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We present electrical transport studies of two ammonium hexafluorometallates of general formula (NH4)3GaxV1−xF6, highlighting the intriguing relationship between structure and electrical and electrochemical properties. Part of this study uses a method adapted to probe the solid-state electrochemical characteristics on individually contacted single crystals. For compound 1, x varies over 0.15 < x < 0.3, and for 2, x varies over 0.3 < x < 0.4, as determined by physical and chemical characterization. Electronically, compounds 1 and 2 are found to be wide bandgap electronic materials at room temperature. Variable temperature electrical measurements on single crystals of 1 and 2 show temperature-activated behavior for both. Within the temperature range probed, possible conduction pathways are discussed in relation to the structure and in comparison to other hexafluorometallates. We show that solid-state electrochemical studies on single crystals of 1 and 2 can probe redox properties of the metal centers in materials with low electrical conductivity, of interest in electrochemical energy storage applications. [ABSTRACT FROM AUTHOR]

We report an organocatalytic trans hydroboration of 3-substituted-propiolonitriles. In the presence of catalytic amounts of tributylphosphine and pinacolborane, regioselective hydroboration of the internal triple bond proceeded in a stereoselective fashion under mild conditions to afford the corresponding (E)-1,2-vinylcyanoborane derivatives. The mechanism is proposed to occur through a 1,2-phosphine addition instead of a canonical 1,4-conjugate addition pathway. [ABSTRACT FROM AUTHOR]

Three [2]rotaxanes (4, 7, and 12) and one [3]rotaxane (8) were synthesized based on the dibenzo-30-crown-10/viologen binding motif. To the best of our knowledge, these are the first rotaxanes formed from dibenzo-30-crown-10 and viologens. The rotaxanes were all characterized by 1H NMR, 13C NMR, and HRMS. An X-ray crystal structure of one of the [2]rotaxanes (7) was obtained. This work demonstrates for the first time that dibenzo-30-crown-10 does form pseudorotaxane complexes with viologens in solution. [ABSTRACT FROM AUTHOR]

Abstract: The commonly used paraquat guest N,N′‐dimethyl‐4,4′‐bipyridinium bis(hexafluorophosphate) (7) was targeted for structural alterations to improve the binding constants with crown ethers and cryptands. The association constant was improved by one order of magnitude (to Ka = 1.00 × 106 mol L−1) with the dibenzo‐30‐crown‐10 pyridyl cryptand host 5 by changing the N‐methyl groups to benzyl and the counterions from PF6 to TFSI, that is, 11. Moreover, through addition of a p‐bromobenzyloxy moiety on the 4‐position of the pyridyl ring of cryptand 18, an association constant of Ka = 5.35 × 106 mol L−1 was achieved with paraquat 11. [ABSTRACT FROM AUTHOR]

Phytochemical investigation of the ethyl acetate and methanol extracts of the bark of Madagascan endemic and medicinal plant Cinnamosma fragrans led to the isolation of two drimane sesquiterpene derivatives: cinnafragroside A ( 1 ) and cinnafragrin E ( 2 ), two aromatic glycosides: 3,4,5-trimethoxyphenol 1- O - β - d -apiofuranosyl-(1→6)- β - d -glucopyranoside ( 3 ) and 3,4-dimethoxyphenyl-1- O - β - d -apiofuranosyl-(1→6)- β - d -glucopyranoside ( 4 ), together with 12 known compounds identified as: helicide ( 6 ), 1-( α - l -rhamnosyl(1→6)- β - d -glucopyranosyloxy)-3,4,5-trimethoxybenzene ( 7 ), vanilloloside ( 8 ), cinnamadin ( 9 ), ugandensolide ( 10 ), cinnamosmolide ( 11 ), cinnamolide ( 12 ), polygodial ( 13 ), cinnamodial ( 14 ), bemadienolide ( 15 ), 4-isopropyl-6-methyl- α -tetralone ( 16 ), and capsicodendrin ( 17 ). Another new compound, 11-norcinnafragrolide-9-one ( 5 ), was obtained during chemical derivatization of capsicodendrin and gave a hint to understanding the structure required for the antiproliferative activity of 17 . The structures of the new compounds were elucidated based on the interpretation of their spectroscopic data including one and two dimensional nuclear magnetic resonance (1D- and 2D-NMR) and mass spectroscopic data. All isolated compounds were evaluated against the hormone dependent breast cancer cell line MCF-7. Compound 17 exhibited the most potent activity with an IC 50 value of 0.6 μM. Our preliminary SAR study showed that the hydroxyl group at C-12′ and the presence of conjugated carbonyl contribute to the antiproliferative activity. [ABSTRACT FROM AUTHOR]

A two-dimensional manganese(II)-based coordination polymer [Mn(L)4(CH3COO)2] [L=1,4-bis(1-imidazolyl)benzene] has been synthesised. Its X-ray structure revealed that the layers of the 2D structure are stacked together by two types of weak interactions extending to form a three-dimensional supramolecular structure. The thermal stability of this coordination polymer is described and the compound has been used as a heterogeneous catalyst in oxidation of cyclohexene to cyclohexene oxide. A density functional study of structural parameters, position of the HOMO and LUMO energies, electrophilicity and global hardness is reported. [ABSTRACT FROM AUTHOR]

Tetranuclear dioxomolybdenum cluster complex (TMC) [CHN][MoO(OCH)]·CHOH has been synthesized by the reaction of MoO(acac) with 1,2-di(4-pyridyl)ethylene. The cluster core is composed of four molybdenum atoms arranged in the rhombus shape bridged by two oxo ligands, one bridging O, and three methanol molecules. The TMC [CHN][MoO(OCH)]·CHOH is comprised of two moieties of pyridyl cation [CHN] (1,2-di(4-pyridyl)ethylene) and cluster anion [MoO(OCH)]. The cluster is stabilized by two intermolecular interactions (hydrogen bond and π- π stacking interactions). The 1D chain is formed as a result of the hydrogen interaction between (1, 2-di(4-pyridyl)ethylene) and [MoO(OCH)]. Thermogravimetric analysis clearly indicated the thermal stability of the cluster. Electrochemical measurement showed two irreversible reduction processes at scan rates (−1 to −2 V) and an irreversible one-electron oxidation at +0.79 V. Optical absorption measurement shows that the fundamental absorption edge obeys Tauc's relation for the allowed non-direct transition. Optical band gap ( E) values equal 2.4 eV. [ABSTRACT FROM AUTHOR]

Two cationic complexes [Mn(II)(terpy)2]·2(PCP) and [Mn(II)(dipy)3]·2(PCP) (terpy = 2,2':6',2''-terpyridine) (dipy = 2,2-dipyridyl) (PCP = pentacyanopropenide) have been synthesised. Single crystal X-ray diffraction revealed that the PCP ligand acts as a counter ion. The thermal stability of these compounds was investigated. Optical absorption measurements show that the fundamental absorption edge obeys Tauc's relation for the allowed non-direct transition. The optical band gap (Eg) values equal ∼2.7 eV for both complexes. [ABSTRACT FROM AUTHOR]

The reaction of 1,4-bis((2 H-benzo[ d]imidazol-2-yl)methyl) naphthalene and pyridinium 1,1,2,3,3-pentacyanopropenide (PCP) with Zn(II) salts yielded two-dimensional (2D) chain coordination polymer ([Zn (CHN)][CN]). The 2D structure was synthesized via solvothermal synthesis; and structurally characterized by elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. The X-ray single crystal revealed that [Zn(CHN)][CN] is comprised of the [Zn(CHN)] cationic chains and PCP anion [CN]. As a result of the porous nature of the cationic 2D network, the PCP-anions are located at the rhombic windows that balance the charge of 2D structure. The luminescent and thermal properties were also investigated. The fluorescence emission of the coordination polymer was investigated in the presence of hydrocarbon molecules such as (anthracene, toluene, and benzene). [ABSTRACT FROM AUTHOR]

Two supramolecular metal complexes [Cu(II)(terpy)(PCP)(NO)] (1) and [Zn(II)(terpy)(NO)] (2) (terpy=2,2′:6′,2″-terpyridine) (PCP = Pentacyanopropenide) were synthesized and structurally characterized by Single-crystal X-ray diffraction. Single-crystal X-ray diffraction revealed that the PCP ligand coordinated to Cu(II) ion through one CN group, and it was absent from the coordination sphere of Zn(II) complex. In complexes ( 1) and ( 2), 1D chain was formed through C1-H1···O1 and C4-H4···O2 hydrogen-bonding interactions, respectively. The crystal structure was further stabilized by π-π stacking interactions. The thermal stabilities of these compounds were investigated. Furthermore, antimicrobial activities of these compounds were investigated against eight types of bacteria. The copper complex exhibited a significant activity against three types of bacteria with minimal inhibitory concentrations (MICs) under one microgram per milliliter. [ABSTRACT FROM AUTHOR]

One-dimensional structure of Zinc(II) metal organic framework ([Zn(CHN)(NO)]) has been synthesized at room temperature and structurally characterized by elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. The five-coordinated Zn(II) complex exhibits trigonal bipyramidal coordination geometry. The Zn(II) ion is stabilized by three-connected nodes to form 1D ladder structure. The 1D chain is further connected to each other via hydrogen bonding to form 2D structure. Disordered CHCl solvent molecules were trapped in the pores. The luminescent and thermal properties have been also investigated. In addition, the activation thermodynamic parameters, ΔE, ΔH, ΔS and ΔG are calculated from the DTA curves using Coats-Redfern method. [ABSTRACT FROM AUTHOR]

Abstract: Two dioxomolybdenum(VI) complexes, [Mo2O4(HBAP)2L] (1) and [MoO2(HMBI)] (2) (HBAP=((E)-2-(2-hydroxybenzylidene)amino)phenol, HMBI=((E)-N′-(2-hydroxy-3-ethoxybenzylidene)isonicotinohydrazide) and L=(4,4′-dipyridyl)), have been synthesized and structurally characterized by elemental analysis, 1H NMR spectroscopy and X-ray single crystal diffraction analysis. In complex (1), a 1D-chain is formed through C⋯H⋯O hydrogen-bonding interactions. In complex (2), a dimer is formed through O⋯H⋯N hydrogen-bonding interactions. This dimer is extended into a 1D chain through secondary C⋯H⋯O hydrogen-bonding interactions, in addition to π–π stacking interactions. Electrochemical measurements showed that both complexes undergo an irreversible reduction in DMF solution. The thermogravimetric analyses clearly indicate that the complexes have high thermal stability. [Copyright &y& Elsevier]

Cyclohexyl ketone substrate analogue inhibitors (Ac--pSer-ψ[C = OCH]-Pip--tryptamine) of Pin1, the cell cycle regulatory peptidyl-prolyl isomerase (PPlase), were designed and synthesized as potential electrophilic acceptors for the Pin1 active site Cys113 nucleophile to test a proposed nucleophilic addition-isomerization mechanism. Because they were weak inhibitors, models of all three stereoisomers were docked into the active site of Pin1. Each isomer consistently minimized to a trans-diaxial cyclohexane conformation. From this, we hypothesize that Pin1 stretches substrates into a trans-pyrrolidine conformation to lower the barrier to isomerization. Our reduced amide inhibitor of Pin1 adopted a similar trans-pyrrolidine conformation in the crystal structure. The molecular model of 1, which mimics the L-Ser-L-Pro stereochemistry, in the Pin1 active site showed a distance of 4.4 Å, and an angle of 31° between Cys113-S and the ketone carbon. The computational models suggest that the mechanism of Pin1 PPIase is not likely to proceed through nucleophilic addition. [ABSTRACT FROM AUTHOR]

We report a transition metal‐free, regio‐ and stereo‐selective, phosphine‐catalyzed method for the trans hydroboration of 1,3‐diynes with pinacolborane that affords (E)‐1‐boryl‐1,3‐enynes. The reaction proceeds with excellent selectivity for boron addition to the external carbon of the 1,3‐diyne framework as unambiguously established by NMR and X‐ray crystallographic studies. The reaction displays a broad substrate scope including unsymmetrical diynes to generate products in high yield (up to 95 %). Experimental and theoretical studies suggest that phosphine attack on the alkyne is a key process in the catalytic cycle. [ABSTRACT FROM AUTHOR]

Abstract: A pseudocryptand-type [2]pseudorotaxane was formed via the self-assembly of a dipyridyl bis(meta-phenylene)-32-crown-10 (BMP32C10) derivative and a paraquat derivative. Due to the basicity of the pyridyl group, which forms the third pseudo-bridge of the pseudocryptand, this pseudorotaxane possesses two finite acid–base adjustable association constants. [Copyright &y& Elsevier]

The first dual component pseudocryptand-type [2]pseudorotaxanes were designed and prepared via the self-assembly of synthetically easily accessible bis(meta-phenylene)-32-crown-10 pyridyl, quinolyl, and naphthyridyl derivatives with paraquat. The formation of the pseudocryptand structures in the complexes remarkably improved the association constant by forming the third pseudobridge via H-bonding with the guest and π-stacking of the heterocyclic units. [ABSTRACT FROM AUTHOR]

Abstract: Ethyl tricyanoethylenecarboxylate (ETCE) is a one-electron acceptor related to tetracyanoethylene that can serve as a building block for the construction of molecule-based magnets. The reactions of ETCE with decamethylmetallocenes, (M=Cr, Mn, Fe) give three new charge-transfer salt magnets, [ETCE] 1, [ETCE] 2 and [ETCE] 3. The expected mixed pi stacking of anions and cations is obtained, with the ETCE radical anion exhibiting typical disorder over two nearly equivalent footprints. Powder diffraction supports the belief that all three compounds are isomorphous. Magnetic measurements indicate that 1 is a soft ferromagnet, ordering below a critical temperature, T c, of 3.8K. Compound 2 exhibits complex magnetic behavior consisting of two frequency-dependent peaks in the ac susceptibility, the first at about 11.2K and the second at about 7K. At 1.8K, the compound is hysteretic and exhibits a coercive field of 10kG. Compound 3 is a glassy, apparently canted, ferromagnet displaying an out-of-phase ac susceptibility signal below about 3K. [Copyright &y& Elsevier]

The article presents two transition metal coordination polymers of the 7,7,8,8-tetracyanoquinodimethane dianion (TCNQ2-). The first compound is composed of a ribbon coordination polymer that have µ4-TCNQ2- radical anion ligands. While the other compound has asymmetry operator that generates one-dimensional zigzag chain of octahedral iron II focusing on µ4-TCNQ2-. Schematic diagrams characterizing the compounds are also presented.

Photochemically generated benzyl radicals react with Sc3N@C80-Ih to produce a dibenzyl adduct [Sc3N@C80(CH2C6H5)2] in 82% yield and high regioselectivity. The adduct's 1H spectrum revealed high symmetry: only one AB pattern was observed for the methylene protons. The 13C NMR spectrum suggested a C2-symmetrical structure. DFT calculations reveal that a 1,4-adduct is more favorable than a 1,2-adduct by >10 kcal/mol. The 1,4-structure on [566] ring junctions was unambiguously confirmed by X-ray crystallographic analysis. UV-vis spectra revealed that the removal of two p orbitals from the π system of the cage together with the benzylic substituents change the electronic properties of the metallofullerene in a manner similar to those reported for disilirane and trifluoromethyl moieties. Under the same conditions from Lu3N@C80-Ih we prepared (63% yield) Lu3N@C80(CH2C6H5)2, which demonstrated properties similar to the 1,4-dibenzyl adduct of Sc3N@C80-Ih. [ABSTRACT FROM AUTHOR]

Abstract: The heteroleptic complexes, [(MePhtpy)RuCl(dpp)](PF6) and [(tpy)RuCl(dpp)](PF6), have been synthesized, characterized, and investigated with respect to their photophysical, redox, and DNA photocleavage properties (where MePhtpy=4′-(4-methylphenyl)-2,2′:6′,2′′-terpyridine and dpp=2,3-bis(2-pyridyl)pyrazine, tpy=2,2′:6′,2′′-terpyridine). The X-ray crystal structure confirms the identity of the new [(MePhtpy)RuCl(dpp)](PF6) complex. These heteroleptic complexes were found to photocleave DNA in the presence of oxygen, unlike the previously studied complex, [Ru(tpy)2](PF6)2. The photophysical, redox, and DNA photocleavage properties of the heteroleptic complexes were compared with those of the homoleptic complexes, [Ru(MePhtpy)2](PF6)2 and [Ru(tpy)2](PF6)2. The heteroleptic complexes showed intense metal to ligand charge transfer (MLCT) transition at lower energy ([(MePhtpy)RuCl(dpp)](PF6), 522nm; [(tpy)RuCl(dpp)](PF6), 516nm) and longer excited state lifetimes as compared to the homoleptic complexes. The [Ru(MePhtpy)2]2+ complex was found to photocleave DNA in contrast to [Ru(tpy)2]2+. The introduction of a methylphenyl group on the tepyridine ligand not only enhances the 3MLCT excited state lifetime but also increases the lipophilicity and thereby the DNA binding ability of the molecule. An increase in lipophilicity upon addition of a methylphenyl group on the 2,2′:6′,2′′-terpyridine ligand was confirmed by determination of the partition coefficient ([(MePhtpy)RuCl(dpp)](PF6), log P =+1.16; [(tpy)RuCl(dpp)](PF6), log P =−1.27). The heteroleptic complexes photocleave DNA more efficiently than the homoleptic complexes, with the greatest activity being observed for the newly prepared [(MePhtpy)RuCl(dpp)](PF6) complex. [Copyright &y& Elsevier]

Abstract: A tetracyanoethylene (TCNE) bridged coordination polymer, [Mn(cyclen)(μ2-TCNE)]·TCNE (1), (cyclen=1,4,7,10-tetraazacyclododecane, TCNE=tetracyanoethylene), has been synthesized by combining [MnII(cyclen)]2+ and the potassium salt of TCNE radical anion, K[TCNE]. The compound crystallizes in two polymorphs. Both structures feature formal TCNE radical anion ligands in an unusual geminal (or 1,1−) bridging geometry between two high spin Mn(II) centers. The NTCNE–Mn–NTCNE bond angles of two bridging TCNE ligands are 88.07(9)°1a and 85.44(14)°1b, respectively. Each bridging TCNE is π stacked with an uncoordinated TCNE to form what can be construed as a diamagnetic dianion, , containing a 4-center 2-electron (4c/2e−) bond. The results of variable-temperature magnetic susceptibility measurements indicate behavior consistent with weak antiferromagnetic coupling between two Mn(II) centers with no significant contribution of spin from the organic radicals. [Copyright &y& Elsevier]

Abstract: A series of zinc phosphite hybrid structures with trimethylene dipyridine as the linking ligand and templated on the aromatic alcohols, hydroquinone, 1,2,3-trihydroxybenzene, nitrophenol, and bromophenol are reported. The aromatic alcohols interact with the framework by hydrogen bonding to oxygen atoms that bridge zinc and phosphorus atoms in the inorganic portion of the network. In addition, three hydrogen-bonded networks that contain trimethylene-dipyridine and either hydroquinone or 1,2,3-trihydroxybenzene are reported. In these structures, the aromatic alcohol acts as a hydrogen bond donor to trimethylene-dipyridine. The flexibility of trimethylene-dipyridine is important to the construction of the new frameworks. Calculations using PM5 parameters demonstrate that trimethylene-dipyridine can adopt a wide variety of conformations with a minimal energy expense. [Copyright &y& Elsevier]

The structures and magnetic properties of two products that result from the reactions of [Mn(TPA)(CH3CN)2](ClO4)2, TPA = tris(2-pyridylmethyl)amine and potassium tetracyanoethylenide, KTCNE, are reported. [Mn(TPA)(TCNE)]2-[μ2-(TCNE)2] (1) and [Mn(TPA)(μ4-C4(CN)8)0.5]·CIO4 (2) are obtained by using two different ratios of the initial reactants. Each was intended to possess two or more cis-TCNE radical anions (TCNE·/-) as ligands. 1 is a dinuclear species that crystallizes in the triclinic system in the space group P1¯, with a = 10.4432(17), b = 12.2726(16), and c = 13.708(2) Å; α = 88.505(12), β = 75.560(14), and γ = 87.077(12)°; V = 1698.9(4) ų· and Z = 1 and features two metal centers each with three nearly orthogonal TCNE·/- ligands. However, the three TCNE·/- ligands are all dimerized via the formation of four-center, two-electron bonds: two bridge the two Mn(ll) centers, and a third TCNE·/- ligand forms an intermolecular bond to another equivalent TCNE·/-. 2 crystallizes in the tetragonal system in the space group P42212, with a = 17.170(3), b = 17.170(3), and c = 17.1837(6) Å; V = 5065.9(13) ų· and Z = 8. It consists of a ribbon-like coordination polymer containing the previously observed but still relatively rare octacyanobutyl dianion. The [C4(CN)8]2- anion is derived from the dimerization of two TCNE radical anions via the formation of a new σ bond, and each anion bridges four Mn(ll) centers. Both 1 and 2 display magnetic behavior consistent with only weak antiferromagnetic coupling between the high-spin d5 Mn(ll) in which the TCNE·/- are rendered diamagnetic through dimerization. [ABSTRACT FROM AUTHOR]

Abstract: To examine the effect of negatively charged steroidal amphiphiles on antimicrobial activity, two pairs of epimeric, dendritic tricarboxylato amphiphiles – 4-(2-carboxyethyl)-4-[3-(5α-cholestan-3-yl)ureido]heptanedioic acid (1) and 4-(2-carboxyethyl)-4-[3-(5α-cholestan-3-yloxycarbonylmethyl)ureido]heptanedioic acid (2) – were synthesized. A broad antimicrobial screen of 11 microbes revealed that these amphiphiles only showed good activity against a methicillin-resistant isolate of Staphylococcus aureus (MRSA) and modest activity against an unrelated strain of S. aureus. The best activity, a minimal inhibitory concentration (MIC) of 27μM, was found for the 3β epimer of 1 against MRSA. [Copyright &y& Elsevier]

Abstract: The first cryptand/monopyridinium salt [3]pseudorotaxanes were prepared from two cryptand hosts and two bispyridinium guests as confirmed by proton NMR characterization, electrospray ionization mass spectrometry, and X-ray analysis. It was found that the two monopyridinium binding sites are independent of each other for the formation of one [3]pseudorotaxane. [Copyright &y& Elsevier]

Abstract: Seven diquat-based inclusion [2]complexes were studied by proton NMR spectroscopy, electrospray ionization mass spectrometry, and X-ray analysis. The hosts used in these inclusion [2]complexes are bis(5-hydroxymethyl-1,3-phenylene)-32-crown-10, a bis(m-phenylene)-26-crown-8-based cryptand, and five bis(m-phenylene)-32-crown-10-based cryptands. Bis(m-phenylene)-32-crown-10-based cryptands have been proved to be able to complex diquat much more strongly than bis(m-phenylene)-32-crown-10 itself and one containing a pyridyl moiety has one of the highest K a values reported to date. These hosts form 1:1 complexes with diquat in solution and in the solid state. It was found that the improved binding from bis(m-phenylene)-32-crown-10 to bis(5-hydroxymethyl-1,3-phenylene)-32-crown-10 was due to a supramolecular cryptand structure formed by chelation of the two terminal OH moieties of bis(5-hydroxymethyl-1,3-phenylene)-32-crown-10 with a water molecule as a hydrogen-bonding bridge. [Copyright &y& Elsevier]

The pure In isomer of Sc3N@C80 was allowed to react with N-triphenylmethyl-5-oxazolidinone via the corresponding azomethine ylide. The reaction results in the formation of two monoadducts; one (1b) is the kinetic product, and the other (1a) is thermodynamically more stable. Small amounts of the bisadducts were also formed. The structure of the thermodynamic monoadduct 1a was shown conclusively by NMR spectroscopy and X-ray crystallography to result from addition across the 5,6-ring junction. The kinetic product lb was demonstrated to be the 6,6-ring juncture adduct on the basis of NMR experiments and X-ray crystallography. In refluxing chlorobenzene pure lb was converted to the more thermodynamically stable la isomer. These N-tritylpyrrolidino derivatives are potentially useful precursor compounds for further derivatization for various applications. [ABSTRACT FROM AUTHOR]

Abstract: An infinite chain of hydrogen bonded loops of 8 and 10 water molecules are stabilized by the neutral zinc phosphite cluster [Zn4(HPO3)4(2,2′-bipy)4]·11H2O. The cluster is prepared either by direct synthesis or by transformation of a (2,2′-bipy)2Zn2(HPO3)2 4-ring. [Copyright &y& Elsevier]

Abstract: The synthesis of molecule-based magnets derived from decamethylchromocene, , and dialkyl dicyanofumarates, DRDCF, R= n-propyl (nPr) and isopropyl (iPr) yields two new members of a family of charge transfer (CT) salts, these being metamagnetic solids isomorphous with and reminiscent of the known diethyl (R=Et) homolog. The antiferromagnetic properties of these compounds contrast sharply with the previously reported ferromagnetic dimethyl (R=Me) compound. An examination of the four crystal structures provides an explanation for the observed behavior: although the pseudo-one-dimensional mixed stack structure is retained in all of the solids, a new relationship between the stacks is observed for the higher homologs that is different from that found for the DMeDCF salt. In the corresponding decamethylmanganocene, , family, CT salts with DnPrDCF and DiPrDCF are both metamagnets that appear to enter a spin glass state well below their T N’s, exhibiting hysteresis with large very coercivity at 1.8K, again similar to behavior previously seen for the corresponding diethyl compound and different from the dimethyl compound. These and other results reported herein indicate that meaningful structure–property correlations are possible in this class of compounds. [Copyright &y& Elsevier]

Abstract: The first crown ether/monopyridinium threaded structures, which are [2]pseudorotaxanes based on a new bis(m-phenylene)-32-crown-10/monopyridinium recognition motif, were successfully prepared as confirmed by proton NMR spectroscopy, electrospray ionization mass spectrometry, and X-ray analysis. [Copyright &y& Elsevier]

The syntheses and structures of five new zinc phosphites [Zn(HPO3)(C4H6N2)] (1), [Zn2 (HPO3)2 (C10H10N2)2]2 (2), [Zn(HPO3)(C14H14N4)0.5] (3), [Zn2 (HPO3)2 (C14H14N4)]·0.4H2O (4), and [Zn2 (HPO3)2 (C14H14N4)] (5) are reported. In compounds 1–3, the zinc atoms are ligated by 1-methylimidazole, 1-benzylimidazole, and 1 ,4-bis(imidazol-1-ylmethyl)- benzene, respectively, while compounds 4 and 5 are synthesized in the presence of the same bifunctional ligand, 1 ,3-bis(imidazol-1-ylmethyl)benzene. The inorganic framework of compound 1 is composed of vertex-shared ZnO3N and HPO3 tetrahedra that form 4-rings, which, in turn, are linked to generate a one-dimensional ladder structure. In 2, the inorganic framework is composed of 4-rings and 8-rings to form the well-known 4.8² 2D network. This is connected via C—H···π interactions between 1-benzylimidazole Iigand to generate a pseudo-pillared-layer structure. In 3, the inorganic framework again has the 4.8² topology pillared by the bis(imidazole) Iigand, 1 ,3-bis(imidazol-1-ylmethyl)benzene. In 4, a new layer pattern is observed. Specifically, three edge-sharing 4-rings form triple-fused 4-rings. These tertiary building units are further connected to form 12-rings. The alternating triple 4-rings and 12-rings form a previously unknown 20 inorganic sheet. The sheets are joined together by the bis(imidazole) ligand, 1 ,3-bis(imidazol-1-ylmethyl)benzene, to generate a 3D pillared-layer structure. In 4, benzene rings and imidazole rings stack in a zigzag pattern in the interlayer space. A significant role for the triple 4-ring tertiary building unit in the formation of hybrid inorganic/organic metal phosphite structures is proposed for 4 and 5. In 5, the triple 4-rings fuse to give a 1 D stair-step structure. Calculations show that the triple 4-ring pattern observed in the linear ladder structure of 1 is more stable than that in the stair step pattern of 5. [ABSTRACT FROM AUTHOR]

Methyl tricyanoethylenecarboxylate, MTCE, has been used as a one-electron acceptor building block for the synthesis of isomorphous decamethytmetallocene charge-transfer salt magnets of the formula [MCp*2][MTCE], M = Cr, Mn, and Fe. Functionally and electrochemically, MTCE is a hybrid between tetracyanoethylene (TCNE) and dimethyl dicyanofumarate (DMeDCF), two acceptors that have previously been found to support ferromagnetism. The X-ray crystal structure of the chromium analogue, (CrCp*2]-[MTCE], shows it to exist in the expected mixed stack structure in the orthorhombic space group Pnma with a = 14.739(3) Å, b = 10.7869(19) Å, and c = 15.771(3) Å and Z= 4. As anticipated, all three family members exhibit dominant ferromagnetic coupling, which is presumed to reflect intrastack interactions. However, the bulk magnetic properties mostly differ from simple interpolations or extrapolations of the properties of their TCNE and DMeDCF analogues. Density functional theory calculations have been used to shed some light on this observation. [ABSTRACT FROM AUTHOR]

The single-crystal X-ray structure of Ru3(CO)12 is reported at 8 pressures ranging from 1 atm (0.0 CPa) to 8.14(5) GPa. Although intramolecular bonding parameters remain relatively constant, intramolecular and intermolecular nonbonding contact distances decrease by an average of 4% and 15%, respectively. At 8.14 CPa, O···O, C···O, and C···C intermolecular distances as short as 2.54(4), 2.64(6), and 3.07(4) Å, respectively, are observed, and the unit cell compresses to 75% of the ambient pressure volume. Raman and infrared spectroscopic measurements show that carbonyl stretching frequencies shift to higher wavenumber values by as much as 80 cm-1, even though Ru-C and C-O distances stay roughly constant throughout the entire pressure range studied. Compression of the sample to above 18 GPa with laser radiation results in an irreversible transformation due to either decomposition or a total collapse of D3h molecular geometry accompanied by color darkening. [ABSTRACT FROM AUTHOR]

Explores the selective tin-carbon bond cleavage reactions of trimethylstannylzirconocene dichloride with electrophiles. Electrophilic halogenation reactions; General comparisons of tin and silicon; Reactivities of halostannylated complexes toward nucleophiles.

Reports on the structural characterization of OC3OPor capped porphyrins. Crystallographic data; Syntheses; Description of structures; Metrical data for selected systems; Porphyrin distortions.

Describes the synthesis of three five-atom-linked capped porphyrins. Synthesis of the aldehyde arms; Synthesis of caps; Reaction schemes; Structure and properties.

Describes the preparation and structures of two sterically protected ruthenium porphyrin compounds of the type Ru(Por)(H2O)in(CO)out. Structure determination by single-crystal X-ray diffraction methods; Discrete porphyrin units with solvate molecules; Linear arrangement of the carbonyl groups.

Presents a study dealing with the structures of a number of sterically protected porphyrins which have been determined by single-crystal X-ray diffraction methods. Structure of each pocket porphyrin; Types of sterically encumbered porphyrin have been synthesized; Material and techniques used in experiment; Findings from the experiment; Description of porphyrin.

Three new hydroxyl-functionalized secondary benzyl ammonium salts were synthesized and complexed with dibenzo-24-crown-8. Three [2]semirotaxanes and then their two [2]rotaxanes each with two different stoppers were prepared successfully by reactions of the hydroxyl groups with bulky reagents. X-ray analysis of a single crystal of a [2]semirotaxane confirmed its structure. The formation of the [2]semirotaxanes can be reversibly controlled by adding KPF6 and 18-crown-6 sequentially. These new unsymmetrical [2]rotaxanes afford a way to prepare planar chiral rotaxanes and related supramolecular systems. [ABSTRACT FROM AUTHOR]

The adventitious isolation and crystal structure of a pseudorotaxane complex of a trans-substituted dibenzo-27-crown-9-based pyridyl cryptand (6) and N,N'-dimethyl-4,4ʹ-bipyridinium bis(hexafluorophosphate) (5) are reported. [ABSTRACT FROM AUTHOR]

The two isomers 6 and 9 of cis(4,4'-)-dicarbomethoxydibenzo-27-crown-9 with tri- and tetra-(ethyleneoxy) linkages transposed were synthesized regiospecifically in high yields (94 and 92%, respectively) by the Wang-Pederson-Wessels (WPW) protocol and were converted via the corresponding diols 7 and 10 to the corresponding pyridyl cryptands 3 and 4 by reaction with pyridine-2,6-dicarbonyl chloride. As expected from Corey-Pauling-Koltun (CPK) models, the cryptand with the tri(ethyleneoxy) arm para to the ester linkages, "short-armed" cryptand 3, did display a higher binding constant (Ka = 2.4 × 105 M-1) with paraquats than the analogous dibenzo-30-crown-10-based cryptand previously studied; however, the effect was only twofold. Its binding to diquat was reduced by an order of magnitude (1.5 × 105 M-1), as expected on the basis of its narrower cavity. Also as expected, the cryptand with the tetra(ethyleneoxy) arm para to the ester linkages, "long-armed" cryptand 4, possessed diminished binding with both paraquats and diquat relative to the 30-crown-based analogue; in these systems, 2:1 H:G complexes were also detected by mass spectrometry. A crystal structure is reported for 3·DQ(PF6)2. [ABSTRACT FROM AUTHOR]

Pyridinium bis(trifluoromethylsulfonyl)imide (PyTFSI)-templated syntheses of 2,6-pyridyl cryptands of cis(4,4')-dibenzo-30-crown-10 (3a), the p-bromobenzyloxy derivative 3b, bis(m-phenylene)-32-crown-10 (5), cis(4,4')-dibenzo-27S-crown-9 (7), cis(4,4')-dibenzo-27L-crown-9 (9), and cis(4,4')-dibenzo-24-crown-8 (11) are reported. Here we provide a fast (12 h), high-yielding (89%, 74%, 80%, and 62% for 3a, 3b, 5, and 9, respectively) templation method without the use of a syringe pump. The yields for 7 (19%) and 11 (26%) were lower than with the previous pseudo-high-dilution method, indicating ineffective templation in these cases. Coupled with our previously developed templated syntheses of dibenzo crown ethers, this protocol makes powerful cryptand hosts readily available in gram quantities in good yields from methyl 4(or 3)-hydroxy-3(or 4)-benzyloxybenzoate. [ABSTRACT FROM AUTHOR]

We report a tri-n-butyl phosphine catalyzed regio- and stereo-selective hydroboration of ynamides to yield (Z)-β-borylenamides in good yields. Surprisingly, a formal cis addition to the triple bond was observed as confirmed by NMR and X-ray crystallography. 31P NMR studies suggest that a zwitterionic vinylphosphonium intermediate is key in the mechanism. The resulting products were further transformed to β-CF3 enamides via stereoretentive trifluoromethylation. [ABSTRACT FROM AUTHOR]

The readily prepared dipicolinate, diquinaldate, and dinaphthyridate ester derivatives 1c – 1e of bis( m -phenylene)-32-crown-10 (BMP32C10) diol 1b demonstrated improved association constants with diquat ( 3 ) compared with BMP32C10 itself ( 1a ). Importantly, the association constant of dinaphthyridyl BMP32C10 ( 1e ) with diquat is even higher than some BMP32C10-based cryptands, which are synthetically difficult to obtain. An unusual pseudocryptand-type alternating poly[2]pseudorotaxane was formed between 1e and diquat in the solid state. [ABSTRACT FROM AUTHOR]

The lithium aluminosilicate mineral petalite (LiAlSi4O10) has been studied with high-pressure single-crystal X-ray diffraction (HP-XRD) up to 5 GPa. Petalite undergoes two fully reversible pressure-induced first-order phase transitions, not previously reported in the literature, at ca. 1.5 and 2.5 GPa. The first of these transforms the low-pressure α-phase of petalite (P2/c) to an intermediate β'-phase that then fully converts to the high-pressure β-phase at ca. 2.5 GPa. The α → β transition is isomorphic and is associated with tripling of the unit-cell volume. Analysis of the HP-XRD data show that although the fundamental features of the petalite structure are retained through this transition, there are subtle alterations in the internal structure of the silicate double-layers in the β-phase relative to the α-phase. Measurement of the unit-cell parameters of petalite as a function of pressure, and fitting of the data with third-order Birch-Murnaghan equation of state, has provided revised elastic constants for petalite. The bulk moduli of the α- and β-phases are 49(1) and 35(3) GPa, respectively. These values indicate that the compressibility of the α-phase of petalite lies between those of the alkali feldpsars and alkali feldspathoids, whereas the β-phase has a compressibility more comparable with layered silicates. Structure analysis has shown that the compression of the α-phase is facilitated by the rigid body movement of the Si2O7 units from which the silicate double-layers are constructed. [ABSTRACT FROM AUTHOR]

The new triterpene turranoic acid(1) and the newN-containing nor-triterpene turraenine (2), along with triptocallic acid B (3) and esculentoicacid (4) were isolated from leaves of a Turraeasp. Compounds 1–3showed weak tomoderate in vitro antiplasmodial activity against the chloroquine-resistant Plasmodium falciparumstrain FCM29. Compound 1also displayed weak cytotoxic activity against the nonsmall lungcancer cell line H522-T1 with an IC50value of 16.4 μM. [ABSTRACT FROM AUTHOR]

We report a chemoselective, phosphine‐catalyzed semireduction of primary and secondary propiolamides. In the presence of stoichiometric pinacolborane and catalytic n‐tributylphosphine, a variety of propiolamides were successfully converted to the corresponding acrylamides in excellent yield with (E)‐stereoselectivity. The reaction condition is tolerant of various functional groups including alkene, alkyne, ketone, or ester. Deuterium labeling studies established that the hydride from activated pinacolborane is added to the α‐carbon and the proton on the amide nitrogen is abstracted by the ß‐carbon to furnish the (E)‐acrylamides. DFT calculations revealed a clear energetic driving force for the (E)‐ over the (Z)‐isomer. [ABSTRACT FROM AUTHOR]

Abstract: Two new cobalt(II) and zinc(II) coordination networks constructed from an anthracene based bis imidazole ligand, 9,10-bis(imidazol-1-ylmethyl)anthracene ligand (L), are reported. The compounds {[Co (HBTC2−) (L) (H2O)2]·H2O}∞(1) and {[Zn (HBTC2−) (L) (H2O)2]·H2O}∞(2) were synthesized under solvothermal conditions and structurally characterized by single X-ray diffraction analysis and thermogravimetric analysis. Both 1 and 2 have a one-dimensional covalently bonded (1D) zigzag chain structure that is linked into infinite two-dimensional (2D) sheets by inter-chain π···π stacking and hydrogen bonding. [Copyright &y& Elsevier]

Enantiopure amino-acid derived 1H-benzo[e][1,4]diazepin-2(3H)-ones (BZDs) undergo highly retentive deprotonation/alkylation reactions. To confirm the role of stereolabile, axially chiral intermediates in these reactions and to determine the precise stereochemical course of deprotonation and alkylation, a new alanine-derived BZD (S)-1d was prepared. Because of slow diazepine ring inversion of the C3-alkylated derivatives of 1d, it proved possible to determine that electrophiles react at the concave face of the enolate derived from 1d. Furthermore, an enantiopure silyl enol ether derivative of (S)-1d was prepared and characterized by X-ray crystallography, confirming that deprotonation resulted in an (M)-configured axially chiral enolate. Activation parameters for diazepine ring inversion in the potassium enolate of 1d were determined experimentally and are well-matched by density functional calculations. Finally, the factors leading to concave-face alkylation of the enolate derived from 1d are analyzed based on calculated alkylation transition structures. Minimization of torsional effects at the BZD ring fusion and maximization of imine and amide resonance are proposed to favor concave-face alkylation. [ABSTRACT FROM AUTHOR]

Abstract: The ligand 4,4′-bisimidazolylbiphenyl has been used to prepare three new 2D hybrid networks: (C18H14N4)CuSO4 ·H2O (1), (C18H14N4)2Ni(H2PO3)2 (2), and (C18H14N4)3Ni3(H2PO4)2(HPO4)2 ·4H2O (3). All structures have been fully elucidated by single-crystal X-ray diffraction. The 2D hybrid sheets in crystal structures of complexes 1 and 2 are packed in simple AAA stacking arrangement. Conversely, in 3 the sheets are interdigitated. The topologies of the two nickel-based networks are strongly dependant on the nature of the acid employed in the synthesis procedure. [Copyright &y& Elsevier]