resumo
Reaction of NaH with a THF solution of Eu(BTA)(3)(PYPzH) [BTA = 1-benzoyl-3,3,3-trifluoroacetonate, pypzH = 2-(3-pyrazolyl)pyridine] leads to the formation of the europium-free tetrasodium complex [Na-4(pypzH)2(mu(4)-BTA)(2)(L-2-BTA)(2)]. Single-crystal Xray diffraction studies revealed the presence of a centrosymmetric Na+ hybrid tetramer, which fully occupies the contents of the triclinic unit cell. The crystal structure contains two individual Na+ cations, Na(1) and Na(2), which have highly irregular {NaN2O3} and {NaO6} local coordination environments, respectively. One of the key features is the presence of a central {Na4O6} core, which is unprecedented for Na+. Externally to this {Na4O6} cluster pyrazolylpyridine organic molecules are N,N-chelated to Na(l). Even though all of the organic residues contain aromatic rings, the crystal packing of individual centrosymmetric tetrasodium [Na-4(pypzH)(2)(t(4)-BTA)(2)(mu(2)-BTA)(2)] molecular moieties is essentially driven through geometrical aspects combined with weak C-H... 71 interactions, rather than the expected a priori pi-pi interactions. The material also contains classical strong hydrogen bonds, even though these do not directly contribute to the packing driving forces.
palavras-chave
CRYSTAL-STRUCTURES; DIOXOMOLYBDENUM(VI) COMPLEXES; METAL IONS; EPOXIDATION; EUROPIUM(III); CATALYSIS; DATABASE; LIGANDS; OLEFINS
categoria
Chemistry
autores
Coelho, AC; Paz, FAA; Klinowski, J; Pillinger, M; Goncalves, IS
nossos autores
Filipe Alexandre Almeida Paz
Investigador Principal
Isabel Maria de Sousa Gonçalves
Professor associado