7 research outputs found
Intra- and supramolecular interactions in cis,mer-diaquatris(1H-imidazole-κN 3)(terephthalato-κO)cobalt(II) monohydrate
In the title compound, [Co(C8H4O4)(C3H4N2)3(H2O)2]·H2O, the cisoid angles are in the range 85.59 (5)–93.56 (5)°, while two equal transoid angles deviate significantly from the ideal linear angle, the third being almost linear. One carboxylate group is almost coplanar [1.23 (13)°] with the plane of its parent aromatic ring, although it has one O-atom donor involved in one coordination and one hydrogen bond as acceptor. The other carboxylate group does not coordinate and is rotated out of this plane with a torsional twist of 17.27 (20)°. The coordination neutral entity, based on aqua ligands and two cyclic co-ligands seems, at first sight, monomeric. Strongly tight, via one intramolecular hydrogen bond between aqua and carboxylate O atoms, it brings out a quasi-planar six-membered ring around the CoII atom, turning the CoN3O3 coordination octahedron into a new building block. The rigidity of this feature associated with several hydrogen-bonded arrays yields an extended structure. In the resulting supramolecular packing, a binuclear hydrated CoII assembly, built up from triple strands driven by different heterosynthons, embodies the synergy of coordination, covalent and hydrogen bonds
Complexes with functional phosphines. 14. Coupling reactions of MeO2CC.tplbond.CCO2Me with .beta.-phosphino ketonate complexes leading to nickel, palladium, and platinum alkenyl complexes
2D-NMR, X-ray crystallography and theoretical studies of the reaction mechanism for the synthesis of 1,5-benzodiazepines from dehydroacetic acid derivatives and o-phenylenediamines
The synthesis of 1,5-benzodiazepines by the reaction of o-phenylenediamines (o-PDAs) with dehydroacetic acid DHAA [3-acetyl-4-hydroxy-6-methyl-2H-pyran-2-one] or conjugate analogues is largely reported in the literature, but still with uncontrolled stereochemistry. In this work, a comprehensive mechanistic study on the formation of some synthesized 1,5-benzodiazepine models following different organic routes is established based on liquid-state 2D NMR, single-crystal X-ray diffraction and theoretical calculations allowing the classification of two prototropic forms A (enaminopyran-2,4-dione) and B (imino-4-hydroxypyran-2-one). Evidences are presented to show that most of the reported 1,5-benzodiazepine structures arising from DHAA and derivatives preferentially adopt the (E)-enaminopyran-2,4-diones A. (C) 2014 Elsevier B.V. All rights reserved