- Template-directed synthesis of mechanically interlocked molecular bundles using dynamic covalent chemistry
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Mixing the dipyrido[24]crown-8 derivatives carrying one or two formyl group(s) on the 4 position(s) of their pyridine ring(s) with a 3-fold symmetrical trisammonium ion template in a 3:1 ratio in CD3NO 2 results in the formation of t
- Northrop, Brian H.,Arico, Fabio,Tangchiavang, Nick,Badjic, Jovica D.,Stoddart, J. Fraser
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- Chiral and phase transfer agents 8. Synthesis of two chiral monoaza-18-crown-6 ethers from 1,3:2,4-di-O-ethylidene-D-glucitol and pyridine-2,6-dimethanol
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Starting from 1,3:2,4-di-O-ethylidene-D-glucitol (1), two regioisomeric monoaza-18-crown-6 ethers with C2 symmetry were synthesized.A simple route was suggested for the preparation of a diol that is a convenient intermediate for the synthesis o
- El'perina, E. A.,Struchkova, M. I.,Serkebaev, M. I.,Serebryakov, E. P.
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- Synthesis, structural aspects, antimicrobial activity and ion transport investigation of five new [1+1] condensed cycloheterophane peptides
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Five novel [1+1] condensed cycloheterophane peptides were synthesized via reaction of pyridine-2,6-bis(2-aminothiophenoxymethyl) with several diacid chlorides: glutaryl dichloride, adipoyl dichloride, 2,2′-thiodiacetyl chloride, dithiodiglycoloyl chloride and 3,3′-thiodipropionoyl chloride combinations (L 1 -L 5 ). The compounds were characterized by elemental analyses, mass, FT-IR, 1H, and 13C NMR spectral data. The antimicrobial activities of the compounds were evaluated using the disk diffusion method in dimethyl sulfoxide as well as the minimal inhibitory concentration dilution method, against several bacteria and yeast cultures. The results were compared with those of commercial antibiotic and antifungal agents. Structure activity relationships were also discussed. Permeability of compound L 5 against Na+ and K+ were also investigated. Graphical abstract: Five novel cycoloheterophane amides were synthesized. Mass spectra reveal their [1+1] cyclic condensation. The compounds exert moderate microbial activity. Thia and aza groups seem to be a key element of microbial potency.[Figure not available: see fulltext.]
- Zaim, Oemer,Aghatabay, Naz Mohammed,Guerbuez, Mustafa Ulvi,Baydar, Caglar,Duelger, Basaran
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- Synthesis, spectroscopic characterization and density functional studies of a bis-benzimidazole derivative and of its complexes with palladium(II) halides
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The 2,6-bis(benzimidazol-2′-ylthiomethyl)pyridine (L) ligand and its palladium(II) complexes [Pd(L)X]X (X = Cl, Br, and I) have been synthesized and characterized by spectroscopic data acquisition. The ligand (L) was prepared by conventional heating as well as by microwave irradiation. Microwave irradiation shows additional features, including an easy workup, a much faster reaction and higher yields. The molar conductivity data reveal that the complexes form a 1:1 electrolyte in DMSO. The geometries, ground-state energetics and vibrational spectra of (L) and of its complexes have been elucidated, in terms of quantum chemical calculations. In the mononuclear complexes, the palladium atom is coordinated to three nitrogen atoms and one terminal halogen atom in a slightly distorted square planar arrangement. The present elemental analyses, FT-IR (mid, far), 1H and 13C NMR spectra are in good accordance with the square planar geometry around the Pd ion. The thermal behaviors of the complexes have been assessed by thermal gravimetric and differential thermal analyses.
- Aghatabay, Naz Mohammed,Altun, Ahmet,Gürbüz, Mustafa Ulvi,Türkyilmaz, Murat
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- Group 12 Metal Complexes of an 18-Membered N2O2S2 Macrocycle Incorporating Two Pyridines: First Examples of an Infinite Mercury(I) Complex and a Dumbbell-Shaped Heteronuclear Complex with a Macrocyclic Ligand
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Homo- and heteronuclear group 12 metal (Zn2+, Cd2+, and Hg2+) complexes 1-6 containing a newly designed 18-membered N2O2S2 macrocycle incorporating two pyridine subunits (L) were prepared a
- Seo, Sujin,Ju, Huiyeong,Kim, Seulgi,Park, In-Hyeok,Lee, Eunji,Lee, Shim Sung
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- P-stereogenic diphosphacrowns: Facile incorporation of aromatic rings
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P-Stereogenic diphosphacrowns containing naphthalene and pyridine rings were synthesized. Facile incorporation of aromatic rings, and chains of different lengths, into the diphosphacrown skeleton was achieved by altering the electrophile in our previously
- Kato, Ryosuke,Watanabe, Hiroyuki,Morisaki, Yasuhiro,Chujo, Yoshiki
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- New advances in the synthesis of tripyridinophane macrocycles suitable to enhance the luminescence of Ln(III) ions in aqueous solution
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A series of four new 18-membered hexaaza macrocyclic ligands bearing three endocyclic pyridine units and acetate or methylenephosphonate pendant arms has been prepared. The new synthetic procedure is based on the use of amine and diamine precursors incorporating masked carboxylate or phosphonate functions and on an efficient sodium template effect which controls the crucial macrocyclization step (yields of macrocyclization reactions: 62–88%). This procedure appears as a suitable alternative compared to the classical Richman-Atkins methodology generally used for the preparation of this class of macrocycles. As demonstrated with the EuIII and TbIII complexes derived from two ligands, these tripyridinophane chelators form luminescent and stable mononuclear LnIII complexes in aqueous solution at physiological pH. In such a medium, TbIII complexes exhibit a brightness of 1700 (λexc = 279 nm) and 3000 (λexc = 268 nm) M?1 cm?1.
- Leygue, Nadine,Perez e I?iguez De Heredia, Aritz,Galaup, Chantal,Benoist, Eric,Lamarque, Laurent,Picard, Claude
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- The enantiomeric recognition of chiral organic ammonium salts by chiral pyridino-macrocycles bearing aminoalcohol subunits
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Pyridine-based macrocycles were prepared by treating 2,6-bis[[2′6′-bis(bromomethyl)-4′-methylphenoxy]methyl]pyridine 3 with the appropriate chiral aminoalcohols. The enantiomeric recognition of these macrocycles bearing aminoalcohol subunits of the pyridinocrown type ligand was evaluated for chiral organic ammonium salts by UV titration. The important differences were observed in the Ka values of (R)-Am2 and (S)-Am2 for (S,S,S)-1, (S,S,S)-2 and (S,S,S)-3 hosts, KS/KR = 5.0, KS/KR = 2.4 and KS/KR = 5.0, respectively. There seems to be a general tendency for hosts to recognise (S)-enantiomers for both Am1 and Am2.
- Ozer, Hayriye,Kocakaya, Safak Ozhan,Akgun, Abuzer,Hosgoeren, Halil,Togrul, Mahmut
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- Switching from Ethylene Trimerization to Ethylene Polymerization by Chromium Catalysts Bearing SNS Tridentate Ligands: Process Optimization Using Response Surface Methodology
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Two types of chromium catalysts bearing pyridine and amine based SNS ligands under the title of (pyridine-SNS-alkyl/CrCl3) and (amine-SNS-alkyl/CrCl3) were synthesized. Different thiolates such as octyl, pentyl, butyl, cyclohexyl and cyclopentyl thiolates were reacted with 2,6-pyridine-dimethylene-ditosylate (PMT)/THF solution at room temperature. Then, the purified pyridine-based SNS ligands (1–5) were reacted with CrCl3 (THF)3 to obtain the pyridine-SNS-alkyl/CrCl3 catalysts (6–10) in 50–70% yields. MMAO-activated pyridine-SNS-alkyl/CrCl3 catalysts were capable of oligomerizing ethylene. Statistical experimental design was conducted using the central composite design method and surface methodology to study of the effect of important parameters such as ethylene pressure, Al/Cr ratio, catalyst concentration and the reaction temperature on 1-C6 productivity of catalyst (7). A quadratic polynomial equation was developed to predict the 1-C6 productivity. Ethylene oligomerization using the catalyst (7) was lead to a optimized reaction conditions, including the ethylene pressure of 19.5?bar, the temperature of 58.2?°C, the MMAO co-catalyst, Al/Cr = 841 and the catalyst concentration of 8.7?μmol. The catalytic properties for ethylene oligomerization are strongly affected by reaction temperature. The experimental results indicated the reasonable agreement with the predicted values. The transformation from ethylene trimerization to ethylenev polymerization of catalyst system (7) was occurred by exchanging the reaction pressure. Influence of ligand structure with different substitutions on sulphur atom on productivity and selectivity was investigated. 1-C6 with the high selectivity and productivity 4318 (g 1-C6/g Cr h) was obtained for catalyst (7). In the second part, 1-C6 was obtained with high selectivity and productivity around 141 × 103 (g 1-C6/g Cr h) for amine-based catalyst. All amine-based catalysts (14–16) showed considerably higher catalytic activities compared to pyridine-based catalysts. According to the TGA analysis the thermal stability of pyridine-based catalysts was found to be higher than the amine-based catalysts. Graphical Abstract: Chromium complexes bearing pyridine and amine based SNS ligands have been synthesized and their catalytic performance in ethylene oligomerization has been investigated. A switching from ethylene trimerization to ethylene polymerization of the catalyst (7) was obtained utilizing exchanging of the ethylene pressure. [Figure not available: see fulltext.].
- Soheili, Majid,Mohamadnia, Zahra,Karimi, Babak
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p. 3685 - 3700
(2018/10/15)
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- Improved synthesis of symmetrically & asymmetrically: N -substituted pyridinophane derivatives
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The N,N′-di(toluenesulfonyl)-2,11-diaza[3,3](2,6)pyridinophane (TsN4) precursor was sought after as a starting point for the preparation of various symmetric and asymmetric pyridinophane-derived ligands. Various procedures to synthesize TsN4 had been published, but the crucial problem had been the purification of TsN4 from the larger 18- and 24-membered azamacrocycles. Most commonly, column chromatography or other laborious methods have been utilized for this separation, yet we have found an alternate selective dissolution method upon protonation which allows for multi-gram scale output of TsN4·HCl. This optimized synthesis of TsN4 also led to the development of symmetric RN4 derivatives as well as the asymmetric derivative N-(tosyl)-2,11-diaza[3,3](2,6)pyridinophane (TsHN4). Using this TsHN4 precursor, different N-substituents can be added to create a library of asymmetric RR′N4 macrocyclic ligands. These asymmetric RR′N4 derivatives expand the utility of the RN4 framework in coordination chemistry and the ability to study the electronic, steric, and denticity effects of these pyridinophane ligands on the metal center.
- Wessel, Andrew J.,Schultz, Jason W.,Tang, Fengzhi,Duan, Hui,Mirica, Liviu M.
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p. 9923 - 9931
(2017/12/12)
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- Tuning Catalytic Activity in the Hydrogenation of Unactivated Olefins with Transition-Metal Oxos as the Lewis Base Component of Frustrated Lewis Pairs
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The steric and electronic demands of the catalytic olefin hydrogenation of tert-butylethylene with oxorhenium/Lewis acid FLPs were evaluated. The sterics of the ligand were altered by installing bulkier isopropyl groups in the 2,6-positions of the diamidopyridine (DAP) ligand. Lewis acid/base adducts were not isolated for complexes with this ligand; however, species incorporating isopropyl groups were still active in catalytic hydrogenation. Modifications were also made to the Lewis acid, and catalytic reactions were performed with Piers' borane, HB(C6F5)2, and the aluminum analogue Al(C6F5)3. The rate of catalytic hydrogenation was shown to strongly correlate with the size of the alkyl, aryl, or hydride ligand. This was confirmed by a linear Taft plot with the steric sensitivity factor δ = -0.57, which suggests that reaction rates are faster with sterically larger X substituents. These data were used to develop a catalyst ((MesDAP)Re(O)(Ph)/HB(C6F5)2) that achieved a TON of 840 for the hydrogenation of tert-butylethylene at mild temperatures (100 °C) and pressures (50 psi of H2). Tuning of the oxorhenium catalysts also resulted in the hydrogenation of tert-butylethylene at room temperature.
- Lambic, Nikola S.,Sommer, Roger D.,Ison, Elon A.
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p. 1170 - 1180
(2017/08/09)
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- Synthesis, characterization, and ethylene polymerization behavior of Cr(III) catalysts based on bis(pyrazolylmethyl)pyridine and its derivatives
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New chromium(III) [Cr(III)] catalysts based on 2,6-bis(pyrazol-1-ylmethyl) pyridine derivatives have been synthesized, characterized, and evaluated for ethylene polymerization. All ligands with substituents on the pyrazole rings were analyzed by single-cr
- Woo, Jeong Oh,Kang, Sung Kwon,Park, Jong-Eun,Son, Kyung-Sun
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p. 204 - 210
(2015/05/20)
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- Binding of secondary dialkylammonium salts by pyrido-21-crown-7
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Pyrido-21-crown-7 (P21C7) has been synthesized and shown to form [2]pseudorotaxanes spontaneously with secondary dialkylammonium ions. These complexes are stronger than their benzo-21-crown-7 counterparts and much stronger than their dibenzo-24-crown-8 counterparts. Based on this new P21C7/secondary dialkylammonium salt recognition motif, a [2]rotaxane terminated by phenyl groups as stoppers has been successfully constructed using the threading-followed-by-stoppering technique.
- Zhang, Chuanju,Zhu, Kelong,Li, Shijun,Zhang, Jinqiang,Wang, Feng,Liu, Ming,Li, Ning,Huang, Feihe
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supporting information; experimental part
p. 6917 - 6920
(2009/04/07)
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- Self-complementary [2]catenanes and their related [3]catenanes
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Three [3]catenanes with cavities large enough to accommodate aromatic guests have been designed and synthesized (yields = 5-20%) by means of kinetically controlled self-assembly processes. The X-ray structural analysis of one of three [3]catenanes confirmed the presence of a rectangular cavity (dimensions = 7 ×11 A) lined by π-electron-rich recognition sites and hydro-gen-bond acceptor groups. In spite of their apparently ideal recognition features, none of these [3]catenanes bind guests incorporating a π-electron-deficient bipyridinium unit. However, the template-directed syntheses of the [3]catenanes also produce, in yields of 2-23%, [2]catenanes incorporating a l,5-dioxynaphtho[38]crown-10 inter-locked with a bipyridinium-based tetracationic cyclophane. The X-ray structural analyses of two of these [2]catenanes revealed that a combination of [π...π] and [C-H...π] interactions is responsible for the formation of supramolecular homodimers in the solid state. 1H NMR spectroscopic investigations of the four [2]catenanes demonstrated that supramolecular homodimers are also formed (Ka= 17-31M-1, T= 185 K) in (CD3)2CO solutions. Dynamic 1H NMR spectroscopy revealed that the 1,5-dioxynaphtho[38]crown-10 and tetracationic cyclophane components in the four [2]catenanes and in the three [3]catenanes circumrotate (ΔGC? = 9-14 kcal mol-1) through each other's cavity in (CD3)2CO. Similarly, the 1,5-dioxynaphthalene and the bipyridinium ring systems rotate (ΔGc? =10-14 kcalmol-1) about their [O...O] and [N ... N] axes, respectively, in solution.
- Cabezon, Beatriz,Cao, Jianguo,Raymo, Francisco M.,Stoddart, J. Fraser,White, Andrew J. P.,Williams, David J.
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p. 2262 - 2273
(2007/10/03)
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- A new efficient method for the preparation of 2,6-pyridinedimethyl ditosylates from dimethyl 2,6-pyridinedicarboxylates
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We report here an efficient method for the preparation of 2,6- pyridinedimethyl ditosylate and four of its 4-substituted derivatives, two of them have not been reported in the literature. We also describe here a modification of the reported synthesis for chelidonic and chelidamic acids with improved yields and higher purity.
- Horváth, Gy?rgy,Rusa, Cristian,K?nt?s, Zoltán,Gerencsér, János,Huszthy, Péter
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p. 3719 - 3731
(2007/10/03)
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- Enantiomeric Recognition of Organic Ammonium Salts by Chiral Dialkyl-, Dialkenyl-, and Tetramethyl-Substituted Pyridino-18-crown-6 and Tetramethyl-Substituted Bis-pyridino-18-crown-6 Ligands: Comparison of Temperature-Dependent 1H NMR and Empirical Force
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Six new chiral pyridino-18-crown-6 and one chiral bis-pyridino-18-crown-6 ligands have been prepared.The pyridino-crowns contain either two isopropyl, two isobutyl, two (S)-sec-butyl, two benzyl, two 3-butenyl, or four methyl substituents on chiral macror
- Bradshaw, Jerald S.,Huszthy, Peter,McDaniel, Christopher W.,Zhu, Cheng Y.,Dalley, N. Kent,et al.
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p. 3129 - 3137
(2007/10/02)
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