Mirna R. Estrada

1-Oxa-4,6-Dithia-5-Arsocane and 1,3,6-Trithia-2-Arsocane Dithiocarbamates Competition Between Transannular and Exocyclic Secondary Bonding to Arsenic

1-oxa-4,6-dithia-5-arsocane morpholinyldithiocarbamate (1) and 1,3,6-trithia-2-arsocane 2-diethyldithiocarbamate (2) have been prepared by reacting the corresponding sodium dithiocarbamates with 1-oxa-4,6-dithia-5-arsocane or 1,3,6-trithia-2-arsocane. (1) and (2) were characterized by elemental analyses, IR, MS, 1H and 13CNMR. The X-ray single-crystal molecular structures of (1) [monoclinic, a = 9.931(5), b = 18.253(5), c = 8.076(3) A; β = 92.56(2)°; V = 1462.5(7) A3; space group P21/c; Z = 4; R = 4.33%] and (2) [monoclinic, a = 7.830(2), b = 10.465(2), c = 19.025(6) A; β = 95.82(2)°; V = 1550.8(10) A3; space group P21/c; Z = 4; R = 3.41%], show that the compounds are monomeric and contain an asymetric monometallic biconnective dithiocarbamate ligand with a large distortion in the geometry around the As and a weak heterocyclic arsocane transannular secondary interaction.

Anionic Polymerization of Acrylonitrile with Trivalent Phosphorus Compounds

In order to see if the anionic polymerization of acrylonitrile initiated by trivalent phosphorous compounds is a living polymerization, and to see how high the molecular weight of polyacrylonitrile can be reached, the polymerization of acrylonitrile using triethylphosphite (TEP), phenyldiethoxyphosphine (PEP) and diphenylethoxyphosphine (DPP) was investigated. TEP was found to be a better initiator than the others, producing polymers with extremely high molecular weights. The polymerization system is a living type as the molecular weight increases until the system is exposed to air. However, the molecular weight polydispersity was in the range of 2.2–2.6 due to the complexity of initiation. The average molecular weight (Mw) reached 375,000, while that of a commercial polyacrilonitrile obtained by emulsion polymerization was 113,000. The polymer solutions obtained by the anionic polymerization became gel on standing, but they became sol when more solvent (DFM) was added and heated. The majority of polymers were slightly yellow due to the formation of imide linkages. The copolymerization with methylacrylate resulted in low molecular weight copolymers, with a ratio of acrylonitrile to methylacrylate units of 10.

Ungewöhnliche Koordination am Kalium des 18-Krone-6 Komplexes von Tetraphenyldiselenoimidodiphosphinat und der analogen Schwefelverbindung / Unusual Potassium Coordination in the 18-Crown-6 Tetraphenyldiselenoimidodiphosphinate Complex and its Sulfur Analogue

A [K(18-crown-6)] salt of the (Ph2PSe)2NH ligand was obtained by reaction of [K(Ph2PSe)2N] with 18-crown-6 [monoclinic, space group C2/c with the cell parameters a = 20.310(2), b = 8.894(2), c = 22.978(3) Å, β = 114.66(2)°, and Z = 4], The potassium ion has the rare coordination number 10. It is coordinated to the six oxygen atoms of the crown ether and to four carbon atoms, two from each of the two anionic ligands neighboring the cationic moiety.

Preparation and X-Ray Structure of 3,4,8-Tris(T-Butyl)- 1,6-Bis(4-Trifluormethylphenyl)-2,5,7,9-Tetraza-3λ3, 4λ5 8λ3-Triphospha [4.3.0]Bicyclonona-1,4,6-Trien (4). Study of the Thermal Stability of 4, and two Other Ci- Clocarbophosphazenes

Abstract In this work, we expose the synthesis of the new bicyclocarbophosphazene 4, its x-ray crystall structure and the experimental data obtained. The results of the study of thermal stability of 4 and two related compounds are also presented.