title: Synthesis and structure of a sodium complex of an aromatic beta-diketone and pyrazolylpyridine.
abstract: 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)(micro4-BTA)(2)(micro2-BTA)(2)]. Single-crystal X-ray 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 [NaN(2)O(3)] and[NaO(6)] local coordination environments, respectively. One of the key features is the presence of a central [Na(4)O(6)] core, which is unprecedented for Na+ . Externally to this [Na(4)O(6)] cluster pyrazolylpyridine organic molecules are N,N-chelated to Na(1). Even though all of the organic residues contain aromatic rings, the crystal packing of individual centrosymmetric tetrasodium [Na(4)(pypzH)(2)(micro4-BTA)(2)(micro2-BTA)(2)] molecular moieties is essentially driven through geometrical aspects combined with weak C-H...pi 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.
authors.affiliation: Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal. igoncalves@dq.ua.pt.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Coelho
authors.forename: Filipe A Almeida
authors.initials: FA
authors.lastname: Paz
authors.forename: Jacek
authors.initials: J
authors.lastname: Klinowski
authors.forename: Martyn
authors.initials: M
authors.lastname: Pillinger
authors.forename: Isabel S
authors.initials: IS
authors.lastname: Gonçalves
mesh_terms: D002614:Chelating Agents / Q000737:chemistry; D003460:Crystallization; D007659:Ketones / Q000737:chemistry*; D008024:Ligands; D011720:Pyrazoles / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002614:Chelating Agents; D007659:Ketones; D008024:Ligands; D011720:Pyrazoles; D011725:Pyridines; C118531:pyrazolopyridine; D012964:Sodium