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115 results on '"Grondey H"'

4. Coordination isomerism in pentamethylcyclopentadienyl-substituted iminophosphanes: from classical structure to a pi-complexed iminophosphenium ion

Author

Gudat, D., Schiffner, H.M., Nieger, M., Stalke, D., Blake, A.J., Grondey, H., and Niecke, E.

Subjects
Isomerism -- Analysis, Glutathione transferase -- Analysis, Chemistry
Abstract

Thermolytic or basic-promoted elimination reactions are used to prepare novel Me5C5-substituted iminophosphanes, and analytical and spectroscopic approaches are used to characterize them. Between eta1(sigma) and eta2(pi)-bonding of the Me5C5 ligand, a substitution-induced coordination isomerism is evident.

Published
1992

12. Electrochemical property: structure relationships in monoclinic Li (sub 3-y) V2 (PO4) 3

Author

Yin, S. C., Grondey, H., Strobel, P., Anne, M., and Nazar, L. F.

Subjects
Valence -- Research, Vanadium -- Research, Vanadium -- Electric properties, Vanadium -- Chemical properties, Lithium -- Research, Lithium -- Electric properties, Lithium -- Chemical properties, Chemistry
Abstract

The existence of ordered valence states in monoclinic Li (sub 3-y) V2 (PO4) 3 is studied. It is concluded that the electrons in it are pinned on both long and short time scales.

Published
2003

13. Oriented periodic mesoporous organosilica (PMO) film with organic functionality inside the channel walls

Author

Dag, Ö., Yoshina-Ishii, C., Asefa, T., MacLachlan, M. J., and Grondey, H.

Abstract

The first examples of an oriented periodic mesoporous organosilica (PMO) film, containing a variety of organic groups (ethane, ethene, benzene, thiophene) inside the channel walls, are reported. The mesostructure of the PMO film appears oriented with respect to the surface of the underlying glass substrate. Liquid-crystal topological defects in the precursor gels are replicated in the resulting PMO film and are evident in polarized optical microscopy images, recorded between crossed-polarizers, which show fan-type optical birefringence texture characteristic of the mesostructure.

Published
2001

14. INEPT experiments in solid-state NMR

Author

Fyfe, C.A., Wong-Moon, K.C., Huang, Y., and Grondey, H.

Subjects
Chemical bonds -- Analysis, Nuclear magnetic resonance -- Usage, Chemistry
Abstract

MAS governed solid-state J-coupling based INEPT experiments can detect the through-bond connections of heteronuclei, quadrupolar and spin-1/2 nuclei. The coherence transfer experiments based on heteronuclear J-couplings are easier than the dipolar-based experiments that depend on the degree of reduction or elimination of the averaging effect of MAS on the dipolar coupling.

Published
1995

48. Electrochemical Property: Structure Relationships in Monoclinic Li[sub 3-y]V[sub 2](PO[sub 4])[sub 3].

Author

Yin, S.-C., Grondey, H., Strobel, P., Anne, M., and Nazar, L.F.

Subjects
*PHOSPHATASES, *ELECTROCHEMISTRY
Abstract

Monoclinic lithium vanadium phosphate, α-Li[sub 3]V[sub 2](PO[sub 4])[sub 3], is a highly promising material proposed as a cathode for lithium-ion batteries. It possesses both good ion mobility and high lithium capacity because of its ability to reversibly extract all three lithium ions from the lattice. Here, using a combination of neutron diffraction and [sup 7]Li MAS NMR studies, we are able to correlate the structural features in the series of single-phase materials Li[sub 3-y]V[sub 2](PO[sub 4])[sub 3] with the electrochemical voltage-composition profile. A combination of charge ordering on the vanadium sites and lithium ordering/disordering among lattice sites is responsible for the features in the electrochemical curve, including the observed hysteresis. Importantly, this work highlights the importance of ion-ion interactions in determining phase transitions in these materials. [ABSTRACT FROM AUTHOR]

Published
2003
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49. Sequential Hydroboration–Alcoholysis and Epoxidation–Ring Opening Reactions of Vinyl Groups in Mesoporous Vinylsilica

Author

Asefa, T., Kruk, M., MacLachlan, M. J., Coombs, N., Grondey, H., and Jaroniec, M.

Abstract

We report the sequential transformation of vinyl groups into hydroborate and alcohol as well as vinyl into epoxide and diol functional groups in hexagonal mesoporous vinylsilica materials, denoted meso-vinyl-SiO2. The first transformation proceeds quantitatively through the hydroborylated derivative. After appropriate quenching, the hydroborylated materials are stable at ambient conditions and can undergo transformation into alcohols and various other functional groups. The pore volume and pore size uniformity were found not to be greatly affected by quenching of the hydroboranes with methanol, but they were reduced by quenching with water due to the deposition of boron-containing species in the channels. Complete conversion of hydroborylated materials to alcohol-functionalized materials required basic conditions and treatment time of several hours. Although this led to a significant structural shrinkage, decrease in pore volume, and decrease in ordering, there was no evidence of a partial collapse or removal of substantial parts of the pore walls under optimized synthesis conditions. This is the first successful conversion of organic groups of a functionalized ordered mesoporous silica host in alkaline solution, conditions known to be detrimental for silica frameworks. Epoxidation of the vinyl groups and subsequent conversion of the resulting epoxides into diols are also briefly described. The chemical transformation through epoxidation affords ordered mesoporous silica materials functionalized with potentially chiral organic groups, which could find applications in asymmetric catalysis and chiral separations. It was found that the epoxidation was slower than hydroboration and resulted in a lower degree of conversion. These two examples of hydroboration–alcoholysis and epoxidation–ring opening reactions of terminally bonded vinyl groups in meso-vinyl-SiO2 demonstrate the novel concept of sequential organic chemical transformations harbored inside the ordered channels of mesoporous organosilica materials.

Published
2001
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