Browsing by Author "Figueiredo, Sonia"
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- 4,4 '-Di-tert-butyl-2,2 '-bipyridinePublication . Amarante, Tatiana R.; Figueiredo, Sonia; Lopes, Andre D.; Gonçalves, Isabel S.; Almeida Paz, Filipe A.In the title compound, C18H24N2, the molecular unit adopts a trans conformation around the central C-C bond [N-C-C-N torsion angle of 179.2(3)degrees], with the two aromatic rings almost coplanar [dihedral angle of only 0.70 (4)degrees]. The crystal packing is driven by co-operative contacts involving weak C H center dot center dot center dot N and C-H center dot center dot center dot pi interactions, and also the need to fill effectively the available space.
- Tetrapyridinium mu-oxido-di-mu-sulfato-bis[chloridodioxidomolybdate(VI)]Publication . Fernandes, José A.; Gomes, Ana C.; Figueiredo, Sonia; S. Gago; Lopes, Andre D.; Martyn Pillinger; Ribeiro-Claro; Gonçalves, Isabel S.; Filipe A. Almeida PazThe title salt, (C(5)H(6)N)(4)[Mo(2)Cl(2)O(5)(SO(4))(2)], comprises four pyridinium cations for each [(MoClO(2))(2)(mu-O)(mu-SO(4))(2)]4- anionic unit. The asymmetric unit consists of three aggregates of the empirical formula. The tetraanionic bimetallic molybdenum(VI) cluster is unprecedented and contains two sulfate and one oxide bridges. This structure constitutes the first example of a non-polymeric compound with terminal oxide, sulfate and halide ligands bonded to the same metal. The hydrogen bonds connecting the pyridinium cations to the molybdenum clusters are diverse, varying from strong and directional interactions to bifurcated bonds with a subsequent loss of directionality.
- Tripyridinium cis-tetrachloridodioxidomolybdate(VI) chloridePublication . Fernandes, José A.; Gomes, Ana C.; Figueiredo, Sonia; Gago, Sandra; Ribeiro-Claro, Paulo J. A.; Gonçalves, Isabel S.; Almeida Paz, Filipe A.In the title compound, (C(5)H(6)N)(3)[MoCl(4)O(2)]Cl, the pyridinium cations are N-H center dot center dot center dot Cl hydrogen bonded to the anionic [MoCl(4)O(2)](2-) complexes and to the two crystallographically independent chloride anions (located on C2 axes). The Mo(6+) centre adopts a highly distorted octahedral geometry, being surrounded by four chloride and two terminal oxide groups. The oxide ligands are mutually cis.