Search results for "Periodic table"

Remarkably Robust Group 4 Metal Half-Sandwich Complexes Containing Two Higher Alkyl Ligands:  X-ray Structure and Reactivity of the Di-n-butyl Comple…

1997

The reaction of LiR with M(η5:η1:η1-C5Me4SiMe2NCH2CH2OMe)Cl2 (1, M = Zr (a), Hf (b)) gives the isolable, thermally stable complexes M(η5:η1:η1-C5Me4SiMe2NCH2CH2OMe)R2 (R = Et (2), nPr (3), nBu(4)), which contain two alkyl ligands with β-hydrogen atoms.

A New Building Block for Organometallic–Inorganic Hybrid Polymers: The Mixed Group 15/16 Element Ligand Complex [Cp* 2 Mo 2 (μ,η 2:2 ‐PSe) 2 (μ‐Se)] …

2010

The synthesis and spectroscopic characterization of [Cp*2Mo2P2Se3] (1; Cp* = C5Me5) and its use as a molecular building block in the formation of copper(I) halide polymers is described. The reaction of 1 in CH2Cl2 with 2 equiv. of CuBr and CuI in CH3CN under diffusion conditions gave [(Cp*2Mo2P2Se3)2(CuBr)2] (2) and [(Cp*2Mo2P2Se3)(CuX)3(CH3CN)]n (X = I; 3/4), respectively. The structure of 2 is distinguished by a central Cu2Br2 ring coordinated on each side by a tripledecker complex through one of its P atoms. A 2D network is formed by weak interactions between Se atoms of neighboring molecules. Compound [(Cp*2Mo2P2Se3)(CuI)3(CH3CN)]n exists in two isomeric forms 3 and 4. The crystal struc…

The role of the transfer group in the intramolecular [5+2] cycloadditions of substituted β-hydroxy-γ-pyrones: a DFT analysis

2005

The intramolecular [5+2] cycloaddition reactions of a series of 3-OR (R=SiMe3, H, CHO, Me) substituted β-hydroxy-γ-pyrones bearing tethered alkenes were studied using DFT methods at the B3LYP/6–31G* level. The role of the transfer R group was analyzed considering two alternative channels: (i) in channel a the process is initialized by the transfer of the R group with formation of an oxidopyrylium ylide intermediate, which is followed of an intramolecular [5+2] cycloaddition; (ii) in channel b, the process is initialized by the intramolecular [5+2] cycloaddition on the γ-pyrone followed by the transfer of the R group. Copyright © 2005 John Wiley & Sons, Ltd.

ChemInform Abstract: Comparative Lipase-Catalyzed Hydrolysis of Ethylene Glycol Derived Esters. The 2-Methoxyethyl Ester as a Protective Group in Pep…

2010

(1aR,2aS,5aS,5bS)-Perhydro-4H-oxireno[3,4]cyclopenta[1,2-b]furan-4-one

2007

The structure of the title compound, C7H8O3, was determined in the course of our studies of the synthesis of cyclopenta[1,2-b]furan-4-one derivatives. The molecule has four chiral C atoms. The X-ray crystal structure analysis shows the compound to possess an epoxide group with an endo orientation with respect to the lactone group.

Methyl 3-(4-hydroxyphenyl)propionate

2018

The title compound, C10H12O3, crystallizes in the orthorhombicP212121space group. The structure contains a phenolic group with the OH being coplanar with the phenyl ring. The structure exhibits significant hydrogen bonding between the O—H group of one molecule and the CO group of an adjacent one. These O—H...O=C interactions form chains of molecules parallel to thebaxis. No π–π or C—H...π intermolecular interactions are observed.

Water Adsorption Characteristics of Acyclic Oligosaccharides of α-Gluose Studied by Near Infrared Spectroscopy

2013

The adsorption properties of water molecules on maltooligosaccharides are attributed to the OH groups of the glucose rings in maltooligosaccharides. The water molecules are adsorbed onto OH groups by hydrogen bond formation. Near infrared spectroscopic and gravimetric techniques were used in analysing the adsorption characteristics of maltooligosaccharides. Near infrared spectra of the dry maltooligosaccharides were acquired during the adsorption of wa- ter molecules at a relative humidity of 50%. The amounts of water adsorbed by the samples were also recorded by an ana- lytical balance. Second derivative techniques were used in decomposing the OH combination frequency of the adsorbed water…

1,3-Di(hetero)aryl-7-substituted Pyrenes—An Undiscovered Area of Important Pyrene Derivatives

2019

Despite the pyrene derivatives have been covered extensively by scientists during the last years, many interesting properties and applications of pyrene derivatives have been presented, nowadays there are still areas of pyrenes’ chemistry that need to be fulfilled. Most of the described in literature pyrenes are 1,3,6,8-tetrasubstituted followed by 4,5,9,10-tetrasubstituted, 2,7-, and 1,6-, and 1,8-disubstituted pyrene derivatives. In the case of 1,3-di(hetero)aryl-7-substituted, there are only a few examples of derivatives containing at position 7 - tert-butyl group. In this work, the necessity of synthesis of 1,3-di(hetero)aryl-7-substituted pyrenes is presented based on the results of th…

4-Bromophenyl 2,4-dibromophenyl ether

2002

The title compound, C12H7Br3O, belongs to a group of flame retardants known as polybrominated di­phenyl ethers (PBDE). Salient features of the packing of the title compound are infinite intermolecular Br⋯Br contact chains along the b direction.

Extraction Chromatographic Behavior of Rf, Zr, and Hf in HCl Solution with Styrenedivinylbenzene Copolymer Resin Modified by TOPO (trioctylphosphine …

2010

It is of great interest to study chemical properties of the transactinide elements with atomic numbers (Z) ≥ 104. One of the most important subjects is to establish the position of the elements at the extreme end of the periodic table. To this end we perform studies of chemical properties of these transactinides and compare them with those of their lighter homologues and with the ones expected from extrapolations in the periodic table. So far, chromatographic studies of the transactinides have provided experimental proof of placing rutherfordium (Rf, Z = 104) through hassium (Hs, Z = 108) into groups 4 to 8, respectively. 1-10 Quite recently, copernicium (Cn, Z = 112) has been shown to be a…