Search results for "Ethyl group"
showing 10 items of 66 documents
Fragmentations and reactions of protonated O,O-dimethyl ethylphosphonate and some isotopomers produced by electrospray ionisation in an ion trap mass…
2008
Abstract The fragmentation behaviour of protonated O , O -dimethyl ethylphosphonate and its isotopomers deuterated in the α- and β-positions of the ethyl group and their fragment ions, particulary EtP(O)OMe + ( IV ), have been investigated both experimentally in an ion trap mass spectrometer and theoretically by electronic structure calculations at the B3LYP level. Of particular interest is the finding that the phosphonium ion IV eliminates ethene with hydrogen/deuterium loss from both the α-and β-positions. The initial step for both routes involves ethyl migration from P to O to form the ion MeOP + OEt which then loses ethene by two mechanisms, both of which lead to the same products. That…
Ferrocene compounds: methyl 1′-aminoferrocene-1-carboxylate
2010
The title compund, [Fe(C(5)H(6)N)(C(7)H(7)O(2))], features one strong intermolecular hydrogen bond of the type N-H...O=C [N...O = 3.028 (2) A] between the amine group and the carbonyl group of a neighbouring molecule, and vice versa, to form a centrosymmetric dimer. Furthermore, the carbonyl group acts as a double H-atom acceptor in the formation of a second, weaker, hydrogen bond of the type C-H...O=C [C...O = 3.283 (2) A] with the methyl group of the ester group of a second neighbouring molecule at (x, -y - 1/2, z - 1/2). The methyl group also acts as a weak hydrogen-bond donor, symmetry-related to the latter described C-H...O=C interaction, to a third molecule at (x, -y - 1/2, z + 1/2) t…
Infrared and quantum-chemical studies of the structure and vibrations of methyldisilylamine
2002
Abstract Infrared spectra are reported from labelled species of methyldisilylamine (N(CH 3 )(SiH 3 ) 2 ) in the gas and solid phase. Quantum-chemical (QC) calculations of structure and force field have been carried out at HF, MP2 and B3LYP levels using 6-31G ∗ and 6-311G ∗∗ basis sets. The equilibrium structure belongs to the point group C s with the plane of symmetry at right angles to the NSi 2 angle and a slight non-planarity of the CNSi 2 moiety ( C s ,⊥ ). Spectra in the ν SiH region however suggest an effective C 2 v structure, with two distinct types of SiH bond. Two strong SiH bonds lie in the skeletal plane, eclipsing each other. The single ν is CH band in the CHD 2 species suggest…
Effect of the Substituent Position on the Anionic Copolymerization of Styrene Derivatives: Experimental Results and Density Functional Theory Calcula…
2019
In a combined synthetic, kinetic and theoretical study, the living anionic copolymerization of styrene and its ring-methylated derivatives ortho-, meta-, and para-methylstyrene (MS) was examined by real-time 1H NMR spectroscopy in the nonpolar solvents toluene-d8 and cyclohexane-d12 as well as by density functional theory calculations. Based on the NMR kinetics data, reactivity ratios for each comonomer pair were determined by the Kelen–Tudős method and numerical integration of the copolymerization equation (Contour software). The reaction pathway was modeled and followed by density functional theory (DFT) calculations to validate and predict the experimentally derived reactivity ratios. Un…
Tuning the nuclearity of iron(iii) polynuclear clusters by using tetradentate Schiff-base ligands
2014
Three novel octanuclear, hexanuclear and tetranuclear complexes of high-spin Fe(III) ions were obtained by the reaction of the N,N′-bis-(1R-imidazol-4-ylmethylene)-ethane-1,2-diamine ligand (R = H, CH3) and its derivatives with Fe(ClO4)3·6H2O and KSCN. The tetradentate Schiff-base ligand acts as a bis(bidentate) chelating bridge between two adjacent high-spin Fe(III) centers. The presence of a methyl group in the imidazolyl substituent, the change of counterions or the replacement of imidazole by pyridine has a drastic effect on the nuclearity of the cluster. The magnetic properties of all compounds exhibit antiferromagnetic interactions via μ-oxo or μ-hydroxo pathways in Fe(III) dimers.
NMR T1-Relaxation Measurements on Paramagnetic Organolanthanides: An Alternative Tool for Structure Determination in Solution
2005
1H NMR investigations were conducted on four paramagnetic organolanthanides, all bearing the tetraisopropylcyclopentadienyl ligand Cp4i (HC5iPr4) in order to verify whether or not interactions observed in the solid state are maintained in solution. In some cases variable-temperature experiments were necessary to enhance the resolution and determine the best conditions for the study. The 1D NMR spectrum could be interpreted in every case. Complementary 2D COSY experiments allowed the full attribution of the signals. T1 (1H) relaxation values were determined for all the paramagnetic complexes at the most suitable temperature, and compared with those of the diamagnetic KCp4i. The same tendency…
Stimulated emission and optical properties of pyranyliden fragment containing compounds in PVK matrix
2017
This work has been supported by National Research program “Multifunctional materials and composites, photonics and nanotechnology (IMIS2)”. Financial support provided by Scientific Research Project for Students and Young Researchers No. SJZ2015/12 realised at the Institute of Solid State Physics, University of Latvia is greatly acknowledged.
Proton Acid-Catalysed Transformations of Estrogen Derivatives: New Results and Some Mechanistic Aspects of theKober Colour Reaction
1994
The 3-O-methylated estrogen derivatives 1a-d and α-estradiol (1e) underwent sulfuric acid-catalysed transformations to furnish the steroids 2–6. The processes involved in the reaction sequence are regioselective sulfonation and, above all, the Wagner-Meerwein rearrangement of the methyl group at C-13. With the objective of obtaining further information on the course of the Kober colour reaction of estrogens, some UV/VIS and ESR spectroscopic investigations were also carried out. Protonenkatalysierte Transformationen von Estrogen-Derivaten: Neue Ergebnisse und einige mechanistische Aspekte der Kober-Farbreaktion Die O-methylierten Estrogenderivate 1a-d und α-Estradiol (1e) reagieren in Schwe…
Pyranylidene indene-1,3-dione derivatives as an amorphous red electroluminescence material
2011
The organic light-emitting diode (OLED) has promising applications in flat-panel displays and novel light sources. Thus far, OLED structures have mostly been made by thermal evaporation in vacuum. An alternative approach is to use small molecules that form amorphous (glassy) structures from solutions. Such compounds can be used in ink-jet printing technologies and result in reduced OLED prices. We present an original red fluorescent organic compo- und 2-(2-(4-(bis(2-(trityloxy)ethyl)amino)styryl)-6-methyl-4H-pyran-4-ylidene)-1H-indene-1, 3(2H)-dione (ZWK1), and its derivative 2-(2,6-bis(4-(bis(2-(trityloxy)ethyl) amino)styryl)-4H- pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK2), where the m…
A ferromagnetic methoxido-bridged Mn(III) dimer and a spin-canted metamagnetic μ(1,3)-azido-bridged chain.
2012
Two new Mn(III) complexes of formulas [MnL(1)(N(3))(OMe)](2) (1) and [MnL(2)(N(3))(2)](n) (2) have been synthesized by using two tridentate NNO-donor Schiff base ligands HL(1){(2-[(3-methylaminoethylimino)-methyl]-phenol)} and HL(2) {(2-[1-(2-dimethylaminoethylimino)methyl]phenol)}, respectively. Substitution of the H atom on the secondary amine group of the N-methyldiamine fragment of the Schiff base by a methyl group leads to a drastic structural change from a methoxido-bridged dimer (1) to a single μ(1,3)-azido-bridged 1D helical polymer (2). Both complexes were characterized by single-crystal X-ray structural analyses and variable-temperature magnetic susceptibility measurements. The ma…