Search results for "Derivative"

The 5/2,3/2 Spin Admixture in the Chloroiron(III) Derivative of the Sterically Crowded 2,3,7,8,12,13,17,18-Octaethyl-5,10,15,20-tetraphenylporphyrin

1999

Despite similar ring deformations in solution and in the solid state, the chloroiron(III) derivative of 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetraphenylporphyrin ([FeCl(oetpp)], shown schematically) prepared in this study exhibits only a very weak quantum-mechanical admixture of spin S=3/2 (only 4-10 %) with spin S=5/2. In contrast, for the variety of [FeCl(oetpp)] studied earlier by other researchers a 40 % contribution of the S=3/2 state was found.

Rational Synthesis of Multicyclic Bis[2]catenanes

2004

Bis-loop tetraurea calix[4]arene 6 has been prepared by acylation of the wide-rim calix[4]arene tetraamine 1 with the activated bis(urethane) 8 under dilution conditions. Similarly the bis(Boc-protected) tetraamine 2 is converted into the mono-loop derivative 3 which after deprotection and acylation gives the bisalkenyl derivative 5. In apolar solvents this tetraurea calix[4]arene 5 forms regioselectively a single hydrogen-bonded homodimer, from which the bis[2]catenane 10 a is formed in 49 % by a metathesis reaction followed by hydrogenation. Bis-loop derivative 6 forms no homodimers for steric reasons, but a stoichiometric mixture with the open-chain tetraalkenyl derivative 7 a contains e…

Synthesis, crystal and molecular-electronic structure, and kinetic investigation of two new sterically hindered isomeric forms of the dimethyl[methyl…

2017

Two new structural isomers – 2,4-dimethyl-5-[methyl(phenylsulfonyl)amino]benzenesulfonyl chloride (1) and 2,4-dimethyl-3-[methyl(phenylsulfonyl)amino]benzenesulfonyl chloride (2) were synthesized by interaction of N-(2,4-dimethylphenyl)-N-methyl-benzenesulfonamide or N-(2,6-dimethylphenyl)-N-methylbenzenesulfonamide with chlorosulfonic acid. Both compounds have been structurally characterized by X-ray single crystal diffraction at 100 K. The crystals of 1 are triclinic: space group View the MathML source, a = 8.1542(2), b = 11.0728(3), c = 11.2680(3) Å, α = 116.557(3), β = 95.155(2), γ = 108.258(2)°, V = 831.97(4) Å3, Z = 2, R = 0.0251 for 2429 reflections; the crystals of 2 are monoclinic:…

Symmetric Fluoroborate and its Boron Modification: Crystal and Electronic Structures

2019

Four boron-carrying molecules were synthesized and purified. These were found to be (a) relatively neutral with respect to the parent BF derivative and (b) functionalized by donor&ndash

The Instability of Ni{N(SiMe3 )2 }2 : A Fifty Year Old Transition Metal Silylamide Mystery.

2015

The characterization of the unstable Ni(II) bis(silylamide) Ni{N(SiMe3 )2 }2 (1), its THF complex Ni{N(SiMe3 )2 }2 (THF) (2), and the stable bis(pyridine) derivative trans-Ni{N(SiMe3 )2 }2 (py)2 (3), is described. Both 1 and 2 decompose at ca. 25 °C to a tetrameric Ni(I) species, [Ni{N(SiMe3 )2 }]4 (4), also obtainable from LiN(SiMe3 )2 and NiCl2 (DME). Experimental and computational data indicate that the instability of 1 is likely due to ease of reduction of Ni(II) to Ni(I) and the stabilization of 4 through dispersion forces.

Triazolopyridines. 14. Substitution reactions of 7-amino[1,2,3]triazolo[1,5-a]pyridines.

1993

Abstract Reaction between 7-aminotriazolopyridines 1 or 2 and sulphuric acid gives hydroxyalkylpyridines 3 and 4 ; bromination gives brominated pyridine 5 or triazolopyridine 6. The anions from amines 1 or 2 are ambident, acylating on N but alkylating on N or on C6; in the latter case triazolylalkenylcyanides 16 – 20 or the 6,6-dialkylated derivative 19 are obtained. An X-ray diffraction study has confirmed structure 19.

Mechanistic Understanding of Food Effects: Water Diffusivity in Gastrointestinal Tract Is an Important Parameter for the Prediction of Disintegration…

2013

Much interest has been expressed in this work on the role of water diffusivity in the release media as a new parameter for predicting drug release. NMR was used to measure water diffusivity in different media varying in their osmolality and viscosity. Water self-diffusion coefficients in sucrose, sodium chloride, and polymeric hydroxypropyl methylcellulose (HPMC) solutions were correlated with water uptake, disintegration, and drug release rates from trospium chloride immediate release tablets. The water diffusivity in sucrose solutions was significantly reduced compared to polymeric HPMC and molecular sodium chloride solutions. Water diffusivity was found to be a function of sucrose concen…

ChemInform Abstract: Reactions of (η5-C5H5) (CO)2Fe-Substituted N-Sulfonyl Azadienes with C-Nucleophiles. A Route to 5-Substituted Dihydropyrrolones.

2000

Crystal structure ofp-toluenesulfonylmethyl isocyanide

2015

The molecule of the commercially available title compound, C9H9NO2S, has crystallographically imposed mirror symmetry, the mirror plane passing through the isocyanide group and thepara-C atoms, the methyl C atom and the S atom of the methyl 4-tolyl sulfone moiety. In the crystal, C—H...O hydrogen-bond interactions link the molecules into chains running parallel to thebaxis.

New magnetic conductors and superconductors based on BEDT-TTF and BEDS-TTF

2005

Abstract Here we present our last results in the search for multifunctionality in conducting molecular materials obtained by combining paramagnetic molecular complexes with organic donors to produce paramagnetic molecular metals and superconductors. The structural and physical characterization of two new molecular paramagnetic superconductors ET 4 [H 3 OM(C 2 O 4 ) 3 ].PhBr (M III  = Cr and Fe) are presented (ET = BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene). These salts present a superconductor transition at T c  = 1.5 and 4.0 K, respectively and very anisotropic critical fields H c2a ≈ H c2b ≈0.5 T and H C2C ≈ 8 T for the Fe derivative. We will also present the structural and physica…