On the reduction of the ozonides of selected phenylethylenes by triphenylphosphine

1969 ◽  
Vol 47 (7) ◽  
pp. 1113-1116 ◽  
Author(s):  
Jacques Carles ◽  
Sándor Fliszár

Triphenylphosphine has been found to reduce 18O labelled ozonides of styrene, stilbene, β-methylstyrene, and triphenylethylene by a very selective attack on the peroxidic oxygen atoms of the ozonides. The presence of ln electron withdrawing phenyl group attached to a C atom of the ozonide ring enhlnces the attack on the peroxidic oxygen adjacent to this C atom, whereas the presence of an electron releasing methyl group enhances the attack on the other peroxidic oxygen atom.

2000 ◽  
Vol 55 (10) ◽  
pp. 971-974 ◽  
Author(s):  
Joachim Pickardt ◽  
Sven Wiese

AbstractReactions of 1,13-bis(8-chinolyl)-1,4,7,10,13-pentaoxatridecane (“Cryptand 5”) with HgX2 (X = I, SCN) yield crystals of [(cryptand 5)(HgI2)2] (1) and [(cryptand 5 )2{Hg(SCN)2}4] (2), resp. In both complexes two molecules of HgX2 are bound to one ligand molecule. 1 has symmetry Ci with the oxygen atom O(3 ) of the ether chain on a center of symmetry of the unit cell, each Hg atom is bound to the two I atoms, the N atom of the chinolyl residue, and one oxygen atom, O(1) and O(l)i, resp. of the ligand; neighbouring complex units are connected via iodine bridges thus forming chains. In 2 also two formula units of HgX2 are bound to one ligand molecule, but contrary to 1 the complex is not centrosymmetric. The Hg atoms of the two Hg(SCN)2 groups are co-ordinated differently: both are bound via sulphur atoms to two SCN-groups, one being a terminal SCN group, the other acting as a bridge to the Hg atom of a neighbouring complex unit. The first Hg atom is connected to a chinolyl N atom and too oxygen atoms, the second to a chinolyl N atom and three oxygen atoms. There are two independent complex units per asymmetric unit which are related by a non-crystallographic twofold axis, and which are connected via two SCN bridges. These “double molecules” are also interconnected by thiocyanate bridges, thus forming a chain structure


1967 ◽  
Vol 45 (20) ◽  
pp. 2297-2302 ◽  
Author(s):  
P. K. L. Au ◽  
C. Calvo

Cadmium pyrovanadate crystallizes in the C2/m space group with lattice parameters a = 7.088(5) Å, b = 9.091(5) Å, c = 4.963(5) Å, β = 103°21(5)′, and z = 2. This crystal is an isostructure of the mineral thortveitite and thus the anion consists of a pair of centrosymmetrically related corner-sharing VO4 tetrahedra while the cation resides within a distorted octahedron of oxygen atoms. The anion has a linear V—O—V group, but, as with the isostructural pyrophosphates, the central oxygen atom shows an anomalously high thermal activity. The V—O bond distances are 1.76 Å for the inner bond and 1.70 Å for the terminal bond. The bond angles about the anion and cation are similar to those found for the other analogues of thortveitite.


Author(s):  
O. Shtokvysh ◽  
L. Koval ◽  
V. Dyakonenko ◽  
V. Pekhnyo

Binuclear complex of Zn(II) with cyclohexyl acetoacetate was obtained and structurally characterized for the first time. According to structural data, the crystal system is triclinic, space group P-1; a = 7.6530(4), b = 12.2412(8), c = 12.9102(9) Å; α = 90.198(5), β = 101.071(5), γ = 96.937(5) deg. The molecular structure corresponds to the formula [Zn2(C10H15O3)4(C2H5OH)2]. The complex is located in a special position to the symmetry center of the unit cell. The coordination polyhedrons of the Zn atoms are the same distorted octahedrons formed by six oxygen atoms. Each formed by 4 oxygen atoms in the equatorial position, which belong to three ligand molecules: terminal ligand (2 oxygen atoms) and bridged ligand (1 oxygen atom) which chelate the zinc atom of the named polyhedron and 1 oxygen atom belong to a bridged ligand that chelates the other nucleus and monodentantly coordinated to mentioned one. Two oxygen atoms occupy an axial position, one of which belongs to the terminal ligand, mentioned above and the other to the coordinated ethanol molecule. The bond between the complex nuclei is stabilized by two hydrogen bonds formed by the hydrogen atoms from hydroxyl groups of ethanol molecules and the enol oxygen atoms of the terminal ligands of the other nucleus. The compound was also characterized by IR-spectroscopy, characteristic bands (сm-1) are: ν(C–H) - 2936, 2860, ν(C=O) & ν(C=C) – 1612, ν(C=O) + δ(C–H) – 1532, ν(C=C) & ν(C-CH3)– 1252, δ(C–H) – 1172, π(C–H) – 784, ν(M–O) – 456, 416. IR spectroscopy data confirm the bidentate coordination of cyclohexyl acetoacetate to zinc atoms in deprotonated form with the formation of chelated metallocycles. The structure of the complex is similar to the structures of cobalt and nickel complexes with cyclohexyl acetoacetate. Analysis of XRD-data (which are supplemented with this work) for Co(II), Ni(II) and Zn(II) complexes with acetoacetic acid esters shows that their structure, in particular the number of metal centers in the structures, regardless of the nature of the central atom or the alcohol fragment, but determined the presence of components capable of complementing the coordination sphere of the metal in reaction media.


1995 ◽  
Vol 50 (2) ◽  
pp. 247-251 ◽  
Author(s):  
H. Szillat ◽  
Hk. Müller-Buschbaum

Single crystals of (Cu,Zn)3,75Mo3O12 have been prepared by crystallization from melts and investigated by X-ray diffractometer techniques. (Cu,Zn)3,75Mo3O12 crystallizes orthorhombically, space group D24-P212121, Z = 4, a = 17.947(9), b = 5.092(3), c = 10.685(5) Å. It is isotypic to Cu3,85Mo3O12. All molybdenum atoms are tetrahedrally coordinated by oxygen atoms. There are layers of CuO6 and ZnO6 octahedra, while other metal sites are occupied by copper in a deformed prismatic coordination with one oxygen atom at a remarkably greater distance from copper than the other five. Some of the zinc atoms occupy positions in chains of face-sharing octahedra with an occupancy factor of 0.75. The crystal structure is discussed with respect to the isotypic compound Cu3,85Mo3O12 and compounds of the type CuLnMo2O8.


1988 ◽  
Vol 53 (3) ◽  
pp. 588-592 ◽  
Author(s):  
Antonín Lyčka ◽  
Josef Jirman ◽  
Jaroslav Holeček

The 17O and 13C NMR spectra of eight geminal diacetates RCH(O(CO)CH3)2 derived from simple aldehydes have been measured. In contrast to the dicarboxylates R1R2E(O(CO)R3)2, where E = Si, Ge, or Sn, whose 17O NMR spectra only contain a single signal, and, on the other hand, in accordance with organic carboxylic esters, the 17O NMR spectra of the compound group studied always exhibit two well-resolved signals with the chemical shifts δ(17O) in the regions of 183-219 ppm and 369-381 ppm for the oxygen atoms in the groups C-O and C=O, respectively.


Author(s):  
Leila G. Ranis ◽  
Jacqueline Gianino ◽  
Justin M. Hoffman ◽  
Seth N. Brown

Eight-coordinate MoO2(DOPOQ)2 can donate two oxygen atoms to substrates such as phosphines in a four-electron nonclassical oxygen atom transfer reaction.


1970 ◽  
Vol 24 (1) ◽  
pp. 42-43 ◽  
Author(s):  
Stanley K. Freeman

Raman spectra of 4-methyl isochroman and its aromatic ring substituted derivatives indicate the presence of two conformers in the liquid state and only one in the solid, while the 1- and 3-methyl analog assume one conformation only in both states. The presence of a methyl group adjacent to the ring oxygen atom sterically prevents adoption of one of the two possible conformations due to 1,3-interaction. No such restriction is imposed on the 4-methyl compounds.


2000 ◽  
Vol 78 (12) ◽  
pp. 1535-1543 ◽  
Author(s):  
Antonio Vila ◽  
Enrique Carballo ◽  
Ricardo A Mosquera

The integrated values of the electron population, electron energy, nucleus–electron potential energy interaction, dipole moment and volume of the oxygen atoms, and the main properties of the O—C bond critical points, were determined by employing the theory of atoms in molecules and 6-31++G**//6-31G* wave functions for a series of 25 unbranched alkyl monoethers. These results were used to assess the degree of approximate transferability of the oxygen atom along this series in terms of the particular alkyl radicals bonded to it. It has been found that a set of six different oxygen atoms is necessary to classify all the computed values. It can be established that the oxygen atoms bonded to propyl and larger radicals can be treated, in practice, as a transferable fragment, while those bonded to at least one smaller radical are specific. Though the total HF energy and the available experimental heats of formation are well fitted by a traditional additivity scheme that distinguishes only among O, CH2, and CH3 units, it has been found that the energy properties are influenced by the size of the molecule.Key words: transferability, AIM theory, ethers.


1995 ◽  
Vol 50 (1) ◽  
pp. 128-138 ◽  
Author(s):  
Dagmar Henschel ◽  
Armand Blaschette ◽  
Peter G. Jones

Complexes of Uncharged Molecules, Crystal StructureThe thermally labile ternary complexes 18C6 · 2MeOH · 2 HN(SO2Ph)2 (2a), 18C6 · 2MeOH · 2HN(SO2–C6H4-4-Cl)2 (2b) and 18C6 · 3 MeOH · HN(SO2Me)(SO2Ph) (3) were obtained by co-crystallization of 18-crown-6 (18C6) and the appropriate di(organosulfonyl)amine from methanolic solutions and characterized by low-temperature X-ray diffraction. The crystal structures of 2a (monoclinic, space group P21/n) and 2b (triclinic, space group P1̄) consist of monomeric, centrosymmetric formula units. Each di(arenesulfonyl)-amine molecule is connected to a methanol molecule by an N-Η ··· O hydrogen bond (H ··· O 203 pm in 2a, 190 pm in 2b). The methanol molecules are linked to three alternate crown oxygen atoms via one O-Η ··· O(crown) hydrogen-bond and two weaker C-Η ··· O(crown) interactions (OH ··· O 201 pm in 2a, 186 pm in 2b; CH ··· O 236 and 247 pm in 2a, 240 and 254 pm in 2b); two symmetry-related oxygen atoms of the crown are involved in O-Η ··· O and the other four in C-Η ··· O interactions. The structure of complex 3 (monoclinic, space group P21) is built of infinite chains parallel to [101]. The methyl group of the di(organosulfonyl)amine is bonded by C-Η ··· O(crown) interactions to a set of three alternate oxygen atoms of the cyclic polyether (H ··· O 228, 245 and 247 pm). Starting from the acidic NH function, a sequence of three methanol molecules catenated by hydrogen bonds curves around the bulky phenyl group and links with its terminal MeOH through one O-H ··· O(crown) and two C-Η ··· O(crown) bonds to the second set of alternate oxygen atoms in the adjacent symmetry-equivalent crown (OH ··· O 193 pm, CH ··· O 248 and 250 pm). Within the chain sequence N-H ··· O′(Me)H′ ··· O″(Me)H″ ··· O‴(Me)H, the H ··· O distances are H ··· O′ 184, H′ ··· O″ 189 and H″··· O‴ 183 pm. In the structures of 2a, 2b and 3, the crown rings adopt the frequently observed D3d pseudosymmetry.


1967 ◽  
Vol 45 (20) ◽  
pp. 2303-2316 ◽  
Author(s):  
J. S. Stephens ◽  
C. Calvo

β-Zn3(PO4)2 crystallizes in the monoclinic space group P 21/c with lattice parameters, a = 9.393(3) Å, b = 9.170(6) Å, c = 8.686(3) Å, β = 125.73(10)°, and Z = 4. The three independent cations are strongly ligated to 4, 5, and 5 oxygen atoms, with average Zn—O bond distances of 1.98 ± 0.09 Å, 2.10 ± 0.10 Å, and 2.08 ± 0.13 Å respectively. In addition there are two longer Zn—O distances of 2.51 Å and 2.55 Å in this structure. The PO4 groups exist as independent, nearly regular tetrahedra, with each oxygen atom ligated to two cations. Unlike the structures found for the α and γ phases of Zn3(PO4)2, which contain ribbons and sheets respectively as the basic cation coordination motif, the structure of β-Zn3(PO4)2 contains interconnected sheets.


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