Characterization of 2(0' )8(' 0 )2 by and 13C NMR spectroscopy, IR spectroscopy, and single-crystal X-ray diffraction (-100 °C) is reported. The compound crystallizes in the space group PI with a = 18.262 (4) Á, b = 19.883 (5) Á, c = 12.067 (3) Á, a = 98.59 (1)°, ß = 96.26 (1)°, y = 77.49 (1)°, and Z = 4. 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 µ-O'Pr groups. On opposite sides of this 2(µ-)2 plane, each dimer forms two hydrogen bonds, one each between a coordinated alcohol and a terminal alkoxide. The NMR spectra at 25 °C are so simple as to be structurally uninformative, a result of rapid fluxionality which includes, as one component, proton migration among all O'Pr units. At -80 °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 Ce2(0'Pr)8('Pr0H)2 is not isomorphous, it exhibits an analogous hydrogen-bonded structure in which the 0-0 distance is as short as it is in the Zr analogue, in spite of a metal-metal separation which is longer by 0.28 Á. It crystallizes in the space group PI with a = 1 1.385 (4) Á, b = 12.144 (5) Á, c = 9.009 (3) Á, a = 109.72 (1)°, ß = 111.54 (2)°, y = 65.70 (1)°, and Z = 1. The generality of hydrogen bonding between M-OR and M-0(H)R groups when they are aligned parallel in a metal cluster is reviewed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.