Alcohol adducts of alkoxides: intramolecular hydrogen bonding as a general structural feature

• Published in: Inorganic chemistry Vol. 29; no. 17; pp. 3126 - 3131
• Main Authors: Vaartstra, Brian A, Huffman, John C, Gradeff, Peter S, Hubert-Pfalzgraf, Liliane G, Daran, Jean Claude, Parraud, Stephen, Yunlu, Kenan, Caulton, Kenneth G
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-08-1990
• Subjects: 400201 - Chemical & Physicochemical Properties; 400202 - Isotope Effects, Isotope Exchange, & Isotope Separation; ADDUCTS; ALCOHOLS; ALKOXIDES; BARYONS; CARBON 13; CARBON ISOTOPES; COHERENT SCATTERING; COMPLEXES; Condensed matter: structure, mechanical and thermal properties; CRYSTAL STRUCTURE; CRYSTALS; DATA; DIFFRACTION; ELEMENTARY PARTICLES; EVEN-ODD NUCLEI; Exact sciences and technology; EXPERIMENTAL DATA; FERMIONS; HADRONS; HYDROXY COMPOUNDS; INFORMATION; INFRARED SPECTRA; Inorganic compounds; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ISOTOPES; LIGHT NUCLEI; Metal complexes; MONOCRYSTALS; NMR SPECTRA; NUCLEI; NUCLEONS; NUMERICAL DATA; ORGANIC COMPOUNDS; Physics; PRASEODYMIUM COMPLEXES; PROTONS; RARE EARTH COMPLEXES; SCATTERING; SPECTRA; STABLE ISOTOPES; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; TRANSITION ELEMENT COMPLEXES; X-RAY DIFFRACTION; ZIRCONIUM COMPLEXES; Dinuclear complex; Zirconium Complexes; Transition metal Complexes; Infrared spectrum; Experimental study; NMR spectrum; X ray diffraction; Cerium Complexes; Inorganic compound; Crystalline structure
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic00342a014

Characterization of Zr{sub 2}(O{sup i}Pr){sub 8}({sup i}PrOH){sub 2} by {sup 1}H and {sup 13}C NMR spectroscopy, ir spectroscopy, and single-crystal x-ray diffraction ({minus}100{degree}C) is reported. The unit cell contains four half-dimers in the asymmetric unit, all of which differ only in the rotational conformation about Zr-O and O-C bonds. In each dimer, the edge-shared bioctahedron has two {mu}-O{sup i}Pr groups. On opposite sides of this Zr{sub 2}({mu}-OR){sub 2} plane, each dimer forms two hydrogen bonds, one each between a coordinated alcohol and a terminal alkoxide. The NMR spectra at 25{degree}C are so simple as to be structurally uninformative, a result of rapid fluxionality which includes, as one component, proton migration among all O{sup i}Pr units. At {minus}80{degree}C in toluene, the NMR spectra are now too complex to be accounted for by a single edge-shared bioctahedral structure. The hafnium analogue is isomorphous with the zirconium compound. Although Ce{sub 2}(O{sup i}Pr){sub 8}({sup i}PrOH){sub 2} is not isomorphous, it exhibits an analogous hydrogen-bonded structure in which the O{hor ellipsis}O distance is as short as it is in the Zr analogue, in spite of a metal-metal separation which is longer by 0.28 {angstrom}. The generality of hydrogen bonding between M-OR and M-O(H)R groups when they are aligned parallel in a metal cluster is reviewed. 44 refs., 2 figs., 4 tabs.