is still a need for practical catalysts and many fundamental issues must be answered; such as pin-pointing the site of the reaction and expedition of the reaction rate to the level of that in homogeneous media. We have designed and synthesized a chiral metal-organic framework, ( NbO type framework provides a spacious pore (2 Â 2 Â 2 nm 3 ) and is equipped with potential catalytic sites exposed into the pore. Since the functional group on the organic links, biphenols in this MOF, can be modified further on demand, this MOF can serve as a platform for new heterogeneous catalysis. Two reactions, the carbonyl-ene reaction with modified MOF after replacement of the protons on biphenol on the organic links with Zn(II) and the hetero-Diels-Alder reaction with Ti(IV), respectively, were studied. In this manoeuver, we observed that the reaction occurs entirely inside the pores and the reaction rate of the heterogeneous reaction by this specific MOF is comparable to that of its homogeneous counterpart. In addition, it is also observed that the enantioselectivities are significantly improved by extra steric bias provided from the frames of the MOF. These observations reinforce the legitimacy of the strategy of using a chiral MOF as a highly enantioselective heterogeneous catalyst

A route to high surface area, porosity and inclusion of large molecules in crystals

One of the outstanding challenges in the field of porous materials is the design and synthesis of chemical structures with exceptionally high surface areas(1). Such materials are of critical importance to many applications involving catalysis, separation and gas storage. The claim for the highest surface area of a disordered structure is for carbon, at 2,030 m(2) g(-1) (ref. 2). Until recently, the largest surface area of an ordered structure was that of zeolite Y, recorded at 904 m(2) g(-1) (ref. 3). But with the introduction of metal-organic framework materials, this has been exceeded, with values up to 3,000 m(2) g(-1) (refs 4-7). Despite this, no method of determining the upper limit in surface area for a material has yet been found. Here we present a general strategy that has allowed us to realize a structure having by far the highest surface area reported to date. We report the design, synthesis and properties of crystalline Zn4O(1,3,5-benzenetribenzoate)(2), a new metal-organic framework with a surface area estimated at 4,500 m(2) g(-1). This framework, which we name MOF-177, combines this exceptional level of surface area with an ordered structure that has extra-large pores capable of binding polycyclic organic guest molecules-attributes not previously combined in one material.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62609/1/nature02311.pd

Poly[(μ3-5-tert-butylbenzene-1,3-dicarboxylato)dipyridinecobalt(II)]

In the title compound, [Co(C12H12O4)(C5H5N)2]n, the CoII cation is coordinated by four O atoms from three 5-tert-butylbenzene-1,3-dicarboxylate anions and two N atoms from pyridine molecules in a distorted octahedral geometry. One carboxylate group of the anionic ligand chelates a CoII cation while another carboxylate group bridges two CoII cations, resulting in a polymeric layer parallel to (101). Weak C—H...O hydrogen bonds occur between adjacent polymeric layers. In the crystal, one of pyridine molecules is equally disordered over two positions

Porous zeolitic imidazolate frameworks assembled with highly-flattened tetrahedral copper(ii) centres and 2-nitroimidazolates

Cu(ii)-based zeolitic imidazolates (Cu-ZIFs), Cu-ZIF-gis and -rho, formulated as Cu(nIm)(2) (nIm = 2-nitroimidazolate) have highly-flattened tetrahedral coordination geometry. Cu-ZIF-gis has 2.4 & ANGS; cylindrical pores that can adsorb H-2 gas, and Cu-ZIF-rho has 19.8 & ANGS; cages with a BET surface area of 1320 m(2) g(-1)

Three-Dimensionally Printed Interconnects for Smart Contact Lenses

One of the ultimate wearable heath-monitoring gears, smart contact lens, requires miniaturized devices compounded and interconnected with each other on the lens for a successful system functioning. Because of the different device thickness, the interconnect patterns need to be three-dimensional (3D) conforming the steps given by the diversified on-lens devices. Also, the patterns should be low-temperature processed and flexible considering the mechanical and thermal property of the lens material. We demonstrate the 3D interconnects electrosprayed on a contact lens platform with Ag–Ag nanowire (NWs) composite ink conforming the steps. Quantitative and informative analysis on the interconnects is presented. Thick polyimide film (12.5 μm) in C-shape is employed as a primary substrate to form the 3D patterns that is to be transferred onto the contact lens. The AgNWs act as frames to support the Ag ion inks printed across the steps. The resultant interconnects realized with the Ag/AgNW composite ink with 0.3 wt % AgNW have the sheet resistance (<i>R</i>_s) of 0.396 Ω/□ spanning the height difference of 300 μm. AgNWs also provide durability to the patterns against crack formation and propagation under significant device deformation. Unlike pure Ag pattern which shows the <i>R</i>_s changes of 86.1% in the bending condition, the optimally formulated composite pattern shows the suppressed <i>R</i>_s change of only 15.2% with a bending radius of 3 mm