Search

Although the active centers of manymetalloenzymes have been well-studied,the ability for chemists to imitate the iron porphyrin heme foundin these enzymes remains a challenge. Herein, we report a water/chemical-stablenanoporous covalent heme framework (CHF-1) that can be synthesizedvia the Yamamoto homocoupling reaction. Unlike other artificial enzymes,CHF-1 neatly arranges the heme centers to form a graphene-like two-dimensionalframework bearing a high surface area (1620 m2/g) and highdensity of active sites. Biomimetic catalytic reactions show thatCHF-1 catalyst is an effective heterogeneous catalyst with exceptionallyhigh binding affinities and high catalytic efficiency approachingthat of natural heme-based enzymes. [ABSTRACT FROM AUTHOR]

A change for the better: Exchange of CdII in the catalytically inactive framework MMPF‐5 (see scheme) with CoII afforded a metalloporphyrin‐based nanoreactor, MMPF‐5(Co). This framework, consisting of small cubicuboctahedral cages, demonstrated interesting performances in the catalytic epoxidation of trans‐stilbene with tBuOOH. [ABSTRACT FROM AUTHOR]

Solvothermal reactions of Cu(NO3)2 with azoxybenzene-3,3′,5,5′-tetracarboxylic acid (H4aobtc) or trans-stilbene-3,3′,5,5′-tetracarboxylic acid (H4sbtc) give rise to two isostructural microporous metal−organic frameworks, Cu2(abtc)(H2O)2·3DMA (PCN-10, abtc = azobenzene-3,3′,5,5′-tetracarboxylate) and Cu2(sbtc)(H2O)2·3DMA (PCN-11, sbtc = trans-stilbene-3,3′,5,5′-tetracarboxylate), respectively. Both PCN-10 and PCN-11 possess significant enduring porosity with Langmuir surface areas of 1779 and 2442 m2/g (corresponding to BET surface areas of 1407 or 1931 m2/g, respectively) and contain nanoscopic cages and coordinatively unsaturated metal centers. At 77 K, 760 Torr, the excess gravimetric (volumetric) hydrogen uptake of PCN-10 is 2.34 wt % (18.0 g/L) and that of PCN-11 can reach 2.55 wt % (19.1 g/L). Gas-adsorption studies also suggest that MOFs containing CC double bonds are more favorable than those with NN double bond in retaining enduring porosity after thermal activation, although NN has slightly higher H2 affinity. The excess gravimetric (volumetric) adsorption at 77 K saturates around 20 atm and reaches values of 4.33% (33.2 g/L) and 5.05% (37.8 g/L) for PCN-10 and PCN-11, respectively. In addition to its appreciable hydrogen uptake, PCN-11 has an excess methane uptake of 171 cm3(STP)/cm3 at 298 K and 35 bar, approaching the DOE target of 180 v(STP)/v for methane storage at ambient temperature. Thus, PCN-11 represents one of the few materials that is applicable to both hydrogen and methane storage applications. Two isostructural MOFs based on two predesigned double-bond-coupled bis(isophthalate) ligands, PCN-10 and PCN-11, were synthesized and structurally characterized. One of the MOFs, PCN-11 shows an excess volumetric (gravimetric) hydrogen uptake of 37.8 g/L (5.05 wt %) at 77 K and 50 bar, and an excess methane storage capacity of 171 cm3(STP)/cm3 at 298 K and 35 bar. Thus, PCN-11 represents one of the few materials that is applicable to both hydrogen and methane storage applications. [ABSTRACT FROM AUTHOR]

Abstract: The spontaneous resolution reaction of racemic trans-2,3-dihydro-2,3-dipyridyl-benzo[e]indole 1 with Cd(ClO4)2·6H2O in the presence of 2-butanol under solvothermal reaction conditions favors the formation of crystal 2 [P-Cd(R,R,-1)2(ClO4)2], while a similar reaction in the presence of ethanol only favors the formation of crystal 3 [M-Cd(S,S,-1)2(ClO4)2]. The crystal structural determination shows that both 2 and 3 crystallize in chiral enantiomorphous space groups (P6122 and P6522) and their structures are 1D infinite chain, and are just enantiomorphous pairs most like. The spontaneous resolution process displays estimated ee values of ca. +0.6 for 2-butanol and ca. −0.4 for ethanol. Enantiomerically pure (S,S)-trans-2,3-dihydro-2,3-dipyridyl-benzo[e]indole (S,S,-1) can be obtained through the decomposition of mechanically separated 3. Additionally (S,S,-1) also crystallizes in a chiral space group (P21). The CD (circular dichroism) spectra of both 2 and 3 in the solid state are also approximately enantiomorphous pairs. However, their fluorescent spectra in the solid state display a moderate difference in maximum emission peaks (Δλ =19nm). Crystal data for 2: C44H34Cl2N6O8Cd, M =958.07, hexagonal, P6122, a =10.5488(5), c =68.256(4)Å, α = γ =90°, β =120°, V =6577.8(6)Å3, Z =6, D c =1.451mgm−3, R 1 =0.0498, wR 2 =0.1124, μ =0.679mm−1, S =0.623, Flack χ =−0.02(6). For space group P6522, R 1 =0.0670, wR 2 =0.1602, S =0.725 with a Flack value of 1.03(7); Crystal data for 3, C44H34Cl2N6O8Cd, M =958.07, hexagonal, P6522, a =10.5446(3), c =68.265(3)Å, V =6573.3(4)Å3, Z =6, D c =1.452mgm−3, R 1 =0.0444,wR 2 =0.1002, μ =0.679mm−1, S =0.558, Flack χ =0.01(5). For space group P6122, R 1 =0.0501, wR 2 =0.1178, S =0.599 with a Flack value of 1.00(5). The low Flack parameter indicates that the absolute configurations of 2 and 3 are stated; Crystal data for (S,S)-1, C22H17N2, M =323.39, orthorhombic, P212121, a =9.2598(7), b =9.4617(8), c =19.1452(16)Å, V =1677.4(2)Å3, Z =4, D c =1.281mgm−3, R 1 =0.0417, wR 2 =0.1191, T =293K, μ =0.077mm−1, S =0.862. [Copyright &y& Elsevier]

A highly porous porphyrin-based organic polymer, PCPF-1, was constructed via homo-coupling reaction of the custom-designed porphyrin ligand, 5,10,15,20-tetrakis(4-bromophenyl)porphyrin. PCPF-1 possesses a large BET surface area of over 1300 m2 g−1 (Langmuir surface area of over 2400 m2 g−1) and exhibits strong hydrophobicity with a water contact angle of 135°, and these features afford it the highest adsorptive capacities for saturated hydrocarbons and gasoline among sorbent materials reported thus far, as well as render it the capability to remove oil from water. [ABSTRACT FROM AUTHOR]

The reaction of the ligand rac-(R,S)-2,2'-bipyridine-3,3'-dicarboxylic acid 1,1'-dioxide [(R,S)-H2BDCD] with Mn(CH3COO)2·2H2O gives a novel 2D coordination polymer, {Mn[(R,S)-BDCD](H2O)} (1), which contains a dimeric Mn(II) core with dioxide (O,O atoms of carboxylate ligands) as the bridge units and exhibits ferromagnetic interaction between Mn2+ ions. The reaction of the ligand rac-(R,S)-2,2'-bipyridine-3,3'-dicarboxylic acid 1,1'-dioxide [(R,S)-H2BDCD] with Mn(CH3COO)2·2H2O gives one novel 2D coordination polymer, {Mn[(R,S)-BDCD](H2O)} (1), which contains a core with dioxide (O,O atoms of carboxylate ligands) as the bridge units and exhibits ferromagnetic interaction between Mn2+ ions. [ABSTRACT FROM AUTHOR]

A correction to the article "Catalytic Enantioselective Formal Hetero-Diels Alder Reactions of Enones with Isatins to Give Spiro- ACHTUNGTRENUN Goxindole Tetrahydropyranones" in the 2013 issue.

Abstract: The crystal structures of amarine (1) and isoamarine (2), important intermediates in the preparation of 1,2-diphenyl-diaminoethane, were successfully determined. Their allylation products, 1,3-diallyl amarine (1)(CH2 ph name="dbnd" />CH2)2Br (3) and isoamarine bromide (2)(CH2 ph name="dbnd" />CH2)2Br (4) [the crystal structures of (1)(CH2 ph name="dbnd" />CH2)2PF6(3-Br+PF6) and (2)(CH2 ph name="dbnd" />CH2)2PF6 (4-Br+PF6) are also successfully determined to confirm allylation products], react with CuBr to afford (1)2(CH2 ph name="dbnd" />CH2)4(Cu2Br4) (5) and (2)(CH2 ph name="dbnd" />CH2)2(Cu2Br3) (6), respectively. Crystal structures of 5 and 6 reveal that 5 is an anion discrete complex without olefin moiety coordination, and 6 has a 1D infinite chain with olefin moiety coordination as a bridging spacer. The fluorescent emission spectra of 5 (λ emax =570nm) and 6 (λ emax =642nm) were measured, and display a significant difference that can be used for solid state fluorescent sensing them. [Copyright &y& Elsevier]

The resolution of racemic 2-butanol through intercalation by a chiral metal−organic coordination polymer [Cu(PPh3)(N,N'-(2-pyridyl-(4-pyridyl methyl)-amine))1.5]·ClO4 (1) constructed by an achiral building block provides new insight into the optical-resolution field. This provides encouragement for the role of crystal engineering in separating racemic mixtures and revives the historic practice of mechanically separating crystals of opposite chirality. Crystal data for 1: C69H63Cl2Cu2N9O8P2, trigonal, R3, a = 13.7382(2), b = 13.7382(2), c = 32.72480(10) Å, α = β = 90°, γ = 120°, V = 5348.78(11) Å3, Z = 3, M = 1406.20, Dc = 1.310 Mg m-3, R1 = 0.0703, wR2 = 0.1457, S = 0.928, T = 293 K, μ = 0.774 mm-1; crystal data for 1·1.5 (S)-2-butanol (2): C75H78Cl2Cu2N9O9.5P2, trigonal, R3, a = 13.7282(4), b = 13.7282(4), c = 32.7155(12) Å, α = β = 90°, γ = 120°, V = 5339.6(11) Å3, Z = 3, M = 1517.36, Dc = 1.416 Mg m-3, R1 = 0.0454, wR2 = 0.0605, S = 1.019, T = 293 K, μ = 0.783 mm-1. The resolution of racemic 2-butanol through intercalation by a chiral metal-organic coordination polymer [Cu(PPh3)(N,N'-(2-pyridyl-(4-pyridyl methyl)-amine))1.5]·ClO4 (1) constructed by an achiral building block provides new insight into the optical-resolution field. This provides encouragement for the role of crystal engineering in separating racemic mixtures and revives the historic practice of mechanically separating crystals of opposite chirality. [ABSTRACT FROM AUTHOR]

Cavities up to 4 nm have been introduced into a hierarchically-assembled metal–organic framework by adopting an angular, semi-flexible tetratopic ligand. The resulting MOF possesses permanent porosity and exhibits stepwise sorption isotherms for O2and N2gases. [ABSTRACT FROM AUTHOR]

Although peptide amphiphiles have been explored as nanomaterialsfor different applications, nanostructures formed by hierarchicalmolecular assembly of sequence-specific peptidomimetics are much lessdeveloped. Such protein-like nanomaterials could enhance the currentapplication of peptide-based amphiphiles by enriching the diversityof nanostructures, increasing in vivostability forbiomedical applications, and facilitating the understanding of biomacromolecularself-assembly. Herein we present a biomimetic γ-AApeptide amphiphilewhich forms nanorods. Our results demonstrate the capability of γ-AApeptideamphiphiles as a potential scaffold for the preparation of biomimeticand bioinspired nanostructures. The programmability and biocompatibilityof γ-AApeptides could lead to novel nanomaterials for a widevariety of applications. [ABSTRACT FROM AUTHOR]

Abstract: The solvothermal reactions of N-allyl imidazole with CuIX (X=Cl, Br) afford two unprecedented 3D copper(I)–olefin coordination polymer Cu2X2(N-allyl imidazole) (X=Cl for 1; Br for 2). This is the first 3D copper(I)–olefin coordination polymer synthesized in directed method, compared to most of olefin–Cu(I) coordination polymers prepared by electrochemical method. Of practical interest is that both of them contain 1D zigzag ladder chain composed of basic Cu2X2 dimer unit. Photoluminescent measurements show that 1 displays blue fluorescent emission while 2 has red fluorescent emission at room temperature. [Copyright &y& Elsevier]

Abstract: Under hydrothermal conditions, the reaction of 3,5-diaminobenzoic acid (HDABC) with Cd(ClO4)2∼6H2O affords a novel 2D network, {[Cd(DABC)2][Cd(DABC)2(H2O)2]}n (1), which, represents the first example of 2D neutral polymeric material containing DABC ligand with strong blue fluorescent emission in the solid state. [Copyright &y& Elsevier]