1112-67-0Relevant articles and documents
EFFECT OF THE NATURE OF SOLID METAL FLUORIDES ON THE ALKYLATION KINETICS OF CH-ACIDS IN THE PRESENCE OF ONIUM SALTS
Esikova, I. A.
, p. 2463 - 2468 (1989)
The selective C-alkylation of ethyl 2-methylacetoacetate by prenyl chloride in the presence of solid metal fluorides proceeds at room temperature with yields of from 2.5 to 87.5percent depending on the nature of the deprotonating agent.The alkylation rate increases in going from LiF to CsF.A linear correlation was found between the activation free energy for thealkylation reaction and the crystal lattice energy of the solid metal fluorides.Ion exchange was not observed between tetrabutylammonium chloride and solid KF, CsF, and CaF2 in acetonitrile.The extent of the exchange with KF*2H2O over 10 h did not exceed 6percent.Deprotonation of ethyl 2-methylacetoacetate by the action of the solid metal fluorides was not observed.Loss of the CH-acid is found in the presence of an onium salt, which varies upon changing the nature of the deprotonating agent; LiF ca.NaF ca.KF (30percent), RbF (54percent), CsF (90percent), CaF2 (35percent).
Anion recognition by a macrobicycle based on a tetraoxadiaza macrocycle and an isophthalamide head unit
Bernier, Nicolas,Carvalho, Silvia,Li, Feng,Delgado, Rita,Felix, Vitor
, p. 4819 - 4827 (2009)
(Chemical Equation Presented) A macrobicycle formed by a tetraoxadiaza macrocycle containing a dibenzofuran (DBF) spacer and an isophthalamide head unit, named DBF-bz, was used as receptor for anion recognition. The molecular structure of DBF-bz was estab
The First Triangular Trinuclear Cluster Compounds of Molybdenum with Nine Cluster Electrons: 1-n, n = 1-3
Cotton, F. Albert,Shang, Maoyu,Sun, Zhong Sheng
, p. 6917 - 6922 (1991)
The first four M3X13 type molybdenum triangular trinuclear cluster compounds with nine cluster electrons are described in this paper: (Bu4N)2*Me2CO (1), (Bu4N)*2THF (2), (3), and *THF (4).The first three compounds were obtained by chemical reduction of (Bu4N)*Me2CO, and the last one was prepared as a byproduct from a reaction mixture containing MoCl3(THF)3, Na/Hg, S, NaOAc, and PMe3.In all four compounds, each metal atom has the formal oxidation state + 3 and there are nineelectrons for the metal cluster.Physical measurements indicated that these compounds are paramagnetic and have one unpaired electron, which is in good accord with theoretical calculations.In compound 1 the metal-metal bond distances are 2.617 (1), 2.598 (1), and 2.598 (1) Angstroem.The crystals belong to the space group Cc with Z = 4.The unit cell dimensions are a = 22.600 (3) Angstroem, b = 12.031 (2) Angstroem, c = 23.110 (4) Angstroem, β = 113.51 (1) deg, V = 5762 (2) Angstroem3.In compound 2, the metal-metal bond distances are 2.637 (1), 2.573 (1), and 2.567 (1) Angstroem.It crystallized in the space group P21/c with Z = 4 and the following unit cell dimensions a = 13.419 (3) Angstroem, b = 19.882 (5) Angstroem, c = 18.630 (5) Angstroem, β = 96.27 (2) deg, V = 4940 (2) Angstroem3.Compound 3 belongs to the space group P21/c with a = 10.381 (3) Angstroem, b = 12.680 (2) Angstroem, c = 19.402 (2) Angstroem, β = 90.09 (1) deg, V = 2553.6 (8) Angstroem3, and Z = 4.The metal-metal bond distances are 2.5878 (5), 2.6117 (5), and 2.5764 (5) Angstroem.Compound 4 forms triclinic crystals in the space group P1 with the following unit cell dimensions a = 10.121 (2) Angstroem, b = 11.013 (2) Angstroem, c = 14.628 (3) Angstroem α = 97.71 (2) deg, β = 93.06 (2) deg, γ = 104.62 (2) deg, V = 1556.9 (6) Angstroem3, and Z = 2.The metal-metal bond distances are 2.597 (1), 2.608 (1), and 2.5673 (9) Angstroem.
Infrared Spectroscopic Studies of Hydrogen Bonding in Triethylammonium Slats. Part 4. Rearrangement of Hydrogen-bonded Ion Pairs of Triethylammonium Salts caused by Interaction with Tetrabutylammonium Salts in Solution
Mashkovsky, Alexander A.,Nabiullin, Ahat A.,Odinokov, Stanislav E.
, p. 1879 - 1884 (1987)
Rearrangement of triethyl- and tetrabutylammonium salts in chloroform solution has been revealed from the characteristic features of the ν(N+H) bands caused by Fermi resonance interaction.Temperature changes of the i.r. spectra show this process to be reversible.Rearrangement constant K1 and K-1 and enthalpies -ΔH (for some cases only) of this process have been determined by measuring the total integrated intensities of the ν(N+H) bands of complexes which are in equilibrium.K1 values of the tetrabutylammonium salts increase with decreasing hydrogen bonding strength in triethylammonium salts.The measured enthalpies of rearrangement and those calculated from the ν(N+H) bands of hydrogen-bonded complexes studied are in agreement.It has also been shown that tetrabutylammonium salts anions can participate in the rearrangement of hydrogen-bonded ion pairs like the organic bases studied previously.
Lewis Acidity Scale of Diaryliodonium Ions toward Oxygen, Nitrogen, and Halogen Lewis Bases
Legault, Claude Y.,Mayer, Robert J.,Mayr, Herbert,Ofial, Armin R.
supporting information, (2020/03/13)
Equilibrium constants for the associations of 17 diaryliodonium salts Ar2I+X- with 11 different Lewis bases (halide ions, carboxylates, p-nitrophenolate, amines, and tris(p-anisyl)phosphine) have been investigated by titrations followed by photometric or conductometric methods as well as by isothermal titration calorimetry (ITC) in acetonitrile at 20 °C. The resulting set of equilibrium constants KI covers 6 orders of magnitude and can be expressed by the linear free-energy relationship lg KI = sI LAI + LBI, which characterizes iodonium ions by the Lewis acidity parameter LAI, as well as the iodonium-specific affinities of Lewis bases by the Lewis basicity parameter LBI and the susceptibility sI. Least squares minimization with the definition LAI = 0 for Ph2I+ and sI = 1.00 for the benzoate ion provides Lewis acidities LAI for 17 iodonium ions and Lewis basicities LBI and sI for 10 Lewis bases. The lack of a general correlation between the Lewis basicities LBI (with respect to Ar2I+) and LB (with respect to Ar2CH+) indicates that different factors control the thermodynamics of Lewis adduct formation for iodonium ions and carbenium ions. Analysis of temperature-dependent equilibrium measurements as well as ITC experiments reveal a large entropic contribution to the observed Gibbs reaction energies for the Lewis adduct formations from iodonium ions and Lewis bases originating from solvation effects. The kinetics of the benzoate transfer from the bis(4-dimethylamino)-substituted benzhydryl benzoate Ar2CH-OBz to the phenyl(perfluorophenyl)iodonium ion was found to follow a first-order rate law. The first-order rate constant kobs was not affected by the concentration of Ph(C6F5)I+ indicating that the benzoate release from Ar2CH-OBz proceeds via an unassisted SN1-type mechanism followed by interception of the released benzoate ions by Ph(C6F5)I+ ions.
Formal Gold-to-Gold Transmetalation of an Alkynyl Group Mediated by Palladium: A Bisalkynyl Gold Complex as a Ligand to Palladium
Toledo, Alberto,Meana, Isabel,Albéniz, Ana C.
supporting information, p. 13216 - 13220 (2015/09/15)
The reaction of [Au(C-C n-Bu)]n with [Pd(η3-allyl)Cl(PPh3)] results in a ligand and alkynyl rearrangement, and leads to the heterometallic complex [Pd(η3-allyl){Au(C-C n-Bu)2}]2 (3) with an unprecedented bridging bisalkynyl-gold ligand coordinated to palladium. This is a formal gold-to-gold transmetalation that occurs through reversible alkynyl transmetalations between gold and palladium. Back and forth! Direct gold-to-palladium and reverse palladium-to-gold alkynyl transmetalations effectively produce a deceptively simple gold-to-gold transfer. The resulting bisalkynyl-gold complexes act as bridging ligands to palladium atoms in an unprecedented structural motive (see scheme).
Distinguishing between pathways for transmetalation in Suzuki-Miyaura reactions
Carrow, Brad P.,Hartwig, John F.
supporting information; experimental part, p. 2116 - 2119 (2011/04/23)
We report a systematic study of the stoichiometric reactions of isolated arylpalladium hydroxo and halide complexes with arylboronic acids and aryltrihydroxyborates to evaluate the relative rates of the two reaction pathways commonly proposed to account for transmetalation in the Suzuki-Miyaura reaction. On the basis of the relative populations of the palladium and organoboron species generated under conditions common for the catalytic process and the observed rate constants for the stoichiometric reactions between the two classes of reaction components, we conclude that the reaction of a palladium hydroxo complex with boronic acid, not the reaction of a palladium halide complex with trihydroxyborate, accounts for transmetalation in catalytic Suzuki-Miyaura reactions conducted with weak base and aqueous solvent mixtures.
Synthesis of a C3-symmetric furyl-cyclopeptide platform with anion recognition properties
Molina, Lidia,Moreno-Clavijo, Elena,Moreno-Vargas, Antonio J.,Carmona, Ana T.,Robina, Inmaculada
experimental part, p. 4049 - 4055 (2010/09/10)
A new furyl amino acid derivative was trimerized to give a linear peptide and finally was cyclized. The newly generated cyclopeptide was subjected to a conformational study in order to be considered as a C3-symmetric platform for the ratio nal design of complex receptors. Moreover, the recognition properties towards cyanide, acetate and chloride anions were studied.
Encapsulated binding sites - Synthetically simple receptors for the binding and transport of HCl
Winstanley, Keith J.,Allen, Sarah J.,Smith, David K.
scheme or table, p. 4299 - 4301 (2011/03/19)
We report a receptor with an encapsulated amine/amide binding site, which binds HCl with high affinity in organic media - the rate of HCl transport through an apolar phase is controlled by the degree of encapsulation of the HCl binding site.
Effect of spacer geometry on oxoanion binding by bis- and tetrakis-thiourea hosts
Leung, Annie N.,Degenhardt, Dave A.,Bühlmann, Philippe
, p. 2530 - 2536 (2008/09/18)
Hosts with thiourea groups bind anions by formation of multiple hydrogen bonds. This contribution discusses how spacers linking two or four thiourea groups affect the host affinity and selectivity. While most of the bis-thioureas bind H2PO4- preferentially, the extent of selectivity over chloride, acetate, and H2AsO4- is determined by the size of the binding cavity. A tetrakis-thiourea is shown to exhibit a unique H2AsO4- selectivity, and the discrimination of chloride is enhanced by specific solvation in dimethyl sulfoxide.
