Ligand-Promoted Rh(III)-Catalyzed Coupling of Aryl C–H Bonds with Arylboron Reagents

Rhodium­(III)-catalyzed C–H arylation of arenes with phenylboronic acid pinacol esters has been achieved using a readily removable <i>N</i>-pentafluorophenylbenzamide directing group for the first time. The use of a bidentate phosphine ligand (Binap) significantly increased the yield of the cross-coupling of C–H bonds with organoboron reagents

La Charente

13 octobre 18851885/10/13 (A14,N5373)-1885/10/13.Appartient à l’ensemble documentaire : PoitouCh

Ligand-Promoted Rh(III)-Catalyzed Coupling of Aryl C–H Bonds with Arylboron Reagents

Rhodium­(III)-catalyzed C–H arylation of arenes with phenylboronic acid pinacol esters has been achieved using a readily removable <i>N</i>-pentafluorophenylbenzamide directing group for the first time. The use of a bidentate phosphine ligand (Binap) significantly increased the yield of the cross-coupling of C–H bonds with organoboron reagents

Solvent-modulated zinc^II networks with different stacking arrangements

<div><p>Two Zn^II complexes, [Zn₂(L)₂(DMF)(H₂O)₂]·DMF (<b>1</b>) and [Zn(L)(DEF)]·DEF (<b>2</b>), were synthesized by solvothermal reactions using 4,4′-(2,3,5,6-tetramethylbenzene1,4-diyl)dibenzoic acid (H₂L) and Zn(NO₃)₂·6H₂O in different solvents of DMF, ethanol, and water for <b>1</b> and N,N-diethylformamide (DEF) for <b>2</b>. The L²⁻ with different coordination modes connect [Zn₂(COO)₂] secondary building units (SBUs) to generate a wavy 2-D (4,4) network of <b>1</b> while in <b>2</b> there are paddlewheel [Zn₂(COO)₄] SBUs which are connected by L²⁻ to form a planar 2-D (4,4) network. The 2-D layered structures show different stacking arrangements and are further linked by hydrogen bonding or C–H⋯π interactions to give 3-D architectures. The different structures and stacking arrangements of <b>1</b> and <b>2</b> result from different reaction solvents. Photoluminescence properties of the complexes were investigated.</p></div

Syntheses, Structures, and Sorption Properties of Metal–Organic Frameworks with 1,3,5-Tris(1-imidazolyl)benzene and Tricarboxylate Ligands

Seven new frameworks [Co₃(tib)₂(BPT)₂­(H₂O)₂]­·DMA­·2.5H₂O (<b>1</b>), [Co₃(tib)₂­(BPT)₂­(H₂O)₂]­·DMF·3H₂O (<b>2</b>), [Ni₃(tib)₂­(BPT)₂­(H₂O)₂]­·DMF­·1.5H₂O (<b>3</b>), [Ni₃(tib)₂(BPT)₂­(H₂O)₆]­·2H₂O (<b>4</b>), [Mn­(tib)­(H₂O)₃]­·HBPT·DMF­·2H₂O (<b>5</b>), [Ni₃(tib)₂(BTB)₂­(H₂O)₂]­·14H₂O (<b>6</b>), and [Co₃(tib)₂(BTB)₂]­·2DMF­·6H₂O (<b>7</b>) [tib = 1,3,5-tris­(1-imidazolyl)­benzene, H₃BPT = biphenyl-3,4′,5-tricarboxylic acid, H₃BTB = 4,4′,4″-benzene-1,3,5-triyl-tribenzoic acid, DMA = <i>N</i>,<i>N</i>-dimethylacetamide, DMF = <i>N</i>,<i>N</i>-dimethylformamide] were achieved and structurally characterized. <b>1</b>, <b>2</b>, and <b>3</b> are (3,3,4,4)-connected three-dimensional (3D) frameworks with a point symbol of {8³}₄{8⁵·12}­{8⁶}₂, while <b>4</b>, <b>6</b>, and <b>7</b> are also (3,3,4,4)-connected 3D nets but with different framework structures and topologies. <b>5</b> is a two-dimensional network, which is further joined together by hydrogen bonds to generate a 3D supramolecular framework. Gas, vapor, and dye adsorption properties of the frameworks were examined, and <b>1</b>–<b>7</b> exhibit hysteretic and selective adsorption of CO₂ over N₂. Furthermore, <b>7</b> is a potential adsorbent for removing methylene blue in the aqueous solution

Novel (3,4,6)-Connected Metal–Organic Framework with High Stability and Gas-Uptake Capability

A microporous and noninterpenetrated metal–organic framework [Cu₃(L)₂(DABCO)­(H₂O)]·15H₂O·9DMF (<b>1</b>) has been synthesized using two different ligands, [1,1′:3′,1″-terphenyl]-4,4″,5′-tricarboxylic acid (H₃L) and 1,4-diazabicyclo[2.2.2]­octane (DABCO). As revealed by variable-temperature powder X-ray diffraction (VT-PXRD) measurements, <i>N</i>,<i>N</i>′-ditopic DABCO plays an important role for stabilization of the Cu–L framework. The three-dimensional framework of <b>1</b> exhibits high stability and excellent adsorption capacity for H₂ (54.3 mg g^–1 at 77 K and 20 bar), CO₂ (871 mg g^–1 at 298 K and 20 bar), CH₄ (116.7 mg g^–1, 99 cm³ (STP) cm^–3 at 298 K and 20 bar), and <i>n</i>-pentane (686 mg g^–1 at 298 K and 1 bar). Interestingly, the excellent selectivity toward CO₂ over N₂ at ambient temperature (273 and 298 K) and 1 bar makes complex <b>1</b> possess practical application in gas separation and purification

Novel (3,4,6)-Connected Metal–Organic Framework with High Stability and Gas-Uptake Capability

A microporous and noninterpenetrated metal–organic framework [Cu₃(L)₂(DABCO)­(H₂O)]·15H₂O·9DMF (<b>1</b>) has been synthesized using two different ligands, [1,1′:3′,1″-terphenyl]-4,4″,5′-tricarboxylic acid (H₃L) and 1,4-diazabicyclo[2.2.2]­octane (DABCO). As revealed by variable-temperature powder X-ray diffraction (VT-PXRD) measurements, <i>N</i>,<i>N</i>′-ditopic DABCO plays an important role for stabilization of the Cu–L framework. The three-dimensional framework of <b>1</b> exhibits high stability and excellent adsorption capacity for H₂ (54.3 mg g^–1 at 77 K and 20 bar), CO₂ (871 mg g^–1 at 298 K and 20 bar), CH₄ (116.7 mg g^–1, 99 cm³ (STP) cm^–3 at 298 K and 20 bar), and <i>n</i>-pentane (686 mg g^–1 at 298 K and 1 bar). Interestingly, the excellent selectivity toward CO₂ over N₂ at ambient temperature (273 and 298 K) and 1 bar makes complex <b>1</b> possess practical application in gas separation and purification

Iodoarene-Catalyzed Stereospecific Intramolecular sp³ C–H Amination: Reaction Development and Mechanistic Insights

A new strategy is reported for intramolecular sp³ C–H amination under mild reaction conditions using iodoarene as catalyst and <i>m</i>-CPBA as oxidant. This C–H functionalization involving iodine­(III) reagents generated in situ occurs readily at sterically hindered tertiary C–H bonds. DFT (M06-2X) calculations show that the preferred pathway involves an iodonium cation intermediate and proceeds via an energetically concerted transition state, through hydride transfer followed by the spontaneous C–N bond formation. This leads to the experimentally observed amination at a chiral center without loss of stereochemical information

Iodoarene-Catalyzed Stereospecific Intramolecular sp³ C–H Amination: Reaction Development and Mechanistic Insights

A new strategy is reported for intramolecular sp³ C–H amination under mild reaction conditions using iodoarene as catalyst and <i>m</i>-CPBA as oxidant. This C–H functionalization involving iodine­(III) reagents generated in situ occurs readily at sterically hindered tertiary C–H bonds. DFT (M06-2X) calculations show that the preferred pathway involves an iodonium cation intermediate and proceeds via an energetically concerted transition state, through hydride transfer followed by the spontaneous C–N bond formation. This leads to the experimentally observed amination at a chiral center without loss of stereochemical information

Cucurbit[6]uril-Based Supramolecular Assemblies: Possible Application in Radioactive Cesium Cation Capture

Multidimensional supramolecular assemblies based on cucurbit­[<i>n</i>]­uril (<i>n</i> = 6 or 7) were constructed via the outer-surface interactions of cucurbit­[<i>n</i>]­urils with the polyaromatic compound 4,4′,4″-benzene-1,3,5-triyl-tribenzoate as a structure-directing agent. Most impressively, the cucurbit[6]­uril-based assembly exhibits high selectivity for capture of cesium cations among the common alkali metal ions in a basic medium and releases the cesium cations under acidic conditions. This reversible process enables possible applications in cesium cation capture