Electronic Structure of the Complex Hydride NaAlH4

Density functional calculations of the electronic structure of the complex hydride NaAlH4 and the reference systems NaH and AlH3 are reported. We find a substantially ionic electronic structure for NaAlH4, which emphasizes the importance of solid state effects in this material. The relaxed hydrogen positions in NaAlH4 are in good agreement with recent experiment. The electronic structure of AlH3 is also ionic. Implications for the binding of complex hydrides are discussed.Comment: 4 pages, 5 figure

Crystal and molecular structures of glycolide and lactide: Association through CH center dot center dot center dot O hydrogen bonds

The X-ray crystal structures of glycolide (1,4-dioxane-2,5-dione) and L(-)- and DL-lactide (3,6-dimethyl-1,4-dioxane-2,5-dione) are reported. The geometric parameters of the molecules which have flattened boat conformations, were determined. Short intermolecular H...O distances 2.3-2.4 Angstrom between the methylene and carbonyl groups are considered as hydrogen bonds. This interpretation is supported by spectroscopic data and quantum-chemical calculations

Crystal and molecular structures of glycolide and lactide: Association through CH center dot center dot center dot O hydrogen bonds

The X-ray crystal structures of glycolide (1,4-dioxane-2,5-dione) and L(-)- and DL-lactide (3,6-dimethyl-1,4-dioxane-2,5-dione) are reported. The geometric parameters of the molecules which have flattened boat conformations, were determined. Short intermolecular H...O distances 2.3-2.4 Angstrom between the methylene and carbonyl groups are considered as hydrogen bonds. This interpretation is supported by spectroscopic data and quantum-chemical calculations

Complexes of 2,3-dihydroxypyridine with bivalent metals. Crystal structure of 2,3-dihydroxypyridine

Crystal structure of 2,3-dihydroxypyridine (H2L) is determined. Mn(HL)Cl . H2O, Co(HL)Cl . 2H(2)O, Cu(HL)Cl, Ni(HL)OH . H2O, and Zn(HL)OH . H2O complexes are synthesized by reacting Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) chlorides with H2L in ethanol solutions and identified. In these complexes, 2,3-dihydroxypyridine is involved in coordination as a monoanion. Spectral parameters of neutral and anionic forms of a ligand are determined and the acidity and complex formation constants are calculated. The compositions of complexes are established

Complexes of 2,3-dihydroxypyridine with bivalent metals. Crystal structure of 2,3-dihydroxypyridine

Crystal structure of 2,3-dihydroxypyridine (H2L) is determined. Mn(HL)Cl . H2O, Co(HL)Cl . 2H(2)O, Cu(HL)Cl, Ni(HL)OH . H2O, and Zn(HL)OH . H2O complexes are synthesized by reacting Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) chlorides with H2L in ethanol solutions and identified. In these complexes, 2,3-dihydroxypyridine is involved in coordination as a monoanion. Spectral parameters of neutral and anionic forms of a ligand are determined and the acidity and complex formation constants are calculated. The compositions of complexes are established