@article {1119,
	title = {Determining the geometry of strongly hydrogen-bonded silanols in a layered hydrous silicate by solid-state nuclear magnetic resonance},
	journal = {Journal of Chemical Physics},
	volume = {122},
	number = {5},
	year = {2005},
	note = {ISI Document Delivery No.: 895RGTimes Cited: 7Cited Reference Count: 45},
	month = {Feb},
	pages = {10},
	type = {Article},
	abstract = {High-resolution solid-state NMR spectroscopy is exploited to obtain structural constraints involving strongly hydrogen-bonded silanols in octosilicate, a prominent member of the layered hydrous sodium silicates. Proton-silicon cross-polarization dynamics reveals that octosilicate contains two types of Q(3) silicons present in hydrogen-bonded -Si-O-H...O-Si- and -Si-O{\textendash}type sites which can only be distinguished by their different abilities to cross polarize and the different mobilities of neighboring hydrous species. The theoretical analysis of the oscillating components of the polarization transfer buildup curves suggests that the model of heteronuclear pairs is an adequate description of the quantum spin system within hydrogen-bonded -Si-O-H...O-Si- fragments. We also show that dipolar modulated, slow speed magic-angle Si-29 NMR spectrum provides unique geometric information on strongly hydrogen-bonded silanols. The dipolar modulated spinning sidebands contain all the information necessary to determine the internuclear Si...H distances as well as the magnitude and orientation of the principal elements of the Si-29 chemical shielding tensor in the molecular frame. The data provide definite proof of the intralayer character of strongly hydrogen-bonded silanol groups in a bridging, albeit not symmetric, position between neighboring tetrahedra. The approach developed in this work may be useful to obtain structural information on related layered alkali metal silicates, silica gels as well as on other classes of microporous materials. (C) 2005 American Institute of Physics.},
	keywords = {DYNAMICS, MAGADIITE, MAS, NMR CROSS-POLARIZATION, RESOLUTION, ROTATING SOLIDS, SIDE-BAND, SPECTRA, SPECTROSCOPY, SPIN-EXCHANGE},
	isbn = {0021-9606},
	url = {<Go to ISI>://000226880100042},
	author = {Gardiennet, C. and Marica, F. and Fyfe, C. A. and Tekely, P.}
}
@article {744,
	title = {Assessing the effects of time and spatial averaging in N-15 chemical shift/N-15-H-1 dipolar correlation solid state NMR experiments},
	journal = {Journal of Biomolecular Nmr},
	volume = {26},
	number = {4},
	year = {2003},
	note = {ISI Document Delivery No.: 686MATimes Cited: 30Cited Reference Count: 51},
	month = {Aug},
	pages = {283-295},
	type = {Article},
	abstract = {The effect of time and spatial averaging on N-15 chemical shift/H-1-N-15 dipolar correlation spectra, i.e., PISEMA spectra, of alpha-helical membrane peptides and proteins is investigated. Three types of motion are considered: (a) Librational motion of the peptide planes in the alpha-helix; (b) rotation of the helix about its long axis; and (c) wobble of the helix about a nominal tilt angle. A 2ns molecular dynamics simulation of helix D of bacteriorhodopsin is used to determine the effect of librational motion on the spectral parameters. For the time averaging, the rotation and wobble of this same helix are modelled by assuming either Gaussian motion about the respective angles or a uniform distribution of a given width. For the spatial averaging, regions of possible N-15 chemical shift/H-1-N-15 dipolar splittings are computed for a distribution of rotations and/or tilt angles of the helix. The computed spectra show that under certain motional modes the N-15 chemical shift/H-1-N-15 dipolar pairs for each of the residues do not form patterns which mimic helical wheel patterns. As a result, the unambiguous identification of helix tilt and helix rotation without any resonance assignments or on the basis of a single assignment may be difficult.},
	keywords = {averaging, COAT PROTEIN, GRAMICIDIN CHANNEL, ION-CHANNEL, LIPID BILAYERS, MEMBRANE-PROTEIN STRUCTURE, mobility of membrane helices, MOLECULAR-DYNAMICS SIMULATION, mosaic spread, NUCLEAR-MAGNETIC-RESONANCE, PHOSPHOLIPID-BILAYER, PISA wheels, PISEMA, SPIN-EXCHANGE, time, TRANSMEMBRANE DOMAIN},
	isbn = {0925-2738},
	url = {<Go to ISI>://000183324500001},
	author = {Straus, S. K. and Scott, W. R. P. and Watts, A.}
}
@article {4984,
	title = {Coaggregation of paramagnetic d- and f-block metal ions with a podand-framework amine phenol ligand},
	journal = {Inorganic Chemistry},
	volume = {39},
	number = {3},
	year = {2000},
	note = {ISI Document Delivery No.: 283FQTimes Cited: 37Cited Reference Count: 86},
	month = {Feb},
	pages = {508-516},
	type = {Article},
	abstract = {This report covers initial studies in the coaggregation of nickel (Ni2+) and lanthanide (Ln(3+)) metal ions to form complexes with interesting structural and magnetic properties. The tripodal amine phenol ligand H(3)tam (1,1,1-tris(((2-hydroxybenzyl)amino)methyl)ethane) is shown to be particularly accommodating with respect to the geometric constraints of both transition and lanthanide metal ions, forming isolable complexes with both of these ion types. In the solid-state structure of [Ni(H(2)tam)(CH3CN)]PF6.2.5CH(3)CN.0.5CH(3)OH (1), the Ni(II) center has a distorted octahedral geometry, with an N3O2 donor set from the [H(2)tam](-) ligand and a coordinated solvent (acetonitrile) occupying the sixth site. The reaction of stoichiometric amounts of H(3)tam with the Ni(II) ion in the presence of lanthanide(III) ions provides [LnNi(2)(tam)(2)](+) cationic complexes which contain coaggregated metal ions. These complexes are isolable and have been characterized by a variety of analytical techniques, with mass spectrometry proving to be particularly diagnostic. The solid-state structures of [LaNi2(tam)(2)(CH3OH)(1/2)-(CH3CH2OH)(1/2)(H2O)]ClO4.0.5CH(3)OH.4H(2)O (2), [DyNi2(tam)(2)(CH3OH)(H2O)]ClO4.CH3OH.H2O (6), and [YbNi2(tam)(2)(H2O)]ClO4.2.58H(2)O (9) have been determined. Each complex contains two octahedral Ni(II) ions, each of which is encapsulated by the ligand tam(3-) in an N3O3 coordination sphere; each [Ni(tam)](-)unit caps the lanthanide(III) ion via bridging phenoxy oxygen donor atoms. In 2, La3+ is eight-coordinated, while in 6, Dy(III) is seven- (to "weakly eight-") coordinated, and Yb(III) in 9 has a six-coordination environment. The complexes are symmetrically different, 2 possessing C-1 symmetry and 6 and 9 having CI symmetry. Magnetic studies of 2, 6, and 9 indicate that antiferromagnetic exchange coupling between the Ni(II) and Ln(III) ions increases with decreasing ionic radius of Ln(III).},
	keywords = {AQUEOUS-SOLUTION, COMPARTMENTAL SCHIFF-BASES, COPPER-LANTHANOID COMPLEXES, CRYSTAL-STRUCTURES, DINICKEL(II) COMPLEXES, HEPTADENTATE LIGANDS, MACROCYCLIC COMPLEXES, MAGNETIC-PROPERTIES, MOLECULAR-STRUCTURE, SPIN-EXCHANGE},
	isbn = {0020-1669},
	url = {<Go to ISI>://000085266100018},
	author = {Xu, Z. Q. and Read, P. W. and Hibbs, D. E. and Hursthouse, M. B. and Malik, K. M. A. and Patrick, B. O. and Rettig, S. J. and Seid, M. and Summers, D. A. and Pink, M. and Thompson, R. C. and Orvig, Chris}
}
@article {4984,
	title = {Coaggregation of paramagnetic d- and f-block metal ions with a podand-framework amine phenol ligand},
	journal = {Inorganic Chemistry},
	volume = {39},
	number = {3},
	year = {2000},
	note = {ISI Document Delivery No.: 283FQTimes Cited: 37Cited Reference Count: 86},
	month = {Feb},
	pages = {508-516},
	type = {Article},
	abstract = {This report covers initial studies in the coaggregation of nickel (Ni2+) and lanthanide (Ln(3+)) metal ions to form complexes with interesting structural and magnetic properties. The tripodal amine phenol ligand H(3)tam (1,1,1-tris(((2-hydroxybenzyl)amino)methyl)ethane) is shown to be particularly accommodating with respect to the geometric constraints of both transition and lanthanide metal ions, forming isolable complexes with both of these ion types. In the solid-state structure of [Ni(H(2)tam)(CH3CN)]PF6.2.5CH(3)CN.0.5CH(3)OH (1), the Ni(II) center has a distorted octahedral geometry, with an N3O2 donor set from the [H(2)tam](-) ligand and a coordinated solvent (acetonitrile) occupying the sixth site. The reaction of stoichiometric amounts of H(3)tam with the Ni(II) ion in the presence of lanthanide(III) ions provides [LnNi(2)(tam)(2)](+) cationic complexes which contain coaggregated metal ions. These complexes are isolable and have been characterized by a variety of analytical techniques, with mass spectrometry proving to be particularly diagnostic. The solid-state structures of [LaNi2(tam)(2)(CH3OH)(1/2)-(CH3CH2OH)(1/2)(H2O)]ClO4.0.5CH(3)OH.4H(2)O (2), [DyNi2(tam)(2)(CH3OH)(H2O)]ClO4.CH3OH.H2O (6), and [YbNi2(tam)(2)(H2O)]ClO4.2.58H(2)O (9) have been determined. Each complex contains two octahedral Ni(II) ions, each of which is encapsulated by the ligand tam(3-) in an N3O3 coordination sphere; each [Ni(tam)](-)unit caps the lanthanide(III) ion via bridging phenoxy oxygen donor atoms. In 2, La3+ is eight-coordinated, while in 6, Dy(III) is seven- (to "weakly eight-") coordinated, and Yb(III) in 9 has a six-coordination environment. The complexes are symmetrically different, 2 possessing C-1 symmetry and 6 and 9 having CI symmetry. Magnetic studies of 2, 6, and 9 indicate that antiferromagnetic exchange coupling between the Ni(II) and Ln(III) ions increases with decreasing ionic radius of Ln(III).},
	keywords = {AQUEOUS-SOLUTION, COMPARTMENTAL SCHIFF-BASES, COPPER-LANTHANOID COMPLEXES, CRYSTAL-STRUCTURES, DINICKEL(II) COMPLEXES, HEPTADENTATE LIGANDS, MACROCYCLIC COMPLEXES, MAGNETIC-PROPERTIES, MOLECULAR-STRUCTURE, SPIN-EXCHANGE},
	isbn = {0020-1669},
	url = {<Go to ISI>://000085266100018},
	author = {Xu, Z. Q. and Read, P. W. and Hibbs, D. E. and Hursthouse, M. B. and Malik, K. M. A. and Patrick, B. O. and Rettig, S. J. and Seid, M. and Summers, D. A. and Pink, M. and Thompson, R. C. and Orvig, Chris}
}
@article {7007,
	title = {THE ANALYSIS OF MUONIUM HYPERFINE INTERACTION MEASUREMENTS OF THERMAL RATE CONSTANTS FOR ADDITION-REACTIONS},
	journal = {Journal of Chemical Physics},
	volume = {94},
	number = {4},
	year = {1991},
	note = {ISI Document Delivery No.: EY070Times Cited: 15Cited Reference Count: 48},
	month = {Feb},
	pages = {2794-2806},
	type = {Article},
	abstract = {A new model is developed for the analysis of muon spin relaxation (mu-SR) measurements of muonium (Mu) reaction rates with other chemical species. The kinetics component of the model is specifically developed for addition reactions but can be extended to direct reactions. The polarization component of the model assumes that the adduct formed possesses a single, effective spin precession frequency. The complete model is solved to obtain an analytic expression for the mu-SR signal as a function of time. Both a time-ordered sequence method and a Boltzmann spin equation method give equivalent solutions. These solutions are analyzed under various kinetic conditions. It is concluded that the coefficient controlling the decay of the mu-SR signal is closely related to the adduct formation rate constant, i.e., the high pressure limit of the apparent bimolecular addition rate constant. In the most favorable case, the decay constant gives the adduct formation rate constant directly at all pressures of buffer gas.},
	keywords = {CHARGE-EXCHANGE COLLISIONS, COMPETING PROCESSES, DEPENDENCE, HYDROGEN, KINETIC-EQUATIONS, LOW-PRESSURE GASES, MOLECULAR ION, radicals, SPIN-EXCHANGE, TEMPERATURE-RANGE},
	isbn = {0021-9606},
	url = {<Go to ISI>://A1991EY07000050},
	author = {Duchovic, R. J. and Wagner, A. F. and Turner, R. E. and Garner, D. M. and Fleming, Donald G.}
}
