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Structurally authenticated complexes of the cone-shaped p -sulfonatocalix[4]arene and conformationally flexible p -sulfonatocalix[6]arene devoid of co-ligands/ancillary molecules are limited. Early and late members of the lanthanide series as their trivalent ions, La3+, Er3+, and Yb3+, form complexes from aqueous media under these conditions. For La3+ and Er3+, distinct hydrophobic and hydrophilic bilayers are formed with p -sulfonatocalix[4]arene, whereas for Yb3+, two complexes form that deviate from the well-known bilayer arrangement of calixarenes. Replacing the calixarene with p -sulfonatocalix[6]arene results in a hydrogen-bonded network with alternating hydrophobic–hydrophilic layers associated with primary coordination of Yb3+, with the larger macrocyclic calixarene in a partial cone conformation. Bilayers are created when cone-shaped p -sulfonatocalix[4]arene forms complexes with La3+ and Er3+, whereas with Yb3+ overall assembly deviates from the bilayer arrangement. With conformational flexible p -sulfonatocalix[6]arene, this results in a hydrogen bonded network with alternating hydrophobic-hydrophilic layers associated with primary coordination of Yb3+, with the calixarene crystallised in a partial cone conformation. [ABSTRACT FROM AUTHOR]

An efficient and halogen-free catalytic methodology for the synthesis of β-amino alcohols from aromatic amines and biomass-derived carbohydrates is demonstrated for the first time. The activation of C5/C6 sugars by a ruthenium catalyst selectively generates the C2 alkylating reagent glycolaldehyde. The transformation involves metal-catalyzed hydrogen borrowing for the reduction of the imine intermediate. A series of arylamines bearing various substituents were successfully transformed into the desired products in good to excellent yields. [ABSTRACT FROM AUTHOR]

Nanoparticles of trans-β-carotene are accessible using spinning disk processing (SDP), by varying the reaction conditions and the choice of surfactant, macrocyclic amphiphiles, sulfonato-calix[4,5,6,8]arenes, and α,β-cyclodextrins. SDP ensures rapid mixing and fast kinetics, and nanoparticles of the carotene formed in the presence of the calixarenes are stable with respect to extraction of the carotene into an organic solvent, unlike in the presence of the cyclodextrins. Insight into the supramolecular structure of the carotene nanoparticles has also been established. The mean particle sizes (dynamic light scattering, DLS) have been optimized at 40(2) and 56(1) nm and 71.4(6) and 82(1) nm, respectively, for each sulfonato-calix[5,6 and 4,8]arene, whereas the cyclodextrins form nanoparticles with a mean diameter of 71(1) and 68.5(6) nm, respectively. ζ-Potential studies show stability of all the colloidal dispersions at pH > 4 with values below -30 mV. UV-visible spectroscopy shows a blue shift indicative of H-aggregates of the carotene within the nanoparticles. The surface area derived from BET studies is 39.12 m²/g corresponding to particles of 76.7(5) nm in diameter, in agreement with sizes obtained from DLS and TEM measurements. [ABSTRACT FROM AUTHOR]

Toluene solutions of fullerene C70 and t-Bu-calix[6]arene form a 2:1 inclusion complex that has been structurally authenticated using synchrotron source X-ray diffraction data. Remarkably, the fullerene is not included in the cavity of the calixarene, and this has implications in predicting the structures of fullerene complexes of other calixarenes and container molecules. The fullerenes shroud the exo surface of the calixarene at the van der Waals limit, with the fullerenes arranged into corrugated sheets, with each calixarene interdigitated at the upper rim with the upper rim of two other calixarenes, the macrocycles forming a bilayer separating the sheets of fullerenes. Toluene solutions of fullerene C70 and t-Bu-calix[6]arene form a 2:1 solid-state inclusion complex. The fullerenes shroud the exo surface of the calixarene at the van der Waals limit, with the fullerenes arranged into corrugated sheets, with interdigitated calixarenes through the upper rims forming a bilayer between the sheets of fullerenes. [ABSTRACT FROM AUTHOR]

We report sodium trihydroxyaryl borates as the first robust tetracoordinate organoboron catalysts for reductive functionalization of CO2. These catalysts, easily synthesized from condensing boronic acids with metal hydroxides, activate main group element–hydrogen (E–H) bonds efficiently. In contrast to BX3 type boranes, boronic acids and metal-BAr4 salts, under transition metal-free conditions, sodium trihydroxyaryl borates exhibit high reactivity of reductive N-formylation toward a variety of amines (106 examples), including those with functional groups such as ester, olefin, hydroxyl, cyano, nitro, halogen, MeS–, ether groups, etc. The over-performance to catalyze formylation of challenging pyridyl amines affords a promising alternative method to the use of traditional formylation reagents. Mechanistic investigation supports electrostatic interactions as the key for Si/B–H activation, enabling alkali metal borates as versatile catalysts for hydroborylation, hydrosilylation, and reductive formylation/methylation of CO2. [ABSTRACT FROM AUTHOR]

Zirconium fluoride was utilized to promote efficiently iron‐catalyzed aminocarbonylation between alkynes and amines without the use of extra ligands. In particular, this new system is applicable to a wide range of amine and alkyne substrates affording α,β‐unsaturated amides in good to excellent yields. Preliminary mechanistic studies reveal the activation model involving interactions of ZF4 with both iron catalyst and amine substrates. [ABSTRACT FROM AUTHOR]

1,10-Phenanthroline reacts with malonitrile and aldehydes in the presence of isocyanides as domino-Knoevenagel-nucleophilic cycloaddition for generation of a new class of 10-(aryl)-11-(alkyl- or arylamino-)pyrrolo[1,2- a][1,10]phenanthroline-9-carbonitrile compounds in excellent yield. All compounds are fully characterized with one structurally authenticated by a single X-ray diffraction study. [ABSTRACT FROM AUTHOR]

A series of diverse NH- and CH-acids are used for a one-pot synthesis of stable phosphorus ylides and 1,4-diionic organophosphorus compounds by trapping of the zwitterionic intermediate from the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates under solvent-free conditions. The structural geometry for one of the products was confirmed by single crystal X-ray diffraction analysis. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. [ABSTRACT FROM PUBLISHER]

A new dipicolinate complex of Ru(II), cis-[Ru(phen)2dipic] · 9.5H2O (1), where dipic is dipicolinate or pyridine-2,6-dicarboxylate and phen is 1,10-phenanthroline, has been synthesized and characterized by elemental analysis, spectroscopic (IR, UV-Vis), cyclic voltammetry, and single-crystal X-ray diffraction. ORTEP drawing of cis-[Ru(phen)2dipic] · 9.5H2O shows that the coordination geometry around Ru(II) is a distorted octahedron. It crystallizes in the triclinic system, with space group P 1, a = 10.4633(2) Å, b = 13.6332(4) Å, c = 13.6637(4) Å, α = 67.516(3)°, β = 69.757(2)°, γ = 77.201(2)°, V = 1680.74(8) Å3, Z = 2, and R int = 0.0311. In 1, two phen are bidentate N,N′ ligands. The Ru(II) in 1 is bonded to dipicolinate through pyridine nitrogen and one oxygen of carboxylate groups, thus pyridine-2,6-dicarboxylate is a bidentate N,O ligand. Efficient and selective oxidation of alcohols with NaIO4 as oxidant was conducted by this complex catalyst in CH3OH/H2O as solvents under air at room temperature. [ABSTRACT FROM PUBLISHER]

Abstract: Three mononuclear polypyridyl complexes of Ni(II), [Ni(Ph2phen)3](PF6)2·CH3CN (1), [Ni(dpa)2(phen)](PF6)2 (2) and [Ni(bpy)3](PF6)2 (3), where Ph2phen is 4,7-diphenyl-1,10-phenanthroline, dpa is 2,2′-dipyridylamine, bpy is 2,2′-bipyridine, and phen is 1,10-phenanthroline, were prepared and their solid state structures determined by single-crystal X-ray crystallography. The structural determination shows that the coordination geometry around the Ni(II) center is a distorted octahedron in each complex. The investigation of synthesis procedure and crystallographic data of complex 3 indicates the spontaneous resolution of supramolecular chirality. A careful inspection of the packing pattern in the lattice of each complex reveals that non-covalent interactions of two different types, viz. C–H⋯F and C–H⋯π interactions, are active in the lattice. The packing structures of 1–3 also show that the rings of the polypyridyl ligands, Ph2phen, dpa, bpy, and phen, are not located face-to-face and can not interact through π–π interactions. Cyclic voltammetry data of 1 and 3 show that the Ni(III/II) reduction couple is quasi-reversible and this reduction becomes progressively more difficult on passing from bpy to Ph2phen, while complex 2 shows an irreversible behavior with the peak-to-peak separation of about 500mV. Magnetic susceptibility data derived from paramagnetic NMR revealed effective magnetic moments of 3.12BM for 1, 3.27BM for 2, and 3.14 for 3 at room temperature. [Copyright &y& Elsevier]

Protonation of the highly reactive 1:1 intermediate produced in the reaction between triphenylphosphite and activated acetylene by sulfonamide leads to a phosphonate ylide, which undergoes methanol elimination in the presence of moisture to produce a highly functionalized sulfonamide phosphonate diester. A dynamic nuclear magnetic resonance (NMR) effect is observed in the 1H NMR spectra of this compound as a result of restricted rotation around the single C‒N bond. The coalescence temperature was observed at TC = 352.5 K, and the free energy of activation (ΔG#) for this process is 75.6 ± 2 kJ.mol−1. GRAPHICAL ABSTRACT [ABSTRACT FROM AUTHOR]

Abstract: A one-pot triphenylarsine-catalyzed synthesis of trans-cyclopropane derivatives is achieved by means of the reaction between acetylenic esters and C–H acids in the presence of triphenylarsine. This procedure is simple and proceeds under mild reaction conditions. Its success depends on the choice of solvent, temperature and C–H acid used. [Copyright &y& Elsevier]

Abstract: A facile diastereoselective synthesis of highly functionalised 3-(1-diphenylphosphonylethyl)butyrolactone analogues, 3a–c is achieved from the reaction of dialkyl acetylenedicarboxylates, 2a,b, with thiolated and trifluoromethylated-1,3-diones, CH acids, 1a,b, in the presence of triphenyl phosphite. The resulting products, 3a–c, are obtained in high yields and characterised by 1H/13C, 19F, 31P NMR and X-ray crystallography. [Copyright &y& Elsevier]

Cover Feature: Enhancing Ligand-Free Fe-Catalyzed Aminocarbonylation of Alkynes by ZrF4 (ChemCatChem 21/2019) Keywords: aminocarbonylation; ZrF4; alkynes; iron-catalyzed; , -unsaturated amides B The Cover Feature b illustrates ligand-free Fe-catalyzed aminocarbonylation of alkynes by ZrF SB 4 sb . [Extracted from the article]