Studies of the rhenium-oxygen bond. III. The crystal and molecular structure of 1-oxo-6-ethoxo-2,4-dichloro-3,5-dipyridinerhenium(V)

Abstract

The crystal and molecular structure of the title compound has been examined by single crystal X-ray diffraction. The crystals are monoclinic with a = 28.045(10), b = 8.766(3), c = 12.376(5) Å, β = 91.14(3)°. The space group is C2/c and there are eight molecules per unit cell. A total of 5053 independent reflections, of which 2860 were observed, were examined on a Syntex [Formula: see text] diffractometer. The structure was refined by full matrix least squares to an R2 value of 0.0449. The ligands form a very rough octahedron around the rhenium atom with Re—Cl(1), 2.441(3); Re—Cl(2), 2.366(3), Re—O(1), 1.684(7); Re—O(2), 1.896(6); Re—N(1), 2.144(7); Re—N(2), 2.132(7) Å. The pyridine rings are a dominant factor in determining the details of the molecular structure.

Preparation and structure of oxo-rhenium(V) complexes with 7-azaindole

“…l), in which the neutral azaindole ligand is coordinated via N(7). The same stereoisomer was found in the analogous pyridine compound (36). Selected distances and angles are given in Table 4.…”

“…This type of disorder has also been observed for the phosphine analogues ReO(OEt)X2(PPh3), (X = C1, Br) (29,30). A broad range (138-176") is found in the literature for the Re-0-Et angle (15,29,30,36): our Re-O(2)-C (11) angle (155.9 (15) 1(8)"). The same ligand orientation observed for the pyridine analogue has been ascribed to minimum intramolecular contacts with C1, 0(1), and alkoxo hydrogens (36).…”

“…A broad range (138-176") is found in the literature for the Re-0-Et angle (15,29,30,36): our Re-O(2)-C (11) angle (155.9 (15) 1(8)"). The same ligand orientation observed for the pyridine analogue has been ascribed to minimum intramolecular contacts with C1, 0(1), and alkoxo hydrogens (36). In the present case, the N(1)-H group is close enough to C1 and O(1) to form an intramolecular hydrogen bond (Table 4, Fig.…”

Studies of the rhenium–oxygen bond. II. The crystal and molecular structure of µ-oxobis(cis-dichloro-cis-di(pyridine)-trans-oxorhenium(V)), ORe(C5H5N)2Cl2ORe(C5H5N)2Cl2O

“…", "Why is this particular shape adopted; why not a system similar to Re,O3Cl4(en),, where although the nitrogen atom positions in each half of this dimer are cis, the two halves are related by an inversion centre? ", or "Since the monomer precursor has been postulated to have the pyridine rings trans, and the monomer ethanolysis product has been shown to have the pyridine rings trans (19), why is the structure not that postulated by Johnson et al the answer to all the above questions. We therefore made a series of very simple calculations, based on idealized structures and normal values for bond lengths and van der Waals radii.'…”

Structure of trans-dibromo(ethoxo)oxobis(triphenylphosphine)rhenium(V)

“…In the course of an ongoing study of metal-metal-bonded systems containing aromatic Nheterocyclic bridging ligands (Allaire & Beauchamp, 1989), synthetic routes to Re III dimers via Re v oxo complexes are being developed. The reactivity of [ReX30(PR3)2] and [ReX20(OR)(PR3)2] with pyridines is well documented (Johnson, Taha & Wilkinson, 1964;Lock & Turner, 1977, 1978aBrewer & Gray, 1989) and can be extrapolated to include more complex N-containing ligands. The title compound was considered to be a potential precursor for oxo complexes of controlled stereochemistry with Ncontaining heterocycles.…”